Residual Efficacy of Two Diatomaceous Earths from Greece for the Control of Sitophilus oryzae (L.) (Coleoptera: Curculionidae) and Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae) on Wheat and Maize.

We evaluated the persistence and efficacy of two different, in granulometry and content of diatoms, diatomaceous earth (DE) formulations (i.e., DE5 and DE6), against two major beetle species of stored products, i.e., Sitophilus oryzae (L.) (Coleoptera: Curculionidae) and Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae). The formulations were applied as powders in soft wheat and maize in two doses of 500 and 1000 mg kg-1 (ppm). Samples of the treated grains were taken on the day of application and every 30 days until completion of the six-month period of storage. Adults of S. oryzae and R. dominica were exposed to the treated grains at 25 °C and 55% relative humidity, and the mortality was measured after 7, 14, and 21 days of exposure. Rhyzopertha dominica survival was not affected by any combination of DE formulation, dose, and commodity. Contrariwise, the DEs caused significant adult mortality of S. oryzae, in most of the cases tested. We observed that DE6 was equally effective in both wheat and maize, and no considerable variations were observed in S. oryzae mortality during the 6-month experimental period. Furthermore, DE6 was more effective against S. oryzae than DE5, a difference that could have potentially contributed to the variations in the diatom granulometry between these two DEs. Thus, a DE treatment of 1000 ppm was shown to provide long-term protection of wheat and maize against S. oryzae, but this is strongly dependent on the DE formulation, commodity, and insect species. Overall, such natural resource-based inert silicaceous deposits could be used with success in stored-product protection with only some minor modifications, such as sieving and drying of the raw deposit.

Control of the Mexican bean weevil Zabrotes subfasciatus with kaolin / Controle do caruncho-do-feijão Zabrotes subfasciatus com caulim

The Mexican bean weevil Zabrotes subfasciatus (Coleoptera: Chrysomelidae: Bruchinae) is an important pest of stored beans in tropical regions. The efficiency of kaolin [with or without neem (Azadirachta indica) oil] and diatomaceous earth (DE) (standard treatment) was studied in laboratory aiming to obtain alternatives for chemical control of this insect. Insects were confined in plastic vials containing beans treated with kaolin (2, 4 and 8g kg-1), kaolin + neem [2g kg-1(5 percent neem oil)], diatomaceous earth (1g kg-1) and control. Mortality of adult insects, number of eggs and F1generation beetles emergency were assessed. Kaolin caused mortality of Z. subfasciatus, however higher periods and doses than DE were necessary to promote high mortality (100 percent or close). Kaolin treatments also affected female behavior because many eggs were placed in the vials walls. Number of emerged adults (F1) was similar between DE and kaolin; hence, kaolin constitutes a promising tool to the management of Z. subfasciatus. The mixture of kaolin and neem oil was not efficient in the control of Z. subfasciatus.

O caruncho-do-feijão Zabrotes subfasciatus (Coleoptera: Chrysomelidae: Bruchinae) é uma importante praga de grãos de feijão armazenado nas regiões tropicais. A eficiência do caulim [com ou sem óleo de nim (Azadirachta indica)] e terra diatomácea (TD) (tratamento padrão) foi estudada em laboratório com o intuito de obter alternativas para o controle químico deste inseto. Insetos foram confinados em frascos de plástico com feijão tratado com caulim (2, 4 e 8g kg-1), caulim + nim [2g kg-1(5 por cento óleo de nim)], terra diatomácea (1g kg-1) e controle. Mortalidade de insetos adultos, número de ovos e emergência da geração F1 foram avaliados. Caulim causou a mortalidade de Z. subfasciatus, porém foram necessários maiores períodos e doses que a TD para promover elevada mortalidade (100 por cento ou aproximadamente). Os tratamentos com caulim também afetaram o comportamento da fêmea, pois muitos ovos foram colocados nas paredes dos frascos. O número de adultos emergidos (F1) foi similar entre a TD e o caulim; portanto, caulim constitui uma ferramenta promissora para o manejo de Z. subfasciatus. A mistura de caulim e óleo de nim não foi eficiente no controle de Z. subfasciatus.

Control of the Mexican bean weevil Zabrotes subfasciatus with kaolin

The Mexican bean weevil Zabrotes subfasciatus (Coleoptera: Chrysomelidae: Bruchinae) is an important pest of stored beans in tropical regions. The efficiency of kaolin [with or without neem (Azadirachta indica) oil] and diatomaceous earth (DE) (standard treatment) was studied in laboratory aiming to obtain alternatives for chemical control of this insect. Insects were confined in plastic vials containing beans treated with kaolin (2, 4 and 8g kg-1), kaolin + neem [2g kg-1(5% neem oil)], diatomaceous earth (1g kg-1) and control. Mortality of adult insects, number of eggs and F1generation beetles emergency were assessed. Kaolin caused mortality of Z. subfasciatus, however higher periods and doses than DE were necessary to promote high mortality (100% or close). Kaolin treatments also affected female behavior because many eggs were placed in the vials walls. Number of emerged adults (F1) was similar between DE and kaolin; hence, kaolin constitutes a promising tool to the management of Z. subfasciatus. The mixture of kaolin and neem oil was not efficient in the control of Z. subfasciatus.

O caruncho-do-feijão Zabrotes subfasciatus (Coleoptera: Chrysomelidae: Bruchinae) é uma importante praga de grãos de feijão armazenado nas regiões tropicais. A eficiência do caulim [com ou sem óleo de nim (Azadirachta indica)] e terra diatomácea (TD) (tratamento padrão) foi estudada em laboratório com o intuito de obter alternativas para o controle químico deste inseto. Insetos foram confinados em frascos de plástico com feijão tratado com caulim (2, 4 e 8g kg-1), caulim + nim [2g kg-1(5% óleo de nim)], terra diatomácea (1g kg-1) e controle. Mortalidade de insetos adultos, número de ovos e emergência da geração F1 foram avaliados. Caulim causou a mortalidade de Z. subfasciatus, porém foram necessários maiores períodos e doses que a TD para promover elevada mortalidade (100% ou aproximadamente). Os tratamentos com caulim também afetaram o comportamento da fêmea, pois muitos ovos foram colocados nas paredes dos frascos. O número de adultos emergidos (F1) foi similar entre a TD e o caulim; portanto, caulim constitui uma ferramenta promissora para o manejo de Z. subfasciatus. A mistura de caulim e óleo de nim não foi eficiente no controle de Z. subfasciatus.

Control of the Mexican bean weevil Zabrotes subfasciatus with kaolin

The Mexican bean weevil Zabrotes subfasciatus (Coleoptera: Chrysomelidae: Bruchinae) is an important pest of stored beans in tropical regions. The efficiency of kaolin [with or without neem (Azadirachta indica) oil] and diatomaceous earth (DE) (standard treatment) was studied in laboratory aiming to obtain alternatives for chemical control of this insect. Insects were confined in plastic vials containing beans treated with kaolin (2, 4 and 8g kg-1), kaolin + neem [2g kg-1(5% neem oil)], diatomaceous earth (1g kg-1) and control. Mortality of adult insects, number of eggs and F1generation beetles emergency were assessed. Kaolin caused mortality of Z. subfasciatus, however higher periods and doses than DE were necessary to promote high mortality (100% or close). Kaolin treatments also affected female behavior because many eggs were placed in the vials walls. Number of emerged adults (F1) was similar between DE and kaolin; hence, kaolin constitutes a promising tool to the management of Z. subfasciatus. The mixture of kaolin and neem oil was not efficient in the control of Z. subfasciatus.

O caruncho-do-feijão Zabrotes subfasciatus (Coleoptera: Chrysomelidae: Bruchinae) é uma importante praga de grãos de feijão armazenado nas regiões tropicais. A eficiência do caulim [com ou sem óleo de nim (Azadirachta indica)] e terra diatomácea (TD) (tratamento padrão) foi estudada em laboratório com o intuito de obter alternativas para o controle químico deste inseto. Insetos foram confinados em frascos de plástico com feijão tratado com caulim (2, 4 e 8g kg-1), caulim + nim [2g kg-1(5% óleo de nim)], terra diatomácea (1g kg-1) e controle. Mortalidade de insetos adultos, número de ovos e emergência da geração F1 foram avaliados. Caulim causou a mortalidade de Z. subfasciatus, porém foram necessários maiores períodos e doses que a TD para promover elevada mortalidade (100% ou aproximadamente). Os tratamentos com caulim também afetaram o comportamento da fêmea, pois muitos ovos foram colocados nas paredes dos frascos. O número de adultos emergidos (F1) foi similar entre a TD e o caulim; portanto, caulim constitui uma ferramenta promissora para o manejo de Z. subfasciatus. A mistura de caulim e óleo de nim não foi eficiente no controle de Z. subfasciatus.

Control of the Mexican bean weevil Zabrotes subfasciatus with kaolin

The Mexican bean weevil Zabrotes subfasciatus (Coleoptera: Chrysomelidae: Bruchinae) is an important pest of stored beans in tropical regions. The efficiency of kaolin [with or without neem (Azadirachta indica) oil] and diatomaceous earth (DE) (standard treatment) was studied in laboratory aiming to obtain alternatives for chemical control of this insect. Insects were confined in plastic vials containing beans treated with kaolin (2, 4 and 8g kg-1), kaolin + neem [2g kg-1(5% neem oil)], diatomaceous earth (1g kg-1) and control. Mortality of adult insects, number of eggs and F1generation beetles emergency were assessed. Kaolin caused mortality of Z. subfasciatus, however higher periods and doses than DE were necessary to promote high mortality (100% or close). Kaolin treatments also affected female behavior because many eggs were placed in the vials walls. Number of emerged adults (F1) was similar between DE and kaolin; hence, kaolin constitutes a promising tool to the management of Z. subfasciatus. The mixture of kaolin and neem oil was not efficient in the control of Z. subfasciatus.

O caruncho-do-feijão Zabrotes subfasciatus (Coleoptera: Chrysomelidae: Bruchinae) é uma importante praga de grãos de feijão armazenado nas regiões tropicais. A eficiência do caulim [com ou sem óleo de nim (Azadirachta indica)] e terra diatomácea (TD) (tratamento padrão) foi estudada em laboratório com o intuito de obter alternativas para o controle químico deste inseto. Insetos foram confinados em frascos de plástico com feijão tratado com caulim (2, 4 e 8g kg-1), caulim + nim [2g kg-1(5% óleo de nim)], terra diatomácea (1g kg-1) e controle. Mortalidade de insetos adultos, número de ovos e emergência da geração F1 foram avaliados. Caulim causou a mortalidade de Z. subfasciatus, porém foram necessários maiores períodos e doses que a TD para promover elevada mortalidade (100% ou aproximadamente). Os tratamentos com caulim também afetaram o comportamento da fêmea, pois muitos ovos foram colocados nas paredes dos frascos. O número de adultos emergidos (F1) foi similar entre a TD e o caulim; portanto, caulim constitui uma ferramenta promissora para o manejo de Z. subfasciatus. A mistura de caulim e óleo de nim não foi eficiente no controle de Z. subfasciatus.