Control of grape berry moth and Japanese beetle in concord grape, 2023

This trial evaluated different insecticides used individually or in programs against GBM and JB in grapes. Insecticides were applied to 43-yr-old ‘Concord’ grape vines (Vineyard 1) at the Trevor Nichols Research Center in Fennville, MI, with a tractor-mounted FMC 1029 airblast sprayer calibrated to deliver 50 gpa at 2.5 mph. Plots consisted of one 42-ft long row of 7 vines, with 10-ft row spacing. There was one untreated row between each plot as a buffer. Plots were arranged in a RCB design with four replications.

On 3 Aug, 50 grape clusters per plot were evaluated in the field for the presence of GBM or GMB-induced damage, such as webbing, frass, or feeding wounds. The number of GBM infestations per 50 clusters was recorded (Table 1). On 4 Aug, each plot was evaluated for adult JB using a 2-min timed search on each side of each plot.

A harvest evaluation was conducted on 25 Sept by harvesting 50 clusters per plot, counting the total number of berries in each cluster, and determining the number of berries affected by larval infestations. Data are presented as the mean number of damaged berries per cluster, and the mean percentage of cluster damaged by GBM. The total number of live GBM larvae per 50 clusters was also counted, and data were presented as mean GBM larvae per plot. ANOVA was performed on log transformed data. Transformed treatment means were analyzed using ANOVA and means were separated using Tukey’s HSD at P ≤ 0.05.

There were no significant differences in GBM during the 3 Aug evaluation (Table 1). On 4 Aug, Shenzi significantly reduced the incidence of JB compared to the untreated check. At harvest, only the Verdepryn/Intrepid/Altacor/Delegate/Leverage program significantly reduced the number of berries affected by GBM (Table 2). This same program also resulted in the lowest percentage of infested clusters, and lowest number of live worms per plot, though these reductions were not significantly different than the untreated check.¹

Footnotes