Environmental analytical aspects of mosquito control practice

Aerial application of insecticides was monitored by determination of the active ingredient (deltamethrin) using a gas chromatograph coupled to an electron capture detector. The amount of pesticide active ingredient settled to trays after an hour indicated uneven distribution patterns influenced by micrometeorological conditions as well. Maximum half and typically about 30% of the applied insecticide settled in one hour after the treatment. Pesticide drift observed 50 meters away from the target treatment zone was significant in all cases. The measured values ranged between 7% and 31% of the applied deltamethrin and the highest value was observed for K-OTHRIN 10 ULV formulation. Parallel determination of the spray droplet size distribution and specific droplet numbers also confirmed that the drops reach the soil surface and indicated a substantial spray drift