Control of grape berry moth with plinazolin technology in concord grape, 2023

This trial evaluated the effects of PLINAZOLIN® technology and an industry standard spray program against GBM 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. Plot size was 7 vines by 1 row; each row was 42 ft long with10 ft row spacing. There was one untreated row between each plot as a buffer. Plots were arranged in an RCB design with 4 replications. On 3 Aug, we visually inspected 50 grape clusters per plot for the presence of GBM infestation. Data were recorded as number of GBM infestations per 50 clusters. A single GBM infestation was defined as the presence of frass, webbing, or feeding wounds (Table 1). Means followed by the same letter do not significantly differ (P ≤ 0.05, Tukey’s HSD). aA = 14 Jul (Wild Grape Bloom + 910 GDD), B = 28 Jul (A + 14 days), C = 18 Aug (Wild Grape Bloom + 1620 GDD), D = 24 Aug (C + 7 days), E = 31 Aug (D + 7 days), F = 13 Sep (E + 14 days). bANOVA performed on log-transformed data; data presented are actual means. cANOVA performed on arcsine square root transformed data; data presented are actual means. An evaluation of fruit at harvest 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 affected berries per cluster and the percentage of the cluster damaged by GBM. Live GBM larvae within each cluster were also counted, and data were presented as mean GBM larvae per plot. ANOVA was performed on transformed data. Transformed treatment means were analyzed using ANOVA and means separation by Tukey’s HSD at P ≤ 0.05 (Table 1). Phytotoxicity was evaluated on 21 Jul and 4 Aug, and no phytotoxicity was observed. There were no significant differences in the number of GBM infestations on 3 Aug (Table 1). During harvest evaluations, all treatments significantly reduced the number of berries per cluster affected by GBM compared to the untreated check (Table 1). All of the PLINAZOLIN® technology SC200 treatments also significantly reduced the percentage of cluster damaged by GBM (Table 1). The PLINAZOLIN® technology SC200 3.08 oz treatment significantly reduced the number of live GBM at harvest.1