Effect of Planting Date and Date of Spray Initiation on Control of Peanut Leaf Spots in Florida. F. M. Shokes , Assistant Professor of Plant Pathology, Quincy Agricultural Research and Education Center, University of Florida-IFAS, Quincy 32351. D. W. Gorbet, Associate Professor of Agronomy, Marianna Agricultural Research Center, University of Florida-IFAS, Marianna 32446; and G. E. Sanden, Research and Development Field Representative, Rohm & Haas Co., Colby, KS 67701. Plant Dis. 66:574-575. Accepted for publication 28 September 1981. Copyright 1982 American Phytopathological Society. DOI: 10.1094/PD-66-574.

The earliest initiation (34 days after planting) of a peanut leaf spot spray program with chlorothalonil gave higher yields and less defoliation than seven progressively later initiation treatments in 3 yr of testing. Each 14-day delay in spray initiation resulted in more lesions than for the preceding beginning date when sampled 91, 105, and 119 days after planting. Late planting (21–23 May) resulted in a sixfold increase in the number of lesions per leaflet and a decrease in yield of 764 kg/ha compared with the early planting date (22–25 April).

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