Efeito do desfolhamento no rendinmento do feijoeiro

Abstract

EFFECT OF DEFOLIATION ON BEAN YIELDABSTRACT -The purpose of this study was to correlate loss of yield with percentage of leaf area removed in different stages of bean plant. The cultivars used were Rosinha G2 (type II) and Carioca (type III), evaluating four levels of defoliation (0, 33, 67 and 100%), applied in five developmental stages. The analysis of yield showed that the losses increased proportionally to the levels of defoliation, reaching 59% when the cultivars were submitted to 100% defoliation. Even though the effects on yield were linear, the reductions in the leaf area up to 33% resulted in an average loss of only 5.6% in bean yield. Regarding the yield components, the number of pods per plant was the most affected, showing, for the level of 100% of defoliation, reductions of 45.1% and 42.0% for the cultivars Carioca and Rosinha, respectively.

Artificial Defoliation to Simulate Losses on Production of Bean (<i>Phaseolus vulgaris</i> L. cv. Goytacazes)

“…In contrast, [14] observed that the defoliation of 25% in plants with 10 and 17 days of age did not significantly decrease the production, but in plants with more than 24 days of age the defoliation at all levels reduced the production of the bean. Other authors [4] It has been verified a varied behavior of the bean cultivars against simulated defoliation, as reported by [9], for "Carioca" and "Rosinha", [16], for the cultivar "Pérola", [13], for the cultivar "Capixaba Precoce", [13], for the cultivar "Xamego" and [10] for the cultivar "Caupi". However, no information is available on the levels of leaf area reduction of Goytacazes bean, in relation to the defoliation caused mainly by insect pests, which cause significant losses in grain production in the southern state of Espírito Santo.…”

“…[3] [15] observed greater damage to the crop when defoliation was performed at the beginning of pod formation. [9] and [16] found that flowering was the most damaging stage. In contrast, [14] observed that the defoliation of 25% in plants with 10 and 17 days of age did not significantly decrease the production, but in plants with more than 24 days of age the defoliation at all levels reduced the production of the bean.…”

Desfolha artificial simulando danos de pragas na cultura do girassol (Helianthus annuus L., Asteraceae)

“…Alguns estudos com girassol e feijão descrevem essa interação entre nível de desfolha e estádio de desenvolvimento, relacionando as maiores perdas quando a desfolha ocorre nos estádios reprodutivos (Moura, 1999;Lauer et al, 2004). Resultados semelhantes foram descritos com outras espécies, como relatado por Nurmberg et al (1999), estudando desfolha artificial em batata (Solanum tuberosum L.), que o mesmo nível de desfolha pode ocasionar diferentes perdas, dependendo do estádio em que é efetuada.…”

“…Por outro lado, Muro et al (2001) constataram que desfolhas acima de 33% no estádio R.3 foram as que mais afetaram a produção do girassol. Alguns trabalhos com desfolha artificial em diferentes culturas, como soja e feijão, demonstram que as maiores perdas na produção ocorrem no estádio de formação e enchimento de grãos (Diogo et al, 1997;Gazzoni & Moscardi, 1998;Moura, 1999).…”

Consumo foliar da traça-das-crucíferas em couve e brócolis tratados com sinigrina

“…De acordo com Lara (1992), a quantidade e a qualidade dos alimentos interferem diretamente no ciclo biológico dos insetos, sendo que a perda da área foliar altera componentes do rendimento em decorrência das alterações provocadas na fisiologia das plantas, refletindo na produtividade da planta (Moura, 1999).…”