山茶藻斑病发生规律和空间分布特征

Occurrence Regularity and Spatial Distribution of Camellia Algal Spot

2014年3月上旬到2016年11月下旬,对金华市山茶藻斑病进行了近三年的调查,结果表明:3月始,新的病斑开始零星发生,4月下旬病害发生蔓延较快,在梅雨季节后的6月下旬或7月上旬出现第一个发病高峰,随后病害有所减轻,8月中旬受台风降雨影响,湿度较大,出现第二个发病高峰,8月下旬后,病害发生减缓;不同品种间发病率有差异,玛瑙最易感病,其次是粉霞和绯爪芙蓉,红露珍、十样景、胭脂莲等发病较轻,狮子笑的发病率最低;不同生长环境下发病率有差异,林间遮荫最易发病,其次是孤植遮荫地块,向阳地块发病则较轻;病害大多发生在植株近地面枝条的叶片上,植株下部枝叶较上部枝叶严重,枝条基部叶片发病比顶端叶片严重。

The Camellia algal spot was investigated for 3 years from March 2014 to November 2016 in Jinhua Zhejiang province. The results indicated that the disease initially occurred in March and spread quickly in late April. The first disease peak occurred in late June or early July after plum rain season, and then the disease was declined. The second disease peak appeared in mid August, due to the influence of typhoon rainfall and high humidity, and thereafter the disease severity would be reduced again. Our investigation data showed that resistance against the disease was different among Camellia varieties. The Agate was most susceptible to the disease, followed by Fenxia and Feizhua Furong. Hong-lu-zhen, Shi- yan-jing, and Yan-zhi-lian had the lower disease incidence, while Shi-zi-xiao was the most resistant to the disease. In addition, we found that growth environment of Camellia had a severe effect on the disease occurrence, Forest shade was the most important factor to induce the disease, followed by shielded shade, but less lesions of the plant were observed on sunny plots. The disease frequently occurred on the leaves of the plant near the ground branches, the more severe symptoms were observed on the lower branches and leaves, respectively compared to the upper branches and leaves.