Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/3/2002
Publication Date: 9/9/2003
Citation: Osbrink, W.L., Lax, A.R. 2003. Effect of imidacloprid tree treatments on the occurrence of Formosan subterranean termites, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae), in independent monitors. Journal of Economic Entomology. 96:117-125. 2003. Interpretive Summary: The Formosan subterranean termite (Coptotermes formosanus Shiraki) is the most destructive termite where it occurs. Chemical control strategies have failed to protect structures from this termite, resulting in many millions of dollars of structural damage. Imidacloprid is a new generation, slow acting, non-repellent, insecticide registered for termite control. It has been suggested that because this insecticide is non-repellent, termites continue to contact the treatment and entire populations of termites are controlled in areas beyond the treatment. It is important that we know the actual performance of such treatments so we can use the appropriate strategies to protect valuable buildings. Formosan termite monitors near imidacloprid treated trees were established and regularly evaluated for almost 2 years to see if the treatments controlled termites in areas near the tree treatments. It was determined that Formosan termite populations were suppressed for about 6 months and then recovered. Subterranean termites cost Americans more than a billion dollars a year over most of the continental United States and Hawaii. Our discovery that Formosan termite populations recover in areas adjacent to treatment with this new generation, slow acting, non-repellent termiticide allows us to remain on guard after such treatments have been applied. Information allows us to understand the tools we have so we can integrate them into successful control strategies.
Technical Abstract: Periodic sampling of 87 independent monitors, initially active with Coptotermes formosanus Shiraki, was conducted. Monitors, located in eight sectors adjacent to 7 buildings, were various distances (1-46 m) from 57 trees treated with 0.1% imidacloprid foam. Termites collected from six of the eight sectors showed latent mortality attributed to imidacloprid intoxication at all monitor-tree distances. After approximately 6 mo post treatment, sampling showed recovery of the termite populations in these sectors. Another sector showed termite population suppression for approximately 15 mo, followed by recovery. Imidacloprid tree treatments did not control C. formosanus populations in independent monitors adjacent to the treatments.