Evaluation of biocompatible products for managing cucurbit powdery mildew

The biocompatible products AQ10 (hyperparasitic fungus Ampelomyces quisqual is), JMS Stylet-Oil (medium viscosity mineral oil), M-Pede (potassium salts of fatty acids) and Kaligreen (82% potassium bicarbonate) suppressed, powd ery mildew (Sphaerotheca fusca) on winter squash, muskmelon, and pumpkin an d increased yield compared with nontreated plants under field conditions. A pplications were started after disease detection. JMS Stylet-Oil most effec tively controlled powdery mildew. However, these products did not provide t he degree of full-season control or yield increase obtained with the conven tional fungicide program of Brave (chlorothalonil) plus Nova (myclobutanil) . For example, in muskmelon on 17 August 1995, 7 days after the third appli cation, powdery mildew severity on upper and lower (under) leaf surfaces wa s 66 and 80% for untreated, 3 and 13% for Brave plus Nova, 43 and 44% for J MS Stylet-Oil, 38 and 65% for AQ10, and 53 and 65% for Kaligreen, respectiv ely. Yield (ton/ha) was 22.8, 44.2, 36.4, 40.6, and 38.5, respectively. Suc rose content was 3.5%, 6.6%, 4.6%, 3.2%, and 4.0%, respectively. (C) 1999 P ublished by Elsevier Science Ltd. All rights reserved.