Occurrence Of Dry Rot Zythia Versoniana Sacc. And Its Control In Shaanxi

Dry Rot, Zythia versoniana Sacc. is the most serious disease of pomegranate, causing severe economic lose annually to pomegranate. However, the study on Z. versoniana Sacc. was very rare around the world. In this paper, the dominant pomegranate cultivars, Jingpitian and Tianhongdan, were used to investigate the occurrence, biological characteristics and control of Z. versoniana Sacc. in Lintong Co. Shaanxi Province.The results showed that flowers, fruits and branches of pomegranate were susceptible to the infection of the disease. The most susceptible part was calyx tube. The pathogen could cause the drop of flowers, the drop of fruits and rotten fruits since the flowering date. But the primary period of infection was in the fruit expanding period. The disease occurred rapidly in wounds.The results of bagging trial showed that latent infection and secondary infection were the characteristics of this disease. The pathogen overwintered in mummified fruits and warped barks in the form of mycelia or conidia. The infection of pathogen could occur in the low temperature storage period. The results also showed that the pathogen could infect the apple fruits.Isolation and identification of the pathogen from pomegranate showed that it was Z. versoniana Sacc. The research of biological characteristics showed that the optimum growth temperature of mycelia was 25-32.5℃, the optimum pH was 4-7, the optimum temperature of conidia germination was 27.5℃.The research showed that the treatments by removing stamens and bagging could markedly decrease the occurrence of the disease and improve the quality of fruits. In addition, BTH and SA could prominently improve the disease resistance of fruit trees. The period after anthesis to bagging was the key period in chemical control.