Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/9/2004
Publication Date: 12/20/2004
Citation: Rojas, M.G., Morales Ramos, J.A. 2004. Effects of 3 chitin synthesis inhibitors on egg viability and survival of coptotermes formosanus, (isoptera: rhinotermitidae) incipient reproductive adults. Annals of the Entomological Society of America. Interpretive Summary: The Formosan subterranean termite (FST) (Coptotermes formosanus) is an imported pest in the USA. This insect is causing extensive damage to houses and trees in the Greater New Orleans area and 14 other US states with annual losses in the millions of dollars. Baits are one of the most effective methods to control subterranean termites. Most of the commercially available bait systems in the US use chemicals that inhibit the synthesis of chitin as means to kill the termites. Chitin is the main component of insect skeleton and it is essential for termite growth and development. Three groups of 56 termites each were fed with a matrix containing 10 ppm of each of the CSI. Results showed that all 3 CSI's tested affected the hatching capability of the Formosan subterranean termite eggs. Long term exposure to these chemicals induces mortality of the adult reproductive termites. The effects of CSI's have not been previously reported on subterranean termites in the US. This information increases our present understanding about the mode of action of CSI's and this may enable us to optimize their use to control better this and other urban pests.
Technical Abstract: Effects of the chitin synthesis inhibitors (CSI), hexaflumuron, diflubenzuron, and lufenuron, on Coptotermes formosanus Shiraki reproductives were studied in the laboratory. Incipient colonies were established by collecting and pairing C. formosanus alates and placing them in dishes containing an artificial diet. Three groups of 56 termites each were fed with a matrix containing 10 ppm of each of the CSI. They were compared to a control group fed with no chemicals. All the eggs oviposited by treated young queens failed to hatch at the end of 6 months. Queen fecundity estimated by a graphic integration method was significantly lower in the diflubenzuron and lufenuron treatments compared to the control group. Adult mortality was significantly higher in these 2 treatments at the end of 6 months. All the pairs died within 8 months in the diflubenzuron and lufenuron treatments although treatment was suspended at the end of 6 months. Mortality in the hexaflumuron treatment was significantly higher than in the control group by the end of 9 months. The 3 CSI tested eliminated reproduction in C. formosanus by preventing egg hatching and produced adult mortality. This is the first detailed report on the effects of these CSI's on Formosan subterranean termite in the US. Possible mechanisms by which CSI induce termite adult death are discussed.