Foliar fungicide efficacy on frogeye leaf spot in maturity group IV soybeans, 2016

摘要

A trial was conducted in a silt loam field at Rohwer Research Station near Rohwer, AR, and arranged in a randomized complete block design. The trial contained 12 fungicide treatments in 4 replications. A frogeye leaf spot (FLS) susceptible soybean cultivar 'Amour DK4744' was planted 9 May on 38 in. row spacing and divided into 4-row plots 20-ft long. The center two rows of each plot were sprayed when soybeans reached beginning seed (R5) growth stage. Disease was rated at 3% severity at R5 on 26 Jul,and treatments were applied using a MudMaster (Bowman Manufacturing, Newport, AR) sprayer with a compressed air driven custom multi boom (R&D Sprayers, Opelousas, LA) with 19 in. nozzle spacing. Fungicides were applied at 10 gal/A using Teejet 11002VS tips at 4 mph. Disease ratings were based on percent of disease coverage in the upper one third of the canopy and were taken at application and 8 days post application (DPA). The center two rows were harvested 20 Sep with a plot combine at an average moisture content of 11%. Yield was calculated based on 13% moisture content. Data were subjected to ANOVA followed by means separation of fixed effects using Fisher's protected least significant difference (LSD) P=0.10.