ISSN:
1365-3059
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
The use of soil-surface applications of finely powdered calcium hydroxide (Ca(OH)2) to inhibit Sclerotinia minor sclerotial germination and infection at the collar region of lettuce plants is described. In the laboratory, a pH 〉 8·0 reduced sclerotial germination of the three S. minor isolates tested. In the glasshouse, surface applications of 2–10 t Ca(OH)2 ha−1 raised the pH of the top 1–2 cm of a duplex sandy loam soil above 8·5 for at least 8 weeks without affecting soil pH within the transplant root zone. There was a linear relationship between the rate of Ca(OH)2 applied and disease control, with complete disease suppression at 10 t Ca(OH)2 ha−1. In field trials on two soil types (duplex sandy loam, pH 6·0; and red ferrosol, pH 6·9), a rate of 2·5 t Ca(OH)2 ha−1, maintained soil-surface pH above 8·5 for 1–3 weeks and provided up to 58% reduction in lettuce drop. Application of polyvinyl alcohol (a soil-conditioning polymer) over the Ca(OH)2 layer appeared to reduce Ca(OH)2 loss by wind, but did not improve retention of raised soil-surface pH or disease suppression. Ca(OH)2 treatment gave similar disease control to the industry standard treatment of a procymidone-based fungicide seedling drench. A combined treatment of Ca(OH)2 and fungicide drench gave greater control than either individual treatment, and equivalent control to fungicide drench and three procymidone foliar sprays, offering integrated management options. The use of soil-surface-applied Ca(OH)2 with fungicides, rotation and drip irrigation offers an opportunity for enhanced and sustainable control of lettuce drop.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-3059.2005.01188.x
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