Efficacy of Nets Coated with Different Concentrations of Alpha-Cypermethrin against Two Major Pests of Stored Tobacco

Abstract

In the present study, we examined the insecticidal effect of Carifend® (BASF AG, Ludwigshafen, Germany; 163.2 mg m−2), an alpha-cypermethrin-coated polyester net, as well as Carifend-like nets containing different rates of alpha-cypermethrin, specifically 10, 30, 80, and 325 mg m−2, against two major stored tobacco insect pests, i.e., Lasioderma serricorne (Fabricius) (Coleoptera: Anobiidae) and Ephestia elutella (Hübner) (Lepidoptera: Pyralidae). The nets were glued at the bottom of plastic Petri dishes, and adults of L. serricorne and E. elutella were exposed to the nets for different exposure times (e.g., 1, 5, 15, 30, 60, 90, and 120 min, as well as 12 and 24 h). After each exposure interval, insect mortality was recorded, whereas after the final evaluation, alive individuals were transferred to untreated dishes, and delayed mortality was recorded after an additional period of 1, 3, 5, and 7 d. Based on our results, efficient control of both insect species was achieved with all nets, even the one containing a lower concentration of alpha-cypermethrin (10 mg m−2). High mortality rates were recorded for all treatments, indicating that even short exposure of adults of both tested species to the alpha-cypermethrin-coated nets tested can lead to mortality. For instance, at 30 mg m−2, mortality of E. elutella reached 40% 1 d after exposure for 30 min. Moreover, at the highest concentration (325 mg m−2), mortality reached 70% and 99% 7 d post exposure for 24 h of L. serricorne and E. elutella, respectively. Based on these data, Carifend®, as well as the rest of the Carifend-like nets tested, can be used as an alternative insecticide method for the control of two major stored tobacco insect species, i.e., L. serricorne and E. elutella. Insecticide treated nets can be used in areas in which fumigants and contact insecticides are not accessible.