Before revision: However, crop spraying with insecticides such as DDT and OPs in the 1950s vedalia destruction was most often caused by drift of malathion or DDT applied by airplane during the early spring months.Bartlett BR, Lagace CF (1960) Interference with the biological control of cottony-cushion scale by insecticides and attempts to re-establish a favorable natural balance.
After revision: However, crop spraying with insecticides such as DDT and oganophosphorus insecticides in the 1950s , resulted in high vedalia mortality and cottony cushion scale resurgence; this was especially caused by drift of malathion or DDT applied by airplane during the early spring months.Bartlett BR, Lagace CF (1960) Interference with the biological control of cottony-cushion scale by insecticides and attempts to re-establish a favorable natural balance.