Determining a lethal and non-deterrent concentration range of the ecdysone agonist, halofenozide, alone and in combination with the chitin synthesis inhibitor, noviflumeron, against the Formosan subterranean termite

Insect growth regulators (IGRs) are a group of insecticides that mimic the action of insect hormones and cause mortality by disrupting development in some way.  Termite baiting involves the use of monitoring stations which can be treated with a chitin synthesis inhibitor IGR, such as noviflumuron.  Baiting systems can result in the elimination of entire colonies, but the process can require up to a year.  The insect molting hormone, 20-hydroxyecdysone (20E), and the ecdysone agonist, halofenozide, have unique termiticidal properties that could allow for more rapid colony elimination.  The purpose of this study was to determine a lethal and non-repellent concentration range of halofenozide and 20E, alone and in combination with noviflumuron, for use against the Formosan subterranean termite, Coptotermes formosanus Shiraki. Groups of termites were placed into Petri dishes containing two half-circles of media pad.  One half was treated with a termiticide and Nile blue A dye, and the other with only methanol.  Feeding deterrence was evidenced by termites that did not turn blue, and the lethal time to 50 percent mortality was determined over the course of 30 days for each treatment combination.  Preliminary findings showed that halofenozide was not an effective compound for inducing termite mortality.  Termites treated with 20E, alone and in combination with noviflumuron, exhibited mortality in fewer days than termites exposed to only noviflumuron.  The results of this study will be used in future research to develop a new active ingredient for use in termite baiting systems.