Efficiency of inert mineral dusts in the control of corn weevil

Abstract

Corn weevil (Sitophilus zeamais) may cause great losses in the crop and in stored corn grains. This insect is controlled with the use of chemical insecticides, which may cause serious damage to human health. One alternative of control is the use of inert dusts. The objective of this study was to evaluate the efficiency of inert dusts in the control of S. zeamais under laboratory conditions. The experiment was conducted in 2014, in a completely randomized design, and the treatments consisted of basalt dust with three different granulometries (A, B and C) and diatomaceous earth, each of which at the doses of 2 and 4 kg t-1 and a control (no application). Each treatment had four replicates, and the sample unit consisted of 20 g of corn grains infected with 10 adults of S. zeamais kept in temperature-controlled chamber at 25 °C, 70% RH and photophase of 12 h. The dust efficiency was calculated using the equation of Abbott. The mortality rate was higher with the use of diatomaceous earth, reaching 100% after 5 days of exposure and the percentage of control for basalt dusts, 29 days after treatment, was above 80%.

Insecticidal effect of diatomaceous earth and dolomite powder against Corn weevil Sitophiluszeamais Motschulsky, 1855 (Coleoptera: Curculionidae)

“…DEA-P demonstrated a high effectiveness for the control of pests at low doses in all corn hybrids (Kavalliaratos et al, 2018). Jairoce et al (2016), studying the mortality of S. zeamais exposed to different doses of DE, observed the correlation of the dose to the period of exposure. Longer periods of exposure at the highest doses promoted better control of the corn weevil; however, in the present study, we found that intermediate doses presented high mortality in a short period of time.…”

Agroecological strategies for Sitophilus zeamais handling in maize stored

“…This response was corroborated by collecting some adults in grains where quicklime powder was applied to observe them with a stereoscopic microscope (Olympus SZX7 and Nikon Eclipse 80i) and it was noticed that the joints of the weevils were covered with lime, which prevented them from move, this prevented copulation, oviposition and reproduction. Other inert powders such as volcanic ash and diatomaceous earth are viable for managing S. zeamais, since they act in a similar way to quicklime Jairoce et al (2016), obtained a mortality rate of 100 % five days after establishing the experiment in the laboratory.…”

Eficácia de inseticidas alternativos e biológicos sobre Sitophilus zeamais (Coleoptera: Curculionidae) em grãos de milho

“…Em virtude desses problemas, sucederam-se estudos a respeito de inseticidas naturais na solução de pós-inertes, e dentre os produtos testados, se destacou a terra de diatomácea com eficiência sobre o inseto, principalmente por deteriorar a camada de cera na asa do Sitophilus zeamais provocando morte por dessecação (Jairoce et al, 2016;Korunic, 2013;Marsaro Júnior et al, 2013). Além desse inseticida, apresentaram eficácia expressiva extratos e óleos vegetais como de nicotina (Nicotiana tabacum), nim (Azadirachta indica), eucalipto (Eucalyptus citriodora) uma vez que causam diminuição na população dos insetos sem acarretar intoxicação humana e deixar resíduos na massa de grãos (Gomes & Favero, 2011;Ootani et al, 2011;Vedovatto et al, 2015).…”