Evaluation of fungicides for prevention and management of powdery mildew on watermelon

摘要: Powdery mildew of watermelon, caused by Podosphaera (sect. Sphaerotheca) xanthii, has been present throughout the southern United States since at least 1999. This study evaluated efficacy contact and systemic fungicides a biofungicide (Bacillus subtilis) for preventing powdery curative applications managing mildew. The azoxystrobin, pyraclostrobin, myclobutanil were applied preventatively in alternation with mancozeb or B. subtilis during first part season. In other treatments, was preventively myclobutanil, benomyl, azoxystrobin added curatively after detected. Alternating preventative one most effective fungicide combinations tested to prevent manage this disease. Curative generally less than applications. treatments that included tank mixes required greater amount material any treatment. both years, four five made Melcast melon disease forecaster weekly schedule, respectively, before Mean weight individual fruit from nonsprayed plots significantly lower mean across all sprayed (P<0.003). decreased yields (R2=61.5, P=0.001 linear regression area under progress curve marketable over years), but no treatment consistently increased yield compared control.