Abstract

In their natural habitat (i. e. Australia), although a large number of fungi are known to be associated with Eucalyptus, only two of them namely Phytophthora cinnamomi and Armillariella luteobubalina have attained status of serious pathogens. When Eucalyptus is introduced into new habitats under 'artificial' ecosystems, usually there may not be any specialized disease problem in the initial stages of establishment. However, this freedom from disease is generally short lived possibly because pathogens from its native country may find their way into new habitats and they may become more disastrous than in the country of their natural occurrence. Further more, indigenous pathogens may also adopt the new host straight away or adapt to it in due course. The latter situation is applicable to Kerala, where the healthy growth and survival of Eucalyptus is seriously threatened by four native pathogens namely, Cylindrocladium spp. and Rhizoctonia solani in nursery and Cylindrocladium