Study on the Shoot Dieback Of Pines
Wei Chujiang;Liu Lilin;Lin Jilang;Lin Shilong(Forestry Department of Fujian Province, Fuzhou 350003)Lin Xiangjiang;Guo Xiang(State-owned Forest Farm of Nanyu, Minhou 350100) (Forestry Bureau of Changle City. Fujial 350200)
The shoot dieback of pines in Fujian is caused by Diplodia pinea (Desm) Kickx, which can attack Pinus taeda,P. elliottii and other 19 species of the genus in this province,lts symptoms are basically similar to what reported before, but it can infect annual young cones to stop their developing and dieback. The pycnidia of the pathogen occur on the dead needles, sheathes, scaly-leaves, young shoots and seedling's stems.There are three abandant conidia releasing periods every year, infect respectively the spring shoots and thesummer shoots as well as overwintering buds. The disease develops mainly from April to the middle ten daysof November. Their conidia production and releasing, and the disease development have close relation to temperature, relative humidity and rainfall. The pathogen are not found on seed, but the fungi can infect pinesfrom the young seedlings to overgrown trees.