Variation in pathogenicity of different Leptographium terebrantis isolates to Pinus taeda L.

Variation in the pathogenicity of 42 isolates of Leptographium terebrantis to Pinus taeda was examined. Stems of 1-year-old P. taeda seedlings were artificially inoculated with the fungal isolates. Eight weeks following inoculation, L. terebrantis isolates caused dark necrotic lesion and sapwood occlusion in the seedling stems. The fungal isolates varied in their ability to cause lesion and tissue occlusion. Lesions caused by fungal isolates were, however, significantly longer than the control. Results suggest that different isolates of L. terebrantis may not put the health of P. taeda at equal risk.