Apple, LC50 Values for Methomyl (Lannate 1.8 L) on Eggs of Pest and Beneficial Insects and Mites, 1981

Egg masses laid by summer generation Piatynota spp. females were collected on Aug 18 from Red Delicious trees in a commercial apple orchard in Nelson Co., VA and brought back to the laboratory for study. Treatment rates ranged from 0.47 litre (16 oz) to 0.06 litre (2 oz) of Lannate 1.8 L/378.5 litres (100 gal) plus a water control. The leaf clusters bearing Piatynota spp. egg masses were dipped in the respective treatment solutions and were maintained in 50-dram clear plastic vials until egg hatch. One egg mass was used per vial and four, one-vial replicates were used per treatment. Data were recorded as percent hatch. Apple leaves bearing eggs of P. ulmi were collected from a research orchard in Winchester, VA on Aug 4 and were transported to the laboratory. Irregular-sized Teaf sections containing mite eggs were cut out with scissors and affixed to double-coated Scotch tape on a microscope slide. Ten eggs were used per slide and three replicates were used per treatment. Prepared slides were dipped in methomyl treatments which ranged from a rate of 0.95 litres (32 oz) to 8.52 litres (288 oz) of Lannate 1.8 L/378.5 litres (100 gal) water plus a water control. When eclosion ceased, data were recorded as percent hatch. Adult L. pomonella, reared from field collected larvae-infested apples, oviposited on waxed paper in the laboratory. Sections (7 mm diameter) of the paper with egg(s) in situ were removed with a paper punch and stuck on double-stick Scotch tape on a microscope slide. Ten eggs were affixed to each slide and three slides were used per treatment.