Resumo -O objetivo deste trabalho foi avaliar os efeitos do óleo de mamona sobre a broca-grande do tomateiro, Helicoverpa zea, e sobre o parasitoide de ovos Trichogramma pretiosum. Foi determinada a mortalidade larval da broca, que foi submetida ao óleo de mamona por ingestão e contato às concentrações 0,5, 1,0, 1,5, 2,0, 2,5 e 3,0% (v v -1 ). A ação do óleo de mamona sobre T. pretiosum foi determinada mediante testes de seletividade e suscetibilidade. As maiores mortalidades de larvas foram observadas no tratamento por contato com as menores concentrações (0,5 e 1,0%), enquanto com as concentrações intermediárias (1,5; 2,0 e 2,5%), não houve diferença entre as vias de aplicação. À maior concentração testada (3,0%), o tratamento por ingestão proporcionou mortalidade superior àquela obtida por contato. O número de ovos parasitados por T. pretiosum, no teste de seletividade, foi afetado negativamente pelo óleo de mamona, contudo, os demais parâmetros avaliados quanto à seletividade e à suscetibilidade não foram afetados. O óleo de mamona reduz a sobrevivência de larvas de H. zea tanto por ingestão quanto por contato. Além disso, não prejudica o desenvolvimento de T. pretiosum, desde que as pulverizações sejam realizadas após as liberações do parasitoide.Termos para indexação: Ricinus communis, broca-grande, parasitoide de ovos. Toxicity of Castor bean oil on Helicoverpa zea and Trichogramma pretiosumAbstract -The objective of this work was to evaluate the effects of castor bean oil on the tomato fruitworm, Helicoverpa zea, and on the egg parasitoid Trichogramma pretiosum. Mortality of tomato fruitworm was determined for larvae subjected to castor bean oil ingestion and contact at concentrations 0.5, 1.0, 1.5, 2.0, 2.5 e 3.0% (v v -1 ). The castor bean oil action on T. pretiosum was determined by selectivity and susceptibility tests. The greatest larvae mortalities were observed in the treatment by contact with the lowest concentrations (0.5 and 1.0%), while at intermediate concentrations (1.5, 2.0, and 2.5%) there were no differences between the ways of application. At the highest tested concentration of castor bean oil (3.0%), the ingestion treatment caused a higher mortality, in comparison to the treatment by contact. The number of eggs parasitized by T. pretiosum was negatively affected by castor bean oil in the selectivity test; however, other evaluated parameters for selectivity and susceptibility were not affected. Castor bean oil reduces survival of H. zea larvae both by ingestion and contact. In addition, it does not affect the development of T. pretiosum, since sprayings are performed after releasing of the parasitoid.
Pyrethroid insecticides are widely recommended against various defoliating pest species, but usually lack efficacy against sucking pests such as aphids, which are preferred prey of lacewing larvae. Interaction of pyrethroids and lacewings are likely to occur in fields infested by both defoliating and sap-sucking pests and should provide a complementary control. Therefore, our study aimed to estimate dose-mortality curves and behavioral changes by Chrysoperla externa exposed to lambda-cyhalothrin. We tested the susceptibility of two populations from different locations and insecticide history exposure through topical application. Based on the LD-calculated, the population exhibiting the greater LD was exposed to resistance enhancement (Sel) by treating larvae once for seven successive generations. The population with lower LD was kept without selection (Nsel). Subsequently, walking, predation and oviposition behavioral after exposure to dried insecticide residues were investigated. After seven generations with insecticide selection, the resistance rations between Sel and Nsel populations were 5.85- and 9.37-fold higher for larvae and 3.38- and 2.75-fold higher for adults, respectively. Selected females caged in partially treated arenas laid similar eggs number on both treated and untreated surfaces, while Nsel females laid fewer eggs on treated surfaces. Insecticide repellency was not observed in either population, although irritability was observed for Nsel larvae. Selected larvae confined on fully and partially treated surfaces walked further, for a longer time, and with greater speeds compared to Nsel larvae. Furthermore, Sel and Nsel larvae had reduced predation rates when confined on treated surfaces, and Nsel larvae consumed less prey than Sel larvae. Results indicate changes in susceptibility, behavior, and predation rate of C. externa following exposure to lambda-cyhalothrin.
Oligonychus ilicis (McGregor) (Acari) (Tetranychidae) é uma das principais pragas de Coffea canephora Pierre & Froehner. Neste trabalho, avaliou-se o efeito de diferentes temperaturas no desenvolvimento desse ácaro-vermelho em folhas de C. canephora, em laboratório. Confinaram-se 80 fêmeas em 40 arenas, constituídas de disco foliar de 4 cm, para oviposição nas temperaturas de 21, 24, 27, 30 e 33 ºC. Foram selecionados ao acaso pelo menos dois ovos para avaliar o desenvolvimento embrionário. Após a eclosão da larva, foram realizadas avaliações a cada 12 horas para obtenção da duração e sobrevivência larval. Para avaliar a longevidade foi transferido um ácaro macho da criação para as arenas com uma fêmea para acasalamento. O limite térmico de desenvolvimento inferior e a constante térmica foram determinados para a duração do desenvolvimento de ovo a adulto. O tempo de desenvolvimento das fases imaturas diminuiu com o aumento da temperatura. As fases de ovo, larva, protocrisálida, protoninfa, deutocrisálida, deutoninfa e teleiocrisálida variaram, respectivamente, de 10,4 a 4,3; 2,4 a 1,2; 2,0 a 1,0; 2,3 a 1,2; 1,9 a 1,0; 3,0 a 1,5 e 2,3 a 1,0 dias. O aumento da temperatura afetou o período de desenvolvimento, reduzindo a duração de ovo-adulto e a longevidade. O limite térmico inferior foi de 9,0 ºC para o período de ovo-adulto e constante térmica de 256,4 graus-dias. Em condições de laboratório, a faixa de temperatura que favorece o desenvolvimento do ácaro em C. canephora foi de 24 a 30 ºC. O limite térmico inferior não é limitante para ocorrência de O. ilicis em áreas cultivadas com C. canephora no estado do Espírito Santo.
The Neotropical green lacewing Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) is a key predator of various small soft-bodied pest species. Chrysopidae species are known as 'green lacewings' due to their overall green body coloration. However, yellow mutant individuals were observed emerging from our lacewing rearing colony. Thus, the mode of inheritance of the yellow trait was studied and the hypothesis of an autosomal recessive allele for yellow color was tested using hybridization and backcrossing techniques. Furthermore, the possible implications of this color variation on specific life-history characteristics of C. externa and the predation rates of each morph were evaluated. In both yellow and green morphs, basic life-history characteristics were monitored, including time to hatching and viability of eggs, duration, and viability of larval and pupal stages, emergence rate and survivorship of adults, and fecundity and longevity of females. The yellow and green morphs were indistinguishable with respect to all life-history traits evaluated and the predation rate of their larvae. Crossing experiments revealed the yellow color to be caused by a homozygous recessive allele, without sex-linked expression. We conclude that the allele for yellow color is occurring at high frequency in the laboratory colony, supporting the existence of a genetic polymorphism for body ground color.
AGRONOMIA (AGRONOMY) RESUMO: Beauveria bassiana (Bals.) Vuillemin e o óleo de mamona são ferramentas promissoras no manejo integrado de pragas. Assim sendo, este trabalho determinou concentrações de óleo de mamona que sejam biologicamente compatível com isolados de B. bassiana. No teste de compatibilidade, foram utilizados cinco isolados de B. bassiana e sete concentrações do óleo de mamona. O delineamento experimental foi inteiramente casualizado no esquema fatorial 5 x 7 (isolados de B. bassiana x concentração de óleo de mamona), totalizando 35 tratamentos. Os parâmetros biológicos de germinação, crescimento vegetativo e esporulação foram avaliados e usados para calcular o índice biológico (IB). O isolado CCA-UFES/Bb-4 apresentou a germinação de conídios e esporulação sempre igual ou superior aos demais isolados, em todas as concentrações de óleo de mamona. O isolado CCA-UFES/Bb-11 apresentou crescimento vegetativo igual ou maior que os demais isolados, exceto à 0,5% (v/v) de óleo de mamona. O grau de fungitoxicidade do óleo de mamona é variável em função do isolado de B. bassiana. Palavras-chave: controle biológico; fungos entomopatogênicos; inseticidas botânicos In vitro compatibility between Beauveria bassiana and castor oil ABSTRACT: Beauveria bassiana (Bals.) Vuillemin and castor oil are promising tools for integrated pest management. This work determined concentrations of castor oil that are biologically compatible with B. bassiana isolates. In the compatibility test, five isolates of B. bassiana and seven concentrations of castor oil were used. The experimental design was completely randomized in the factorial scheme 5 x 7 (isolates of B. bassiana x concentration of castor oil), totaling 35 treatments. The biological parameters germination, vegetative growth and sporulation were evaluated and used to calculate the biological index (BI). The CCA-UFES/ Bb-4 isolate showed the conidia germination and sporulation always equal to or greater than the other isolates, in all concentrations of castor oil. The CCA-UFES/Bb-11 isolate showed vegetative growth equal to or greater than the other isolates, except at 0.5% (v/v) of castor oil. The degree of fungitoxicity of castor oil varies according to B. bassiana isolate.
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