Activity of buprofezin on the green leafhopper Empoasca kraemeri (Ross & Moore, 1957) (Hemiptera, Cicadellidae) under laboratory conditions

Abstract

Empoasca kraemeri is a key pest of dry beans (Phaseolus vulgaris L.) in Latin America and chemical control is necessary when the pest reaches high infestation levels (threshold). The objective of this work was to study the effect of buprofezin on first instars of Empoasca kraemeri under laboratory conditions. This pest stage presented high susceptibility to the insecticide, with an estimated CL50 of 0.112 mg L-1. In another bioassay, virgin couples recently emerged were placed in contact with bean plants previously treated with buprofezin. The average longevities for females/males were: 46/27, 18/16 on treated plants with 10 and 50 mg L-1 of buprofezin, respectively, and 16/14 days on untreated plants. An average of 120 eggs / female was observed on untreated plants and 0.9 and 0.1 eggs/female on plants treated with 10 and 50 mg L-1 of buprofezin, respectively. The egg-laying frequencies, that determinates insect longevity, were: 2.31 on check plots and 0.09 and 0.01 eggs/female/day for treatments of 10 and 50 mg L-1 of buprofezin, respectively. In the last experiment, the effect of buprofezin on adults was investigated. Males or females were kept in contact with leaves treated with 1,000 mg L-1 of buprofezin and then placed in contact with the opposite sex not treated with the insecticide. The average longevity observed for females and males was: 46/27 days on the untreated and 35/23 and 27/13 days for treated individuals kept in contact with buprofezin, respectively. Differences among treatments were not observed on egg-laying frequency: 2.31, 2.56 and 2.42 eggs/female/day, on check, treated females and males with buprofezin, respectively.