Blackmargined Aphid Control, 2013 *

Efficacy of several insecticides was evaluated for BMA control. This study was conducted in a commercial pecan orchard near Fabens, TX. A single pecan tree constituted an experimental unit. Each experimental unit was bordered by untreated pecan trees as buffers to help reduce potential drift contamination. Experimental units were arranged in a RCBD with 10 treatments replicated four times. Insecticide or water applications were made using a high-pressure sprayer calibrated to deliver 100 gpa at 100 psi. From each experimental unit, three randomly selected compound leaves were examined for BMA. Alate and apterous aphids found were counted separately and recorded. Treatments were applied on 11 October after pretreatment samples had been collected. Posttreatment samples were taken 10 and 25 DAT. Mean alate and mean apterous aphid densities were subjected to analysis of variance. Treatment mean separation was performed using Fisher's Protected LSD ( P  = 0.05).

Although total BMA densities were moderately high, they never exceeded economically damaging population densities (25 BMA/3 compound leaves) throughout the duration of this test ( Table 1 ). Prior to treatment application, BMA alate and apterous population densities were statistically equal among untreated check and treated trees. At 10 DAT the Endigo, Water, Voliam Xpress, Fulfill, and Beleaf treatments significantly reduced BMA alate population density. All treatments except Agri-Flex and Admire Pro significantly reduced BMA apterous population densities at 10 DAT. At 25 DAT only the Beleaf-treated trees had significantly lower BMA alate population densities relative to the untreated check trees and BMA apterous populations were not significantly lower in any of the treated trees relative to the untreated check. Interestingly, the Induce and Agri-Flex-treated trees had significantly higher apterous BMA population densities relative to the untreated check trees at 25 DAT. Phytotoxicity was not observed during the course of this study.

Author notes