ALBERT

Notes: A novel hybrid stubble turnip, Appin, bred by the Scottish Plant Breeding Station (Brassica campestris ssp. rapifera cv. Tigra ×B. campestris ssp. nipposinica cv. Mizuna) was compared in small-plot cutting trials with stubble turnip (B. campestris ssp. rapifera cv. Ponda), forage rape (B. napus ssp. biennis cv. Canard) and fodder radish (Raphinus sativus cv. Neris) for 3 years, 1975–77, samples being taken from October to December or January each year to cover the likely period of utilization by grazing lambs. Except for the first year, Appin proved to yield less DM than Ponda, and be inferior in digestibility and metabolizable energy (ME) content, though N contents were on occasion higher. Canard had the highest overall ME content. In dry conditions in autumn 1977, Ponda proved the more reliable crop, suffering less depression in yield than other species. Anti-metabolite contents were determined in freeze-dried samples taken in winter 1976-77 and showed Canard to have the most brassica anaemia factor (S-methyl cysteine sulphoxide): contents of thiocyanate were generally similar between crops.As the degree of utilization of such forages when grazed can outweigh differences in recorded above-ground DM yields from cutting trials, it was considered that claims of better root anchorage and hence better utilization for Appin warranted evaluation in a grazing trial.

Notes: Two grass silages made from perennial ryegrass, and with D-values of 0·216 and 0·255, were offered ad libitum to 18 Ayrshire cows in two feeding experiments. On the control treatment the silages were supplemented with soybean meal only, and on the other two treatments with equal weights of DM from either barley or dried molassed sugar-beet pulp plus the same weight of soya as on the control treatment. The daily intakes of silage DM were not significantly different on the barley and beet-pulp treatments, and, on average, the intake of silage DM was reduced by 0·24 and 0·20 kg by feeding 1 kg barley and beet pulp DM respectively.The daily milk yields were not significantly different on the barley and beet-pulp treatments with mean values of 19·2 and 19·2 kg per cow respectively compared with 17·2 kg on the control treatment. On the barley and beet-pulp treatments the fat, SNF, CP and lactose concentrations in the milk and the live weights of the cows were not significantly different. It is concluded that the barley and beet pulp had similar feeding values and replacement rates when used as supplements with grass silage, and that the two feeds were interchangeable on an equal DM basis.

Notes: An experiment examining the relationship of daily herbage disappearance (DHD) and daily herbage allowance (DHA) is described. Cows with calves were grazed at three stocking rates on Kleingrass and Coastal Bermudagrass pastures. DHD and DHA were monitored at 14-d intervals. A significant positive linear relationship was noted between DHD and DHA (P〈inlineGraphic alt="leqslant R: less-than-or-eq, slant" extraInfo="nonStandardEntity" href="urn:x-wiley:01425242:GFS9:les" location="les.gif"/〉0·25). Equations derived for Coastal Bermudagrass and Kleingrass were not significantly different and resulted in a combined equation Ŷ= 0·275X + 0·209 with an r2 vaiue of 0·27. As DHA exceeded 6–9 kg DM per 100 kg live weight, efficiency of defoliation by the cows and calves declined.

Notes: The effects of five herbicides on seed yield and viability of perennial ryegrass cv. S24 were tested at two sites. Benzoylprop-ethyl, chlorfenpropmethyl, difenzoquat, ethofumesate and flam-prop-isopropyl were safe to use at doses recommended for use in other crops. When applied at three times the recommended dose, only difenzoquat reduced the yield and germination of seed and benzoylprop-ethyl reduced seed germination. The recommended doses of difenzoquat and ethofumesate were safe when applied on cv. Barlenna at different growth stages. Difenzoquat reduced seed yield only after three times the recommended dose was applied to tillered plants. Ethofumesate, even at three times the recommended dose, did not affect seed yield but plant numbers were reduced by early treatment. The results suggest that the herbicides tested may be safe to use in perennial ryegrass seed crops at the recommended doses but more work is needed on the safety of difenzoquat in relation to crop growth stage.

Notes: The digestibility of herbage selected by dairy cows, milk-fed calves, weaned calves and wether sheep was examined on four occasions each day as they strip-grazed together a daily allocation of herbage. The average quality of the material selected by each group was similar. Organic matter digestibility of the herbage selected declined from 0·274 to 0·223 as the average height of the sward fell from 16 to 6 cm; this decline was slightly more rapid for the cows than for the other stock. A similar trend was also evident in samples cut from the sward to simulate the horizon removed prior to each sampling time.

Notes: Grass silage made in May from S24 perennial ryegrass had a DM concentration of 262 g kg-1 and an in vitro D-value of 0·698, and was given ad libitum to twelve Ayrshire cows in a 16-week feeding experiment. In addition supplements of hay with a mean in vitro D-value of 0·603 were offered in one of three forms—long, chopped (12·1 mm) or ground (0·80 modulus of fineness) and cubed—and of concentrates given at either 2 or 4 kg per 10 kg milk. Hay averaged 18·2% of total forage DM intake with mean daily intakes of 1·28, 1·22 and 2·26 kg DM per cow in the long, short and ground forms respectively. The highest daily intakes of forage, i.e. silage plus hay, occurred on the ground hay treatments, with values of 10·24 and 9·25 kg DM per cow on the 2 and 4 kg concentrate treatments respectively. The mean daily milk yields were 18·2,18·2 and 19·2 kg per cow on the long, short and ground hay treatments respectively but the increase in yield with the ground hay was only significant at the low level of concentrate intake. The hay treatments had small and non-significant effects on milk composition. It is concluded that ground hay was superior to either long or chopped hay as a supplement for silage, but the small advantages depended on the level of concentrate intake.

Notes: Book review in this article Energy from Biomass in Europe Edited by W. Palz and P.

Notes: The water loss from tall fescue cv. S170, perennial ryegrass cv. S24, Italian ryegrass cv. RvP and timothy cv. S352 when dried as a thin layer under controlled conditions at 20°C and r.h. 50% is described. Comparisons were made on six occasions between mid-April and mid-June. Tall fescue dried faster than the other species and the time to reach a water concentration of 0·2 g water per g dry matter varied little between the six harvests. In contrast, the drying time for the ryegrasses and timothy increased to maximal values in mid-May and then fell. Drying time was dependent on the initial water concentration of the grass, the ratio of leaf to stem and on the amount of true stem exposed to the drying environment. The practical implications in relation to haymaking are discussed.

Notes: The results are reported of an examination of detailed measurements on the ingestive behaviour of calves and lambs in response to variations in the surface characteristics of swards under strip-grazing and continuous stocking managements. It is shown that intake per bite and the short-term rate of herbage intake were both sensitive to the height of the surface horizon above ground level but, at least under strip-grazing management, not to variations in herbage density in the grazed horizon. The rate of biting was less sensitive to variations in sward conditions, particularly under strip-grazing.Both intake per bite and rate of intake were more sensitive to variations in grazing height under strip-grazing, where sward changes were rapid, than under continuous stocking, where they were slow. Under continuous stocking, ingestive behaviour was more sensitive to changes in sward conditions in lambs than in calves.

Notes: In an experiment of four years duration, the competitive relationships between three cultivars of white clover (Trifolium repens L.) and ten cultivars of perennial ryegrass (Lolium perenne L.) were studied under a N fertilizer regime of 200–240 kg ha-1 a-1. The clover cultivars were selected to embrace the various leaf sizes from medium large to small and the ryegrasses included early, mid-season and late cultivars with a known range of persistence.During the experiment there was a progressive decline in the contribution of clover, though the different characteristics of each of the clover and ryegrass cultivars produced substantial deviations from the average trend. The clover cultivar Kersey was significantly more aggressive towards the companion grass cultivars than either S100 or S184. It produced consistently greater clover contribution to total yield than the other two cultivars and significantly depressed the yields of some of the companion grass cultivars. There was evidence that compatibility of the ryegrass cultivars with clover was inversely related to persistence; the non-persistent ryegrass cultivars S321 and Presto consistently produced lower grass yields than the more persistent cultivars and consequently permitted greater clover contribution. In the second and third years yield substitution effects between clover and grass components substantially reduced differences in the total grass-clover yield.The interactions revealed in the experiment showed that both ryegrass and clover cultivars have the potential to influence each other when in association although, with minor exceptions, total annual yields were similar for all grass and clover mixtures at the moderately high level of N applied.

Notes: White clover (cv. S184 or Blanca) or marsh trefoil (cv. Grasslands 4703 or Grasslands Maku) were sown alone and in combination with a companion grass (tall fescue, red fescue, perennial ryegrass or ryegrass cleanings) on a peat area of hill land originally dominated by Juncus articulatus and Molinia caerulea.Lime and ground rock phosphate were applied in 1973, the area rotavated to a shallow depth and seeds sown in May 1974. No fertilizers were applied except at sowing time and two harvests were taken per annum for 4 years.Differences in yield and legume content between companion grass treatments were small. After the first full harvest year Blanca swards usually had the lowest DM yields and those containing Maku the highest. The contribution of marsh trefoil to total herbage yield increased from 4·2% in 1975 to 22% in 1978, whereas white clover decreased from 4·2 to 1·2%. Legume yields in 1978 were less than half those in 1977. Overall, N yields were low, Maku swards fixing most N estimated to be highest in 1977 at 35 kg ha-1.It is concluded that marsh trefoil grows well on upland peat but more information on its response to grazing is necessary before conclusions can be drawn about its value in hill land improvement.

Notes: An experiment extending over a 2½-year period from June 1976 to October 1978 assessed the effect on herbage yield of method of establishment, species and level of N application.Perennial ryegrass cv. Gremie and Italian ryegrass cv. RvP were established by broadcasting or drilling into cultivated ground or by direct-drilling, using a Howard Rotaseeder, into paraquat-sprayed but uncultivated ground. These treatments were combined with annual rates of N application of 0, 120, 240 or 360 kg ha-1.Over the experiment drilling into cultivated ground gave the highest yield—3·6 and 4·8% higher than the broadcast and direct-drilled treatments, respectively. Italian ryegrass consistently outyielded perennial ryegrass, with an overall mean dry matter yield advantage of 23·7%. There was no significant interaction between sowing method and species; direct-drilled Italian ryegrass produced a mean yield 17·3% higher than that of drilled perennial ryegrass.

Notes: The length of life of the root axes of a plant was taken as the interval between the prevention of the plant from producing any further axes and the death of the shoot. Of the cultivated species studied Lolium perenne had the shortest lived roots and Dactylis glomerata the longest with Phleum pratense, Festuca arundinacea, F. pratensis and F. rubra intermediate. Holcus lanatus and Nardus stricta had long lived roots comparable with Dactylis glomerata. The ranked order of species is in general agreement with the observations reported in the literature.

Notes: Flowering behaviour of plants of six cultivars of Trifolium repens (Kent Wild White, Grasslands Huia, S100, Blanca, Olwen and Milkanova) growing in field plots at the Grassland Research Institute, Hurley, was recorded in mid-July. Half of each plot had been defoliated in early May, the other half in mid-June. In all cultivars defoliated in May, inflorescence initiation had stopped even though the natural photoperiod at that time was well above the critical daylength for initiation Defoliation in mid-June had led to a renewal of inflorescence initiation in all cultivars.The results confirm that the stimulatory effect of defoliation on inflorescence initiation in plants that have stopped initiation in long days, which has previously been observed in Grasslands Huia in controlled environments, also occurs in the field and in other cultivars.

Notes: The mineral composition of Lolium perenne, Dactylis glomerata, Trifolium repens, Lotus corniculatus and six non-leguminous broadleaved herbs was determined at two sites on copper-deficient soils with and without soil-applied copper sulphate at 2 kg Cu ha-1. D. glomerata was richer than Lolium perenne in P, Mn and Cu, and T. repens was richer than either grass species in Ca, P, Mg and Cu. D. glomerata cultivars differed in Ca, P, Na and Mg concentrations, and L. perenne cultivars in Ca concentration. Lotus corniculatus contained less Ca, P, Na and Mn but more Zn than T. repens. Achillea millefolium was rich in K, Cichorium intybus in K, Mg and Zn, Petroselinum crispum in Na and Zn, Rumex acetosa in K, P, Mg and Zn and Taraxacum officinale in Na, Mg and Zn. Rumex was low in Na and Plantago lanceolata in Na and Mn. None of these herbs was richer than T. repens in Cu. Copper sulphate application raised the Cu concentration of the herbage only slightly, species or varieties differing little in their response to applied Cu. It is concluded that adjustment of botanical composition, with or without copper sulphate application, will not help to prevent hypocupraemia in grazing stock.

Notes: Two experiments are described in which groups of lactating cows, non-lactating cattle and weaned calves grazed a sequence of swards varying in maturity and herbage mass under strip grazing management at a daily herbage allowance of 60 g dry matter per kg live weight. Lactating cows ate 43% and 76% more herbage than non-lactating cattle of similar weight in the two experiments but herbage OM intakes per unit live weight by the calves and lactating cows were similar.Variations in diet digestibility and herbage intake in the lactating and non-lactating cattle with changes in sward conditions were similar. In the first experiment the calves were experienced grazers; the variation in the digestibility of the herbage selected was less in the calves than the adult cattle, but the variation in herbage intake was greater. The calves in the second experiment were younger, and they were inexperienced grazers; their ability to increase herbage intake in response to changing sward conditions was poorer than that of adult cattle, though variations in diet digestibility were similar in all classes.The practical implications of these results are discussed briefly.

Notes: A mathematical model which simulates the response of grass to irrigation over a range of rainfall and soil conditions is described. Using the model the probable costs and benefits from investing in irrigation facilities for intensive beef and dairy production have been determined. Irrigation only appears to show a reasonable return on investment where the mean summer rainfall is less than 350 mm or the water-retaining capacity of the soil is low. Furthermore, investment in irrigation is only likely to be logical where the rate of fertilizer N applied is greater than 300 kg N ha-1. It also appears that a strategy of partial irrigation is unlikely to yield the maximum financial gain. Overall the indications are that for the foreseeable future only a small percentage of the total grassland area in the UK can be irrigated profitably.

Notes: Six red clover cultivars, three diploid—Essex, Sabtoron and Violetta—and three tetraploid— Teroba, Red Head and Hungaropoly—were sown alone and with each of three companion grasses—timothy (S48), tall fescue (S170) and perennial ryegrass (S24). The productivity and persistency of the red clover cultivars were compared over 4 years. Dry matter (DM) yield, DM digestibility and the crude protein (CP) concentration were assessed and botanical analyses conducted on herbage samples from each treatment at each of three harvests per annum. Annual fertilizer application consisted of 165 kg P and 312 kg K ha-1.Comparing clover cultivars alone Essex was significantly less productive and less persistent than the other five cultivars. Yield and persistency of the five other cultivars did not differ markedly within years with the exception that the diploids were significantly less productive than the tetraploids in the fourth year. Over all 4 years mean annual total DM and clover DM yields of the five cultivars were between 12·2 and 13·2 t ha-1 and between 9·2 (79·2% of total DM yield) and 10·2 (83·2%) t ha-1 respectively, and differences were not significant.Up to the end of the third year there was little or no advantage gained by the inclusion of a companion grass, annual total DM yields being between 11·2 and 14·2 t ha-1 for clover alone and between 10·2 and 14·2 t ha-1 for clover-grass mixtures. In the fourth year there was an overall tendency for the yield of the clover alone to be lower, between 7·2 and 12·2 t ha-1, than that of the clover-grass mixture, between 8·2 and 13·2 t ha-1, and this was more pronounced with the diploid than with the tetraploid clover cultivars. Sown with companion grasses, Essex and Hungaropoly were lower in yield and in contribution than the other cultivars over the 4 years. The influence of the companion grass on total dry matter yield showed that the contribution of timothy was low relative to that made by tall fescue and perennial ryegrass. Perennial ryegrass made the most varied contribution from year to year. Tall fescue was the most consistent contributor with all clover cultivars and at the end of 4 years both yield and clover-grass balance had not changed materially.No pronounced differences in DM digestibility were evident between treatments.Crude protein concentration of the pure clover was similar to that of the clover-timothy treatments and both would appear to be superior to either the clover-perennial ryegrass or clover-tall fescue mixtures.It is considered that red clover dominant swards are suitable for use under a cutting regime and can provide high yields of DM at a low cost for up to 4 years. Such swards are self-sufficient in N and in addition soil N accumulation can be exploited in the production of succeeding crops.

Notes: The effects of severity of grazing on the herbage intake and milk production of continuously stocked British Friesian cows calving in February–March were examined in three experiments conducted in the years 1976–78 (experiments 1–3 respectively) using a put-and-take technique. In experiment 1 four grazing severities were imposed by maintaining swards with different herbage masses (2500, 3000, 3500, 4000 kg OM ha-1); in experiments 2 and 3 there were two severities of grazing maintained by keeping swards canopies at constant heights of 5 and 7 cm (experiment 2) and 5 and 7·2 cm (experiment 3). Cows were reallocated to treatment every 8 weeks in experiments 1 and 2 and there were three periods, whereas they all grazed throughout a 23-week period on the same treatment in the final trial.A decrease in the quantity of herbage on offer or in sward height reduced herbage intake and milk production in all experiments. Mean daily herbage OM intakes were 11·2, 12·2, 12·2 and 12·2 kg respectively in experiment 1, 12·2 and 13·2 kg respectively in experiment 2 and 12·2 and 152 kg respectively in experiment 3. Mean daily solids–corrected milk yields were 14·2, 15·2, 15·2 and 16·2 kg respectively in experiment 1, 14·2 and 16·2 kg respectively in experiment 2 and 12·2 and 17·2 kg respectively in experiment 3. It was apparent from the data obtained in the first two trials that grazing at a sward canopy height of 7 rather than 9 cm had little effect, but that at 5 cm there were significant depressions in both herbage intake and milk production. Milk yield was depressed to a greater extent when cows were kept on the same treatment for the whole season.

Notes: Twenty-four Hereford × Friesian cows and their South Devon cross calves were allocated to three herbage allowances allotted daily for three periods of 8 weeks in a Latin square design. The daily allowances were 17, 34 and 51 g dry matter per kg cow plus calf live weight. Milk production was depressed by 0·2 and 1·2 kg d-1 at the medium and low allowances. The corresponding falls in liveweight gain were for cows 0·26 and 0·25, and for calves 0·27 and 0·24 kg d-1. Residual sward height after grazing gave a better indication of the animals' reaction to sward conditions and the management imposed than actual herbage allowance. The quantity per unit area and the composition of material present were important factors influencing intake. Calves were unable to compete with their dams to maintain herbage intake at the lower allowances and therefore are likely to benefit from additional feeding or creep grazing when residual sward height falls below 6cm for periods in excess of 1–2 weeks.

Notes: The data from 12 individual cattle grazed on a uniform sward were used to compare field sampling of faeces with three time-schedules for rectal sampling of faeces. Estimates of digestibility from a faecal nitrogen equation were compared with estimates based on in vitro digestibility, or modified acid-detergent fibre determinations, on clipped herbage samples.Field sampling gave a lower coefficient of variation (8%) in chromic oxide content than did grab sampling (14%). Grab sampling introduced an upward bias in estimates of faecal output compared with field samples. The estimate of digestibility based on the faecal index was intermediate to those based on clip samples from the upper and lower horizons of the sward. There was no difference in the mean digestibilities estimated from in vitro or MAD fibre.

Notes: Groups of eight Hereford × Friesian cows and their South Devon cross calves were set stocked over a 24-week grazing season at 3·23 (low), 3·21 (medium) or 4·24 (high) cows ha-1 together with their calves. For the first 8 weeks only two-thirds of the total area was grazed. Increasing the stocking rate from low to medium reduced daily milk yield and cow and calf liveweight gains by 1·2, 0·24 and 0·29 kg d-1 respectively, and from medium to high by 1·2, 0·24 and 0·23 kg d-1. The main sward factor influencing faecal output and herbage intake was the quantity of organic matter on the pastures but the digestibility of the herbage selected also exerted a significant effect on the intake of cows. Major depressions in the herbage intake of cows occurred once the average sward height fell below 7 cm. Output of calf live weight was 628, 658 and 743 kg ha-1 for the 3 stocking rates from low to high, and for cows 246, 179 and 30 kg ha-1. It was concluded that decisions on pasture management should be taken in relation to the cow rather than the calf on set-stocked swards.

Notes: Swards of L. perenne and P. annua were treated at the 2–3 leaf stage with recommended rates of ethofumesate (5 and 10 kg a.i. ha-1). P. annua ceased normal growth, became swollen at the shoot base and eventually showed signs of senescence. L. perenne showed no visible defects, treated swards being more vigorous than untreated. Scanning electron micrographs showed that the developing leaf primordia of P. annua had been affected by the ethofumesate. In both grass species, ethofumesate induced abnormalities in cell division. These abnormalities caused irreversible damage to P. annua but only slight distortion of L. perenne which later recovered and resumed normal growth. More detailed biochemical studies are required to determine the specific effects of ethofumesate on cell growth.

Notes: A description is given of equipment designed to be fitted to either sheep or cattle, and to record automatically information on the jaw movements associated with both grazing and ruminating, movements of the head in plucking mouthfuls of herbage, and the time spent in grazing. The equipment has been successfully tested against alternative visual and mechanical methods of measuring grazing behaviour.The use of modified equipment in detailed studies has shown (a) that the maximum acceleration of the head in a longitudinal plane when plucking mouthfuls of herbage was twice as great in sheep as in cattle and in the sheep, but not in the cow, increased as sward height decreased; and (b) that the ratio of jaw movements to head movements was always greater than unity in both sheep and cattle, and was greater on tall than on short swards in two out of three comparisons. The rate of biting was significantly lower on tall than on short swards.

Notes: In experiments to determine the minimum fertilizer requirements for improved pasture on deep peat, yields were initially low and declined rapidly. Within 2 years persistence of sown species was poor when only 2·5 t lime ha-1 was applied. Analytical data suggested that K deficiency and low soil pH were contributory factors. When K was omitted from a composite nutrient solution, clover yield was reduced by 50% when 2·5 t lime ha-1 was applied but was not significantly reduced with 5·0 t lime. Clover alone produced little response to either P or K separately, but highly significant positive interactions were recorded. Clover, but not ryegrass, responded to K topdressing in field cut-herbage experiments. There was a 3-fold increase in ryegrass yield with combined P and K topdressing under grazing; 10 times more N and K were recycled in urine on this treatment than on the control.It was concluded that at least 5·0 t lime, 60 kg P and 80 kg K ha-1 are required for pasture establishment and that soil pH should be maintained above 5·0 to minimize K requirements. The significance of nutrient cycling and of lime × K and P × K interactions is discussed in relation to the persistence of sown species and the maintenance of improved swards on deep peat.

Notes: Two growth experiments were carried out in January-March 1978 in which simulated swards of perennial ryegrass were (1) heated by soil warming cables to give soil surface temperatures of approx. 7·5-9·C above ambient temperature, (2) shaded with netting to reduce light levels by approx. 50%, or (3) both heated and shaded.Heating alone increased leaf appearance, death, extension, lamina size, leaf area index (LAI), tillering (month 1)and whole plant weight (month 2) and reduced stubble water-soluble carbohydrates and specific leaf weight (SLW).Shading alone increased leaf extension, lamina size and LAI but to a lesser extent than did heating. Shading decreased SLW, leaf death rate, tillering (month 2), stubble carbohydrates and whole plant weight, but not herbage weight.The effects of heating plus shading were similar to those of heating alone, except that the increases in leaf size, extension and LAI were even greater, and shoot bases and roots had low or negative growth rates.In general the heating treatments caused a rapid turnover of leaf material, but net herbage growth was relatively insensitive. It is concluded that (1) temperature rather than light was limiting whole plant growth, especially from mid-February to mid-March and (2) mild, dull weather in winter is likely to induce tiller death associated with reduced investment in carbohydrate reserves.

Notes: The experiment was undertaken to examine the interactions between yield responses to secondary applications of fertilizer N and length of regrowth interval following three levels of primary N. A sward of S24 perennial ryegrass received all combinations of three fertilizer treatments, nil, 50, and 100 kg ha-1 N for primary growth harvested on 21 May and four treatments, nil, 33, 66 and 100 kg ha-1 N for the second growth harvested 2, 3, 4, 5, 6 or 7 weeks later.Cubic equations of growth were derived from the yields of dry matter and both the direct response to secondary N and the residual responses to primary N increased as regrowths developed. A positive residual effect to increasing primary N was obtained at the three lower levels of secondary N for weeks 4–7 but a negative response was obtained with the highest level of secondary N. The implications are discussed in terms of target responses and yields and the growth interval required to attain these targets.

Notes: Four grass silages of two chop lengths and two D-values were made from S23 perennial ryegrass, and compared in a feeding experiment with lactating cows and in an eating-behaviour study with non-lactating cows. The median chop lengths were 11·6 and 11·5 mm in the short silages and 18·2 and 19·5 mm in the medium silages. Chop length had negligible effects on D-value and on pH with values of 3·81 and 3·94 on the short and medium silages respectively.Silage DM intakes were higher on the short than on the medium-chop silages in both experiments except where the high D-value silage was supplemented with concentrates. Milk yields were not affected significantly by chop length with daily values of 19·3 and 19·7 kg per cow on the short and medium treatments respectively with the high D-value silage, and 18·2 and 18·3 kg per cow with the low D-value silage. Chop length had only small and non-significant effects on milk composition.Eating times expressed as min per kg DM were significantly lower on the short than on the medium-chop silages.It is concluded that the small differences between the short- and the medium-chop silages were of no economic importance.

Notes: The practise of sward desiccation using glyphosate or paraquat followed by direct drilling of seed gave an environment which increasingly inhibited germination and establishment when the interval between spraying and drilling was decreased from 21 days to nil. Burning or removal of old sward improved establishment. Calcium peroxide used as a seed dressing improved seedling establishment in most treatments.

Notes: Book review in this article Tropical Pastures and Fodder Crops By L. R. Humphreys The Role of Nitrogen in Intensive Grassland Production Edited by W. H. Prins and G. H. Arnold. Agricultural Botany, 1. Dicotyledonous Crops, 2. Monocotyledonous Crops, By N. T. Gill and K. C. Vear, Third edition revised by K. C. Vear and D. J. Barnard

Notes: A DNA hybridization assay was used to detect isolates of Escherichia coli that have the genetic potential to produce toxin. This method was compared with the traditional Y-1 mouse adrenal cell method for detecting pathogenic E. coli isolated from humans. Results showed that the DNA hybridization method has the potential to detect foodborne bacterial pathogens. The advantages and disadvantages of this genetic method are compared with those of the traditional assays for pathogenicity.

Notes: Salmonella typhimurium H391 neurotoxin was sensitive to gamma radiation under in vivo conditions but resistant under in vitro conditions. Cells were detoxified after exposure to a radiation dose of 500 krad while isolated neurotoxin retained toxicity up to a dose of 3,000 krad. Detoxification of S. typhimurium H391 cells after exposure to 500 krad was accompanied by loss of antigenic properties which may be attributed to changes in the physico-chemical behavior of the neurotoxin moiety after in vivo radiation.

Notes: The presence of monolauryl-glyceride (monolaurin) in the heating menstruum (phosphate buffer, reconstituted non-fat dry milk or cream style corn) of Bacillus stearothermophilus 1518 spores increased the rates of spore inactivation at 113–121°C by 2–3 fold. The ZD-values for the spores heated with and without monolaurin were 8.7 and 6.9°C, respectively. Rates of inactivation of B. subtilis A spores also were enhanced, but spores of Clostridium perfringens NCTC 879B, C. sporogenes PA 3679, C. botulinum 62A, or C. botulinum 213B were unaffected.Increasing the concentration of monolaurin from 0.4 mM to 3.6 mM increased the rate of inactivation, but concentrations higher than 3.6 mM did not appear to influence the effectiveness of monolaurin. All monoglyerides containing C8-C16 saturated fatty acids appeared to increase the inactivation of B. stearothermophilus spores, but the enhancement of spore inactivation declined as the fatty acid chain length increased beyond 10 carbon atoms. The influence of monolaurin on B. stearothermophilus spores did not appear to be pH dependent over the range of pH 6 to 8.The spore-monolaurin interaction was not due to heat-injury of the spores, although the interaction was dependent on the heat treatment. The increased inactivation appeared to be due to a heat enhanced chemical inactivation of the spores.

Notes: Antimicrobial activity of fatty acids and their glycerol and sugar esters against a film-forming yeast isolated from raw soy sauce was determined in diluted soy sauce. In a series of fatty acids (alkyl chain length of 7, 9, 11 and 13) and their monglycerides, capric acid and monolaurin had the highest inhibitory activity. Two selected sugar esters (sucrose monocaprate and sucrose monolaurate) could not completely inhibit the growth of test organism throughout 3 weeks.

Notes: A study was conducted to determine the effects of sorbic acid and several derivatives of fatty acids (amides, aminimides, and monoglycerides) upon toxigenic cultures of Aspergillus flavus and A. parasiticus. A synthetic medium was inoculated with spores, incubated for 48 h at 27°C, and then supplemented with sorbic acid and fatty acid derivatives. Cultures were then incubated for an additional 5 days. Aflatoxins were extracted, separated, and quantitated. Mycelial mats were dried, weighed, and analyzed for lipid and mineral content. Cerulenin (8 μg/ml) was the most effective fatty acid derivative examined, reducing mycelial growth by 37% and completely inhibiting extracellular accumulation of aflatoxins. Other derivatives, in decreasing order of effectiveness, included M-20 (an aminimide), lauribic, and lauricidin. Mycelia grown in the presence of fatty acid derivatives contained less phosphorus, potassium, magnesium, phosphatidyl ethanolamine, phosphatidyl serine, cholesterol, and triglycerides, but more cardiolipin, phosphatidyl choline, free fatty acids, fatty acid esters, and diglycerides. Levels of monoglycerides and cholesterol esters remained essentially unchanged. Inhibition by sorbic acid was nonspecific, affecting both mycelial growth and extracellular aflatoxin accumulation to approximately the same extent. Utilization of fatty acid derivatives for determining mechanisms of aflatoxin accumulation and lipid biosynthesis appears promising.

Notes: The nutritional requirements for the synthesis of a cholera toxin-like toxin from Salmonella enteritidis serotype braenderup were examined. Toxin levels of both culture filtrates and sonicates were determined by the modified Chinese hamster ovary (CHO) floating cell assay. With few exceptions, most amino acids which contained charged polar R groups were stimulatory for Salmonella toxin synthesis. Glycerol enhanced toxin production to the largest extent; however, glucose was a poor carbon source suggesting that Salmonella toxin elaboration may be subject to catabolite repression. Biotin and Mn++ were shown to increase the synthesis as well as release of this toxin. An ideal defined medium, supplemented with all the nutritional factors shown to stimulate toxin synthesis, was formulated. The amount of Salmonella toxin produced in this supplemented medium was about 82% of the total toxin elaborated when cultured in Casamino acids plus yeast extract.

Notes: Five plating media, Hektoen enteric (HE) and xylose lysine deoxycholate (XLD) agars with and without 80 and 5 μg/ml of novobiocin (N), respectively, and brilliant greeen sulfadiazine (BGS) agar with 80 μg/ml of the antimicrobial agent, were analyzed for the recovery of salmonellae from various fresh beef, pork, and poultry meat products. Of the total Samonella positive samples, 50.0% and 82.5% were found on XLD and XLD-N agars, respectively, 75.0% and 85.0% on HE and HE-N agars, respectively and 65.0% on BGS agar. HE-N and BGS media isolated three times more false positives than did XLD-N agar, while XLD and HE agars gave the highest numbers of false positives. The major H2S producing false positive on XLD and HE agars was Proteus mirabilis. With the addition of N, P. mirabilis was eliminated, and the major H2S producing false positive was almost exclusively Citrobacter freundii. The false positives on BGS agar were predominately distributed among C. freundii, Enterobacter sp., and Klebsiella sp.

Notes: Cynomologus monkeys (Macaca fascicularis) were tested for their sensitivity and specificity to staphylococcal enterotoxin A (SEA). Thirty-two of 38 monkeys vomited within 5 h in response to intragastric feeding of 4.8–18 μg of crude SEA. Twenty-four of these 32 responding monkeys were subjected to specificity study by feeding crude SEA which was neutralized with specific Antiserum A. Twenty-two (92%) of the 24 demonstrated specificity by not vomiting when fed neutralized crude SEA. The remaining two (8%) monkeys showed specificity only with purified SEA neutralized with the Antiserum. The emetic dose -50 for crude SEA was 6.5 μg per monkey. These suggest that cynomologus monkeys are suitable for SE bioassay and for identification of new enterotoxins.

Notes: A kinetic study was performed on the combined effect of monolaurin and heat on the death of Escherichia coli. The following results were obtained: (1) Monolaurin was about eleven times more active than that of sodium laurate; (2) Temperature enhanced the effect of monolaurin. True enthalpyentropy compensation effect was shown in this death reaction. The value of 341.9°K was obtained from the formula of ΔH*= Tc·ΔS*+ b and 331.5°K from Arrhenius plots as a compensation temperature; (3) The apparent minimum enhancing concentration of monolaurin ranged from 0.0056 mM to 0.013 mM, varying with the heating temperature. It may be concluded from the results of this study that the enhancing effect of monolaurin on the thermal death of E. coli corresponds to that of the amphoteric surfactant type (S type) agent defined in our previous report.

Notes: The antimicrobial effects of monolaurin and sorbic acid were compared in laboratory media, cottage cheese and a pork homogenate. Sorbic acid (250–1000 ppm) was more effective than monolaurin (250–1000 ppm) in inhibiting the growth of Staphylococcus aureus S-6 and Salmonella enteritidis 13076 in pH 5.2 trypticase soy broth. Monolaurin was more effective than sorbic acid against the growth of S. typhimurium 13311 under similar conditions. No synergistic effects were observed when combinations of monolaurin and sorbic acid were tested. In the cottage cheese study, 800 ppm sorbic acid effectively inhibited the growth of coliforms and yeasts and molds, but only slightly inhibited the growth of psychrotrophs. Monolaurin at 800 ppm was ineffective in controlling the growth of any of the microorganisms tested. The use of 3000 ppm monolaurin in a pork homogenate had no effect on the outgrowth and gas formation by Clostridium sporogenes PA3679, whereas 3000 ppm sorbic acid delayed outgrowth and gas formation. Combinations of monolalurin and sorbic acid indicated that sorbic acid was the active anticlostridial agent.

Notes: Twenty kinds of ciguatoxic fishes such as grouper, moray eel, barracuda, catfish and snapper, etc. were collected from fish markets in Bangkok, Chanthaburi and Chonburi. Liver and meat were extracted with ether and the presence of ciguatoxin was checked by the mouse test. Ciguatoxin was not detected in any of the samples. On the other hand, water-extracted fractions under acetic acidic conditions from meat, skin, intestine, liver and ovary of five kinds of puffer collected from Chanthaburi, Samut Sakorn and Trat caused mouse paralysis or death. The ovaries of the green rough-backed blowfish and the starry blowfish, which are very popular in Thailand, contained large amounts of tetrodotoxin. The starry blowfish contained 1482.0 mouse units of tetrodotoxin per gram of ovary.

Notes: A review of plasmids in Clostridium perfringens is presented. The characterization of the caseinase mediating plasmid pHB101 based upon limited DNase treatment, restriction endonuclease treatment, and agarose gel electrophoresis is described. Antibiotic profiles for the wild type strain and the cured strain were determined. The plasmid pHB101 was non self-transferable. The curing procedure resulted in a stable morphological change from rod to coccoid or bacillary-coccoid shape. A screening of C. perfringens strains showed the general presence of a 9.4 Mdal plasmid which may have been overlooked in the past due to chromosomal DNA masking effects.

Notes: Book reviewed in this article Food Safety. Edited by H. R. Roberts.

Notes: Repeated (five) doses of pyridoxine chloride (vitamin B6, 10 mg) reduced botht he neurological symptoms caused by ethylidene gyromitrin, the main poisonous compound of the mushroom false morel (Gyromitra esculenta pers. Fr.), and the overall mortality due to ethylidene gyromitrin poisoning in mice treated orally with this poison (400 mg/kg). In contrast, little or no effect was found when the mice were treated with γ-aminobutyric acid (1 mg) or vitamin C (10 mg) after treatment with poison. The significance of these findings is discussed in perspective to possible treatments of human poisonings caused by false morel.

Notes: Glyceryl monolaurate when used in the proportion of 5 g per kg of meat slurry (pH 6.0–6.2) inhibited toxin production by Clostridium botulinum type A (strain 73A), type B (strain OKRA) and type E (strain RIV 2). The concentration of glycerol monolaurate required for inhibition was not reduced by addition of lactic acid to the meat slurry until the pH was lowered to pH 5.2 or below. In meat slurry (pH 6.0–6.2), potassium sorbate inhibited production of type B toxin at 32 g/kg. The addition of butylated hydroxy-anisole to glyceryl monolaurate had no effect upon the concentration needed for inhibition of botulinum toxin production.

Notes: A lipid-enveloped virus (Semliki Forest virus: SFV) and a nonenveloped virus (coxsackievirus B4) were treated with neutral lipids known to be present in human milk or able to be generated by lipase activity in human milk. Triglycerides and diglycerides were inactive compared to monoglycerides and free fatty acids which were active against SFV (90% inactivation) at concentrations as low as 0.7 μM. Of the compounds tested monolinolein was the most active against SFV. None of the lipids tested were active against coxsackievirus B4. A synthetic milk (Almiron-M2), high in unsaturated triglycerides, was inactive against either virus.

Notes: A cultivar of Lolium perenne L. (Causeway) selected for tolerance to foliar-applied paraquat was shown also to be tolerant at seed germination and establishment.When seeds were germinated in paraquat solutions (1, 3, 9, 27 ppm), Causeway was more than ten times as tolerant as a normal cultivar of L. perenne.When germination and survival were studied in a soil which had been sprayed with paraquat (0.0, 0.3, 0.9, 2.7 kg/ha) before sowing, Causeway was nearly three times as tolerant as a normal cultivar. Holcus lanatus L. was about equal to normal L. perenne, but Poa trivialis L. was less tolerant. Phytotoxicity was greater in a 10.5% organic than a 4.8% organic soil.It is concluded that the mechanism of paraquat tolerance operates in the non-photosynthetic tissues of germinating seedlings as well as in the photosynthetic tissues of older plants, although the degree of tolerance varies according to the mode and stage of application of the herbicide. There might be advantages in using a paraquat tolerant cultivar of L. perenne when direct drilling grass after sward destruction by paraquat.

Notes: Spring-produced seeds of Lamium amplexicaule L. were buried in pots of soil in an unheated glasshouse in June 1978, and at 1–2-month intervals, for 27 months, they were exhumed and tested for germination in light and darkness at temperatures simulating those in the habitat from early spring to late autumn. Freshly-matured seeds were dormant, but by autumn 85% or more germinated in light at 15/6, 20/10, 25/15 and 30/15°C but only 7% or less in darkness. During late autumn and winter germination in light decreased at 25/15 and 30/15 °C but not at 15/6 and 20/10 °C, and germination in darkness increased at 15/6 and 20/10 °C. During late winter and early spring germination in light at 15/6 and 20/10 °C decreased, and seeds lost the ability to germinate in darkness. By the second autumn of burial, seeds germinated to near 100% in light at 15/6 to 30/15 °C and to 10–25% in darkness at 15/6 and 20/10 °C. The cycle of germination responses was repeated during the second winter and spring and the third summer of burial. Autumn-produced seeds were dormant when buried in November 1979, but by spring they germinated to 81 and 36% at 15/6 and 20/10 °C, respectively, in light. These seeds afterripened further during summer. The consequence of seasonal changes in germination responses is that (1) seeds can germinate in the habitat in late summer, autumn and spring but not in early- to mid-summer or in late autumn and winter and (2) during both germination seasons, seeds produced during the previous spring(s) and/or autumn(s) can germinate.

Notes: Linuron (0.21 and 0.28 kg/ha) and linuron + MCPA (0.21+0.56 kg/ha) in a tank mixture with field rates of barban, difenzoquat and flamprop-methyl reduced the phytotoxicity of these herbicides to Avena fatua. When linuron was applied immediately following or 6 days after the A. fatua herbicides no reduction in phytotoxicity to A. fatua occurred, suggesting that the antagonism may be occurring as a result of physical or chemical incompatability when the herbicides are mixed together. The possibility of obtaining broad-spectrum weed control with one trip over the field by applying linuron and one of these wild oat herbicides separately but at the same time using a double-boom, double-tank system deserves evaluation. When linuron was applied in a tank mixture (0.21 and 0.28 kg/ha), immediately after, or 6 days after diclofop-methyl (0.70 kg/ha), there was no reduction of A. fatua control, and wheat tolerance to the tank mixture was good. This tank mixture offers potential for control under field conditions of A. fatua and some broad-leaved weeds in one spray operation. Linuron + MCPA (0.21+0.56 kg/ha) in a tank mixture severely reduced A. fatua control with diclofop-methyl. No loss of phytotoxicity to Fagopyrum tataricum occurred when the A. fatua herbicides tested were tank mixed with linuron or linuron + MCPA. Lutte contre Avena fatua et Fagopyrum tataricum avec des mélanges extemporanés de linuron ou de linuron + MCPA et des applications successives de linuron et d'herbicides de postlevée actifs contre A. fatua

Notes: The effect on seed dormancy of exposing the mother plants to different environmental conditions was studied in Datura ferox. Reducing incident radiation and withholding water to provoke water stress, during the period from fruit set until seed ripening, caused a decrease in the degree of dormancy of the harvested seeds. A significantly smaller amount of the basic fraction inhibitors was found in the seeds with the lesser degree of dormancy. It is suggested that one of the ways in which the environmental conditions to which the mother plants are exposed can influence seed behaviour is by changing the endogenous inhibitor levels

Notes: A bioassay technique based on Poa annua growth showed that ethofumesate applied at 2.0 kg/ha in October to a newly-sown ryegrass (Lolium perenne) sward had a half-life of just over 8 weeks. After 7 months there was still sufficient herbicide present to cause about a 50% reduction in P. annua growth. The movement of ethofumesate, as measured in soil cores taken 15 months after spraying, was confined mainly to the upper 2 cm of the soil profile. Seeds on the soil surface at spraying were very sensitive to ethofumesate. The implications of the findings for weed control in newly-sown grass leys are discussed.

Notes: When sprayed as a post-emergent, foliar herbicide propanil destroyed Echinochloa crus-galli (L.) with little or no visible injury to rice, confirming its selective contact action. In treated rice leaves there was, however, a temporary decrease in dry weight, pigments, proteins and photosynthetic products followed by complete recovery in 4–5 days. In both rice and E. crus-galli, at lower concentrations propanil inhibited the electron flow in a manner similar to that of DCMU, but at higher concentrations it damaged the primary electron donor. In vivo chlorophyll a fluorescence kinetics determined at various times after spraying 1% propanil in the field confirmed progressive weed deterioration. Rice leaves showed a decreased fluorescence for a few hours but exhibited partial recovery from the effects of propanil within 6 h and total recovery within 48 h after spraying. When the leaves were infiltrated with propanil solutions there was good recovery of fluorescence in both weed and crop leaves at 0.01% while at 1% both were drastically affected. With 0.1% propanil, fluorescence in the weed leaves deteriorated progressively while the crop leaves recovered after 4 h of incubation. This suggests that the crop has also an effective endogenous detoxifying mechanism.

Notes: The distributions of two herbicides and two radioactive ions in field plots at two sites were determined at periods up to 187 days following surface applications in the spring. The results demonstrated the variability characteristic of field situations. At one site some fluometuron moved a short distance down the profile but after 187 days most remained above 6 cm whereas at the other site there was essentially no movement below 3 cm. At both sites simazine was almost entirely confined to the top 3 cm. The adsorption characteristics of the two compounds are similar so the greater mobility of fluometuron is probably a consequence of its greater solubility, Measurements of 36Cl− indicated a significant movement of water through the 30 cm depth studied. 144Ce3+ used as a tracer of soil particles was of similar mobility to simazine.In general the movement of chloride and the two herbicides can be interpreted in terms of the concept of mobile and immobile fractions of soil water in which a proportion of the mobile water does not reach equilibrium with solutes in the bulk of the soil. Soil structural effects may therefore be more important than adsorption in controlling the movement of solutes and redistribution in association with soil particles can be significant. A parallel laboratory experiment showed that the results from a standard leaching column procedure did not necessarily indicate field performance.

Notes: Absorption of methazole by leaves of onion (Allium cepa), Stellaria media, Matricaria matricarioides and Veronica persica was rapid for the first 24 h after treatment and continued at a slower rate for up to 6 days to reach a maximum of between 35 and 60% of the amount applied. Differences in absorption between species were generally small. Absorption by the cotyledon of onion was greater than absorption into true leaves. Methazole on the leaf surface degraded to 3-(3,4-dichlorophenyl)-1-methylurea (DCPMU) and small amounts of this degraded to 3-(3,4-dichlorophenyl) urea (DCPU). Methazole absorbed into leaves was relatively stable in M. matricarioides and DCPMU accumulated slowly. The rate of degradation was more rapid in the cotyledons than in the true leaves. Both in leaves and in cotyledons of onion and S. media, methazole degraded rapidly to DCPMU and this accumulated; in those of V. persica, DCPMU was degraded quickly to DCPU and unidentified products. The amount of DCPMU accumulated in the shoots was broadly correlated with the relative phytotoxicity of methazole to the different species, except for young seedlings of V. persica which contained no DCPMU but were susceptible to methazole.

Notes: Effects of glyphosate, paraquat, trifluralin and atrazine on activities of dehydrogenase, phosphatase and urease in one soil were measured. Only glyphosate at 21.6 kg/ha was found to inhibit the enzyme activities and generally the results were not statistically significant. Enzyme activity associated with micro-organisms proliferating in soil supplemented with lucerne meal was similarly not affected by the herbicides. Interpretation of results from enzyme activity measurements in soils treated with herbicides is discussed. It is proposed that effects of natural stress can be used to judge the relative importance of herbicide induced change.

Notes: Large losses in grain yields due to weed competition were found in studies conducted in irrigated dry seeded rice at Gezira Research Station, Sudan. These losses could exceed 50%. Weed competition lowered panicle number per unit area by 37%, number of filled grains per panicle by 13%, and weight of 1000 grains by 4%. Tillering was the critical growth phase most affected by weed competition.Grain yields were increased as number of hand weedings increased. The best yield (4.1 t/ha) was obtained from 3–4 weedings carried out at 15, 30, 45 and 60 days after rice emergence.Oxadiazon (0.5 kg/ha) gave good residual weed control of the dominant weed species, Phyllanthus niruri L., Leucas urticifolia L., Heliotropium F.W.Andr. and Echinochloa colona (L.) Link, for 6–7 weeks. The combination with continuous flooding from 6 weeks after rice emergence gave excellent weed control during the entire season, and comparable or even better yields than frequently weeded rice.

Notes: Par des observations sur la germination dans différentes conditions et sur le développement végétatif en conditions non compétitives, les auteurs comparent des biotypes sensibles et résistants de quatre espèces chez lesquelles on a découvert des populations résistantes: Chenopodium album, Amaranthus retroflexus, Solanum nigrum et Polygonum lapathifolium. Malgré des niveaux de signification différents les résultats indiquent un meilleur développement végétatif des plantes sensibles, Cependant, ces données peuvent être modulées selon les conditions de croissance. Par ailleurs, les valeurs élevées des variances des caractères mesurés traduisent une hétérogénéïté très importante, au moins dans les lots sensibles. En revanche, les semences des plantes résistantes de Polygonum lapathifolium et, dans une moindre mesure, d'Amaranthus retroflexus germent plus facilement aux basses températures. A la lumière de ces données les auteurs discutent les avantages que peuvent conférer ces caractéristiques aux différents lots, mais surtout soulignent la nécessité de considérer chaque espèce séparément et de prendre en compte la nature des génotypes comparés. Enfin, il est difficile, à partir de telles donnés et tant que l'on ignore précisément le déterminisme de la résistance, d'en déduire dans les stations d'origine et en l'absence de traitement, une moindre valeur adaptative des résistants par rapport aux sensibles.

Notes: The responses of onion (Allium cepa). Veronica persica, Matricaria matricarioides and Stellaria media to post-emergence applications of methazole were measured in field and glasshouse experiments. Stellaria media was the most susceptible species and V. persica the least. Plants of all species became more tolerant the larger they were at the time of treatment, and this was most pronounced in onion. Onion generally retained less spray per unit of dry weight than the other three species and retention was less on old compared with young plants, whereas with the weed species, this did not change appreciably with age. There was a progressive increase in the amount of structured crystalline wax on successive onion leaves which resulted in larger contact angles between droplets and the leaf surfaces and lower spray retention per unit of dry weight. There was less wax development on the leaf surfaces, increased spray retention, and increased susceptibility to methazole in onion treated pre-emergence with ethofumesate thus confirming that these factors are interrelated. While the increased tolerance of onion to methazole with age could be explained in part by decreased retention of herbicide, this was not so for the weed species, and other factors must determine their change in tolerance with age.

Notes: Inheritance of resistance to simazine was investigated in reciprocal pair crosses of resistant and susceptible genotypes of Senecio vulgaris. The simazine resistant genotypes had been selected in a screening experiment and were unaffected by 2.8 kg ha−1˜’a.i. simazine. Reciprocal differences for resistance and susceptibility to simazine in F2 families showed that resistance is maternally inherited. The practical implication of maternal inheritance is that a resistant field population will build up very rapidly from a very low initial frequency of the resistant genotype.

Notes: The effects of different concentrations of aqueous leachate of Datura stramonium seeds and leaves on germination and radicle elongation of Linum usitatissimum were examined.Germination and radicle elongation of L. usitatissimum were depressed at high leachate concentrations. Radicle elongation usually appeared more sensitive to the effects of the leachate than did germination. Preliminary investigations showed that D. stramonium leaf leachate had similar effects to those of seed leachate.Chemical analysis of the leachates by spot-tests and by high-voltage electrophoresis indicated the presence of tropane alkaloids, in particular scopolamine. The presence of both scopolamine and hyoscyamine was confirmed by gas chromatography/mass spectrometry. It was shown that varying concentrations of pure scopolamine and scopolamine plus hyoscyamine solutions had effects similar to those of seed and leaf leachates on germination and radicle elongation of L. usitatissimum.

Notes: The response of etiolated cucumber (Cucumis sativus L. cv. National Pickling) cotyledons to fluridone was investigated in terms of inhibition of photosynthetic pigments, and utility as a bioassay. At a light intensity of 35 W/m2, chlorophyll levels were higher in the controls, than at either 12.9 W/m2, or 75 W/m2. Fluridone inhibition was also more pronounced at that intensity. Significant differences between treatments were established as early as 24 h after exposure to light, when at the lowest fluridone concentration of 0.001 μg/ml, chlorophylls and carotenoids were inhibited 25 and 35% respectively. The system's simplicity and sensitivity suggest its use as a bioassay. It is shown that simple monochromatic absorbances of acetone extracts can satisfactorily estimate chlorophylls and carotenoids. Concentrations of fluridone as minute as 10−9 moles/ litre are easily delected, and the system could feasibly detect even lower levels.

Notes: The effects of reduced-cultivation Systems on weeds in cereals are reviewed. Increasing dependence of these Systems upon Chemical weed control together with changes in the soil physical environment are expected to modify existing weed floras. Annual-grass weeds are likely to remain a problem with the use of minimal cultivations, particularly when early drilling is practised, while hitherto unimportant species may become more prevalent, e.g. Bromus spp. Furthermore, reduced cultivations may encourage the establishment of wind-disseminated species. However, annual dicotyledonous species characteristic of arable land are expected to continue to decline.

Notes: Dissipation of atrazine after pre-emergence application to irrigated grain sorghum was investigated in an experiment on a Birganbigil clay loam at Yanco Agricultural Research Centre in the Murrumbidgee Irrigation Areas of New South Wales. Dissipation followed first-order kinetics with a half-life of 70 days. This rate of disappearance did not differ significantly between application rates of 2.5 and 10 kg/ha. Removal of volunteer plant growth with non-residual chemicals or by cultivation during the winter fallow periods had no significant effect on the levels of atrazine residues in the soil and dissipation rate did not differ significantly between the 2 years of the experiment. A laboratory incubation experiment demonstrated that dissipation of atrazine in Birganbigil soil was more rapid than in three other soils from the Murrumbidgee and Murray Valleys. Dissipation rate and atrazine adsorption were both correlated with the organic carbon content of the soils, which ranged from 1.43% to 0.72%. There was no correlation between either dissipation rate or adsorption and clay content, even though clay contents ranged from 37 to 78%.

Notes: Changes in the numbers of Avena fatua seed, incorporated into soil, were monitored in four successive spring barley crops which were harvested early for silage to prevent seed shedding.In the first year there were four times as many seedlings after tine cultivation compared with ploughing, but this was reversed in the second year as re-ploughing brought up dormant seeds and gave more seedlings than tine cultivation. Only 11–14% of the sown seeds produced seedlings during the 4 years. When the seeds were first buried to 25 cm by ploughing, and the barley was direct drilled without cultivation, only 0.4% emerged as seedlings.Few viable seeds remained in the soil after 4 years whether the soil was cultivated annually or not but seed numbers decreased more rapidly with tine cultivation than with ploughing. A few of the deeply buried seeds persisted where the land was direct drilled without cultivation.

Notes: Des études d'adsorption et de dégradation d'analogues du propyzamide [dichloro-3,5-N-(dimethyl-1,1 propynyl-2) benzamide] dans différents sols ont été réalisées. Une bonne corrélation entre adsorption et teneur en matière organique des sols a été trouvée. Cette adsorption est reliée linéairement à un paramètre hydrophobique (coefficient de partage octanol — eau). Par contre la dégradation dans différents sols de ces composés ne montre pas de relation simple avec la nature des sols ou avec la structure chimique des composés. L'importance de ces phénomènes sur les résultats de biotests est aussi analysée.

Notes: An established sward of red clover cv. Hungaropoly sown pure received approx. 30 kg P ha-1 and 200 kg K ha-1 each year for 3 successive years. The P and K were applied either as cattle slurry, inorganic fertilizer or combinations of these. Treatments were applied either in spring or after the first harvest. There were a total of six treatments and these were harvested three times each year. The average yields of total herbage DM over all the treatments in the first, second and third years were 15·2, 14·2 and 14·2 t ha-1 respectively and the various treatments had no significant effect on the overall yields.Treatments had a significnt effect on red clover DM yields and percentage red clover in one harvest in each of the first 2 years and all three in the third year. Yields of red clover were lower and grass higher in treatments receiving cattle slurry only. On this treatment there was a total yield of 23·2 t ha-1 red clover DM in the 3 years compared with 30·2 t ha-1 on the inorganic fertilizer treatments. However, by applying P and K fertilizer in the spring, followed by cattle slurry after the first harvest, it was possible to maintain a high proportion of red clover in the sward and to produce yields of red clover DM similar to those on the inorganic fertilizer treatments.

Notes: Book review in this article Physiological and Environmental Limitations to Wool Growth Proceedings of a National Workshop, Leura, New South Wales, Australia, April 1978 Edited by J. L. Black and P. J. Reis Ecology of the English Chalk By C. J. Smith Range Science: A Guide to Information Sources Edited by J. F. Vallentine and P. L. Sims Grass: its Production and Utilization Edited by W. Holmes Grassland in the British Economy Edited by J. L. Jollans Proceedings of the XIII International Grassland Congress, Leipzig, German Democratic Republic, 18-27 May 1977 Edited by E. Wojahn and H. Thöns

Notes: The present study was aimed at testing the hypothesis that a dense maize stand (320–720·203 plants ha-1) will produce more dry matter of acceptable quality than a stand sown at the density generally advocated (105 plants ha-1). It was also aimed at proving that grain is not essential in order to obtain a high yield of good-quality forage maize.It was found that dry matter yield increased with density, especially at the early stages of growth. When ear-formation was depressed by increasing plant density, the resulting reduction of ear yield and its quality due to the absence of ear was partly compensated for by the increased yield and quality of the stem.

Notes: Growth measurements were made on Lolium perenne-dominant vegetative swards during 4-week regrowth periods following grazing or cutting.In the grazing study, the ryegrass (Lolium perenne) swards were grazed for 12-d periods with stock numbers set according to initial herbage allowances per animal of 16, 32 and 64 kg organic matter per sheep. One area was grazed in summer and another area in the autumn.In the cutting experiment four ryegrass swards growing in boxes were prepared by cutting to either 2 or 6 cm at either 14- or 28-d intervals. The swards were cut back in autumn to 2 or 6 cm. During the regrowth period half the boxes were retained in full light and half shaded to 48% of incident light.Herbage weight, rates of leaf extension, senescence, leaf appearance and tillering, water soluble carbohydrate reserve levels in tiller bases and, in the cutting experiment, sheath tube lengths and lamina lengths of leaves which had grown through the sheath tube were measured at intervals during the regrowth period.Final herbage weights reflected management history but net herbage accumulation over the four-week regrowth period, though affected by season, pretreatment and light level, was similar on swards subjected to different grazing or cutting treatments.This result was partially explained by changes in the balance between growth and senescence per tiller as herbage weight increased with time during regrowth, and partially by the reduced production per tiller in harder-grazed swards being offset by a rapid increase in tiller numbers.There was a positive curvilinear relationship between lamina length and the length of the sheath tubes through which the laminae emerged.Carbohydrate reserve levels declined rapidly after grazing or cutting, the extent of the decline being related lo the severity of the defoliation. Recovery commenced after four days in summer and was complete within 3 weeks but reserve levels remained low in plants grazed or cut in autumn.The need is discussed for more detailed descriptions of sward states in management studies and for more information on component processes of growth, the factors affecting them and how these interact with different kinds of management systems.

Notes: The effect of artificial dehydration and processing of red clover on nutrient digestion and absorption has been studied with sheep. A total of three diets were fed, each at an intake of 900 g DM d-1; comprising frozen (to represent fresh control), wafered and pelleted red clover.Dehydration caused small depressions in energy and N digestibility. Grinding and pelleting had no further effect, although both treatments reduced the amount of energy digestion occurring in the rumen, frozen 63, dried 60, pelleted 48 MJ per 100 MJ digestible energy. Digestion of energy in the caecum and colon was increased on both dried diets, and in the small intestine on the pelleted diet.Almost 40% of the extra duodenal energy on the pelleted diet was due to increased cellulose flow, with only 79% of digestible cellulose being digested in the rumen compared with 96% on the other two diets. There was an associated decrease in ruminal volatile fatty acid production of approx. 20%. Approximately half of the extra energy was due to an elevated flow of protein on the pelleted diet, but this increase was not reflected in amino acid absorption due to a reduced efficiency with the dried diets (frozen 72%, dried diets 54%).The results demonstrate that dehydration and processing of red clover can markedly influence nutrient digestion and supply and thus offer attractive means of improving the nutritive value.

Notes: Cruciferous catch crops are an important source of forage, particularly in sheep systems, but due to their late sowing date, commonly July or early August, soil moisture is often a limiting factor in crop establishment and subsequent growth, causing wide variations in yield from year to year. Crops of stubble turnip (Brassica campestris ssp. rapifera), forage rape (B. napus ssp. biennis) and fodder radish (Raphanus sativus) were grown at Hurley between 1969 and 1977. Fodder radish was the most variable in dry matter (DM) yield, while stubble turnip was the most stable. Both DM yields and in vitro digestibilities rose during the autumn, reaching a maximum in mid-December for stubble turnip and forage rape, and in mid to late November for fodder radish. Yield and digestibility subsequently declined. The N concentrations of the forages exhibited a contrary trend, reaching minimum values at about the time of the highest DM yields. The gradual changes in crop quality suggest that the crops are well suited to grazing utilization, in which management is simplified if crop quality shows little variation.

Notes: In experiments in 1979 and 1980 in eastern England, the spread of eriophyid mites and ryegrass mosaic virus (RMV) from transplanted old sward through plots of newly sown Italian ryegrass greatly exceeded spread by windborne mites from outside the plots. During the summer and autumn of each year, mites and RMV spread at least one metre through the ryegrass (6/7 rows) from the old sward. Applying aldicarb (10 kg/ha equivalent) to the seedbed before sowing the Italian ryegrass prevented colonisation by mites and greatly decreased spread of RMV from old sward. It is concluded that old diseased swards should be completely killed before reseeding and that RMV is likely to spread quickly to plants slot-seeded into old pastures. The use of acaricides might prevent this spread but would be costly.

Notes: Between mid-July and the end of August in 1977 and 1978, wheat bulb flies were caught in white water-traps at 16 oviposition sites in eastern Scotland. The numbers of females caught per site and the subsequent egg populations, estimated from soil-cores from each site, were linearly related. Water-trapping may therefore provide a reliable and early forecast of egg numbers, independent of soil-sampling, and so enable seed treatment to be limited to years when the risk of damage is great.

Notes: As a protection against invading Megaselia halterata adults, a newly spawned mushroom crop was treated for four weeks with intermittent sprays of small volumes of dichlorvos from an automatic atomiser. Efficient control of adults was obtained in small- and large-scale tests by spraying 0.3 mg/m3 of air every 24 min. Automatic spraying of dichlorvos achieved better and cheaper control than that obtained by the incorporation of diazinon in the compost (30 mg/kg).

Notes: Since the mid 1950s, there have been many developments in serological techniques for testing for plant viruses. Certain of these can provide great savings in time, labour and cost in routine testing situations and are well suited for use by advisory services, certification schemes and healthy stock programmes, statutory and quarantine authorities, and plant breeders. The recent developments are described under the headings flocculation in liquid media, gel diffusion, labelled antibodies and electron microscope serology, Flocculation tests depend on observation of aggregates formed in a liquid medium. The microprecipitin and chloropiast agglutination tests are simple forms which are still widely employed routinely. However, sensitivity is greatly improved by using flocculation tests in which antibodies are adsorbed to the surface of larger inert carrier particles, such as polystyrene latex spheres, tanned red blood cells or bentonite. Latex particles are the most widely used of these because they are easy to sensitise with antibodies, little antiserum is required and the sensitised latex can be stored for years without loss of activity. The latex test is also very simple to do, is well suited for routine checks on either small or large numbers of samples which can be grouped and can be used with many virus–crop combinations.Gel diffusion tests depend on observation of precipitin lines formed in an agar gel medium. They are of two main types, single (= simple) diffusion and double diffusion. Both can be used effectively with viruses which have isometric or ‘near isometric’ particles but not with those which have elongated particles because these do not diffuse readily through agar. Recent developments which involve breaking elongated particles into sub-units or fragments which can diffuse through agar now permit gel diffusion to be applied with almost all viruses. Various treatments are useful in breaking particles, the most effective of which employ detergents or other disruptive chemicals such as pyridine, pyrrolidine and ethanolamine, However, although gel diffusion tests which incorporate one or other of these treatments have been employed routinely for testing for viruses in several different crops, such tests are relatively insensitive, require much antiserum and conditions must be carefully controlled to avoid formation of nonspecific precipitin lines.Antibodies can be labelled to make virus—antibody aggregates readily observable, or to obtain increased sensitivity in testing, or both. The only form of labelled antibody test widely employed in routine screening for plant viruses is enzyme-linked immunosorbent assay (ELISA), in which antibody is labelled with an enzyme and positive results are observed as an enzyme-mediated colour reaction. Since its introduction to plant virology in 1976, ELISA has been very widely applied in situations where large numbers of either individual or grouped

Notes: In 1980, 110 adults of the Colorado beetle, Leptinotarsa decemlineata (Say), were found associated with imports in England and Wales; 89 of these specimens were alive. This is the highest annual total for three years and the highest annual total of live beetles for 28 years. Details of these finds are presented. The outstanding features were the large numbers associated with imports of Italian spinach (55) and Portuguese timber (25). Fourteen beetles were found in Scotland of which one was alive and 13 were dead preserved specimens reported as a hoax. No breeding colony of Colorado, beetle was found. Live female beetles kept in the laboratory after capture laid an average of 871 eggs each (range 165–2462) and the average percentage hatch was 46 (range 0–73). Observations on egg laying by beetles found during the past six years showed that 34 per cent of females were capable of laying fertile eggs when they arrived in the United Kingdom.

Notes: In May 1979 an outbreak of Liriomyza trifolii (Burgess) was detected on glasshouse chrysanthemums, at Efford Experimental Horticulture Station in Hampshire, England. The pest spread to glasshouse tomatoes and then to cultivated and wild hosts outside. An intensive eradication campaign included pest and weed control, monitoring adults with yellow sticky traps, and extensive surveys of potential host plants to determine the spread of the pest. Eleven new hosts of the pest were recorded. In November 1980, following a series of surveys, the pest was deemed not to have survived in the area.

Notes: The American serpentine leaf miner, Liriomyza trifolii (Burgess), was first seen in England in 1977, at a nursery where chrysanthemums were being grown from cuttings imported from Kenya and Malta. Eradicatory action was taken at this and 14 other nurseries where infestations were found during that year. In 1978, 12 infestations were found, originating on chrysanthemum cuttings from Kenya and the Canary Islands and on Gerbera from the Netherlands. In 1979, 132 infestations were found; by then the sources also included Denmark and the USA. Following the withdrawal of the licence permitting imports of chrysanthemum cuttings from Kenya, 63 infestations were found in 1980 and 48 in 1981.Eradication measures rarely required the destruction of infested crops hut frequently required the selective destruction of infested imported plants, together with the application of various insecticidal treatments. To kill adults, fogs and smokes were used; to kill larvae, foliar sprays were applied and persistent systemic insecticides were incorporated in the planting beds; to kill pupae, soil drenches and sterilants were necessary.By the adoption of this control programme and the vigilance of the plant health authorities, eradication of L. trifolii has been, achieved wherever it has been found in England and Wales.

Notes: From 1973 to 1977 the spread of crown rot (Phytophthora cactorum(Leb. & Cohn) Schroet.) in glasshouse-grown strawberries at East Malling Research Station (EMRS) threatened to disrupt the production of virus-tested stocks. An eradication programme involving trickle irrigation of plants, rooting ranners above the level of mother plants, regular inspection for disease and routine tests for latent infection, special precautions at repotting and annual renewal of mother plants eliminated the disease in two years, except in a quarantine house containing new importations.Isolates of P. cactorum from strawberry plants and apple trees were moderately or highly virulent to their original hosts but caused only latent infection or limited necrosis in reciprocal inoculations. This supports the separation of the strains commonly attacking these hosts as distinct pathotypes. The evidence suggests that crown rot entered the strawberry stocks at EMRS with infected introduced plants and not from local field sources.

Notes: Plots of potatoes in eastern England were covered at planting with finely slit, clear polyethylene film which remained over the foliage until harvest. Spread of potato virus Y and the numbers of aphids on the leaves in these plots were compared with those in uncovered plots. In two years fewer tubers of covered plants were infected with potato virus Y and in the first year the covered plants had fewer Myzus persicae(Sulz.) and Macrosiphum euphorbiae (Thos.).

Notes: In an orchard in Kent, metalaxyl applied to the soil at 0.5 or 1.5 kg/ha on 20 July and to fruit as a 0.03 per cent spray on 3 September 1979 controlled rotting of Cox's Orange Pippin apples by Phytophthora syringae. There was also a residual effect of similar treatments applied in the previous year. Dipping fruits in 0.03 per cent metalaxyl controlled infections which had been developing on zoospore-inoculated apples for five days at 10°C but not when the incubation period was longer. In post-harvest dip treatments, the ability of metalaxyl at 0.01 per cent to control the spread of rotting by contact with apples inoculated with P. syringae was not affected if it was mixed with 0.05 per cent benomyl.

Notes: Lures containing different doses of (E)-10-dodecen-l-yl acetate (E 10–12: Ac), a sex atfractant for the pea moth, Cydia nigricana (F.), were evaluated for use in monitoring traps at sites in eastern England in 1977 and 1979.A natural-rubber serum stopper impregnated with 3 mg E10–12: Ac was shown to be an effective and long-lasting lure; it was equally effective at different population densities and remained constantly attractive for at least the whole flight season of the male moth. Such lures, which are being used by growers in the United Kingdom to monitor moth populations in dried pea crops, do not need to be renewed during the season nor allowances made for reduced attractiveness.

Notes: In agar plate tests, all 45 isolates ol Pyrenophora teres Drechsler tested were less sensitive to methoxyethyl mercury acetate (MEMA) as ‘Panogen M’ than to phenyl mercury acetate (PMA) as‘Agrosan D’, In further tests with eight isolates selected at random, mean ED50 values (p.p.m. Hg) for inhibition of mycelial growth at 17°C were 0.620 for MEMA, 0.098 for PMA, 0.070 for ethyl mercury phosphate and 0.060 for phenyl mercury chloride.In field trials on spring barley in 1980 at seven different sites throughout England and one in Scotland, mean seedling infection of 5.8 percent was reduced to 1.2 per cent by PMA and to 1.9 per cent by MEMA.

Notes: Laboratory and glasshouse tests showed that seed from barley crops in south-west England with much net blotch was often infected with Pyrenophora teres Drecksler. After sowing, mycelium in the caryopsis grew to infect the developing coleoptile and hence was carried above ground. On the growing foliage the fungus multiplied by conidial infection and also formed perithecia in late summer. The perithecia persisted in debris and released many ascospores in autumn which may infect volunteer plants and newly emerging barley seedlings. Pycnidia also developed on debris but the pycnidiospores were non-infective.Mycelial infection from seed often produced streaks on the coleoptile that quickly penetrated to the underlying leaves. This symptom was therefore often distinguishable from those resulting from air- or splash- dispersed conidia or from ascospores. In optimum weather (20°C, 100 per cent r.h.) net blotch lesions developed and sporulated within five days from inoculation and if suitably positioned could kill a leaf within 15 days.Severe leaf infection during tillering of winter barley (cv. Sonja) grown in pots outdoors significantly decreased yield both by decreasing the number of grains per ear and the thousand grain weight. In a fungicide trial on winter barley (cv. Hoppel) field plots sprayed with propiconazole yielded 23 per cent more than untreated plots, mostly because individual grains were larger.

Notes: Although Botrytis fabae Sard, was frequently isolated from spring-sown Scottish field bean crops in 1976–80, chocolate spot is not regarded as such a serious problem in Scotland as it is in England and Wales, where a large proportion of the crop is autumn-sown. Pieces of leaf (with lesions) from bean crops grown on two farms at different sites in Scotland were plated on agar during the five seasons 1976–80. The calculated date on which B. fabae was recovered from 50 per cent of the pieces each year was consistently earher on one farm than on the other, despite apparently similar climates. There was a highly significant correlation (coefficient of 0.90) between the severity of chocolate spot disease in different regions of England and Wales and temperatures during May. This, however, may merely reflect regional differences in the proportions of autumn- and spring-sown crops.