Effect of In-Furrow and Early-Season Banded Applications of Fungicides on Incidence of Early Leaf Spot of Peanut

• DOI: 10.1094/php-rs-15-0029
• Publication Date: 2018-07-27T17:28:21Z
• Authors: Albert K. Culbreath; Robert C. Kemerait; Yun-Ching Tsai; Timothy B. Brenneman; Katherine L. Stev...; Emily G. Cantonwine
• Keywords: 2. Zero hunger; 0106 biological sciences; 01 natural sciences

Field experiments were conducted in Tifton, GA, in 2012-2014 to determine the effect of in-furrow applications of prothioconazole and early-season banded applications of prothioconazole or pyraclostrobin on incidence of early leaf spot (Cercospora arachidicola) of peanut (Arachis hypogaea). In each year, border rows were planted in May as a source of inoculum for plants in the treatment plots. Plots were planted in August or September after epidemics of early leaf spot were severe in the border plots. Fungicide application regimes included two rates (100 and 200 g a.i./ha) of prothioconazole applied in-furrow at planting, and 200 g a.i./ha of prothioconazole or 164 g a.i./ha of pyraclostrobin applied concentrated in a 30-cm band 21 days after planting (DAP). Incidence (percent of leaflets with one or more leaf spot) of early leaf spot was monitored until 54 to 57 days after planting in each year. In all years, disease incidence was below 10% at 28 DAP in plots treated with 200 g a.i./ha of prothioconazole in-furrow compared to over 40% in nontreated plots at the same time. In-furrow applications of 100 g a.i./ha of prothioconazole were less effective, but suppressed leaf spot incidence compared to the control. Banded applications of either fungicide at 21 DAP resulted in a decrease in leaf spot incidence, and prevented increase in leaf spot incidence for 19 days or longer. Accepted for publication 30 November 2015. Published 3 December 2015.