Extratos vegetais na germinação carpogênica de Sclerotinia sclerotiorum em ágar-água e solo

Abstract

The study aimed to evaluate the carpogenic germination of S. sclerotiorum under different plants extracts in water-agar, the mycelial growth of the pathogen under different concentrations of essential oil of Schinus terebinthifolius; identify the proportion of sand and soil most suitable for carpogenic germination of S. sclerotiorum; evaluate the effect of plants extracts sprayed in soil:sand (1:1) on the carpogenic germination of the pathogen and verify the effect of methanol extracts of S. terebinthifolius, Palicourea crocea and Annona cacans on common bean. The experiments were conducted in a greenhouse or in the Laboratory of Agricultural Microbiology and Plant Pathology of the Faculdade de Ciências Agrárias of Universidade Federal da Grande Dourados. For experiments evaluating the germination carpogenic and identify the best ratio soil:sand gerboxes were used containing 20 sclerotia. Weekly was calculated the percentage of carpogenic germination. For the evaluation of the essential oil mycelial growth of S. terebinthifolius was incorporated into potato-dextrose-agar and poured into Petri dishes that received a mycelial disc of the pathogen. The evaluations were performed daily by measuring the diameter of the colonies. To evaluate the effects of the extracts on bean plants, polyethylene trays were used and 30 days after sowing, the plant extracts were sprayed on the plants. In agar-water extracts of P. crocea, Geophilla repens and A. cacans fraction ethyl acetate and fraction chloroform reduced the germination carpogenic. Sclerotia of S. sclerotiorum showed higher germination carpogenic when placed on soil and sand 1:1. There was a lower carpogenic germination when extracts of vetch fraction ethyl acetate and S. terebinthifolius fraction ethyl acetate, was spread in the substrate soil: sand (1:1) at 30 days after installation of the test. The extracts showed no phytotoxicity to common bean.