Submitted to: Journal of Entomological Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/1/2006
Publication Date: 4/1/2006
Citation: Tillman, P.G. 2006. Effect of selected insecticides on the Leaffooted Bug (Hemiptera: Coreidae). Journal of Entomological Science. 41(2):184-186. Interpretive Summary: The feather-legged fly, Trichopoda pennipes, is one of the most successful natural enemies of the adults of southern green stink bug, Nezara viridula. Since the leaffooted bug, Leptoglossus phyllopus, is an alternative host of this natural enemy, killing leaffooted bugs could reduce the number of flies available to attack the stink bug pest. Therefore, the objective of this study was to determine the toxicity of Assail, Bidrin, Centric, and Vydate to leaffooted nymphs and adults. Residual toxicity experiments were conducted to determine the effect on leaffooted bugs when walking on residues of insecticides. In these tests, all the insecticides were highly toxic to young leaffooted nymphs. Residues of Bidrin were more toxic than residues the other three insecticides to adults. Oral toxicity experiments were conducted to determine the effect on leaffooted bugs when feeding on food contaminated with insecticide residues. In these tests, Vydate was non-toxic to leaffooted bug nymphs and adults. The other three insecticides were moderately toxic to young leaffooted nymphs. Bidrin was very toxic to adults feeding on insecticide-contaminated food. Centric was moderately toxic while Assail was non-toxic to leaffooted adults. Overall in both tests, Bidrin was the most toxic insecticide to leaffooted bugs.
Technical Abstract: The tachinid fly Trichopoda pennipes (F.) is one of the most successful parasitoids of the southern green stink bug, Nezara viridula. Disruptions of populations of the leaffooted bug, Leptoglossus phyllopus, an alternative host of the parasitoid, could have a negative impact on parasitoid populations. Therefore, the objective of this study was to determine the susceptibility of L. phyllopus 2nd instars, 4th instars, and adults to acetamiprid, dicrotophos, oxamyl, and thiamethoxam. In residual toxicity tests, all the insecticides were highly toxic to L. phyllopus 2nd instars. Residues of acetamiprid, dicrotophos, and oxamyl were highly toxic to 4th instars, but thiamethoxam was only slightly toxic to these immature leaffooted bugs. For adults, residues of dicrotophos were more toxic than residues of the other three insecticides. In oral toxicity tests, oxamyl was non-toxic to all developmental stages of L. phyllopus. The other three insecticides were moderately toxic to L. phyllopus 2nd instars. Dicrotophos was very toxic to adults feeding on insecticide-treated food. Thiamethoxam was moderately toxic while acetamiprid was non-toxic to L. phyllopus 4th instars and adults. Overall in both tests, dicrotophos was the most toxic insecticide to leaffooted bugs.