EFFECT ON GERMINATION AND POST-GERMINATION DEVELOPMENT OF COLLETOTRICHUM-DEMATIUM VAR CIRCINANS DUE TO LIGHT AND DARK INCUBATION AND COVERSLIP PLACEMENT

Light regime was not a major factor in germination of spores of Colletotrichum dematium var circinans. Number of germ-tubes and appressoria formed were affected by incubation regime and coverslip placement. Most germ-tubes and appressoria were produced on spores under shimmed coverslips. Light incubation favored germ-tube production and dark incubation favored appressoria production. Predicted time to 100% germination was affected by treatments. Shortest times were predicted for light incubated spores under shimmed coverslips. Longest times were predicted for non-coverslipped spores. A significant number of appressoria were produced sessile on spores. Most sessile appressoria were produced on dark incubated spores. Approximately 56 % of all spores germinated, and approximately 60% of all germ-tubes and appressoria were produced on these spores which were situated closest to coverslip or droplet edges. Placement of germ-tubes on spores was not affected by treatments. However, percentages of germ-tubes, initiated from various areas of spores, were significantly different. This variation appears to be due to factors internal to spores. © 1979 Kluwer Academic Publishers.