Research On Occurrence Regulation And New Chemical Pollution-Free Control-Techniques Of Apple Canker In Shaanxi

Shaanxi province is one of the biggest optimized zones for apple industry in China, which is also the only district where many indexes tested measure up to the level of the most optimized region. In 2006, the apple cultural area in Shan xi province occupied the first place among all regions, and the yield also held the lead place. Recently, apple canker occurs seriously, and the range of infection are very broad, including young or senescence trees; The disease even can result in imperil of whole apple orchard. In order to provide available measurement, we carry out the systemic research on apple canker, including the distribution and the condition of occurance or infestation; pathogen sources; The correlation between some agences and the development of apple canker; The evaluation of Nuisance free control technology against apple canker was also one of major tasks. The result was:1.From South to North, and From East to West, the infection of apple canker in shaanxi province becomes more serious. The general situation of the development of the disease In the Weibei plateau was: the most seriously in Shanbei hilly donga and Weibei plateau donga ,more seriously in west of Weibei plateau and seriously in east of Weibei plateau.2.Varied part of different kinds of tree age can be infected by the pathogen in shaanxi province, the major symptoms are canker and branch dried up, the former occurs more frequently; Two pathogen strains are isolated from 16 counties where produce apple. Identification according to the principle of Koch's postulates showed that the major pathogens which lead to apple canker in shaanxi province are Cytospora sp.and C.carphosperma Fr.3.Two pinnacle of the occurance of the disease of apple canker, In Mar, new infected spot appear and expand with the available condition. The first pinnacle comes forth from May to June, but the amount of spectacles decrease abruptly in July. The second pinnacle emerge in August and September, and the spread of the disease nearly come to a standstill in October. In the period of later 5 months ,there is hardly appearance of new streaks and further expansion of the pathogens.4.The correlation between some major agences and the level of occurance of the disease of apple canker demonstated :The occurance of apple canker are infuenced by many agencies ,including cultivated density,tree ages,variety,the type of soil,the geomorphic feagure and the management.5.We take the statistical analysis on the relation between weather conditions and the prevalence of the disease ,the result indicated that :The EL was influenced by T3(average temperature in May),T12(average temperature in December),RH8(relative humidity in August)andRF7(rainfall precipatition in July).We also establish the most optimized predictive model of prevalence of apple canker, return measurement accords with main survey. All of the results can provide theoretical foundation for control against the disease.6.Tebuconazole that is a high efficiency inner absorbent fungicide is producted to Tebuconazole PC at first.It can heal plant wound rate is 59.5%, better than other fungicide. Finding a good way to control apple canker and protect pollution-free production of apple.