TOBACCO FLEA BEETLE MORTALITY FOLLOWING EXPOSURE TO IMIDACLOPRID TREATED LEAVES, 2012

As part of an ongoing project to monitor the potential for resistance development in TFB, we collected live, active TFB adults in a commercial tobacco field in Johnston County, NC that had been treated in the greenhouse with 0.9 fl oz per 1000 plants of a 2F imidacloprid formulation. TFB were transported to the laboratory and exposed to 60 mm tobacco leaf discs that had either been: dipped in a solution equivalent to the lowest foliar rate of Admire Pro (0.7 fl oz/acre); dipped in a solution equivalent to the highest foliar rate of Admire Pro (1.4 fl oz/acre); collected from a field grown plants that had been treated with 1.2 fl oz/ Admire Pro 1000 plants in the greenhouse 5 week prior; or excised from completely untreated leaves (UTC). Simulated foliar treatments were diluted in 1000 ml water, based on a 30 GPA application volume, and leaves were allowed to dry before TFB exposure. Greenhouse treated leaves and UTC leaves were used as is. Leaves were placed in 60 mm diameter Petri dishes lined with slightly damp filter paper. Ten (10) TFB adults were placed in each dish, and each treatment was replicated 6 to 10 times. Arenas were randomly arranged on a laboratory bench and held at 25°C and 12:12, L:D. Survivorship was assessed at 24 and 72 h after exposure, and the number of TFB feeding holes per leaf disc was counted at the end of the experiment. Data were analyzed via ANOVA using Proc Mixed (SAS v. 9.2.1; Cary, NC) with replicate as a random variable and treatment as a fixed variable. Means were separated via Fisher’s Protected LSD (α = 0.05).