Major Crops Affected by Phytophthora

Phytophthora pathogens are responsible for some of the most serious diseases of cocoa including phytophthora pod rot (PPR) or black pod, stem canker, leaf and seedling blight, chupon wilt and flower cushion infections. PPR causes 10–30% annual losses in production of cocoa beans globally, and much higher losses locally in particularly wet and humid conditions. Stem canker causes further losses and also tree deaths. Eight species of Phytophthora have been isolated from diseased cocoa, but most losses in production are caused by Phytophthora palmivora, P. megakarya and P. citrophthora, which cause similar diseases with slightly varying symptoms. Worldwide, P. palmivora is one of the most serious pathogens on cocoa, and in Southeast Asia this species accounts for almost all of the phytophthora diseases of cocoa. The most effective control measures are the introduction of resistant cocoa genotypes and farm management practices such as removal of infected pod husks, proper pruning of the canopy and judicious selection of shade species and