Efficiency of ground-applied naled (Dibrom 14), based on caged mosquito bioassays in a moderately vegetated coastal southeastern Florida citrus grove, proved to be significantly associated with downwind distance. However, association analysis between wind speed, temperature or relative humidity revealed no correlation between these meteorological factors and mosquito mortality. Tests conducted with 3 of the commonly used ULV machines demonstrated no significant differences in efficiency. Equipment modifications to simulate aerial application by elevating the spray release point proved ineffective. Increasing the dosage of naled to 3 times the labeled rate for ground treatment resulted in greater than 95% mortality.