Efeito do bioprotetor com Cunninghamella elegans e da quitosana de crustáceo no estado nutricional e na defesa de Vigna unguiculata (L.) Walp contra Sclerotium rolfsii Sacc

Abstract

The use of chemicals in the control of plant pathogens has caused many detrimental effects on the environment. The bioprotector and chitosan, both obtained by the fungus Cunninghamella elegans and that obtained from crustaceans, have been used as alternative agents in the control of pathogens in plants, in addition, chitosan provides positive effects for plant nutrition, soil fertilization, and nutrient uptake by plants. Chitosan acts to increase plant tolerance to stress and to activate defense responses in order to become more resistant against phytopathogenic microorganisms.Thus, the objective of this work was to evaluate the effect of crustacean chitosan and bioprotect in the defense of Sclerotium rolfsii and in the nutritional state of cowpea, Vigna unguiculata (L.) Walp. The present work was divided in two chapters, in which 11 treatments (1) control treatment were used: soluble fertilizer (FNPK) without chitosan; (2) Protector (PNPK) 50% of the recommended dose; (3) PNPK 100%; (4) PNPK 150%; (5) worm humus (HM); (6) HM + chitosan 2 mg / mL; (7) HM + chitosan 4 mg / mL; (8) HM + chitosan 6 mg / mL; (9) mixed biofertilizer 150%; (10) control 1: soil without pathogen; (11) control 2: soil with pathogen. In the first chapter, an in vitro assay was performed to verify the action of different chitosan concentrations (0.5, 1.0, 1.5, 2.0, 4.0 and 6.0 mg / mL) in the control of the pathogen, Then the most promising concentrations (2, 4 and 6 mg / mL) were used in spraying on cowpea leaves, in greenhouse treatments 6, 7 and 8.To obtain the bean plants, sowing was carried out in pots, containing autoclaved soil and not autoclaved. After 48 hours of spraying, inoculation was performed on the lap of the plants in all treatments, except treatment 10. In the first chapter the following analyzes were carried out: disease severity; Soluble protein content; Activities of the enzymes ascorbate peroxidase (APX) and catalase (CAT), and in Chapter 2 were (N, P and K) and soil (N, P, K, Mg and Ca). In relation to the results of chapter 1, it was concluded that treatments with PNPK 50%, 100% and 150%, HM + chitosan 2, 4 and 6 mg / mL and FNPK treatment are more effective in controlling the severity of the disease. In the analysis of the soluble protein, the use of mixed biofertilizer, HM + Q 4mg / mL, HM + Q 6mg / mL and FNPK presented higher levels in the plant. In the catalase activity, the treatments that increased its concentrations are HM + Q 2mg / mL and PNPK 150%; And in the activity of ascorbate peroxidase, the use of HM + Q 6mg / mL was and what activates greater production of this enzyme in the plant. As regards the results of chapter 2, it can be seen that the treatments BNPK, PNPK 150% and earthworm humus containing the different concentrations of chitosan express the best results for nutrient analyzes performed, with values equal to or higher than the treatment that used the Conventional fertilizer (FNPK) and always higher than control 1 and 2. In view of the obtained results, it can be suggested that the application of bioprotector, biofertilizer and earthworm humus containing different concentrations of chitosan in the cowpea act on the cowpea defense mechanism, besides promoting greater availability of nutrients in the soil and in the plant.Thus, the bioprotector, earthworm humus and chitosan applied via the leaf are a viable alternative with great potential to substitute conventional fertilizers.