Ferrisia gilli Control in Pistachio, 2015 *

This project evaluated the effectiveness of insecticides for Gill’s mealybug control in pistachio. The trial was conducted near Blackwell’s Corner, Kern Co., CA in a 0.5 acre portion of an orchard with tree spacing of 18 × 20 ft. On 2 July 2014, we surveyed ∼120 trees to determine the average number of mealybugs per cluster within each tree. Trees were assigned randomly to one of eight insecticide treatments or the untreated check in an RCB design with nine treatments and four blocks with blocking based on pretreatment mealybug densities. Treatments were applied to individual trees on 15 July 2014 using a hand gun at 150 psi with a water volume of 200 gpa with the surfactant Dyne-Amic at 4 fl oz/100 gal. Mealybug densities were evaluated in each plot on 30 July, 13 August and 27 August. On each sample date, we counted the total number of mealybugs in each of 20 random nut clusters per tree. Data were combined to determine the average number of mealybugs per nut cluster for each plot. Average mealybugs per cluster were analyzed by analysis of varianceusing transformed data (square root(x + 0.5)) with means separated by Fisher’s Protected LSD ( P  = 0.05).

Precounts were not significantly different compared with the untreated check at the start of the trial on 2 July. On 30 July, Assail, Movento, and Sequoia significantly reduced the mealybug density compared with the untreated check ( Table 1 ). On 13 August, Assail, Belay, Centaur, Movento, and Sequoia significantly reduced mealybug densities compared with the untreated check. Assail, Belay, Bexar, Centaur, Movento, and Sequoia resulted in significant reductions in mealybug density compared with the untreated check on 27 August. Pyrifluquinazon and Sivanto were not significantly different compared with the untreated check on any evaluation date.

Author notes