Blunt-Nosed Leafhopper Control in Cranberries, 2014 Open Access

This experiment tested the efficacy of Exirel 10SE, Voliam Flexi, two rates of Closer SC, three rates of Lorsban 4E, and two bifenture products: Brigade 2EC and Fanfare 2EC for controlling blunt-nosed leafhoppers in cranberries. The treatments and rates were Exirel 10SE at 13.5 fl oz/acre, Voliam Flexi at 4.25 oz/acre, Closer SC at 2.5 and 4.25 fl oz/acre, Lorsban 4E at 0.75, 1.5, and 3.0 pt/acre, and Brigade 2EC and Fanfare 2EC at 6.4 fl oz/acre. The experiment was conducted in an ‘Early Black’ cranberry bed located at the Rutgers PE Marucci Center in Chatsworth, New Jersey. Plots were 122 × 122 cm each, replicated four times in a CRB design. Control plots received no insecticide. Applications were made with an R&D CO₂ backpack sprayer, using a 1-liter plastic bottle. The sprayer was calibrated to deliver 50 gal of vol per acre at 30 psi, using a single Teejet vs 110015 nozzle, yielding 69.5 ml per plot. Treatments were applied in the morning on 6 Jun 2014. Treated uprights were randomly selected from the central portion of each plot and clipped for use in a laboratory assay on 0 and 6 DAT. Sampling dates were 6 and 12 Jun 2014, respectively. A buffer zone of 30 cm from plot edges was not sampled. Three to four insecticide-treated uprights were inserted in florists’ water picks, enclosed in a ventilated 40-dram plastic vial, and secured on Styrofoam trays. Ten vials were set up for each treatment on 0 and 6 DAT with 5–6 leafhoppers placed in each vial; each vial was considered a replicate. All leafhoppers used in the trial were collected using a sweepnet on 6 and 12 Jun from a commercial cranberry bog in Chatsworth, New Jersey, and used on the same day of collection. Collected leafhoppers were a mixture of late-instar nymphs and young adults. Plants and insects were placed on a light bench in the laboratory at approximately 25°C, on a 15:9 (L:D) h cycle. Mortality was assessed at 3 and 6 days after exposure to treated foliage (72 and 144 h, respectively). Number of leafhoppers (alive or dead) was recorded and percent mortality was calculated. Data were analyzed using ANOVA and means separation by Tukey test at P = 0.05. Percent data were arcsine square-root transformed prior to analysis.

All treatments, except for Exirel 10SE, increased mortality of leafhoppers compared to controls 0 and 6 DAT (Table 1). The most effective insecticides were Lorsban at 1.5 and 3 pts/acre, Voliam Flexi, Closer SC at 4.25 fl oz/acre, and the two bifenture products. No phytoxicity symptoms were observed following any of the insecticide treatments.

This research was supported by industry gifts of pesticide and/or research funding.