SELECTIVITY OF INSECTICIDES USED IN CORN CROPS TO EGGS AND NYMPHS OF THE EARWING DORU LINEARE (ESCHSCHOLTZ, 1822) (DERMAPTERA: FORFICULIDAE)

M.J. Zotti A.D. Grützmacher D.D. Grützmacher R.V. Castilhos J.F.S. Martins About the authors

ABSTRACT

The goal of this work was to evaluate the selectivity of insecticides used in corn crops for the control of Spodoptera frugiperda (J.E. Smith, 1797) (Lepidoptera: Noctuidae) on first-instar nymphs and eggs of the earwig Doru lineare. For the bioassays the standardized methodology of IOBC/WPRS was used in terms of temperature (25 ± 1º C), relative humidity (70 ± 15%) and photophase (14 hours). In the bioassay with nymphs for residual contact, the applications of insecticides was conducted with equipment pressurized by CO2 to 50 psi. For applications of insecticides on eggs, a Potter’s tower was used, with pressure of 10 psi. In both forms of spraying the deposit was 1.75±0.25 mg cm-2 of aqueous solution in accordance with the IOBC/WPRS methodology. The mortality of nymphs was used to classify insecticides as harmless (< 30%), slightly harmful (30-79%), moderately harmful (80-99%) and harmful (> 99%). Viability of eggs and survival of hatched nymphs were both evaluated by comparing with the positive (Sevin 480 SC) and negative (water) controls. The viability of eggs was reduced by Certero, Dimilin, Engeo Pleno, Karate Zeon 250 SC, Lorsban 480 BR, Match EC and Sevin 480 SC. The survival of nymphs from treated eggs was reduced by the insecticides Decis EC, Dimilin, Engeo Pleno, Karate Zeon 250 CS, Lorsban 480 BR and Sevin 480 SC. For nymphs of D. lineare in residual contact, all the insecticides were harmful.

KEY WORDS
Biological control; chemical control; integrated pest management; toxicity; Zea mays

Instituto Biológico Av. Conselheiro Rodrigues Alves, 1252 - Vila Mariana - São Paulo - SP, 04014-002 - São Paulo - SP - Brazil
E-mail: arquivos@biologico.sp.gov.br