广西桉树梢枯病发病规律初步调查

Preliminary investigation on occurrence regularity of eucalyptus shoot blight in Guangxi

桉树梢枯病是近年来广西桉树林中新发生的主要病害之一。作者对病害症状及发展年变化和林间发病规律开展调查。结果表明:该病在广西各地均有发生,病区发病株率高达92%以上,以桂东南发病相对严重。病害先是嫩芽枯死,叶片脱落,后枝条枯死;在广西南宁,病害初始期4月中旬,高峰期7—10月,停止期12月,高温多雨利于病害流行。病害主要发生在海拔150 m以下,萌芽林及林龄2 a以上发病率高;林地有机质、N、K、Zn缺乏值大,病害加重;广西主栽品种广林9号和D2-29接种测定及林间调查抗病性无差异;病害造成3,4 a生桉树林蓄积量分别减少78.15,92.25 m3/hm2,年均分别减损14.23%,10.4%。

Shoot blight of eucalyptus is a main disease newly occurred in Guangxi recently. Disease symptom,intraannual variation and occurrence regularity of eucalyptus shoot blight were investigated. The results indicated that the disease could be found all over Guangxi Zhuang Autonomous Region with incidence of over 92%. It was relatively serious in south-east of Guangxi. The disease started at tender bud, then leaves, at last branches. The initial period in Nanning was in mid-April,peak period was from July to October, and it stopped in December. High temperature and raininess conducive to the preva- lence of the disease. It mainly occurred under 150 meters above sea level with higher morbidity in sprout forest and forest over 2 years. Lack of organic matter, N, K and Zn could aggravate the disease. GL-9 and DH32-29 were widely grown varieties in Guangxi with no significant difference between them in both inoculation test and disease resistance investigation. Forest volume would decrease in dis- ease areas： volume decreased 78. 15m3/ hm2 （ 14. 23% per year） and 92. 25 m^3/ hm2 （ 10. 4% per year） in 3 and 4 years old stands respectively.