Aphid Control on Blueberries, 2018

This experiment tested the efficacy of eight insecticides for controlling aphids in highbush blueberry. The treatments and rates were Assail 30SG (acetamiprid) at 5.3 oz/acre, Beleaf 50SG (flonicamid) at 4.3 oz/acre, Bifenture 10DF (bifenthrin) at 16 oz/acre, Closer SC (sulfoxaflor) at 5.75 fl oz/acre, Exirel 10SE (cyantraniliprole) at 20.5 fl oz/acre, Lannate LV (methomyl) at 1.5 pt/acre, Movento 240SC (spirotetramat) at 10 fl oz/acre (+ Dynamic 0.5% v:v), Sivanto (flupyradifurone) at 4.3 fl oz/acre, and an untreated control. Note: all insecticides were used at the recommended label rate for the crop, except for Sivanto that was used at a lower rate. The experiment was conducted in blueberry field cv. ‘Bluecrop’, a mid-season variety, located at the P.E. Marucci Blueberry/Cranberry Center in Chatsworth, New Jersey. Plots consisted of nine bushes (one bush per treatment), with treatments repeated on five plots in a CRB design, and separated by at least two buffer bushes and a buffer row. Applications were made with an R&D CO₂ backpack sprayer, using 2-liter plastic bottles. The sprayer was calibrated to deliver 40 gal of volume per acre at 30 psi, using a single ConeJet TXVS 10 nozzle, yielding 125.1 ml (4.23 fl oz) per bush. Treatments were applied on the morning of 17 Jun. Treated foliage (new-growth terminals with 3–4 leaves attached) was randomly sampled from each bush on days 1 and 3 after treatment (1 DAT, 3 DAT) on 18 Jun and 20 Jun, respectively. Zero precipitation was recorded during this period by an on-site weather station. Each terminal was inserted in a florists’ water pick, enclosed in a ventilated 40-dram plastic vial, and secured on Styrofoam trays. Five vials were set up for each treatment, with each vial considered a replicate. A single adult aphid and 5 nymphs were placed on the foliage in each vial within a few hours of the foliage being removed from the field. Aphids used in the trial were from a greenhouse colony reared on blueberries and established from individuals collected from an organic blueberry farm in Hammonton, New Jersey, on 24 May 2018. Assay vials were placed on a light bench in the laboratory at approximately 25°C, on a 15:9 (L:D) h cycle. Aphid numbers were assessed at 48 h after exposure to treated foliage, with the total number of live nymph and adult aphids recorded. Percent control was calculated for each treatment as % control = [1 − (avg total aphids on treated foliage/avg total aphids on control foliage)] × 100. Data were analyzed using ANOVA and means separation by Tukey tests at P = 0.05.

At 1 DAT, all insecticides, except for Exirel and Movento, significantly reduced number of aphids when compared with controls (Table 1). Beleaf, Closer, Lannate, and Sivanto reduced aphids by >65% when compared with controls. At 3 DAT, only Closer and Sivanto reduced number of aphids when compared with controls (Table 1). No phytoxicity symptoms were observed following any of the insecticide treatments.

Funding

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