Problems of Phytophthora bark canker on cocoa in Papua New Guinea
1986
Prior, C.
Canker, black pod and chupon infections caused by Phytophthora palmivora were present on 13% of trees in a block of three and half year-old hybrid cocoa at Keravat, Papua New Guinea, an unusually high level of infection at this age. In these trees, cankers arose most frequently from infected pods and chupons and in the jorquette. Cankers on both hybrid and Trinitario trees spread intermittently. Actively growing cankers produced sporangia in cracks in the bark, providing a perennial on tree source of inoculum. Many naturally occurring cankers stopped growing and were sloughed off but some remained, enlarged and eventually killed the cambium. Canker infections were cumulative and eventually lethal and treatment should begin when the trees were young
显示更多 [+] 显示较少 [-]