Toxicity, repellency, and effects of acetamiprid on western subterranean termite (Isoptera: Rhinotermitidae)

The insecticidial and biological activity of the cyano-substituted neonicotinoid acetamiprid was determined against the western subterranean termite, Reticulitermes hesperus Banks (Isoptera: Rhinotermitidae). Acetamiprid was very active against termites ill topical applications, with all LD50 = 0.02 ng per termite. Even though acetamiprid was extremely toxic ill topical applications, deposits >= 50 ppm oil sand were required to consistently provide >90% kill of termites within 7 d after a 1-h exposure. Termites were quickly affected by brief exposures to sand treated with 1 ppm acetamiprid and within 1 h, their locomotion was dramatically impaired. Acetamiprid was transferred front donors to recipients only when donors were held oil deposits >= 50 ppm for 1 h. Deposits even as low its 1 ppm were repellent and termites failed to tunnel into treated sand, and there was no significant mortality. Exposure to acetamiprid impaired locomotion of termites as did other slow-acting neonicotinoids, such as imidacloprid. Acetamiprid was repellent at all concentrations tested, acting like type I pyrethroid treatments ill soil. A new subcategory of type III soil termiticides is proposed-that incorporates the sublethal and delayed effects observed ill neonicotinoid insecticides, and repellency at certain concentrations.