
New Money-Saving Strategies for Controlling Pecan Scab By Tara Weaver August
12, 1998Pecan growers could save as much as $18 an acre in pecan scab control costs
and cut chemical use by eliminating or delaying the typical first spray,
according to Agricultural Research Servicescientists. Current scab control strategies often require nine to 11 fungicide sprays
per season. Growers typically begin spraying as leaves emerge from swelling
buds around the first or second week in April. ARS scientists found that these
newly emerging leaves are not vulnerable to scab; foliage only becomes
susceptible after the leaves have grown for about 10 to 14 days. Pecan scab, caused by the fungus Cladosporium caryigenum, is
generally the most damaging pecan disease. It causes lesions to appear on
leaves as small, concentric circles, charcoal gray to black in color. Severe
infection causes defoliation, fruit abortions and smaller, poorly filled fruit,
reducing crop yields. It is active throughout the growing season, and if
unchecked, can cause near total crop losses. The disease is particularly troublesome for commercial pecan
varieties--Desirable, Schley, and Stuart--grown in the Carolinas, Georgia,
Alabama, Florida, Mississippi, Louisiana and east Texas, where the climate is
generally moist. Overall, the disease costs pecan growers at least $22 million
each year in losses and control costs. Detailed information on this research appears in the August issue of Agricultural
Research magazine. The story is also on the World Wide Web at: http://www.ars.usda.gov/is/AR/archive/aug98/scab0898.htm Scientific Contact: Bruce W. Wood and Charles C. Reilly, USDA-ARS
Southeastern
Fruit and Tree Nut Research Laboratory, P.O. Box 87, Byron, Ga. Phone
(912) 956-6420, fax (912) 956-2929, [email protected],
[email protected]. U.S. Department of Agriculture | |