Influence of a Mineral Insecticide Particle Size on Bait Efficacy

We examined the efficacy of termiticidal baits comprised of powdered acellulose and a mineral insecticide, cryolite crystals, in laboratory bioassays against pseudergates ofEastern subterranean termites [Reticulitemzesjavipes (Kollar)]. The influence of cryolite crystal size [0 (control), 0.2, and 20 pm diameter particles] on the overall mortality of termites consuming the bait was determined in forced feeding bioassays. Only baits containing 20 pm diameter cryolite crystals increased termite mortality significantly above the control treatment. An additional study examining feeding on stained bait (control and 20 pm diameter cryolite crystals only) indicated that termites will consume the bait, and that termite mortality from feeding on the bait increases over time.