Controle biológico de Monosporascus cannonballus com Chaetomium

melon collapse caused by monosporascus cannonballus is one of the main diseases that affect this cucurbit. the objective of this research was to study the biological control of m. cannonballus by chaetomium. infested substrates with 0.5, 1, 2, 4 and 8 x 105 cfu g-1 were introduced in plates where seeds of melon type piel de sapo cv. ps 1430 were sowed in seeding trays after two weeks of incubation. the seedlings were transplanted to pots with a similar substrate, infested additionally with 2.5 x 104 cfu of chaetomium per gram and 20 cfu of m. cannonballus per gram of substrate. three controls were considered: one infested with chaetomium alone, another with m. cannonballus and one without any treatment. the experimental design was completely randomized with five replicates. general disease index and control percentage were evaluated forty-five days after transplant. the general disease index varied according to the increased chaetomium concentration. the results demonstrated that 4 and 8 x 105 cfu of chaetomium g-1 were equivalent to 0.9 and 0.6, respectively. the statistical analysis showed that 4 and 8 x 105 cfu g-1 of chaetomium concentration were the most efficient treatments, with control percentage higher than 55 %, indicating the potential of chaetomium to control m. cannonballus.