Occurrence of fungaldiseases in vanilla (Vanilla planifolia Andrews) in Kerala

Abstract

A study was carried out to evaluate the distribution and incidence of various fungal diseases on vanilla (Vanilla planifolia Andrews) in major vanilla growing tracts of Kerala. The study included both survey and assessment of diseases as and when reported by farmers. Survey was conducted during April, May and August 2003, March 2004 and November 2005. A total of 111 locations (72 locations during survey and 39 locations from farmer's reports) distributed in six districts were subjected for the study. The major disease noticed in survey during April -May 2003 was yellowing and premature bean shedding (YPBS). The disease was found associated with Colletotrichum vanillae Massae, predisposed by high temperature and low relative humidity. During August 2003, Phytophthora incited stem and bean infection was noticed in isolated areas in Kozhikode and Idukki districts. Survey during March 2004 . at Kozhikode revealed the recurrence of flower shedding and YPBS, besides root rot caused by Fusarium oxysporum f. sp. vanillae . Survey during November 2005 in Wyanad area revealed• the prevalence of stem and root rot incited by Fusarium species along with leaf axil rot incited '.' by Colletotrichum sp. In addition, Rhizoctonia solani, Cylindrocladium quinqueseptatum and M raeemosus were also isolated as pathogens from different symptomatic parts. Other infections noticed were leaf rot, bean rot and brown rot. Fusarium and Colletotrichum sp. the predominant pathogens found to be associated with most of the infections on The association of Mucor sp. with leaf and bean rot and C. quinqueseptatum with brown were observed as new reports of its kind on vanilla.