Testing contact and systemic insecticides against southern chinch bugs with a new bioassay

The southern chinch bug, Blissus insularis Barber, is a key pest of St. Augustinegrass that has repeatedly developed resistance to insecticides. Implementing a successful resistance management program requires evaluation of insecticide efficacy and response of B. insularis populations to insecticides. However, the conventional assay used is not effective for systemic insecticides. A new method that evaluates both the contact and systemic activity of insecticides against B. insularis was developed. The five insecticides tested included bifenthrin, carbaryl, clothianidin, imidacloprid, and trichlorfon. This new bioassay allows for easier observation of individual insects and reduces evaluation time. This assay also more closely predicts the in-field exposure to contact and systemic insecticides compared to previous assays, providing baseline information to monitor insecticide resistance development in B. insularis populations.