The present study was designed to identify strategies for tolerance to hydric deficit in Eucalyptus urocan seedlings. The experiment was conducted in a green house with 100% solar radiation capture. The completely randomized block design was used with five treatments (plants irrigated daily with water corresponding to 25, 50, 75, 100 and 125% daily evapotranspiration) and five replications. 120-day-old E. urocan seedlings (hybrid result from the crossing between Eucalyptus Urophylla x Eucalyptus camaldulensis) were planted in pots containing 8 L of substrate composed by oxisol, sand and muck at 3:1:0.5 ratio, respectively. The seedlings were irrigated with different volumes of water for 13 days and then analyzed. Under hydric deficit condition, E. urocan plants showed significant investment in the root system, reduced the breathing rate and kept enough turgor for growth. E. urocan plants at initial growth stage are tolerant to hydric deficit and show dehydration delay as a strategy to tolerate drought.
Spodoptera eridania (Cramer) is a growing pest in crops that has been causing damage due to defoliation and lesion in reproductive structures, which requires studies of development in different types of hosts. The objective of this study was to evaluate the development of S. eridania in different species of host plants. The larvae were reared in laboratory in cotton plants of the Delta Opal cultivar. The caterpillars of newly hatched larvae were placed in Petri dishes and fed on these plants: black velvet bean (Stizolobium aterrimum), guandu bean (Cajanus cajan), jack bean (Canavalia ensiformes), forage radish (Raphanus sativus), sunnhep (Crotalaria juncea) and millet (Pennisetum americanum). The following parameters were evaluated: attractiveness and consumption in a multiple choice test; viability; larval and pupal period and weight; sex ratio; adult longevity; and total duration of the development cycle. The jack bean and forage radish plants showed greater attractiveness and were the most consumed ones by S. eridania caterpillars. The larval period was shorter among the larvae fed on black velvet beans in comparison to guandu beans, jack beans, forage radish and C. juncea. Larvae fed on forage radish and C. juncea leaves had the heaviest pupal weight. The best progress of caterpillars was obtained in the following hosts: guandu bean, forage radish and C. juncea. The millet had a negative influence on the biological parameters of caterpillars, thus not proving to be a viable host, since larval mortality was of 100%.KEYWORDS: black caterpillar; nutritional ecology; alternative host. RESUMO:Spodoptera eridania (Cramer) é uma praga em expansão nas culturas, que vem causando prejuízos pela desfolha e pela lesão nas estruturas reprodutivas, o que leva à necessidade de estudos de desenvolvimento em diferentes tipos de hospedeiros. O objetivo do trabalho foi estudar o desenvolvimento de S. eridania em diferentes espécies de plantas hospedeiras. As lagartas foram criadas em laboratório em plantas de algodoeiro do cultivar Delta Opal. As lagartas recém-eclodidas foram individualizadas em placas de Petri e alimentadas com as plantas: mucuna-preta (Stizolobium aterrimum), feijão--guandu (Cajanus cajan), feijão-de-porco (Canavalia ensiformes), nabo-forrageiro (Raphanus sativus), Crotalaria juncea e milheto (Pennisetum americanum). Os parâmetros avaliados foram: atratividade e consumo em teste com chance de escolha; viabilidade; período e peso larval e pupal; razão sexual; longevidade de adultos; e duração total do ciclo de desenvolvimento. As plantas de feijão-de-porco e nabo--forrageiro apresentaram maior atratividade e foram as mais consumidas pelas lagartas de S. eridania. O período larval foi menor nas lagartas alimentadas com mucuna-preta do que com feijão-guandu, feijão-de-porco, nabo-forrageiro e C. juncea. Lagartas alimentadas com folhas de nabo-forrageiro e C. juncea tiveram os maiores peso de pupa. Os melhores desenvolvimentos das lagartas foram obtidos nos hospedeiros feijão-guandu, nabo-forrageiro e...
Chrysodeixis includens and Spodoptera eridania caterpillars have been considered the most important pests for Glycine max in Brazil. This study evaluated different control strategies for these two important soybean caterpillars and the effects on crop productivity. The control strategies adopted were: BC, IPM, PUI and C (without pest control) and 2 cultivars (BMX Desafio - conventional and TEC Power IPRO – transgenic – Cry 1Ac). The experimental design was in randomized blocks in a factorial scheme (2 x 4) with four replications. The transgenic cultivar TEC Power IPRO presents efficiency in the control of Chrysodeixis includens and low efficiency for Spodoptera eridania. Harmonious practices such as IPM are the best alternative for soybean crops, to minimize Chrysodeixis includens and Spodoptera eridania infestations. The control strategy adopted did not influence soybean productivity.
O presente estudo teve como objetivo identificar o efeito de diferentes concentrações de giberelina, especificamente ácido giberélico (GA3) no crescimento de clones de eucalipto urocam oriundos do cruzamento de Eucalyptus urophylla x Eucalyptus camaldulensis. O trabalho foi realizado na Universidade Estadual de Goiás, Câmpus Ipameri, Goiás. As mudas de eucalipto urocam (E. urophylla x E. camaldulensis) aos 100 dias de idade foram transferidas para vasos de cinco litros, contendo solo, areia e esterco, na proporção de 3:1:0,5, respectivamente. O experimento foi realizado em bancada a pleno sol, seguindo o delineamento inteiramente casualizado com seis tratamentos (plantas de E. urocam com 150 dias de idade foram tratadas com 30 ml de GA3, nas concentrações de 0 mg L-1; 25 mg L-1; 50 mg L-1; 100 mg L-1; 150 mg L-1; e 200 mg L-1 em aplicação única via foliar com auxílio de borrifador manual) e seis repetições. Aos 30 dias após a imposição dos tratamentos as plantas foram analisadas. A aplicação de giberelina proporcionou ajuste morfofisiológico das plantas alocando mais fotoassimilados para o caule, porém isso, resultou em menor particionamento do carbono para os órgãos fontes (folhas) e, por isso, a redução do crescimento em biomassa sob baixas concentrações de GA3. No entanto, nas concentrações superiores a 100 mg L-1 de GA3 as plantas apresentaram alocação de matéria seca para o caule e significativo incremento de biomassa total, sugerindo adequado investimento em órgãos fonte (folhas) e raízes para maior absorção de solução do solo para suportar o incremento no crescimento. A aplicação de ácido giberélico (GA3) em plantas de E. urocam proporcionou vigoroso crescimento vegetativo possibilitando maior estabelecimento em campo com elevado potencial de acúmulo de biomassa de interesse econômico (caule).
Avaliou-se a toxicidade de extratos de sementes de Azadirachta indica (Neen) e de Jatropha curcas (Pinhão manso) à Plutella xylostella (Traça das crucíferas). Discos foliares de couve (Brassica oleracea var. acephala) cultivar Portuguesa foram imersos nos extratos de Neen e Pinhão manso nas concentrações de 0,5 % e, depois, fornecidos como alimento para as lagartas. Após isso, acompanhou-se o seu ciclo biológico. Todas as fases de desenvolvimento do inseto investigadas foram afetadas pela aplicação de óleos vegetais de A. indica e J. curcas. A aplicação de óleos vegetais de A. indica e J. curcas reduz a sobrevivência da praga. Palavras-chave: Pesticida natural; Praga de Brassicaceae; Plantas inseticidas.The aim of this study was to evaluate the toxicity of seed extracts of Azadirachta indica (Neen) and Jatropha curcas (Pinhão manso) to Plutella xylostella (Diamondback moth). Leaf discs of Portuguese Cabbage cultivar (Brassica oleracea var. Acephala) were immersed in extracts of Pinhão manso and Neen in concentrations of 0.5% and then provided as food for the moth. After this, followed up its biological cycle. All stages of development of this pest were affected by the application of vegetable oils of A. indica and J. curcas. The use of vegetable oils A. indica and J. curcas reduces survival of the pest.
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