ALBERT

Description: Decision support systems (DSS) have the potential to support farmers to make the right decisions in weed management. DSSs can select the appropriate herbicides for a given field and suggest the minimum dose rates for an herbicide application that can result in optimum weed control. Given that the adoption of DSSs may lead to decreased herbicide inputs in crop production, their potential for creating eco-friendly and profitable weed management strategies is obvious and desirable for the re-designing of farming systems on a more sustainable basis. Nevertheless, it is difficult to stimulate farmers to use DSSs as it has been noticed that farmers have different expectations of decision-making tools depending on their farming styles and usual practices. The function of DSSs requires accurate assessments of weeds within a field as input data; however, capturing the data can be problematic. The development of future DSSs should target to enhance weed management tactics which are less reliant on herbicides. DSSs should also provide information regarding weed seedbank dynamics in the soil in order to suggest management options not only within a single period but also in a rotational view. More aspects ought to be taken into account and further research is needed in order to optimize the practical use of DSSs for supporting farmers regarding weed management issues in various crops and under various soil and climatic conditions.

Description: E. colona is a C4 annual summer grass which is troublesome to major summer annual and perennial crops. Due to recent complaints by the farmers, the objectives of the present study were to evaluate the efficacy of penoxsulam, profoxydim, cycloxydim, cyhalofop-butyl, florpyrauxifen-benzyl and glyphosate against six E. colona accessions, and also to evaluate the response of these accessions to different rates of glyphosate in a dose-response experiment. In the first experiment, herbicides were applied at their maximum recommended label rates, while in the dose-response experiment, glyphosate was applied at six doses corresponding to 0, 1/4X, 1/2X, X, 2X, and 4X of the recommended rate. The dry weight of the biotypes TH8 and TH7 treated with profoxydim was 66% and 68% of the untreated control, respectively. The efficacy of cyhalofop-butyl against three accessions was lower than 30%, while two accessions were susceptible to this herbicide. The efficacy of penoxsulam against the biotypes ET2 and ET4 was lower than 10%, while dry weight of FT5 and TH8 was only reduced by 23%–28% as compared to the control. Cycloxydim application provided control higher than 75% at 21 days after treatment (DAT) of three accessions, while the majority of E. colona accessions was adequately controlled by the application of florpyrauxifen-benzyl. The response of the different accessions to glyphosate varied. The results of the glyphosate dose-response experiment revealed that the GR50 values of the resistant E. colona accessions ET2 and ET4 were up to 1098 and 1220 g a.e. ha−1 of glyphosate, respectively, whereas the GR50 value of the susceptible accession (FT5) was only 98 g a.e. ha−1. The resistance indices of ET2 and ET4 were 12.4 and 11.2, respectively, indicating that they have already developed resistance to glyphosate. Three more accessions could be also of developing resistant to glyphosate. This is the first report of glyphosate resistance from E. colona accessions in Greece, with indications of multiple resistance also present. Further research is needed in order to evaluate the efficacy of several herbicides under different soil and climatic conditions, conduct baseline sensitivity studies, reveal the evolvement of resistance patterns to glyphosate from accessions of Echinochloa spp., and search for alternative options of weed management in annual and perennial crops due to the clear indications of multiple resistance situations.

Description: Shattercane (Sorghum bicolor (L.) Moench subsp. drummondii) and weedy sunflower (Helianthus annuus L.) are two examples of crop wild relatives (CWRs) that have become troublesome weeds in agriculture. Shattercane is a race belonging to a different subspecies than domesticated sorghum (Sorghum bicolor (L.) Moench subsp. bicolor). Weedy sunflower populations are natural hybrids between wild and domesticated sunflower (Helianthus annuus L.). Both species have key weedy characteristics, such as early seed shattering and seed dormancy, which play an important role in their success as agricultural weeds. They are widely reported as important agricultural weeds in the United States and have invaded various agricultural areas in Europe. Shattercane is very competitive to sorghum, maize (Zea mays L.), and soybean (Glycine max (L.) Merr.). Weedy sunflower causes severe yield losses in sunflower, maize, soybean, pulse crops, and industrial crops. Herbicide resistance was confirmed in populations of both species. The simultaneous presence of crops and their wild relatives in the field leads to crop–wild gene flow. Hybrids are fertile and competitive. Hybridization between herbicide-tolerant crops and wild populations creates herbicide-resistant hybrid populations. Crop rotation, false seedbed, cover crops, and competitive crop genotypes can suppress shattercane and weedy sunflower. Preventative measures are essential to avoid their spread on new agricultural lands. The development of effective weed management strategies is also essential to prevent hybridization between sorghum, sunflower, and their wild relatives and to mitigate its consequences.