Ferrugem e mancha angular do feijoeiro: efeito de fungicidas no desenvolvimento do hospedeiro e no progresso das doenças. / Bean rust and angular leaf spot of bean: effect of foliar fungicides on the host vegetative development of host and on the progress of the diseases.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2002

RESUMO

Four trials were carried out on dry beans (Phaseolus vulgaris), variety Carioca with goal to verify the possibility of implementation of an integrated management system for rust and angular spot after the application with of oxycarboxin (Hokko Plantvax 750 - 700 g/ha) and trifenil stannic hydroxide (Mertin â - 660 ml/ha) fungicides, applied in different timings. The damage quantification in these pathosystems were done analyzing the possible existing relation among the integral variables AUPDC (Area Under Disease Progress Curve), HAD (Healthy Area Duration) and HAA (Healthy Area Absorption) and its correspondents HLAI (Healthy Leaf Area Index) and HRI (Healthy Radiation Intercept) with yield (grams/plant) through linear and non linear regression. The best results were obtained using the variables HAD and HAA with the determination coefficients (R 2 ) from 0.19 to 0.56 for HAD and 0.23 to 0.49 for HAA. When HLAI and HRI were related with yield, the determination coefficient ranged from 0.24 and 0.57 for HLAI and 0.28 to 0.56 for HRI. From weekly assessments of HLAI and HRI, linear regression analysis were done between those variables and yield (grams/plant). The angular coefficient were related with the different crop stages and the stability of curves was observed between R5-R8 stages for rust - dry bean pathosystem and between V4-V8 stages for angular spot – dry bean pathosystem when HLAI and HRI were analyzed. In these experiments, Leaf Area Indice (LAI) was also assessed with direct (manual) and indirect measures with a ceptometer. The measures obtained using this set provided necessary sensibility to catch HLAI variation and, therefore, may be used in an integrated management system of rust and angular spot in dry beans.

ASSUNTO(S)

ferrugem (doença de planta) angular leaf spot feijão bean fungicidas fungicides bean rust mancha angular

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