Relative Toxicities of Insecticides to Entomophagous Species and Colorado Potato Beetle Larvae, 1983

Abstract

Abstract Potatoes were planted with 12 inch (30.48 cm) spacing in 50 ft (15.38 m) rows 36 inch (0.914 meters) apart on 25 Apr near Prairie Home, MO. Insecticides were applied to 12 ft (3.66 meters) sections of rows replicated 4 times in a randomized complete block design, with the 5 treatments applied to alternate rows with an untreated row as a butter between each treatment row. The sprays were applied on 16 Jun with a 2 gal (7.57 liter) hand held compressed-air sprayer calibrated to deliver 100 gal/acre (935.27 1/ha) 30 psi (2109 g/cm2). Just prior to spray application, 1 laboratory reared Colorado Potato Beetle (CPB) egg mass was stapled to the underside of the first large leaf down from the terminal of 2 plants in each replicate. Ten adult E. puttleri for 3rd instar P. maculventris were released on the plant to which the CPB eggs had been attached in each replicate ca. 3 h post application. The released CBP eggs were recovered 2 days post spray to assess effects of the compounds tested on predation, and/or host feeding and parasitization by E. puttleri. Evaluation criteria were direct counts of CPB larvae and entomophagous species/8 plants, parasitization and host feeding by E. puttleri parasitization and predation of the CPB egg masses recovered, and observed instances of predation.