影响桑赤锈病初次发病率因素的分析

Analysis of factors affecting on primary infection rates of mulberry rust

采用逐步回归方法对17年历史资料进行相关分析得出,影响春季桑赤锈病初次发病率的极显著因素有:上年夏季发病率(r=0.7717**)、上年秋季发病率(r=0.7184**)、上年秋季桑树长势(r=0.6998**)、上年夏季降雨量(r=0.6712**);显著因素有:夏季温度(-0.5029*)影响初次发病率从气象条件上分析有上年夏季高温干旱和秋季干旱;首次提出了秋季桑赤锈的发生程度与来年春季初次发病有极显著相关性。解释了2005年春桑赤锈病初次发病率较低和桑赤锈病初发病的病芽集中在桑枝中上部的现象,并对传统桑赤锈病防治模式提出了修改意见。

Correlation analysis of seventeen years＇ information by stepwlse regress method showed that there was a significant relationship between primary infection rate of mulberry rust in Spring and infection rate of the last Summer or infection rate of the last Autumn or growth tendency of mulberry in the last Autumn or rainfall of the last summer or average temperature of summer season. Their correlation coefficients were 0.7717 ^＊＊ , 0.7184^＊＊ , 0.6998^＊＊ ,0.6712^＊＊ , and - 0.5029^＊ , respectively. It was first found that there was a significant relationship between infection rate of mulberry rust in Autumn and primary infection rate of mulberry rust in Spring of the coming year. The results of this study explained the phenomena on very low primary infection rate in Spring mulberry rust in 2005 and the disease sprouts of primary infection in mulberry rust fastening on the middle and top of mulberry braiches. The paper put forward the perfect suggestions on controlling the disease.