Insecticidal Control of Green Peach Aphid on Pansies, 2020

The purpose of this study was to determine the efficacy of Pradia (Cyclaniliprole & Flonicamid) and KleenGrow (Didecyl dimethyl ammonium chloride) for control of green peach aphids on pansies grown under caged greenhouse conditions. The trial was conducted between 12 Jun 2020 and 10 Jul 2020 in the IPM greenhouse at the AgriLife Research & Extension Center in Overton, TX. Eight aphids (4th instar to adults) were introduced to each plant using a fine brush on 29 May 2020. On 12 Jun 2020, pansy plants were divided into seven replications of each treatment and arranged in a CRD (Table 1). A single replicate constituted one pansy plant in a 4-inch pot placed inside a 47.5 × 47.5 × 47.5-cm netted observation cage (44545F, BugDorm). Temperature and humidity in the greenhouse were recorded using a Hobo Logger (U23, HOBOWARE). All foliar sprays were applied with an R&D CO₂ sprayer (Model D-203S) fitted with a 601FA single nozzle spray boom (Bellspray, Inc.) for even coverage and drenches were applied as 125 ml of formulated treatment per pot (Table 1). Assessment of aphid quantities consisted of a 60-second count (all life stages together) per plant and phytotoxicity ratings (0–10) at 0, 3, 7, and 14 DAT. Whole model treatments were compared using a generalized linear mixed model with treatment and DAT as fixed interacting factors and plant ID as random factor (P < 0.05), and Dunnett’s post hoc test with water check as the control group for each DAT. Aphid quantities were assessed at 0, 3, 7, and 14 DAT. Aphid densities caused the quality of several untreated control plants to decline, and a secondary infestation of thrips and spider mites caused a severe decline in plant quality in the treatment replications. Therefore, no aphid counts were conducted by 28 DAT.

All rates and methods of Pradia significantly reduced mean aphids by 3 DAT (Table 2) compared to the untreated check. Two of the Pradia treatments, the foliar and one drench, had 0 aphids on pansies by 7 DAT. By 14 DAT, all Pradia treatments had 100% suppression of aphids on the pansies (Table 2). KleenGrow had significantly fewer aphids than the untreated control by 3 DAT (Table 2), but it did not completely suppress the aphids for the duration of the trial. No signs of phytotoxicity were observed in any of the Pradia or KleenGrow treatments for the duration of the trial.¹

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