Use of Aeroplanes in the Control of the Larvae of Malaria Mosquitos

Abstract

This is a considerably fuller account than one already noticed [R.A.E., B, xix, 21] of tests on dusting with Paris green from an aeroplane against the larvae of Anopheles maculipennis, Mg., carried out in 1929 near Moscow. Larvae of the third and fourth instars were killed more rapidly than the younger ones, which is explained by the fact that the mouth brushes of the latter are less capable of catching the particles of Paris green. In a few cases pupae were also killed, though the reason for this is not known. Laboratory investigations showed the minimum lethal dose of Paris green for the larvae to be about 0.002 mg. Paris green had no effect on the plankton, and when used at the rate of about 1 Ib. to the acre of water surface was quite harmless to fish, birds or mammals. In laboratory experiments, in which larvae of A. bifurcatus, L., were employed, there was practically no difference in the time taken to kill them when a given amount of Paris green was applied undiluted or mixed with 5 or 20 parts talc. When, however, 50 and 100 parts talc were used, death was retarded by one and nine hours, respectively. As it is hardly practicable to apply pure Paris green, a mixture of the latter with some carrier in a proportion not exceeding 1: 1 is recommended for aeroplane dusting.