The Study On Occurrence Regulation And Major Impact Factors Of Peach Gummosis In Guangxi

Gummosis(peach tree gummosis) was one of the main diseases occurred on peach tree,which causing gummosis in main stem, main branch,shoots and fruits,and,decreasing the tree vigor,productivity and fruits quality under severe gummosis condition. As far as we known,there were neither clear mechanism nor effective control method of gummosis. Gummosis was becaming a major limiting factor that impeding the healthy development of peach industry in Guangxi. In this study,we investigated the occurrence of the four major peach-producing counties in Guangxi province. Studying on the ZhongYou5cultivar, which was the main cultivar in Guangxi, we surveyed the gummosis occurrence in Haiyang town Lingchuan couty Guilin,where the occurrence was the highest;Xiangyang town and Bala town,Tian"e couty Hechi,where the occurrences were the lowest, In order to search the occurrence regulation and major impact factors of peach gummosis and provide a reference on gummosis prevention, here we investigated systemically and had a integrated comparation such as nutrient, physiology and cropping system on the three places where had different envirement and weather conditions. The results showed that:1.A11of the peach cultivars in Guangxi suffering gummosis deseases, but the degree of the gummosis was different between different species and cultivars,The nectarines had the highest disease occurrence and the average disease index was70.43, and the wild peach had a lower disease occurrence and the average disease index was58.11. The wild peach cultivars such as ChunMei,ChunXue,Piqiu peach and Guizhou peach,had higher disease occurrence; the juicy peach such as Tianjin juicy peach、South Korea’s great white peach、 Guoqing peach、Kawanakajima peach had lower disease occurrence, and the local variety Gongcheng Xiazhi peach had the lowest disease index15.6.2.The gummosis occurrence rate was variant at different places. The places range in ascending order by disease index as follows:Lingchuan county>Gongcheng county> Luzhai count>Tian’e county. Gummosis was becaming a major limiting factor that impeding the development of peach industry in Lingchuan county and Gongcheng county;The occurrence rate in Luzhai count was lower and the occurrence rate in Tian’e county was the lowest.3. The pathogenic bacteria of peach gummosis was Botryosphaeria parva, B.dothidea species,which had the widest spread and highest pathogenicity in China.The pathogenic bacteria was addicted to high temperature, and the optimum temperature for spore germination was25-35℃.4. The Nutrition levels and soil fertility had no influences on gummosis occurrence,but high potassium and calcium was a great help to retard gummosis disease.5. Annual average temperature had no significant correlations with gummosis occurrence.Rainfall and high temperature in summer had significant correlations with gummosis occurrence.The mean temperature in July, the days that daily maximum temperature above35centigrade degree all the year, and annual rainfall had a high-positive correlation with gummosis occurrence. So that, high humidity and high temperature during spring and summer in the southern areas was helpful for gummosis occurrence,while, cool and dry weather was infaust for gummosis occurrence,...