Evaluation of OMRI and Reduced-Risk Insecticides for Control of Eggplant Flea Beetle in Eggplant, 2019

The objective of this experiment was to assess the efficacy of various OMRI and reduced-risk insecticides for control of EFB on eggplant in a central West Virginia field environment. Nine-wk-old ‘Calliope’ eggplant was transplanted on 4 Jun at a privately owned farm in Clay County, WV. The experiment consisted of six treatments arranged in an RCB design with four replicates. Plots consisted of single rows containing 10 plants spaced 46 cm apart with 0.9 m between rows and 0.9 m between treatments. Treatments included BoteGHA ES (11.3% solution of Beauveria bassiana Strain GHA; 2 × 10¹³ viable spores/quart) at 1 qt/acre, Entrust SC (spinosad) at 3 oz/acre, Neemix 4.5 (Azadirachtin) at 16 oz/acre, Pyganic EC 5.0 (pyrethrins) at 17 oz/acre, Verimark SC (Cyantraniliprole) at 13.5 fl oz/acre, and an untreated check. Verimark was applied as a transplant tray drench 3 d before transplanting eggplant into the field. All other insecticide treatments were applied as foliar sprays at approximately weekly intervals on 15, 22, and 29 Jun, and 6, 11, and 22 Jul using a CO₂ pressurized backpack sprayer calibrated to deliver 57 GPA at 30 psi through a single TeeJet 8002VS flat fan nozzle. Sampling was conducted prior to application of foliar-applied insecticides. The number of EFB on six plants from the center of each plot was recorded. Leaf feeding injury was also assessed from all plants in each plot using the following percent defoliation scale: 1 = no defoliation; 2 = 1–20% defoliation; 3 = 21–40% defoliation; 4 = 41–60% defoliation; and 5 = >61% defoliation. All data were analyzed using ANOVA, and means were separated using Fisher’s LSD test (P ≤ 0.05).

EFB pressure was moderately high, resulting in more than 50% defoliation injury in some plots. Although yields were not recorded, there were no observable differences in plant growth and fruit set among treatments. On 11 and 22 Jul, there were significant effects of treatment on numbers of EFB per six plants (Table 1). However, none of the insecticide treatments provided a significant reduction in EFB numbers compared with the untreated check. On 29 Jun, and 6 and 11 Jul, there were significant effects of treatment on defoliation ratings (Table 2). Verimark applied as a transplant tray drench had consistently lower incidences of defoliation injury than all other treatments.

This research was partially supported by industry gifts of products and research funding.