Control of Grape Berry Moth in Concord Grape, 2020

Grape berry moth (GBM) larvae feed on grapes by burrowing into the fruit and making the grapes susceptible to diseases and attracting secondary insect pests. This trial evaluated month-long management programs containing three insecticide applications in a 20-yr-old ‘Concord’ grape vineyard at the Trevor Nichols Research Center near Fennville, MI. Applications began on 13 Aug at 1620 GDD after wild grape bloom to coincide with third-generation GBM egg laying. A MSU Enviorweather predictive model was used to determine the number of GDD using local wild grape bloom as the biofix date. Applications were made with a tractor-mounted FMC 1029 airblast sprayer calibrated to deliver 50 GPA at 2.5 mph. Plots consisted of two 42 ft-long rows of vines spaced at 6 × 10 ft arranged in an RCB design with four replications.

Fruit evaluations were made prior to treatment on 4 Aug and again on 2 Sep, 13 Sep, and 5 Oct. Fruit evaluations were conducted by counting the number of GBM larval infestations per cluster, number of damaged berries, and number of total fruit in each of 10 clusters per plot. Data of the GBM larval infestations per cluster, number of damaged berries per cluster, and percentage of damaged berries were analyzed by ANOVA with means separated by Tukey’s HSD at P = 0.05 after square root transformation of percentages.

The three-spray program, including Intrepid, Verdepryn, and Leverage significantly reduced the GBM larval infestations and number of damaged berries on 2 Sep, and number and percentage of damage berries on 5 Oct (Tables 1–3) compared to the untreated check (Tables 1–3).¹

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