Management of subterranean termites, Reticulitermes spp. (Isoptera : Rhinotermitidae) in a citrus orchard with hexaflumuron bait

The eastern subterranean termite, Reticulitermes flavipes (Kollar) is a pes t of young citrus in Florida, killing trees by girdling at or just below th e soil line. Reticulitermes virginicus (Banks), another inhabitant of citru s groves, may cause similar damage. Chemical and cultural methods developed previously to create barriers to termites around young citrus trees provid ed temporary or incomplete control. However, baiting systems may provide lo nger lasting control by eliminating or at least reducing termite activity. Triple mark-recapture with Nile blue dye was used to delineate foraging ran ges and to estimate populations sizes of two R. flavipes and one R. virgini cus colony located in two different blocks of a south Florida citrus grove. This dye has been observed to be detectable from 6 to 9 months after inges tion by subterranean termites, and not to be transferred between individual s by tropholaxis (Su, unpublished data). Termite activity was monitored by counting workers and estimating wood consumption at buried monitoring stati ons. Termites were recruited to bait stations initially containing spruce w ood which was then replaced with 0.1 or 0.5% hexaflumuron in either a parti culate (wood flour) or non-particulate (paper) cellulose matrix and consump tion was monitored. After a 2-3 month baiting period, no new termite activi ty was detected within the areas of baited R. flavipes. Similar amounts of toxicant were consumed per termite in all cases. No subsequent tree injury was observed within the areas of the baited colonies. Baiting with hexaflum uron appears to be a viable alternative for managing subterranean termites in citrus and possibly other agricultural systems. (C) 2001 Published by El sevier Science Ltd.