This is the first characterization of S. frugiperda resistance to Vip3Aa protein. Our results provide useful information for resistance management programs designed to prevent or delay resistance evolution to Vip3Aa proteins in S. frugiperda. © 2016 Society of Chemical Industry.

No abstract

No abstract

Transgenic Agrisure Viptera 3 corn that expresses Cry1Ab, Vip3Aa20, and EPSPS proteins and Agrisure Viptera expressing Vip3Aa20 are used for control of Spodoptera frugiperda (J.E. Smith) and Diatraea saccharalis (F.) in Brazil. To support a resistance management program, resistance risk assessment studies were conducted to characterize the dose expression of Vip3Aa20 protein and level of control against these species. The Vip3Aa20 expression in Agrisure Viptera 3 and Agrisure Viptera decreased from V6 to V10 stage of growth. However, Vip3Aa20 expression in Agrisure Viptera 3 at V6 and V10 stages was 13- and 16-fold greater than Cry1Ab, respectively. The Vip3Aa20 expression in lyophilized tissue of Agrisure Viptera 3 and Agrisure Viptera diluted 25-fold in an artificial diet caused complete larval mortality of S. frugiperda and D. saccharalis. In contrast, lyophilized tissue of Bt11 at the same dilution does not provide complete mortality of these species. Agrisure Viptera 3 and Agrisure Viptera also caused a high level of mortality against S. frugiperda and D. saccharalis. Moreover, 100% mortality was observed for S. frugiperda larvae (neonates through fifth-instar larvae) when fed in corn with the Vip trait technology. Viptera corn achieves a high level of control against S. frugiperda and D. saccharalis providing a high dose, which is an important determination to support the refuge strategy for an effective resistance management program.

No abstract

Transgenic maize expressing the insecticidal protein Vip3Aa20 is increasingly being adopted in Brazil. In this study, we determined the baseline susceptibility of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) and Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) to Vip3Aa20, as part of an Insect Resistance Management (IRM) program. Diet-overlay bioassays were conducted with neonates exposed to Vip3Aa20 for 7 d. The baseline susceptibility data were obtained for seven field populations of H. armigera and six of H. zea collected from major soybean-, cotton-, and maize-producing areas in Brazil. To validate the diagnostic concentration, 11 field populations of H. zea were tested from 2014 to 2015. The LC50 for H. armigera populations ranged from 2.97 to 8.41 µg Vip3Aa20/cm2 (threefold variation), and for H. zea populations from 0.04 to 0.21 µg Vip3Aa20/cm2 (fivefold variation). The EC50 for H. armigera ranged from 0.099 to 0.455 µg Vip3Aa20/cm2 (fivefold variation), and for H. zea from 0.004 to 0.020 µg Vip3Aa20/cm2 (fivefold variation). H. armigera was more tolerant to Vip3Aa20 protein than was H. zea (≈40- to 75-fold, based on LC50). Based on the LC99 value, the concentration of 6.4 µg Vip3Aa20/cm2 was defined as a diagnostic concentration for susceptibility monitoring in H. zea, and >44 µg Vip3Aa20/cm2 for H. armigera. Our baseline susceptibility data for Vip3Aa20 in H. armigera and H. zea populations will be useful in IRM programs in Brazil.

No abstract

Resumo -O objetivo deste trabalho foi avaliar a efi ciência de produtos alternativos na proteção da videira (Vitis vinifera) contra o míldio (Plasmopara viticola), bem como determinar a infl uência desses produtos na qualidade dos frutos da cultivar Merlot. Para o controle da doença, foram utilizados produtos à base de extratos vegetais, manano-oligossacarídeos fosforilados, fosfi tos e acibenzolar-S-metil, além de fungicidas tradicionais. A intensidade do míldio em folhas e cachos, a produtividade, o número total de cachos por parcela, o peso médio do cacho e baga e as características analíticas do mosto foram avaliados nas safras de 2007/2008 e 2008/2009. Os fosfi tos proporcionaram proteção contra o míldio da videira, com produtividade semelhante à do tratamento com fungicidas tradicionais. Os tratamentos baseados em manano-oligossacarídeos fosforilados, acibenzolar-S-metil e extratos vegetais não apresentaram controle efi ciente do míldio. Os produtos alternativos testados não infl uenciam a qualidade analítica dos frutos, mas proporcionam, em geral, peso médio de cachos e de bagas menor que o do tratamento com fungicidas.Termos para indexação: Plasmopara viticola, Vitis vinifera, extratos vegetais, fosfi tos. Alternative products for the protection of vine against downy mildewAbstract -The objective of this work was to evaluate the effi ciency of alternative products for the protection of vine (Vitis vinifera) against downy mildew (Plasmopara viticola), and to determine the infl uence of these products on the quality of Merlot cultivar grapes. Products based on plant extracts, phosphorylated mannanoligosaccharides, phosphites and acibenzolar-S-methyl, besides traditional fungicides, were used for the disease control. The intensity of downy mildew on leaves and bunches, productivity, total number of bunches per plot, average weight of bunch and berry and analytical characteristics of grapes were assessed during the 2007/2008 and 2008/2009 seasons. Phosphites provided protection against downy mildew, and the yield was similar that of to the treatment with traditional fungicides. Treatments based on phosphorylated mannanoligosaccharides, acibenzolar-S-methyl and plant extracts showed no effective control of downy mildew. The alternative products tested do not infl uence the analytical quality of the grapes, but generally provide lower average weight of bunches and berries than the treatment with fungicides.