Ampelomyces quisqualis, a new biofungicide to control powdery mildew in grapes

The use of high levels of pesticides to control powdery mildew disease increases dramatically the cost of grape production to viticulturists throughout the world. Although chemical fungicides are still able to provide adequate control of mildews in most growing regions, fungicide resistance and other concerns have heightened the interest of manufacturers to develop alternative methods of control to replace chemicals. Ecogen Inc., has developed one suck product, AQ10(TM) biofungicide based on the hyperparasitic fungus Ampelomyces quisqualis, or A.q., for the control of powdery mildew disease (Uncinula necator) in gapes among other crops. The product was recently registered and launched for commercial sale in the United States. A product has also been submitted for registration in the EU where it is expected for the 1997 season. A.q. is produced using large-scale fermentation and is formulated as a stable water dispersible granule (WDG) containing fungal spores as the active ingredient. Germinating spores form hyphae that are capable of attacking and penetrating the propagating hyphae of the host via a very specific host-parasite interaction. This process will eventually lead to suppression and/or complete elimination of the powdery mildew pathogen. Results obtained in wine producing regions throughout the world have shown that powdery mildew can be effectively controlled with A.q., if applied to vines at stages where disease incidence is very low and good coverage of the entire vine canopy is attained. The product has also been successfully used in integrated pest management (IPM) programs occurring during bud-break, between bloom and bunch closure and just prior to veraison. The results of representative efficacy trials are discussed.