Technical notes. Removal of lead arsenate from green tobacco leaf

Abstract

About 1950 the area of irrigated tobacco crops was expanded in Queensland, and consequently field planting in spring, rather than as previously after early summer rains, became general practice. As a result the pest status of the tobacco looper (Plusia argentifera Gn.) was increased considerably. This insect when in large numbers was not controlled satisfactorily by the insecticides used for other pests at that time, and lead arsenate, which had been used for many years for controlling leaf pests of tobacco, was applied intensively during the later stages of crop growth. During the 1951-52 season quantities of Queensland leaf were condemned because of excessive arsenic residues: the official tolerance is 1 grain As2 O3 per lb. of moisture-free cured leaf.