Semiselective Medium for Colletotrichum gloeosporioides and Occurrence of Three Colletotrichum spp. on Pepper Plants. J. B. MANANDHAR, Research Fellow, International Rice Research Institute, P.O. Box 933, 1099 Manila, Philippines. G. L. HARTMAN, Research Plant Pathologist, USDA-ARS, University of Illinois, Urbana 61801; and T. C. WANG, Associate Specialist, Asian Vegetable Research and Development Center (AVRDC), Shanhua, Tainan 741, Taiwan, ROC. Plant Dis. 79:376-379. Accepted for publication 16 December 1994. Copyright 1995 The American Phytopathological Society. DOI: 10.1094/PD-79-0376.

Inhibition of mycelial growth of Colletoirichum capsici and C. gloeosporioides was significantly (P = 0.01) less than that of Alternaria sp. and Fusarium spp. when grown on a semiselective medium, C. gloeosporioides pepper isolate medium (CGPIM) containing one-quarter strength potato-dextrose agar amended with fenarimol and vinclozolin at 5 µg/ml each, chloramphenicol and erythromycin at 6.5 µg/ml each, iprodione at 15 µg/ml.neomycin sulfate at 20 µg/ml, and tetracycline hydrochloride at 25 µg/ml. Fenarimol enhanced the detection of C. gloeosporioides as cream-yellow sporulating colonies formed around infected and/or infested pepper (Capsicum spp.) seeds. When pepper seeds were placed on CGPIM and wet filter paper, C. capsici occurred at equal frequencies, but the frequency of C. gloeosporioides was significantly (P = 0.01) higher on CGPIM than on wet filter paper. C. capsid was detected on 14.5% of the seeds from var. LSU Sport, while C. gloeosporioides detection was less frequent. C. gloeosporioides was isolated from 30 and 1% of diseased fruits harvested and stored for 130 and 225 days, respectively. CGPIM and wet filter paper were equally effective in evaluating the occurrence of C. capsid, but the occurrence of C. gloeosporioides and Olomerella cingulata appressoria was significantly (P = 0.01) higher on CGPIM than on wet filter paper. C. capsid was recovered more frequently than either C. gloeosporioides or G. cingulala on inoculated leaves.