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An isolate of Ampelomyces quisqualis obtained from a Oidium sp. infecting Catha edulis in Israel, proved to be infective to several powdery mildew fungi belonging to the genera Oidium, Erysiphe, Sphaerotheca, Podosphaera, Uncinula, and Leueillula. In field trials, A. quisqualis parasitized the powdery mildews of cucumber, carrot and mango and reduced the disease. Hyperparasitism on Oidium mangiferae is reported for the first time. A. quisqualis was tolerant to many fungicides currently used to control powdery mildews and/or other plant diseases. In one experiment, treating powdery mildew of cucumber (cv. Hazera 205) with spores of A. quisqualis alone, significantly decreased disease severity and increased cucumber yields by approximately 50 %. However, a greater increase in yield was obtained by using the fungicide pyrazophos alone or in combination with the hyperparasite. In a second experiment, using cv. Dalila, all treatments increased the yield over the untreated control which did not produce fruits.

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Two hundred strains of the Aspergillus flavus group isolated from groundnuts (peanuts) growing in Israel were examined for their ability to produce mycotoxins in potato dextrose (PD) broth. Almost 77% of the isolates produced aflatoxin; aflatoxins B1 and B2 were formed by most of the isolates. Simultaneous production of aflatoxins of groups B and G was detected in only 0.5% of the isolates. Microscopic examination revealed that 98% of the isolates were A. flavus and only 2% A. parasiticus. Cyclopiazonic acid (CPA) was detected in 22.5% of the isolates, including 3.5% that produced only CPA. Sterigmatocystin was detected in only 2% of the isolates and only one isolate produced aflatoxin simultaneously with CPA and sterigmatocystin. The dry weight (DW) of mycelium, 7 days after inoculating the medium, was between 71-110 mg/30 ml medium in more than 70% of the isolates. A general decrease in the pH was observed and 75% of the isolates reduced the pH to 4.5 or below. After 14 days, a small increase in DW and an increase in the pH toward neutrality was observed. On PD agar, 30% of the isolates produced sclerotia, including 5% that produced them profusely. No correlation between mycelial growth, changes in pH of the medium, sclerotium formation, and aflatoxin accumulation could be observed. The mycotoxigenic potential of the A. flavus strains isolated from groundnuts seems to be relatively high and may present a potential threat to human and animal health.