Efficacy of various ground-applied pyrethroids against adult Anopheles quadrimaculatus in the rice growing region of Arkansas.

Ground-applied ULV, cold aerosol, insecticide sprays were evaluated against caged adult female Anopheles quadrimaculatus. Treatments included 2 rates each of resmethrin, permethrin and a water-based permethrin formulation. Mortality at 24 h posttreatment was not significantly (P greater than or equal to 0.05) different between the resmethrin and water-based permethrin treatments. Both rates of permethrin were significantly (P less than 0.05) less effective than the other treatments.

Efficacy of various ground-applied cold aerosol adulticides against Anopheles quadrimaculatus.

Ground-applied ULV, cold aerosol insecticides were tested against adult female Anopheles quadrimaculatus. Treatments included high (H) and low (L) rates of Permanone (permethrin), bioresmethrin and esbiothrin. Malathion was applied as a standard. Mortality at 24-h posttreatment was highest with Bioresmethrin H at 15 m. Permanone H exhibited good control out to 60 m (88.9%), but dropped to an unacceptable level (65.5%) at 90 m. The low rates of all compounds produced unsatisfactory results at 24-h posttreatment. Recovery from knockdown occurred in all treatments with the exception of malathion.

Efficacy of Bacillus sphaericus formulations against Psorophora columbiae larvae in small rice plots.

Bacillus sphaericus formulations were evaluated against Psorophora columbiae larvae in small rice plots. All formulations tested provided good control (greater than 84%) for all rates tested at 2 days posttreatment. At 10 days posttreatment, fair control (greater than 70%) was recorded for ABG-6232 (0.184 kg/ha), ABG-6262; 27-242-BA (0.766 and 2.298 liters/ha), and ABG-6262; 29-293-BA (2.298 liters/ha). At 7 days posttreatment mortality was below 66%. Control did not exceed 27% at 15 days posttreatment for any formulation tested. Application rates for all formulations tested had little relationship with observed mortality, and control levels often were greater at the lower dosages tested. Bacillus sphaericus provided an effective means for controlling Ps. columbiae, but additional research is needed to determine the lower limit of effective treatment dosages and spore persistence in the rice field environment.

Evaluation of Bacillus sphaericus 2362 against Culex quinquefasciatus in septic ditches.

Four application rates of Bacillus sphaericus strain 2362 were tested for efficacy in septic ditches against Culex quinquefasciatus 2nd-4th instar larvae. Trials were conducted over a 2-year period. In 1987, all dosages applied to dairy effluent ditches resulted in substantial reductions after 48 h. Differences among dosages did not differ significantly (P greater than or equal to 0.05). After 5 days, mosquito larval numbers increased with dosage rates of 0.6, 0.9 and 1.2 liters/ha. Residual control was maintained, however, at 2.4 liters/ha for 17 days. In 1988, B. sphaericus applied to domestic sewage effluent ditches at rates of 1.2 liters/ha, and 2.4 liters/ha induced greater than 79% suppression for a period of 15 days, and the 1.2 liters/ha rate induced greater than 79% suppression for a period of 20 days. A rate of 0.9 liters/ha provided good to excellent control (greater than 88%) for a period of 10 days. A rate of 0.6 liters/ha produced less than 50% suppression after 48 h.

Chromatin-bound protease: (3H)diisopropyl fluorophosphate labeling patterns of chromatin.

The nuclei and chromatin of rat liver contain three major proteins reacting with diisopropyl fluorophosphate (DFP). The molecular weights of the three proteins determined by gel filtration in the presence of sodium dodecyl sulfate and sodium dodecyl sulfate-polyacrylamide gel electrophoresis are 70000, 60000, and 25000. The chromatin isolated from whole liver, instead of nuclei, contains an additional DFP-binding protein whose molecular weight is 100000 in the presence of sodium dodecyl sulfate and beta-mercaptoethanol. The small molecular weight DFP-binding protein can be fractionated from chromatin by 0.25 N HC1 and was found to be a protease which is active in the most commonly used solution for chromatin dissociation, that is, 2-3 M NaCl-5 M urea. This enzyme appears to be the major DFP-binding chromatin-bound protease in the chromatin of most rat tissues. The acid-soluble protease is converted from a 25000-dalton form to a 20000-dalton form during 0.25 N HC1 acid extraction from chromatin, which retains proteolytic activity.