Suspensions of BHC, lindane, and aldrin applied at 20 pounds and of dieldrin at 40 pounds per acre to the soil surface in a band about the tree rows a few days after planting gave complete protection against woolly apple aphids (Eriosoma lanigerum (Hausm. )) on the roots of apple nursery stock without injuring the trees. Unfortunately, such heavy dosages are impractical and lighter ones failed to give complete control. Heavy dosages of demeton and chlordane were also ineffective. Dipping the roots of apple seedlings into pastes made up of 1 to !t teaspoonfuls of BHC (10% gamma isomer), 50% dieldrin, an aldrin wettable powder containing 25% of the active ingredient with 1 1/2 pounds of Attaclay or charcoal in 1 quart of water reduced the infestation and did not injure the trees but was cumbersome to carry out. Tn trunk-spray experiments moderate practical dosages of BHC, Sevin® (1-naphthyl methylcarbamate), demeton, and Guthion®O,O-dimethyl S-(4-oxo-3H-1,2,3-benzotriazine- 3-methyl) phosphorodithioate), (about 6 to 10 ounces per acre) near the ground and to a narrow band of soil about the tree rows gave an encouraging degree of control and caused no injury. The minimum effective dosages remain to be determined. Trithion® (S-(p-chlorophenyltllio)methyl O,O-diethyl phosphorodithioate), sehradan, and Nemagon (1,2-Dibromo-3-chloropropane) were less effective.
Document Type: Research Article
Publication date: April 1, 1960
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