Effects of an Abbreviated Pecan Disease Control Program on Pecan Scab Disease Increase and Crop Yield. T. R. Gottwald, Research Plant Pathologist, U.S. Department of Agriculture, ARS, 2120 Camden Road, Orlando, FL 32803. P. F. Bertrand, Extension Plant Pathologist, University of Georgia, P.O. Box 1209, Tifton, GA 31794.. Plant Dis. 72:27-32. Accepted for publication 8 July 1987. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1988. DOI: 10.1094/PD-72-0027.

Disease intensity of pecan scab on foliage fluctuated with cultivar and the prevalence of new growth, whereas disease intensity on fruit increased most during those periods when fruit expanded most rapidly. Cumulative fruit drop was independent of disease control strategy. The amount of drop associated with early-season disease was later offset by natural midseason and late-season fruit abortion. Yield and percentage of kernel associated with different abbreviated disease control strategies demonstrated that fungicide applications after the nut and nut shuck were fully expanded had little effect on end-of-season disease severity and no significant effect on crop yield or nut quality. End-of-season disease appeared to be largely cosmetic and not significant to crop value. This demonstrated the possibility for an abbreviated scab disease control program, depending on cultivar.

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