Epidemiología de algunas enfermedades foliares de la yuca en diferentes sistemas de cultivo, 2: Roya y muerte descendente

The incidence and severity of cassara rust (Uromyces sp) were studied in 5 different cropping patterns during the 1974-75 growing season at Turrialba, Costa Rica. The cropping patterns studied were cassara monoculture and cassara associated with corn, common bean, sweet potato and cassara associated with both corn and common bean. The incidence and severity of cassara die back (Glomerella cingulata) was also studied in cassara monoculture, cassara associated with corn and cassara associated with both corn and common bean. Each one of these last three cropping patterns were studied at two management levels differing primarily in amount of fertilizers and weeding frequency. Maximum severity and incidence values for rust were 28 and 67.7 percent respectively. No statítical differences were found among treatments. In every treatment the infection rate was less than 10 units a day. Die back was more intense in cassara monoculture under a low management level. This disease was less intense in the cropping patterns including more crops and high level of management.