The southern armyworm (SAW) Spodoptera eridania (Cramer) is one of the most common armyworm species defoliating soybeans. Preliminary screening trials have indicated that some soybean genotypes exhibit resistance to SAW. Therefore, in this study, we evaluated the development of SAW larvae fed on ten soybean genotypes in order to identify genotypes with antibiosis-type resistance. Neonate SAW larvae were daily fed with young leaves collected from plants at the vegetative growth stages V4-V5. Larval development and survival were recorded. Genotypes PI 227687 and PI 227682 delayed larval, pupal, and larva-adult development and yielded larvae with the lowest weight and survival and pupae with the lowest weight. Genotypes IAC 100 and DM 339 also negatively affected larval and pupal development and larval survival but at a lower level. Based on our results, the soybean lines PI 227687 and PI 227682 could be used as sources of genes for soybean breeding programs aiming to develop high yield, SAW-resistant cultivars. Moreover, further trials must be carried out under field conditions to validate if the commercial cultivars IAC 100 and DM 339, which expressed moderate levels of antibiosis-type resistance in the laboratory, are effective in suppressing SAW larvae populations.
); iGnÁCio JosÉ de GodoY ( 3 ); MarCos doniseTi MiCHeloTTo ( 4 ); alessandra pereira fÁvero ( 5 ) RESUMO no Brasil, diversas pragas podem atacar o amendoinzeiro, sendo o tripes-do-prateamento, Enneothrips flavens Moulton (Thysanoptera: Thripidae), a principal delas. Com o objetivo de avaliar a infestação e os sintomas dessa praga em diferentes acessos de espécies silvestres, anfidiplóides e cultivares de amendoinzeiro, foi instalado um experimento em campo, no município de pindorama (sp), no ano agrícola de 2007/2008. o delineamento estatístico adotado foi o de blocos ao acaso, com 48 tratamentos e cinco repetições. a formação das mudas foi feita em copos com substrato em casa de vegetação, sendo o plantio realizado em outubro/novembro de 2007. foram realizadas amostragens a partir dos 30 dias após o plantio das mudas no campo, repetidas a cada 15 dias, num total de cinco avaliações, em cinco folíolos fechados por planta. foram anotadas a presença e ausência de tripes em folíolos ainda fechados e atribuídas notas dos sintomas de dano aos folíolos recém-abertos, baseando-se em uma escala de notas variando de 1 a 5, sendo nota 1 sem dano de ataque; nota 2 limbo foliar com 1% a 25% da superfície com estrias e deformações; nota 3, 26 a 50%; nota 4, 51 a 75%; e, nota 5, 76% a 100%. os acessos com menor porcentagem de presença de tripes e notas de sintomas foram vs14957 ( . villosa). dentre os acessos mais sensíveis ao tripes situaram-se v12549 (Arachis hypogaea),ac2562 (A. hypogaea) e as cultivares IAC Caiapó (A. hypogaea) e iaC runner 886 (A. hypogaea). Palavras-chave:Thripidae, Enneothrips flavens, resistência de plantas, oleaginosas. ABSTRACT evaluaTion of Wild speCies and CulTivars of peanuT for resisTanCe To THeENNEOTHRIPS FLAVENS MoulTon in Brazil, various pests are reported to infest peanut crop, being the thrips Enneothrips flavens the most important. Accesses of wild peanut species, anfidiploide and peanut cultivars were evaluated in field conditions at pindorama, são paulo state, at the agricultural year of 2007/2008. The experiment consisted of a complete ramdomized block design with 48 treatments and five replications. The material was sown in small bags under greenhouse conditions. plantings were carried out in october/november 2007. starting at 30 days after planting in the field, evaluations were done at 15-day intervals, in five closed leaves of each plant. The following data were obtained: presence or absence of thrips in each leaf; symptoms of thrips damage in recently opened leaves, based on a 1-5 scale where 1 = without damage, 2 = 1 to 25% of the leaf surface with damage (grooves and deformations), 3 = 26 to 50%, 4 = 51 to 75% and 5 = 76 to 100% of damage symptoms. The accesses with the least damages and insect presence were: vs14957 (A. gregoryi), v13832 (A. stenosperma), v8979 (A. kuhlmannii), v9912 (A. kuhlmannii), v7639 (A. kuhlmannii) e vMiirlbGv14309 (A. villosa). The most sensitive accesses were v12549 (A. hypogaea), ac2562 (A. hypogaea) and the commercial A. hypogaea genotypes IAC Caiapó ...
ResumoEste trabalho teve como objetivos avaliar a atratividade, não preferência para alimentação e antibiose em cultivares de amendoim de hábitos de crescimento ereto e rasteiro a Stegasta bosquella (Chambers). Avaliaram-se oito cultivares, sendo quatro de hábito de crescimento ereto (IAC Tatu, IAC 22, IAC 8112 e IAC 5) e quatro de hábito rasteiro (IAC Runner 886, IAC 147, IAC 125 e IAC 503). Foram realizados testes de não preferência para alimentação com e sem chance de escolha, utilizando-separes de discos foliares sobrepostos de 1,0 cm de diâmetro, os quais foram dispostos em placas de Petri onde foram liberadas lagartas de terceiro instar de S. bosquella. Avaliou-se a atratividade das lagartas em tempos pré-estabelecidos, além da massa seca consumida. No teste de antibiose, foram avaliados os parâmetros biológicos: período e viabilidade larval, de pré-pupa, pupal e total, pesos de lagartas e pupas, razão sexual e longevidade. Nenhuma das cultivares de amendoim de hábito de crescimento rasteiro apresentaram resistência do tipo não preferência para alimentação. Dentre as cultivares de hábito de crescimento ereto, IAC 5 e IAC 22 foram as menos atrativas e consumidas no teste de não preferência para alimentação com chance de escolha, e IAC 5 e IAC 8112 foram as menos atrativas no teste sem chance de escolha. As cultivares de hábito rasteiro IAC 147 e IAC Runner 886 afetaram a sobrevivência larval de S. bosquella, apresentando resistência do tipo antibiose. Para as cultivares de hábito ereto, IAC 22 e IAC 8112 afetaram a viabilidade larval, apresentando resistência do tipo antibiose. As cultivares de hábito de crescimento rasteiro e ereto não influenciaram os parâmetros biológicos de peso de pupa, razão sexual e longevidade de S. bosquella. Palavras-chave: Arachis hypogaea, lagarta-do-pescoço-vermelho, oleaginosas, resistência de plantas a insetos AbstractThis work aimed to evaluate the attractiveness, non-preference for feeding and antibiosis in straight and runner growth habit peanut cultivars to Stegasta bosquella (Chambers). Eight cultivars were evaluated, four of straight growth habit (IAC Tatu, IAC 22, IAC 8112 and IAC 5) and four of runner growth habit (IAC Runner 886, IAC 147, IAC 125 and IAC 503). Free-choice and no-choice feeding tests were performed, using pairs of overlapped leaf discs with 1.0 cm diameter, which were placed in Petri dishes where third instar larvae of S. bosquella were released. The attractiveness to the larvae was assessed
ABSTRACT. Effect of bean genotypes, insecticides, and natural products on the control of Bemisia tabaci (Gennadius) biotype B (Hemiptera: Aleyrodidae) and Caliothrips phaseoli (Hood) (Thysanoptera: Thripidae). The influence of bean genotypes associated with neem oil as insecticide was evaluated to control B. tabaci (Gennadius) biotype B and C. phaseoli (Hood) during the wet season sowing. The experimental design used was the randomized block arrangement in a 4x4x3 factorial scheme, represented by genotypes, neem oil and insecticides respectively, with three replications. The genotypes Carioca, IAC Harmonia, IAC Centauro and Pérola were used. The evaluations were done at 14 and 42 days after seedling emergence, by counting B. tabaci biotype B eggs and nymphs and C. phaseoli nymphs in the genotypes leaf. Conclusion: The B. tabaci biotype B eggs and nymphs number were smaller in IAC Centauro and higher in IAC Harmonia. The tested genotypes were similarly infested by C. phaseoli. IAC Centauro and IAC Harmonia genotypes associated with neem oil (highlighting the full dose -1%) provided lower number of whitefly eggs and thrips nymphs. Neem oil at the full dose also reduced whitefly nymph number. In the tested genotypes the insecticide provided reduction in the number of whitefly eggs and nymphs as well in the thrips nymphs, with increase in the recommend dose.
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