Distribution of St. Louis encephalitis viral antibody in sentinel chickens maintained in Sarasota County, Florida: 1978-1988.

Sentinel chicken flocks monitored arboviral transmission at 12 sites in Sarasota County, Fla., from 1978 through 1988. During this time, 3,452 serum samples were analyzed for hemagglutination inhibition antibody to St. Louis encephalitis virus (SLE) and eastern equine encephalomyelitis virus (EEE). Overall, 91 chickens seroconverted to SLE and three to EEE. The intensity of SLE transmission showed considerable year-to-year variation. Chickens from south-county flocks were more likely to seroconvert to SLE virus than chickens maintained at the north-county sites. The SLE seroconversion rate for midcounty sentinels was intermediate between north- and south-county sites. Chickens were caged in four habitat types: oak hammocks, slash pine-saw palmetto areas, pastures, and urban-residential areas. There was no significant difference in SLE seroconversion rates between habitats.

Evaluation of naled applied as a thermal fog against Culicoides furens (Diptera: Ceratopogonidae).

Naled/diesel oil (1:99), applied as a thermal fog, was tested against the biting midge Culicoides furens. The insects were confined in small cages suspended at 4 heights on poles at progressively greater distances from the fog release point. In terms of population survival 24 hr after treatment, a parabolic equation accurately described the regression of percent survival on distance from the release point. If 10% survival is considered as the maximum acceptable, then the equation predicts adequate control up to 19.6 m (64.3 ft) from the fog release point.

Evaluation of ULV naled applied simultaneously against caged adult Aedes taeniorhynchus and Culicoides furens.

Two experiments were conducted to test application of ULV naled against adult Aedes taeniorhynchus and Culicoides furens exposed simultaneously in cages hung on poles at selected heights and distances from the spray source. ULV spray was released at 0.14 oz active ingredient/acre, droplet size 13.5 micron mmd. In both experiments, insecticide largely carried over the first poles. The greatest mortality occurred at the second pole position, 18.3 and 25.7 m, respectively, from the spray origin, and diminished progressively with increasing distance. Cages at the highest elevation (183 cm) showed the greatest mortality, while those near the ground (15 cm) were substantially less affected. Regression analysis showed that 70% control or better was attained up to a distance (beyond a line 10 m from the release point) of 23 m in the case of Ae. taeniorhynchus and 18 m in the case of C. furens. ULV naled, applied as described, was not particularly effective for control of Ae. taeniorhynchus and C. furens, and was poor for insects exposed in low vegetation.