CHARACTERISTICS OF THE FUSICOCCUM ANAMORPH OF BOTRYOSPHAERIA-RIBIS, APOTENTIAL BIOLOGICAL-CONTROL AGENT FOR MELALEUCA-QUINQUENERVIA IN SOUTH FLORIDA

Eight isolates of the Fusicoccum anamorph of Botryosphaeria ribis (six from Melaleuca quinquenervia; two from Rhizophora mangle) were obtain ed from South Florida. Morphological characteristics of these isolates were studied on various culture media and excised leaves and stems of M. quinquenervia ramets. Mycelial morphology, sporulation attributes, dimension of conidiomata, and growth rate varied among isolates. Coni diophores were short and hyaline with a bulbous base arising from the lining of the stromatal locules. Fresh macroconidia were fusiform, tru ncate at the base, obtuse at the apex, hyaline, aseptate, but some of them developed 1-3 septa when retained in pycnidia on aged and dried c ulture media or germinated in water under coverslips. Regardless of se ptation, 1-5 germ tubes were produced from the polar as well as the la teral sides of conidia. Microconidia were rarely produced by most isol ates. Microconidia did not germinate. The percentage of macroconidia g erminating within 4-8 h was greatest at 25-35 degrees C, was rare or a bsent at 5 degrees C, and viability was lost at 45 degrees C. The tele omorph stage was not observed on any growth media regardless of incuba tion conditions. These morphological characteristics support the chara cterization of the isolates as the Fusicoccum anamorph of B. ribis; al so, many characteristics overlap with reported characteristics of the Fusicoccum and Dothiorella anamorphs of B. dothidea.