SULFOTINETM (LITHIUM PERFLUOROOCTANESULFONATE): A NEW ACTIVE FOR BAITS AGAINST DOMESTIC CRAWLING INSECTS

Abstract:
Lithium perfluorooctanesulfonate (LPOS, proposed common name SulfotineTM) is an isomeric mixture containing approximately 70% of the linear isomer and 30% branched isomers. Molecular formula for LPOS is C8F17LiO3S, and acute oral LD50 is greater than 5,000 mg/kg. LPOS exhibits promising oral toxicity to various domestic insect pests, mainly cockroaches and ants. In laboratory conditions, an experimental solid cockroach bait containing 1% LPOS has been evaluated against laboratory (susceptible) and wild strains (pyrethoids tolerant) of the German cockroach, Blattella germanica (L.). The bait has also been evaluted against laboratory susceptible Oriental and American cockroaches, Blatta orientalis L., Periplaneta americana (L.). Laboratory tests were performed in large glass arenas (1 x 1 m) with adequate competitive food, water and shelter. Mixed populations with naturally developed nymph, male and female rations (approx. 200 per arena) were tested. Pre-counted cohorts of males, females and nymphs were also tested. In both tests, insects were acclimated for 3 days before the bait was introduced. Mortality was recorded daily. LT50 and LT90 values (with 95% fiducial limits) are summarized in Table 1. The first dead individuals of B. germanica were found 4-6 hrs. after LPOS bait introduction. Initial mortality of males started sooner than the other life stages, althrough this speed of kill was not reflected in the LT50 data. The initial kill of B. orientalis and P. americana was slower, starting about 8-12 hrs after initial exposure. All individuals of tested populations died usually during 10-15 days post initial exposure. The LPOS bait exhibited a single feeding feature. When males and females of B. germanica, B. orietalis and P. americana were fed the bait for 2 hrs. (and then the baits were removed), mortality was 100% , 92-100% and 100% respectively, after a 5-7 day holding period. LPOS exhibited distinct secondary kill. B. germanica and B. orientalis that fed on feces and regurgitated intestinal contents were killed during a 3-5 day period. Experimental bait with LPOS has been tested in the field (hospital kitchens and laboratories) in doses of 4-5 baits per 10 square meters of area. Reduction of B. germanica (based on sticky trap counts) ranging from 92 to 100% were observed during a one month to one year post-treatment period.