Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/23/2003
Publication Date: 3/1/2004
Citation: Copes, W.E., Hendrix, F.F. 2004. Effect of temperature on sporulation of botryosphaeria dothidea, b. obtusa, and b. rhodina. Plant Disease. 88:292-296. Interpretive Summary: The objective was to measure the effect of temperature, from 6 to 30 oC, on spore production for B. dothidea, B. obtusa, and B. rhodina. These fungi cause stem dieback on many woody ornamental and fruit plants. All three Botryosphaeria spp. produced conidia over the 6 to 30 oC range, but the greatest numbers of spores or percent spores that are mature, which would live over a longer time span, occurred at 18 to 24 oC. The data will provide basic information to be used in combination with spore trapping data in the field and seasonal recovery of pathogens from plant tissue in developing more accurately timed cultural and chemical control practices. This information should be beneficial to other scientists, extension agents, and fruit and ornamental plant producers.
Technical Abstract: To determine the effect of temperature on sporulation, three Botryosphaeria spp. were grown on autoclaved stems in cotton plugged tubes with constant moisture at 6, 12, 18, 24, and 30 oC. Conidia were counted per pycnidium weekly from 4 to 10 weeks after inoculation. The experiment was repeated 3 times. Maximum sporulation occurred at 24 oC with B. dothidea and at 18 and 24 oC with B. obtusa. Spore production of both fungi showed a quadratic curvilinear response to temperature. Pycnidia were erumpent, typical of their habit in nature. Maximum sporulation of B. rhodina occurred at 12, 24, and 30 oC instead at a distinctive peak. Of the three fungi, B. rhodina produced the greatest number of conidia per pycnidium at all temperatures. Conidial maturation of B. rhodina had a quadratic curvilinear response due to temperature with a maximum maturation at 24 oC. Mycelia and pycnidia of B. rhodina grew on top of the bark atypical of their habit in nature. All three Botryosphaeria spp. produced conidia over the 6 to 30 oC range with a maximum sporulation or spore maturation, which would affect longevity of conidial viability, at 18 to 24 oC.