Influence of Scab on Late Season Nut Drop of Pecans. R. E. Hunter, Research Plant Pathologist, Agricultural Research Service, U.S. Department of Agriculture, Brownwood, TX 76801. W. R. Poage Pecan Field Station, Agricultural Research Service, U.S. Department of Agriculture, Brownwood, TX 76801. Plant Dis. 67:806-807. Accepted for publication 31 December 1982. 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, 1983. DOI: 10.1094/PD-67-806.

Pecans (Carya illinoensis ‘Western’) were graded for scab (Cladosporium caryigenum) on a scale of 1–5 (1 = no scab, 5 = more than 50% of shuck surface infected). Nut drop between 3 August and 20 October 1981 was directly related to scab grades (coefficient of determination of 0.999). Values on this regression line successfully calculated the total percentage of nut drop for sprayed and unsprayed Western trees in plots in 1979 for which scab grades and total nut counts were available. Thus, the relationship between the percentages of late season loss of nuts and scab grades is a general relationship that should be valid every year.

Keyword(s): disease losses, Fusicladium effusum.