DDT dust and spray were applied from an airplane to a cloth-covered cigar-wrapper tobacco shade in 1966. Deposits of both formulations of insecticide were recovered on mineral oil-soaked filter paper traps placed above and within the shade. The traps were located in and above the tobacco rows at three position heights at the center, mid-center, and edge of the swaths. Analyses of the deposits were made to determine, (1) the lateral distribution of the insecticides in the swaths, (2) the amount of insecticide coverage of the upper and lower trap surfaces, and (3) the degree to which the insecticides penetrated the shade-cloth covering. The evidence obtained indicated that (1) more spray than dust was deposited on the trap surfaces, (2) the amount of insecticide deposited on the traps decreased with decreasing height of the traps and increasing distance from the center of the swaths, (3) deposits at the various heights were more· uniform at the edge of the swaths, and (4) more of both forms of insecticide was deposited on the upper than lower trap surfaces. Penetration of the shade cloth was poor for both forms of insecticide, but a percentage comparison of the two indicated an advantage for the dust. Spray deposits, however, were greater than the dust on the traps above and below the cloth indicating poor adherence of the dust to the tobacco foliage. The spray apparently would be more effective for insect control, particularly on the upper portion of the· tobacco plants where the deposits on the traps were the greatest.

(Full article published with kind permission from "Tobacco International")