The biofungicide AQ10 can be used to eliminate and/or reduce applications of sulfur and DMI fungicides such as Rally (myclobutanil) and Rubigan (fenarimol). Registered by Ecogen, Inc., AQ10 parasitizes powdery mildew and can, when applied properly, provide good control at several stages during the season. University of California researcher Dr. Doug Gubler has been working with AQ10 for over five years, learning much about the unique challenges encountered in the field when introducing such a biopesticide.

Research shows that AQ10 can be used as long as disease incidence does not exceed a threshold of 3% on leaves and clusters. At higher levels of pressure, AQ10 must be applied in rotation with sulfur or other products to assure acceptable control.

Good spray coverage is critical to success. High pressure and high volume air carrier sprayers tend to do the best job.

Ongoing research is focused on refinement of a powdery mildew risk assessment model driven by weather data which growers can use to determine when an application might be needed.

Further information on AQ10 can be obtained from Ecogen, Inc (2005 Cabot Boulevard West, PO Box 3023 Langhorne, Pennsylvania, 19047-3023; Phone: 215-757-1590, Fax: 215-757-2956), and an article entitled "Controlling Factor" in the April, 1997 California Farmer (page 28-34).