Extratos vegetais no controle de fungos fitopatogênicos à soja

Abstract

It was evaluated the viability of using plant extracts in the control of phytopathogenic fungi in vitro and in relation to the treatment and storage of soybean seeds. The experimental trials were conducted at the Federal University of Grande Dourados. First, the antifungal potential of ten extracts of plants was evaluated, in the concentration of 20%, testing them for the fungi, Aspergillus sp., Penicillium sp., Cercospora kikuchii, Colletotrichum sp., Fusarium solani and Phomopsis sp. Subsequently, we used aqueous extracts of garlic, clove and cinnamon with different methods of sterilization and concentration, to examine their efficiency on the inhibition of growth of pathogens. These extracts were also used in the treatment of seeds (400 ml/100 kg), more the fungicide Carbendazin + Thiram (200 ml/100 kg) and the control without treatment. The analysis to evaluate the control of fungi associated with seeds were carried out in five storage periods, 0, 35, 70, 105 and 140 days. Were observed that culture medium containing the extracts of clove, cinnamon and garlic showed greater antifungal activity on plant pathogens, when compared to other extracts used. The aqueous extract of clove may be an efficient alternative to in vitro studies, because it completely inhibited the development of all fungi studied, with the advantage of no change in its effect, when submitted to different methodologies of sterilization. However, the extracts of garlic and cinnamon, had its efficiency reduced by different sterilization methodologies. For different concentrations, it was found that the effect of plant extracts on the development of the plant pathogens was dependent on the concentrations used. There was no control of fungi associated with soybean seeds with the use of plant extracts, however, the physiological quality was maintaining by both the chemical and the plant extracts treatments during the seed storage.