Further observations on the zonate eyespot fungus, Drechslera gigantea, in Jamaica

Abstract

Eyespot of banana leaves, caused by Drechslern gigantea (Heald & Wolf) Ito, was found in all major banana-growing areas of Jamaica, chiefly on leaves of young suckers. The disease was not of significant economic importance. Simple eyespot lesions caused by D. gigantea were recorded for the first time on Panicum maximum Jacq., Trichachne insularis (L.) Nees, Andropogon pertusus (L.) Willd., Cenchrus brownii R., S., C. echinatus L., Commelina elegans H.B.K., Teramnus sp., Saccharum officinarum L. and Cocos nucifera L. There was little or no sporulation of D. gigantea on any of these hosts. The evidence suggests that Cynodon dactylon L. frequently serves as the source from which other hosts in the vicinity become infected. Conidia were violently released when transferred from a saturated atmosphere to a dry one. The jolt responsible for release may be due to the sudden development of a gas phase in the conidiophore. During April and May 1962 in St Catherine and St Mary, the daily mean concentration of D. gigantea conidia at a height of 1 m. above diseased Cynodon dactylon averaged less than 10 conidia/m3. of air.