Diatomaceous earth effects on weevils with different susceptibility standard to phosphine

Abstract

A B ST R A C TThe aim of this study was to evaluate the insecticide activity of diatomaceous earth (DE), at different temperatures, on two populations of Tribolium castaneum and Rhyzopertha dominica previously diagnosed as resistant and susceptible to phosphine. The efficiency of DE in the control of the insects was evaluated at temperatures of 20, 25, 30, 35 and 40 ± 2 ºC. The experiments were accomplished in Petri dishes containing 35 g of whole-wheat grain treated with DE in the dose of 1.0 kg t -1. The control was constituted by untreated wheat grain. Each Petri dish was infested with 30 adult insects. Insect mortality was registered seven days after the beginning of the bioassays. The experiment was conducted in a completely randomized design with three replications. The populations of T. castaneum and R. dominica, respectively, resistant and susceptible to phosphine have similar susceptibility patterns. The mortality of two populations of T. castaneum increased with increasing temperature. For R. dominica, the mortality did not change with the temperature. Key words: Tribolium castaneum, Rhyzopertha dominica, alternative controlEfeito da terra de diatomácea sobre carunchos com diferentes padrões de susceptibilidade à fosfina R ESU M O O objetivo deste trabalho foi avaliar a atividade inseticida da terra de diatomácea (TD), em diferentes temperaturas, em relação a duas populações de Tribolium castaneum e Rhyzopertha dominica previamente diagnosticadas como resistentes e susceptíveis à fosfina. A eficiência da TD foi avaliada nas temperaturas de 20, 25, 30, 35 e 40 ± 2 ºC e os experimentos foram realizados em placas de Petri contendo 35 g de grãos inteiros de trigo, tratados com TD na dose de 1,0 kg t -1. O controle foi constituído de grãos de trigo não tratados; ressalta-se que cada placa de Petri foi infestada com 30 insetos adultos, cuja mortalidade foi contabilizada sete dias após o início dos bioensaios. O delineamento experimental utilizado foi o inteiramente casualizado, com três repetições. As populações de T. castaneum e R. dominica, respectivamente, resistentes e susceptíveis à fosfina apresentaram padrões de susceptibilidade semelhantes; por outro lado, a mortalidade das duas populações de T. castaneum aumentou com a elevação da temperatura embora para R. dominica a mortalidade não tenha variado com a temperatura.

Phosphine Resistance in Turkish Populations of Sitophilus oryzae (L., 1763) (Coleoptera: Curculionidae)

“…The levels of resistance in Turkey call for the use of an effective resistance monitoring program that contributes to fumigation operators to make decisions whether or not to use PH 3 in a given situation. Further work is required to continue monitoring for PH 3 resistance in Turkey, to determine strategies to manage resistance to PH 3 and to develop or use alternative fumigants such as sulfuryl fluoride, where PH 3 resistance has developed to very high levels (Opit, Thoms, Phillips & Payton, 2016) and also inert dusts, such as diatomoceus earth can be alternative for resistant strains (Korunic, 1998;Conceição, Faroni, Sousa, Pimentel, & Freitas, 2012;Sakka & Athanassiou, 2021).…”

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

“…The Sitophilus zeamais Mots. (Coleoptera: Curculionidae) is a major corn pest and its by products are found in virtually all storage and processing facilities of Brazil (Aguiar et al, 2010;Conceição et al, 2012). This insect is controlled by pyrethroid and organophosphate insecticides (Guedes et al, 2008) and phosphine fumigant (Sousa et al, 2009).…”