VARIABILITY WITHIN CALONECTRIA-OVATA AND ITS ANAMORPH CYLINDROCLADIUM-OVATUM FROM BRAZIL

Calonectria ovata is presently known only from the Amazonas province o f Brazil, where it causes a severe leaf spot disease of various eucaly pt species. Collections of Ca. ovata from two locations in the Amazon, namely Tucurui and Monte Dourado, revealed isolates from Tucurui to h ave much larger conidia than those from Monte Dourado. Twenty-four iso lates from these sites were subsequently mated in all possible combina tions, and also compared via isozyme analysis. Results from this study supported C. ovatum to be a homogeneous species. Although it was morp hologically more variable than reported earlier, all isolates exhibite d a biallelic heterothallic mating system, and were designated as eith er MAT 1-1 or MAT 1-2 based on their mating type. Furthermore, C. ovat um was found to be an important pathogen commonly associated with leaf spot and cutting rot symptoms of various eucalypt species grown in th e Amazon.