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Disease Control and Pest Management

Effect of Benomyl Field Sprays on Internally-Borne Fungi, Germination, and Emergence of Late-Harvested Soybean Seeds. M. A. Ellis, Graduate Research Assistant, Department of Plant Pathology, University of Illinois, Urbana 61801; J. B. Sinclair, Professor, Department of Plant Pathology, University of Illinois, Urbana 61801. Phytopathology 66:680-682. Accepted for publication 11 November 1975. DOI: 10.1094/Phyto-66-680.

Soybean (Glycine max ‘Beeson’) plants were sprayed with 50, 100, 500, 1,000, or 5,000 µg/ml solutions of benomyl four times at 2-week intervals beginning 55 days after planting. Half the seeds were harvested at maturity (first harvest) and the other half 30 days later (late harvest). Seeds from sprayed plants from the late harvest had fewer seed-borne fungi, including Diaporthe phaseolorum var. sojae (Phomopsis sp.), higher germination in vitro, and greater field emergence than those from nonsprayed plants. Seeds from sprayed and nonsprayed plants from the first harvest had no significant difference in in vitro germination, field emergence, and occurrence of D. phaseolorum var. sojae, Alternaria spp., and Fusarium spp. Fungicide (methyl 2-benzimidazolecarbamate) activity was detected by bioassay approximately 6 months, after the first harvest, in seeds from plants sprayed with 500, 1,000, and 5,000 µg/ml benomyl and in seeds from late-harvested plants sprayed with 1,000 and 5,000 µg/ml benomyl.