Efeito do espaçamento e de Bacillus thuringiensis Berliner sobre Alabama argillacea (Hübner), Aphis gossypii Glover e inimigos naturais no algodoeiro

Some insects are important pests in cotton crops and can cause serious yield losses. Among them we can relate Alabama argillacea (cotton leafworm) and Aphis gossypii (cotton aphid), demanding, often, the use of control measures. This study aimed to evaluate the toxicity of Bacillus thuringiensis (Dipel®) to cotton leafworm and analyze its effect on the occurrence of this pest and the cotton aphid in cotton grown under two system of row spacing, in two places in the State of Mato Grosso, Brazil, as well as in some natural enemies. The toxicity was evaluated using doses of 0.30, 0.50, 0.75 and 1.00 L/ha, considering large cotton leafworm larvae (>1.5 cm) and small ones (<1.5 cm) in a laboratory bioassay. The effect of the biopesticide on A.argillacea and A. gossypii was compared in cotton grown in row spacing of 0.90m (conventional) and 0.45m (reduced). The results indicate that: Dipel® has good efficiency for control A. argillacea caterplillars and is selective for A. gossypii, causing a significant increase in cotton yield; 0.45m row spacing promotes a decrease in density of larvae of A. argillacea and A.gossypii, and yield is similar in both spacing, 0.90 and 0.45m, and bigger in treated areas.Alguns insetos são importantes pragas na cultura algodoeira, podendo provocar sérias perdas na produção, dentre eles pode-se citar Alabama argillacea e Aphis gossypii, os quais exigem, não raras vezes, a utilização de medidas de controle. Esse trabalho teve como objetivo avaliar a toxicidade de Bacillus thuringiensis Berliner var. kurstaki (Bt - Dipel®) para A. argillacea; avaliar seu efeito sobre A. argillacea e A. gossypii em algodoeiro cultivado em dois esquemas de espaçamento, e em alguns inimigos naturais na cultura. A toxicidade de Bt foi avaliada testandose as doses de 0,30; 0,50; 0,75 e 1,00 L/ha sobre lagartas grandes (> 1,5 cm) e pequenas (< 1,5 cm). O efeito do bioinseticida sobre A. argillacea e A. gossypii foi estudado em algodoeiro DeltaOpal cultivado nos espaçamentos entrelinhas de 0,90m (convencional) e 0,45m (reduzido), em duas localidades do Estado de Mato Grosso, Brasil. O Bt foi eficiente no controle de lagartas pequenas e grandes de A. argillacea, provocando aumento significativo na produtividade do algodoeiro quando em comparação com a testemunha, não afetando outros artrópodes; o espaçamento 0,45m promoveu diminuição na densidade de lagartas de A. argillacea e de A. gossypii, quando em comparação com o espaçamento de 0,90m; e a produtividade do algodoeiro foi semelhante nos espaçamentos de 0,90 e 0,45m, e maior nas áreas tratadas

Life-History and Behavior of the Diamondback Moth Plutella xylostella on Brassicaceae Cultivars over Multiple Generations

The diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae), is a cosmopolitan pest that causes leaf-area reduction in Brassicaceae plants. DBM populations have significant genetic variability that manifests in different feeding preferences and reproductive behaviors across generations. We evaluated the influence of Brassicaceae cultivars on biological and behavioral parameters across 18 generations of DBM populations that were separated and held on three varieties of Brassicaceae: Brassica oleracea var. acephala (kale), Brassica oleracea var. italica (broccoli), and Brassica oleracea var. capitata (cabbage). P, F6, F12, and F18 generations were evaluated, and biological aspects of young adulthood and fertility parameters of adults held on each host plant were examined over multiple generations. Additionally, larvae and adults were subjected to dual-choice and multiple-choice (feeding and oviposition) between cultivars, over generations. The results indicated that larvae of P. xylostella consumed greater quantities of kale and broccoli cultivars, on average (4.05 cm2), than cabbage (2.7 cm2). The number of eggs per female in F18 generation was 1.95 and 2.17 times higher than those in the parental (P) generation, when reared on kale and cabbage. The population reared exclusively on kale had higher net population growth rate (R0), intrinsic rate (rm), finite rate (λ) and generation time (T) than that reared on broccoli and cabbage. Last generations evaluated, the larval stage reared on cabbage showed feeding preference (F18) and oviposition preference (F12 and F18) for cabbage. Thus, we note the existence of learning, characterized as pre-imaginal conditioning to cabbage cultivars, over various DBM generations

Whole genome comparisons reveal panmixia among fall armyworm (Spodoptera frugiperda) from diverse locations

Background: The fall armyworm (Spodoptera frugiperda (J.E. Smith)) is a highly polyphagous agricultural pest with long-distance migratory behavior threatening food security worldwide. This pest has a host range of > 80 plant species, but two host strains are recognized based on their association with corn (C-strain) or rice and smaller grasses (R-strain). The population genomics of the United States (USA) fall armyworm remains poorly characterized to date despite its agricultural threat. Results: In this study, the population structure and genetic diversity in 55 S. frugiperda samples from Argentina, Brazil, Kenya, Puerto Rico and USA were surveyed to further our understanding of whole genome nuclear diversity. Comparisons at the genomic level suggest a panmictic S. frugiperda population, with only a minor reduction in gene flow between the two overwintering populations in the continental USA, also corresponding to distinct host strains at the mitochondrial level. Two maternal lines were detected from analysis of mitochondrial genomes. We found members from the Eastern Hemisphere interspersed within both continental USA overwintering subpopulations, suggesting multiple individuals were likely introduced to Africa. Conclusions: Our research is the largest diverse collection of United States S. frugiperda whole genome sequences characterized to date, covering eight continental states and a USA territory (Puerto Rico). The genomic resources presented provide foundational information to understand gene flow at the whole genome level among S. frugiperda populations. Based on the genomic similarities found between host strains and laboratory vs. field samples, our findings validate the experimental use of laboratory strains and the host strain differentiation based on mitochondria and sex-linked genetic markers extends to minor genome wide differences with some exceptions showing mixture between host strains is likely occurring in field populations.Fil: Schlum, Katrina A.. University of Tennessee; Estados UnidosFil: Lamour, Kurt. University of Tennessee; Estados UnidosFil: Placidi de Bortoli, Caroline. University of Tennessee; Estados UnidosFil: Banerjee, Rahul. University of Tennessee; Estados UnidosFil: Meagher, Robert. United States Department Of Agriculture. Center For Medical Agric And Vet Entomology; Estados UnidosFil: Pereira, Eliseu. Universidade Federal de Viçosa; BrasilFil: Murúa, María Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Tecnología Agroindustrial del Noroeste Argentino. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (p). Instituto de Tecnología Agroindustrial del Noroeste Argentino; ArgentinaFil: Sword, Gregory A.. Texas A&M University; Estados UnidosFil: Tessnow, Ashley E.. Texas A&M University; Estados UnidosFil: Viteri Dillon, Diego. Universidad de Puerto Rico; Puerto RicoFil: Linares Ramirez, Angela M.. Universidad de Puerto Rico; Puerto RicoFil: Akutse, Komivi S.. International Centre Of Insect Physiology And Ecology; KeniaFil: Schmidt Jeffris, Rebecca. United States Department Of Agriculture. Center For Medical Agric And Vet Entomology; Estados UnidosFil: Huang, Fangneng. State University of Louisiana; Estados UnidosFil: Reisig, Dominic. North Carolina State University; Estados UnidosFil: Emrich, Scott J.. University of Tennessee; Estados UnidosFil: Jurat Fuentes, Juan Luis. University of Tennessee; Estados Unido

Toxicidade e efeitos subletais de toxinas Cry de Bacillus thuringiensis Berliner em diferentes populações de Plutella xylostella (L.) (Lepidoptera: Plutellidae) em laboratório

Plutella xylostella (Linnaeus , 1758) (Lepidoptera: Plutellidae), diamonback moth, is a major insect pest of crucifers (Brassicaceae) in Brazil and worldwide. Although it can be controlled with synthetic insecticides such as biological products, populations of P. xylostella can be quickly selected for resistance to several chemical or biological insecticides. In addition, different populations of P. xylostella may arise due to geographic isolation, resulting in reproductive isolation and physiologically distinct populations with different sensitivities to various control tactics. This variation requires management systems tailored to particular populations. The most common insecticides used to control P. xylostella based on entomopathogenic bacterium Bacillus thuringiensis (Bacillaceae) (Bt). Although many studies focus on the action way of Bt to several agricultural pests such as P. xylostella, for example, many doubts still persist particularly regarding their sublethal effects, mechanism of action and toxicity of Bt proteins. The objective of this research was to analyze the virulence and sublethal effects of Cry proteins, as well investigate factors affecting the susceptibility of Diamondback to Bt (protein level, the midgut bacteria and mutations in the ABCC2 gene) in five Brazilian populations and one population from England. Susceptibility bioassays with 5 Brazilian populations (PC, PA, PX, SBT and Bt) and one from England (UK) of P. xylostella and Cry1Ac, Cry2Aa, and Cry1IE Bt toxins were performed by estimating its virulence and sublethal effects. How Cry2Aa Cry1IE toxins did not cause larvae mortality for all populations, tests were performed just with Cry1Ac. Enzymatic and molecular experiments with the larvae guts were also performed to investigate the factors that affecting the susceptibility of insects to toxins produced by Bt. In those bioassays were analyzed total protein, the ...Plutella xylostella (Linnaeus, 1758) (Lepidoptera: Plutellidae), a traça-das-crucíferas, é um dos principais insetos-praga de crucíferas (Brassicaceae) no Brasil e em todo o mundo. Embora possa ser controlada tanto com inseticidas sintéticos como biológicos, populações de P. xylostella podem ser selecionadas rapidamente para a resistência a vários inseticidas químicos ou biológicos. Além disso, diferentes populações de P. xylostella podem surgir devido ao isolamento geográfico, resultando em isolamento reprodutivo e em populações fisiologicamente distintas, com diferentes sensibilidades a várias táticas de controle. Tal variação requer sistemas de gestão adaptados às populações em particular. Os bioinseticidas mais comuns utilizados para controlar P. xylostella baseiam-se na bactéria entomopatogênica Bacillus thuringiensis (Bacillaceae) (Bt). Apesar de muitos estudos focarem a ação do Bt em diversas pragas agrícolas, como P. xylostella, por exemplo, muitas dúvidas ainda persistem particularmente quanto aos seus efeitos subletais, mecanismo de ação e toxicidade das proteínas Bt. Assim, o objetivo desta pesquisa foi analisar a virulência e os efeitos subletais de proteínas Cry, bem como investigar fatores que afetam a suscetibilidade de insetos ao Bt (níveis de proteína, bactérias do intestino médio e mutações no gene ABCC2) em cinco populações brasileiras e uma da Inglaterra de P. xylostella. Foram realizados bioensaios de suscetibilidade com 5 populações brasileiras (PC, PA, Px, SBT e Bt) e uma da Inglaterra (UK) de P.xylostella e as proteínas Cry1Ac, Cry2Aa e Cry1IE de B. thuringiensis, estimando-se a virulência e avaliando os efeitos subletais das toxinas. Como as toxinas Cry2Aa e Cry1IE não causaram mortalidade nas lagartas de todas as populações, os testes foram realizados apenas com Cry1AC. Também foram conduzidos experimentos enzimáticos e ..

Índices de consumo e utilização de dietas artificiais e folhas de amoreira por larvas de Bombyx mori L. (Lepidoptera: Bombycidae)

Despite all the benefits that an artificial diet can make to the Bombyx mori rearing, as labor savings, greater production efficiency, raising during creating unfavorable conditions, and rearing virtually free of diseases, was not yet developed an adequate artificial diet for all larval stages. However , in Japan the use of artificial diets is highly diffused to rearing first and second instars silkworm larvae, covering about 50 % of the productions. The objective of this study was to determine the effects of offering artificial diets in the early instars on the consumption of natural diet and metabolism in late instar larvae of B. mori. Three types of treat systems were tested: (i) artificial diet adapted from Miao & Jiang for the first larvae instar and natural diet for others instars; (ii) similar to the previous system, differing from it by the adapted Miao & Jiang diet have been offered to larvae of first and second instars; (iii) artificial diet adapted from Sadiq for the first larvae instar and natural diet for others instars; and (iv) natural diet for all larval instars (check). As natural diet it was used fresh mulberry leaves of the hybrid ‘Shima-Miura”, that was offered five times a day. Consumption and metabolism of fifth instar larvae (late larval stage) were studied by assessing: relative consumption rate, the relative metabolic rate, relative growth rate, efficiency of conversion of ingested food into biomass; conversion efficiency the food digest into biomass; and approximate digestibility. No significant effect of feeding treatment systems was observed in any biological parameter studied, indicating that the supply of artificial diets Sadiq for the first instar larvae, or Jiang & Miao diet for the first and second instars larvae, were not affecting the consumption of natural diet and metabolism of fifth larvae of B. mori, showing that they can be incorporated into a silkworm food system.Despite all the benefits that an artificial diet can make to the Bombyx mori rearing, as labor savings, greater production efficiency, raising during creating unfavorable conditions, and rearing virtually free of diseases, was not yet developed an adequate artificial diet for all larval stages. However , in Japan the use of artificial diets is highly diffused to rearing first and second instars silkworm larvae, covering about 50 % of the productions. The objective of this study was to determine the effects of offering artificial diets in the early instars on the consumption of natural diet and metabolism in late instar larvae of B. mori. Three types of treat systems were tested: (i) artificial diet adapted from Miao & Jiang for the first larvae instar and natural diet for others instars; (ii) similar to the previous system, differing from it by the adapted Miao & Jiang diet have been offered to larvae of first and second instars; (iii) artificial diet adapted from Sadiq for the first larvae instar and natural diet for others instars; and (iv) natural diet for all larval instars (check). As natural diet it was used fresh mulberry leaves of the hybrid ‘Shima-Miura”, that was offered five times a day. Consumption and metabolism of fifth instar larvae (late larval stage) were studied by assessing: relative consumption rate, the relative metabolic rate, relative growth rate, efficiency of conversion of ingested food into biomass; conversion efficiency the food digest into biomass; and approximate digestibility. No significant effect of feeding treatment systems was observed in any biological parameter studied, indicating that the supply of artificial diets Sadiq for the first instar larvae, or Jiang & Miao diet for the first and second instars larvae, were not affecting the consumption of natural diet and metabolism of fifth larvae of B. mori, showing that they can be incorporated into a silkworm food system

Folhas de amoreira tratadas com vitamina e esterol e seus efeitos em parâmetros biológicos de Bombyx mori L.

This study aimed to evaluate the effects of adding different concentrations of the leaf additivesnandrolone decanoate, ascorbic acid, retinol palmitate and retinol acetate on biologicalparameters of Bombyx mori larvae. The results showed that nandrolone and ascorbic acid, bothat 0.5%, provide the best value for the development of the larvae of B. mori, values which do notcorrespond to significant increases in cocoon and silk production; 1.0% of retinol palmitate shownegative effect to larvae development.O objetivo do trabalho foi avaliar o efeito dos aditivos foliares Decanoato de nandrolona, Ácidoascórbico, Palmitato de retinol e Acetato de retinol, em diferentes concentrações, sobre algunsparâmetros biológicos do bicho da seda, Bombyx mori. Verificou-se que o ácido ascórbico e anandrolona, ambos a 0,5%, proporcionam os melhores valores para o desenvolvimento corpóreodas lagartas de B. mori, valores estes que não correspondem a incrementos significativos naprodução de seda; 1,0% palmitato de retinol afeta negativamente o desenvolvimento corpóreodas lagartas de B. mori. Effects of mulberry leaves treated with vitamin and esterol affect biologicalparameters of Bombyx mori L.This study aimed to evaluate the effects of adding different concentrations of the leaf additivesnandrolone decanoate, ascorbic acid, retinol palmitate and retinol acetate on biologicalparameters of Bombyx mori larvae. The results showed that nandrolone and ascorbic acid, bothat 0.5%, provide the best value for the development of the larvae of B. mori, values which do notcorrespond to significant increases in cocoon and silk production; 1.0% of retinol palmitate shownegative effect to larvae development

Efeito do espaçamento e de Bacillus thuringiensis Berliner sobre Alabama argillacea (Hübner), Aphis gossypii Glover e inimigos naturais no algodoeiro

Some insects are important pests in cotton crops and can cause serious yield losses. Among them we can relate Alabama argillacea (cotton leafworm) and Aphis gossypii (cotton aphid), demanding, often, the use of control measures. This study aimed to evaluate the toxicity of Bacillus thuringiensis (Dipel®) to cotton leafworm and analyze its effect on the occurrence of this pest and the cotton aphid in cotton grown under two system of row spacing, in two places in the State of Mato Grosso, Brazil, as well as in some natural enemies. The toxicity was evaluated using doses of 0.30, 0.50, 0.75 and 1.00 L/ha, considering large cotton leafworm larvae (>1.5 cm) and small ones ( 1,5 cm) e pequenas (< 1,5 cm). O efeito do bioinseticida sobre A. argillacea e A. gossypii foi estudado em algodoeiro DeltaOpal cultivado nos espaçamentos entrelinhas de 0,90m (convencional) e 0,45m (reduzido), em duas localidades do Estado de Mato Grosso, Brasil. O Bt foi eficiente no controle de lagartas pequenas e grandes de A. argillacea, provocando aumento significativo na produtividade do algodoeiro quando em comparação com a testemunha, não afetando outros artrópodes; o espaçamento 0,45m promoveu diminuição na densidade de lagartas de A. argillacea e de A. gossypii, quando em comparação com o espaçamento de 0,90m; e a produtividade do algodoeiro foi semelhante nos espaçamentos de 0,90 e 0,45m, e maior nas áreas tratadas