Variability within Calonectria ovata and its anamorph Cylindrocladium ovatum from Brazil
Calonectria ovata is presently known only from the Amazonas province of Brazil, where it causes a severe leaf spot disease of various eucalypt species. Collections of Ca. ovata from two locations in the Amazon, namely Tucurui and Monte Dourado, revealed isolates from Tucurui to have much larger conidia than those from Monte Dourado. Twenty-four isolates from these sites were subsequently mated in all possible combinations, and also compared via isozyme analysis. Results from this study supported C. ovatum to be a homogeneous species. Although it was morphologically more variable than reported earlier, all isolates exhibited a biallelic heterothallic mating system, and were designated as either MAT 1-1 or MAT 1-2 based on their mating type. Furthermore, C. ovatum was found to be an important pathogen commonly associated with leaf spot and cutting rot symptoms of various eucalypt species grown in the Amazon.