Phytophthora palmivora is a ubiquitous pathogen causing many different diseases on a wide range of plants. The pathogen is believed to have originated in Southeast Asia but is now pantropical. It causes significant losses to farmers of tropical fruit and vegetable crops.
P. palmivora infects a thousand or more plant species including ornamental, horticultural and agricultural crops. It is also a common soil inhabitant. Important horticultural hosts include cocoa, canker, papaya (fruit rot), durian (fruit rot) canker, pineapple heart rot, citrus canker, black pepper foot rot and coconut bud rot.
P. palmivora thrives under humid wet conditions, and as a result can cause significant losses in many economically important tropical fruit crops. Symptoms include root rots, collar rots, stem cankers, leaf blights and fruit rot. In the nursery, the pathogen can lead to heavy losses through seedling blight.
Primary inoculum originates from the soil and infected plant material. The pathogen is disseminated through rain splash, insects and human activity intothe canopy of trees, where symptoms appear. Secondary inoculum spreads rapidly through wind and rainsplash, contact and vector activity (Fig e) in humid weather.