Bioactivity of diatomaceous earth to Sitophilus zeamais (Coleoptera: Curculionidae) in different application conditions

Abstract

The objective of this study was to evaluate the insecticidal activity of diatomaceous earth (DE) at different ambient temperatures on adult Sitophilus zeamais and progeny, using different doses and exposure periods. The experiments were performed in Petri dishes containing 40 g of the whole corn kernel, treated with DE at doses of 0, 0.25, 0.5 and 1.0 kg Mg -1 . Each dish was infested with 25 S. zeamais adults and kept at climatic chambers under temperatures of 20, 25, 30, 35 and 40 o C. The insect mortality was recorded after six and 15 days from the beginning of the bioassays. The grains evaluated at 15 days were separated from insects and kept in the dishes for another 75 days under the same temperature conditions. After this period the effect of ambient temperature and of diatomaceous earth doses on the emergence of S. zeamais in the F 1 generation was evaluated. It was found that the mortality of S. zeamais increased with the higher dose and temperature during the exposure period of six and 15 days. The number of insects emerged reduced with increasing temperature in these two exposure periods. The increase of temperature and exposure period favored the efficacy of DE in lower doses for control of S. zeamais.Key words: corn weevil, inert dusts, storage, insect control Bioatividade da terra de diatomácea para Sitophilus zeamais (Coleoptera: Curculionidae) em diferentes condições de aplicação RESUMO O objetivo deste trabalho foi avaliar a atividade inseticida da terra de diatomácea (TD) em diferentes temperaturas ambiente sobre adultos de Sitophilus zeamais e sua progênie, utilizando-se diferentes doses e períodos de exposição. Os experimentos foram realizados em placas de Petri contendo 40 g de grãos inteiros de milho, tratados com TD nas doses de 0; 0,25; 0,5 e 1,0 kg Mg -1 . Cada placa foi infestada com 25 adultos de S. zeamais e mantida em câmaras climáticas nas temperaturas de 20, 25, 30, 35 e 40 °C. A mortalidade dos insetos foi contabilizada após seis e 15 dias do início dos bioensaios. Os grãos avaliados aos 15 dias foram separados dos insetos e mantidos nas placas por mais 75 dias sob as mesmas condições de temperatura. Após este período avaliou-se o efeito da temperatura ambiente e das doses da TD sobre a emergência de S. zeamais na geração F 1 . Verificou-se que a mortalidade de S. zeamais aumentou com o incremento da dose e da temperatura nos períodos de exposição de seis e 15 dias; já o número de insetos emergidos reduziu com o aumento da temperatura nesses dois períodos de exposição. O aumento da temperatura e do período de exposição favoreceu a eficácia da TD em menores doses, para controle de S. zeamais.Palavras-chave: gorgulho-do-milho, pós-inertes, armazenamento, controle de insetos

Effectiveness of Some Native Diatomaceous Earth Against Maize Weevil, Sitophilus Zeamais (Coleoptera: Curculionidae), Under Controlled Conditions

“…The effectiveness of DEs increased with higher doses and temperature. This effect shows that the mortality of insects is dependent on the conditions in which the grains are exposed to DEs (Sousa et al, 2013). The particles and size of DEs have abrasive peculiarities but more importantly the ability to absorb lipid molecules from the cuticle of the insects and subsequently, in water loss, dehydration and death (Quarles and Winn, 1996;Korunic, 1998;Subramanyam and Roelsi, 2000).…”

“…Dusts, such as diatomaceous earth, are known insecticidal or repellant activity products and effectively controls most species of insect pests of storage products (Ebeling, 1971;Sousa et al, 2013). Diatomaceous earth affects larvae and adults, stick to insect's body parts as they move on their surface or inside the treated grain mass (Kavallieratos et al, 2007;Rojht et al, 2010;Shams et al, 2011;Sousa et al, 2013). When dust contacts with insects, it causes the removal of the layer of wax from insect cuticle, bringing about their death by dessication (Rojht et al, 2010).…”

“…Many studies have been conducted in Turkey and other countries to determine the insecticidal, biological and repellent activity of native and trade DEs against storage product pests (Korunic, 1998;Masiiwa, 2004;Ferizli and Beris, 2005;Athanassiou et al, 2004;Sousa et al, 2013;Doumbia et al, 2014;Ertürk and Emekçi, 2014;Wakil et al, 2015;Alkan et al, 2019;Şen et al, 2019;Kılıç and Mutlu, 2020). Whereas, biological efficacy and dose studies of various DEs have been conducted such as on wheat, rice and corn related to S. oryzae and S. granarius species in Turkey, there is no literature available related to efficacy of local DEs for S. zeamais on storage corn kernels.…”

Susceptibility of different genotypes of rice to Sitophilus zeamais Motschulsky 1885 attack (Coleoptera: Curculionidae)

“…The no-choice test was performed as follows: 100 g samples of each rice genotype were placed in 300 mL transparent plastic containers, along with 30 unsexed adult insects of S. zeamais, (Guzzo et al, 2002;Herrmann et al, 2009;Marsaro Júnior & Vilarrinho, 2011;Vásquez-Castro et al, 2012;Sousa et al, 2013) and covered with voile fabric to prevent the escape of insects. No disinfection was performed in the control treatment, which consisted of only rice grains.…”

Effectiveness of Different Doses of Diatomaceous Earth on Mexican Bean Weevil (Zabrotes subfasciatus Boheman) in Culiacan, Sinaloa, Mexico

“…Sousa et al [19], evaluaron el efecto de diferentes dosis de TD y temperaturas contra gorgojo del maíz y los resultados encontrados, mostraron que la mortalidad de S. zeamais aumentó con la dosis y temperatura más alta durante el período de exposición de seis y 15 días, estos mismos resultados fueron observados en la emergencia de la progenie, por lo que se asume que el aumento de la temperatura y el periodo de exposición favorece la eficacia de la TD incluso a dosis bajas en el control de esta plaga de almacén.…”