Jackfruit decline caused by Phytophthora palmivora (Butler)

Abstract

In the late 1990’s a decline syndrome emerged in jackfruit orchards in the Eastern Visayas region of the Philippines. Symptoms included trunk cankers, wilting and dieback of the canopy and, in many cases, tree death. The decline resulted in significant yield losses for farmers. A survey was conducted to assess disease incidence and to identify the causal organism. Fifty two percent of farms surveyed had a disease incidence greater than 50 %. On some farms 100 % of trees were affected. While Fusarium, Pythium, Colletotrichum and Phytophthora species were isolated during disease surveys only Phytophthora was shown to consistently cause decline symptoms in artificially inoculated jackfruit. Healthy jackfruit seedlings, detached leaves and fruit inoculated with Phytophthora isolates expressed similar symptoms to those observed in the field. Based on morphological and molecular characteristics the pathogen was identified as Phytophthora palmivora.