Long term effectiveness of the mixture of diatomaceous earth and deltamethrin on wheat

A mixture of diatomaceous earth (DE) and deltamethrin (DM) was developed to control stored-grain insect pests. The formulation contains a low quantity of DE and small amounts of insecticide deltamethrin technical powder dissolved in solvent and soap. This study was initiated in order to determine how long the mixture DE/DM will provide acceptable protection against infestation by the rice weevil, Sitophilus oryzae (L.), the lesser grain borer Rhyzopertha dominica (F.) and the red flour beetle, Tribolium castaneum (Herbst), when applied to hard red spring wheat (HRSW) and stored under normal storage conditions. Immediately after treatment, all three species were controlled at 100 milligram per kg or parts per million (ppm) of DE/DM mixture. At 100 ppm, DE/DM mixture provided 100% population reduction of all three species for up to 12 months with little or no progeny produced.Keywords: Diatomaceous earth, Deltamethrin, Mixture, Wheat, Protectio

Controle associado de Alphitobius diaperinuse efeito de microrganismos eficazes no desenvolvimento de Beauveria bassiana

O objetivo deste trabalho foi avaliar a eficiência de Beauveria bassiana (Bb), terra diatomácea (TD) e microrganismos eficazes (EM-4), associados ou não, no controle de Alphitobius diaperinus, e o efeito de EM-4 no desenvolvimento de B. bassiana. Os agentes de controle (Bb, TD e EM-4), em diferentes concentrações e combinações, foram aplicados em uma mistura de cama-de-frango e ração, em que os insetos foram acondicionados por dez dias. Avaliaram-se, in vitro: a germinação, as unidades formadoras de colônia (UFC), o crescimento vegetativo e a produtividade de conídios de Bb em contato com suspensão aquosa de EM-4 (1%) não filtrada e filtrada. Os maiores índices de mortalidade foram observados nos tratamentos TD + Bb + EM-4 e TD + Bb, nas maiores concentrações. Verificou-se efeito não-aditivo sinérgico para TD + Bb nas três concentrações. Nos testes com EM-4 filtrado, não houve diferença em relação à testemunha quanto à germinação e às UFC, entretanto, o crescimento vegetativo e a produtividade de conídios foram negativamente afetados. O uso conjunto de B. bassiana e terra diatomácea, para o manejo de populações de A. diaperinus, pode reduzir o uso de produtos químicos

Evaluation of three novel diatomaceous earths against three stored-grain beetle species on wheat and maize

The insecticidal effect of three diatomaceous earths (DEs), that contained different active ingredients, was evaluated under laboratory conditions for the control of adults of the lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae), the rice weevil, Sitophilus oryzae (L) (Coleoptera: Curculionidae) and the confused flour beetle, Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae). The tested DEs were DEBBM, which is a mixture of two natural compounds: bitterbarkomycin (BBM) and DE, DEA which is a mixture of abamectin and DE and DESgBAIT which is a mixture of DE, silica gel Sipernat 50S and food grade bait. They were tested at 200, 400, 600, 800 and 1000 ppm on wheat, Triticum durum Desf., and maize, Zea mays L DEA and DEBBM were generally more effective than DESgBAIT, for all species and commodities. For R. dominica, mortality was high and exceeded 90% for both commodities treated with DEA even at 200 ppm, after 14 d of exposure. Similarly, for the same DE, all adults of S. oryzae were dead on wheat after 14 d for all doses, but mortality was considerably lower on maize. T confusum was the least susceptible species to all three DEs, as compared with R. dominica and S. oryzae. For this species, doses >400 ppm were needed to obtain a satisfactory level of control. The results of the present study indicate that the simultaneous use of a low mammalian toxicity active ingredient with DEs are notably effective against major stored-product insect pests. (C) 2015 Elsevier Ltd. All rights reserved

Laboratory evaluation of diatomaceous earth deposits mined from several locations in central and southeastern Europe as potential protectants against coleopteran grain pests

Diatomaceous earth (DE) deposits from regions of central and southeastern Europe were evaluated for their insecticidal efficacy against Sitophilus oryzae (L.) (Coleoptera: Curculionidae), Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae) and Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae) in comparison with the commercially available DE formulation SilicoSec. The effects of temperature, RH, grain commodity (wheat, barley, maize, rice), application method (spraying vs. dusting) were evaluated. FYROM, a DE from the Former Yugoslavian Republic of Macedonia, was the most effective of the DE deposits for grain treatment, whereas the least effective was from Greece (named Crete). However, for surface treatment, Slovenia was the most effective followed by Elassona 1 and Begora. Increase of temperature increased DE efficacy, while the reverse was noted with the increase of RH. Furthermore, the DEs were more effective in barley or wheat than in maize or rice. Neither the mined DEs nor SilicoSec were able to suppress progeny production of the tested species after previous exposure on the treated commodities. Generally, dust application of DEs was more efficacious than spraying against S. oryzae and T confusum. However, spraying of wheat significantly reduced the bulk density (test weight) compared to dusting. For surface treatment, after 1 d of exposure, Slovenia was the most effective of the mined DEs followed by Elassona 1 and Begora, whereas after 6 d of exposure the mortality was almost complete (> 99%) with all three DEs. More than 6 d of exposure were required for an effective control of T confusum adults with the remainder of the mined DEs. (c) 2010 Elsevier Ltd. All rights reserved

651-966_Proceedings

Abstract In order to mitigate the effect of diatomaceous earth (DE) on bulk density and grain flowability, during the recent years, two new enhanced DEs with synergistic mode of physical and chemical actions have been developed; one with the addition of the soil bacteria metabolite abamectin (DEA) and the other with the addition of the plant extract bitterbarkomycin (DEBBM). Both formulations have very low mammalian toxicity with the oral LD50 for rat higher than 4,500 mg/ kg. The insecticidal effects of both formulations have been extensively evaluated under laboratory conditions. Against the larger grain borer, Prostephanus truncatus (Horn) (Coleoptera: Bostrychidae) and the lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae) 75 ppm of DEA on maize and wheat, respectively, provided 100 % parental mortality after 14 days of exposure. In the case of R. dominica, 75 ppm of DEA provided complete progeny suppression. Similar results were produced in the case of the rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae); however but 125 ppm were required to provide complete progeny suppression. In the case of P. truncatus, it was found that DEA performance remained unaffected in all combinations of the temperature 20, 25 and 30 o C and of the relative humidity (r.h.) levels 55 and 75 %, while mortality was 100 % after only 7 days. For DEBBM, 75 ppm provided 100 % mortality of R. dominica and of the rusty grain beetle, Cryptolestes ferrugineus (Stephens) (Coleoptera: Cucujidae) after 14 d, and complete suppression of progeny production. For a 100 % mortality of S. oryzae and of the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) 100-125 ppm was required, but progeny production was extremely low. Based on these results, it becomes evident that these two formulations could be used with success against stored-grain beetle species, at very low application rates