Efficacy of Foliar Insecticides Against Green Stink Bug and Green Cloverworm in Soybean, 2020

The objective of this trial was to evaluate the efficacy of different insecticides against green stink bug (GSB) and green cloverworm (GCW) in soybean. Asgrow 47X8 soybean was planted on 1 Jun in a farmers’ field in Fairfax, Oklahoma. The first GSB were found in mid-Aug. The plots measured 10 ft × 30 ft planted on 30-inch rows. The plots were arranged in an RCB design with four replications. The pretreatment counts consisting of 15 sweeps per plot were recorded on 25 Aug by counting the number of live GSB (nymphs and adults) and GCW. The mean number of total GSB was 3.2 and mean number of GCW was 13.7, respectively. Treatments were applied on 25 Aug through broadcast spray delivered at 20 gpa using a CO₂ handheld sprayer equipped with Tee Jet AIXR110025 flat fan nozzles mounted on a 6 ft. boom at 50 psi. Posttreatment counts were taken at 9, 14, 21, and 30 DAT in each plot for GSB and 9 and 14 DAT for GCW. Data were analyzed with ANOVA and the means separated with Fisher’s Protected LSD (P ≤ 0.05). Percent control (% reduction of insect number compared to untreated) for any sampling date was calculated as: [untreated count – treated count) / untreated count) * 100.

All of the insecticide treatments reduced GSB compared to the untreated check on all sampling dates (Table 1). GCW numbers had declined in the untreated plots by 14 DAT, and no significant differences among treatments were observed at 9 or 14 DAT (Table 2). Consequently, no more samples were taken for GCW after 14 DAT.¹

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