Characterization and Biological Action of Avermectin Granules on the Moroccan Locust, Dociostaurus maroccanus (Orthoptera: Acrididae).

Granules composed of alfalfa and sunflower meal that were impregnated with avermectins (AVMs) were developed for use against the Moroccan locust, Dociostaurus maroccanus (Thunberg). Laboratory experiments with granules containing 0.15% of AVMs fed to locust nymphs resulted in 100% death within 5 d. The quantification of AVM loss after exposure of AVM-containing preparative forms to UV light for various time periods was performed using high-performance liquid chromatography (HPLC). The results showed no loss of AVMs from the granules after 3 h of their exposure to UV light. The effect of UV radiation on a thin layer of the AVM solution led to the rapid degradation of AVMs. Only 0.2% of the initial AVM amount was detected after 3 h of exposure. In the granulated form, the AVM content remained stable for 10 mo when stored at room temperature in the dark. A method combining solid-phase extraction with HPLC was developed for the quantification of AVMs in locust nymphs. The granulated AVMs are characterized by their high resistance to UVB radiation. The use of plant-based granules impregnated with AVMs can be considered a very promising tool for locust control.