Protection of Stem Crucifers from Cyclodiene-Resistant Maggots in Sandy Loam and Peat Soils1

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Abstract
In experiments from 1962 to 1965, inclusive, in sandy loam and peat soils, insecticides for protection from cabbage maggots, Hylemya brassicae (Bouché), were applied as granules in the soil around the base of stem crucifers or in a band before transplanting, and as emulsifiable concentrates in the transplant water or in drenches over the plants immediately after transplanting. Some treatments allowed production of marketable crops in spite of populations as high as 16 maggots per plant with 66% damage to the root system. The investigation demonstrated that of the 4 crucifers, cauliflower was the most susceptible to attack and Brussels sprouts the least. Lower numbers of maggots inflicted greater losses in mineral soil than higher numbers in peat. The most consistently effective insecticides were: Bayer 25141 (O,O-diethyl O-[P-(methylsulfinyl) phenyl] phosphorothioate); GC 4072 (2-chloro-1-(2,4-dichlorophenyl) vinyl diethyl phosphate); NIA 10242 (2,3-dihydro-2,2-dimethyl-7-benzofuranyl methylearbamate); and Zinophos® (O,O-diethyl O-2-pyrazinyl phosphorothioate). Granules were the most useful formulation, but 2 drenches of Bayer 25141 allowed the least damage to cauliflower in both soils in 1965.