Observations on colony collapse in Reticulitermes flavipes (Kollar) in laboratory and field settings in Wisconsin
F Green III, R A Arango, G R Esenther
Parallel strategies were designed to eliminate Reticulitermes flavipes (Kollar) from a field site in Endeavor, Wisconsin and a simulated field test setup of approximately 20,000 workers in the laboratory. Indoor and outdoor colonies of R. flavipes were baited with commercial cellulose monitoring stations and rolled cardboard stations. If the commercial cellulose baits were attacked, they were replaced with termidicidal baits containing 0.25% diflubenzuron (a chitin synthase inhibitor). In active cardboard stations, termites were dusted with N’N-naphthaloylhydroxylamine (NHA) and released back into the colony. Overtime, diflubenzuron gradually suppressed worker activity and termite numbers both in the laboratory and the field. However, sharp reductions (>90%) in foraging workers were observed in both field and laboratory colonies with the addition of dusting with NHA. Termidicidal baits containing 0.5% hexaflumeron were secondarily evaluated in the field as a comparison to diflubenzuron. Observations indicated five notable characteristics or criteria of a colony on the verge collapse in one or both venues: i) increasing soldier to worker ratios >20% in the lab, ii) decreasing overall counts of workers collected, iii) increasing numbers of secondary reproductives captured in hexaflumeron bait cartridges outdoors, iv) increasing susceptibility to mites, and v) higher microbial load including bacteria, fungi and slime molds within the colony. Shortly after these events occur—foraging workers disappeared from both commercial and cardboard stations and the colony was essentially eliminated. Although laboratory results do not exactly mirror field results, observations regarding colony decline in both venues are significant when attempting termite control. We conclude that combinations of termite toxicants are more effective than either one alone, and that the above observations may be used as an indicator of sucessful termite treatment.