ABSTRACT
The incorporation of plant material in soil can influence the populations of pathogens and/or pathogenic activities. This work aimed to evaluate the potential of green manure in the induction of suppressiveness to monosporascus vine decline of melons in soil naturally infested with Monosporascus cannonballus. Two experiments were carried out, one in greenhouse and the other under field conditions. In the first one, 13 treatments were compared, considering different combinations of melon ‘Piel de sapo’ and green manure (Crotalaria spectabilis, C. juncea, Canavalia ensiformis, Cajanus cajan, Dolichos lablab and Stilozobium aterrimum) in four growing seasons. The highest values of severity (SVD) of monosporascus vine decline were detected in interspersed cultivation with C. cajan or C. spectabilis with melon, successive cultivation of C. ensiformis with incorporation and of melon without incorporation. The highest M. cannonballus population levels in soil were observed in successive cultivation of melon without incorporation, D. lablab with incorporation, and in merged cultivation of C. ensiformis, S. aterrimum, C. cajan, C. juncea or D. lablab with melon. The lowest ascospores densities obtained at the end of experiment were found in soils submitted to successive green manure of C. spectabilis, C. cajan, C. ensiformis, C. juncea and S. aterrimum, and in merged cultivation of C. juncea. In field, the S. aterrimum was the most effective treatment in reducing the vine decline severity and presented, numerically, the highest number of commercial fruits of melon.
Keywords:
Cucumis melo; vine decline; green manure; suppressiveness.