Topical effect of thiamethoxam on adults of Rhynchophorus palmarum L. (Coleoptera: Curculionidae) in laboratory

Valdemir A. da Silva Junior; Aldomario S. Negrisoli Junior

doi:10.37486/1809-8460.ba17001

Authors

Valdemir A. da Silva Junior Universidade Federal de Alagoas-Campus de Engenharias e Ciências Agrárias Delza Gitaí, Br-104, Km 85, s/n Rio Largo-AL, CEP 57100-000 https://orcid.org/0000-0002-4859-2258
Aldomario S. Negrisoli Junior Embrapa Tabuleiros Costeiros- Unidade de Execução de Pesquisa – UEP Rio Largo, Br-104, Km 85, s/n Rio Largo-AL, CEP 57100-000 https://orcid.org/0000-0001-5328-5415

DOI:

https://doi.org/10.37486/1809-8460.ba17001

Keywords:

Cocos nucifera, palm weevil, chemical control, broca-do-olho-do coqueiro, controle químico

Abstract

Due to the ability to locate the host plant over long distances, and the direct and indirect damage that are caused, Rhynchophorus palmarum L. (Coleoptera: Curculionidae) is considered a key pest of coconut crop. Therefore, the objective of this research was to evaluate the efficiency by contact of the insecticide thiamethoxam on adults of R. palmarum, determining the lethal concentrations (LC₅₀and LC₉₀), under laboratory conditions. One mL of insecticide solution was applied to the insect body at concentrations of 1 ppm, 2 ppm, 3 ppm, 4 ppm and 5 ppm. Insect mortality in the treatments was evaluated after five days. The comparison of means was performed by the Tukey test at 5% significance. For determining the lethal concentrations of 50 and 90%, Probit analysis was performed. The LC₅₀ (2.16 ppm) and LC₉₀ (4.23 ppm) remained within the confidence interval. The concentration of 5 ppm caused 100% mortality, evidencing the efficiency of the insecticide by contact, demonstrating a promising alternative in controlling this pest.