Basal Cankers and Coppice Failure of Eucalyptus grandis in Florida

Abstract

Barnard. E. L.. Geary. T.. English,J. T.,and Gilly, S. P. 1987. Basal cankers and coppice failure of Euca/yplus grandis in Florida. Plant Disease 71: 358-361. of Eucalyptus spp. in Brazil and Surinam, respectively, and have reduced coppicing substantially (4,13,14). We have suspected that C. cubensis was a cause of some, if not all, coppice failure of E. grandis in Florida (Fig. 1). Therefore, we surveyed for basal cankers in an 11-yr-old E. grandis plantation that had been studied earlier by Hodges et al (12), isolated from cankered tissues to identify associated fungi, and evaluated coppice regeneration in the plantation after it was harvested at age 13. Preliminary observations from the canker survey have been reported (1). The relationship of basal cankers to coppice failure in a Euca/yptus grandis plantation in southern Florida was investigated. Canker incidence increased from about 15 to 57% over 4 yr. Cr.vphonectria cubensis and Botryosphaeria dothidea were isolated frequently from bark samples removed from cankered trees and stumps. After a February harvest at age 13, 44% of residual stumps failed to generate coppice shoots, or they initiated new shoots that soon died. Incidence of coppice failure was not significantly correlated to the presence or severity of basal cankers, but stumps of cankered trees had significantly fewer coppice-bursting centers. Dead coppice shoots on 99 of 100 randomly selected stumps supported pycnidia and/ or perithecia of c. cubensis at their bases 18 mo after harvest. Dead coppice shoots on 50 of the same 100 stumps supported pycnidial stromata characteristic of those described for C. gyrosa, a species not previously reported in