Indução de resistência em feijão caupi (vigna unguiculata (l.) Walp.) utilizando acibenzolar-s-metil no controle da antracnose

Abstract

The cowpea (Vigna unguiculada (L.) Walp.) is the staple food of the people, playing an important social role in supplying the nutritional needs of people, and play a key role in the Brazilian agricultural production, particularly in the North and Nordeste. A regions search for ways to control diseases that have reduced use of agrochemicals and public awareness about environmental issues is highlighted in the agricultural scenario, especially the control disease. Anthracnose, plant pathology caused by Colletotrichum lindemuthianum is one of the most important diseases of the bean crop. The use of commercial products that induce resistance becomes important in the control of plant diseases, whichis a major means of obtaining high yields in crops. Among them, there is the acibenzolar-S-methyl which operates in several plant species against a wide range of pathogens, including fungi, viruses and bacteria. In infected plants there initially the accumulation of proteins induced after penetration of the pathogen, there are training facilities, which have more or less success in plant defense. The peroxidase, polyphenol oxidase, catalase and ascorbate peroxidase are examples of proteins related to pathogenicity. The study was conducted in a greenhouse in the city of Garanhuns - PE, and the treatments were arranged in a factorial design (5x4x3). The plants were treated with the treatments as follows: TREATMENT 1 (0.15gL-1); TREATMENT 2 (0.30gL-1); 3 TREATMENT (0.45gL-1) and Treatment 4 (0.60gL-1) acibenzolar-S-methyl (Syngenta®) and plants received water only were designated as control. The plants remained in a green house for 35 days. Thus, the study aimed to evaluate the acibenzolar-S-methyl efficiency in cowpea in controlling anthracnose, caused by the fungus Colletotrichum lindemuthianum and activation of enzymes related to pathogenicity. Four days after inoculation of the micro-organism the largest dose of resistance inducer promoted greater activity for pexoridase ascorbate, this enzyme showed significant differences between the other treatments. On the eighth day after inoculation the dose 0.15gL-1 increased the activity of ascorbate peroxidase. On the twelfth day after inoculation when applied 0.30gL-1 inducing resistance catalase showed the highest enzymatic activity. O disease severity index on the fourth day after inoculation was higher than in control. Treatment with higher doses of acibenzolar-S-methyl resulted in higher enzyme activity and consequently greater resistance to bean plants cowpea.