ABSTRACT:Corn rootworm Diabrotica speciosa is an important pest in several crops. The aim of this work was to study the biology of adult D. speciosa and build a fertility life table in the natural diet based on beans, and beans, sliced carrots and honey solution at 10%. The following parameters were: duration of pre-oviposition, oviposition and post-oviposition, total fertility, adult longevity and egg viability. For the fertility life table parameters, the following were determined: generation interval (T), net reproductive rate (Ro), intrinsic rate of increase (rm) and finite rate of increase (λ). From the results obtained, it can be observed that there was an influence of food offered to adults for the duration of pre-oviposition and oviposition, and also in total fertility and viability of eggs. Adult longevity was influenced by diet consisting of bean leaflets. Among the treatments, a diet consisting of beans, carrot and honey provided higher significant longevity of males compared to those fed with beans. The results in the fertility table indicated that the reproductive potential of D. speciosa significantly increases in two successive generations when females are fed on beans, carrots and honey, showing there is improved mass rearing for this insect under laboratory conditions. KEYWORDS: corn rootworm; reproduction rate; host plant. RESUMO:A vaquinha Diabrotica speciosa é uma importante praga em diversas culturas. O objetivo deste trabalho foi estudar a biologia de adultos de D. speciosa e construir a tabela de vida de fertilidade em dieta natural à base de feijão, e à base de feijão, rodelas de cenoura e solução de mel a 10%. Os parâmetros biológicos avaliados foram: duração dos períodos de pré-oviposição, oviposição e pós-oviposição, fecundidade total, longevidade de adultos e viabilidade dos ovos. Para a tabela de vida de fertilidade, os parâmetros determinados foram: intervalo entre gerações (T), taxa líquida de reprodução (Ro), taxa intrínseca de crescimento (rm) e taxa finita de aumento (λ). A partir dos resultados obtidos, pode-se constatar que houve influência do alimento oferecido aos adultos para os períodos de pré-oviposição e oviposição, e também na fecundidade total e na viabilidade dos ovos. A longevidade dos adultos foi influenciada pela dieta constituída de folíolos de feijão. A dieta constituída de feijão, cenoura e mel propiciou maior longevidade significativa dos machos em relação àqueles alimentados com feijão. Os resultados da tabela de fertilidade indicaram que o potencial de reprodução de D. speciosa aumenta significativamente em duas gerações sucessivas quando as fêmeas são alimentadas com feijão, cenoura e mel, demonstrando que há melhoria na criação massal desse inseto em condições de laboratório.
RESUMO - A produção de milho tem sofrido grandes avanços, propiciando aumento de produtividade, no entanto, esta é diretamente afetada pelo ataque de insetos desde o plantio até a sua utilização. Neste contexto, Spodoptera frugiperda (J. E. Smith, 1797) (Lepidoptera: Noctuidae) é considerada o principal inseto-praga. Para a cultura do milho já existem níveis de controle definidos, entretanto, mesmo utilizando os já estabelecidos, ocorrem perdas na produção. Assim, o objetivo do estudo foi reavaliar o nível de dano de S. frugiperda em milho convencional BG7060, por meio de infestação artificial com diferentes densidades populacionais de lagartas (0, 1, 3, 5, 10, 15 e 20 lagartas planta-1) em plantas no estádio fenológico V4-V8 (folhas completamente expandidas) em condições de casa de vegetação. Os resultados obtidos evidenciaram que o aumento do número de lagartas de S. frugiperda por planta afeta todas as variáveis relacionadas à produtividade, exceto a altura de planta e comprimento da espiga, propiciando uma menor produtividade. Constatou-se que o nível de controle de S. frugiperda para o híbrido BG7060 no estádios V4-V8 é 29% de plantas atacadas em uma amostragem de 100 plantas, quando ocorre uma lagarta planta-1.Palavras-chave: nível de controle, monitoramento, manejo integrado de pragas, Zea mays L. LEVEL OF DAMAGE OF FALL ARMYWORM, Spodoptera frugiperda, IN CONVENTIONAL MAIZE IN GREENHOUSE CONDITIONS ABSTRACT - The maize production has advanced considerably providing an increase in productivity, however, this is directly affected by the insect attack in all phases. In this context, the fall armyworm Spodoptera frugiperda (J. E. Smith, 1797) (Lepidoptera: Noctuidae) is considered the main insect-pest. There is a control levels set for the maize production, however, using the level of control already established, production losses occur. In this sense, the purposes of the study was re-evaluate the level of damage of the S. frugiperda in conventional maize, BG7060, through artificial infestation with different populational densities (0, 1, 3, 5, 10, 15 and 20 caterpillars plant-1), of plants at V4-V8 phenological stage (fully expanded leaves) in green house conditions. The results obtained highlighted that the increase in the number of caterpillars of S. frugiperda by plant affects all variables related to productivity, except the plant height and length of the ear, providing a smaller productivity. It was found that the control level of S. frugiperda for the BG7060 maize for V4-V8 stage is 29% of attacked plants in a sample of 100 plants, when there is one caterpillar per plant.Keywords: level control, monitoring, integrated pest management, Zea mays L.
RESUMO -O objetivo desse trabalho foi avaliar os danos causados por diferentes densidades larvais de DAMAGE CAUSED BY CORN ROOTWORM IN CORN FIELD CONDITIONSABSTRACT -The aim of this study was to evaluate the damage caused by different larval densities of Diabrotica speciosa in maize BG 7060 H under field conditions. The experiment was conducted in the field in 2012/2013, at Embrapa Clima Temperado (31°S 52°W 49,268 and 27,472). Each plot consisted of six rows 5 m x 0.70 m and the cultivar used was BG 7060 H. The plants were infested with 5, 15, 30 and 40 larvae/plant, and there was a control (no larvae). The damage, weight and length of roots were evaluated 64 days after infestation (DAI) (22/01/2013). At the harvest, plant and ear height and yield were evaluated. No significant reduction in the weight of roots infested with larvae of beetles was observed. The root length was numerically higher when there was no larval infestation. Plant and ear height was not affected by the infestation. According to Iowa State 1-6 damage scale, regardless of of the number of larvae inoculated to roots, damages were below 2.0 (1.29 to 1.74). According to scale of Iowa 0-3, there was damage less to 0.75 (0.23 to 0.60). In relation to yield, it was observed that, in general, as increased larval density, there was a reduction in yield.
The Diabrotica speciosa (Germar) (Coleoptera: Chrysomelidae) is an important pest for several crops. The purpose of this work was to improve the method of rearing corn rootworm in lab conditions. Four systems were compared for rearing larvae, two with transference and two without transferring the larvae, constituted by maize seedling kept in peat and vermiculite. The following biological parameters were assessed: duration and feasibility in the adult-larva period, pre-oviposition and oviposition periods, males and females longevity, fertility and feasibility, net reproduction rate (Ro), average duration of a generation in weeks (T), innate capacity to increase in number (rm) and increase finite rate (λ) of D. speciosa adults. Based on the results obtained, it could be noticed that there was no influence of the substrates and rearing techniques used in the pre-oviposition and oviposition periods, males and females longevity and also in the whole fertility. However, there was effect on larval feasibility, where a higher feasibility was obtained in the treatment without transferring and with transference when peat and vermiculite were used as substrates, respectively; a bigger duration of the adult-larva period when the insects were reared in vermiculite substrate, regardless the transference; and in the feasibility of the eggs, which was higher in the treatment without transference for the two substrates. The results of the fertility table indicated that the reproduction potential of the D. speciosa significantly increases when the larvae are reared in peat without transference and vermiculite with transference.
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