Outbreak and the Reasons of Apple Valsa Canker in Yantai Apple Producing Area in 2011

2011年烟台苹果产区腐烂病发病情况调查与原因分析(英文)

[Objective] This study aimed to investigate an outbreak of apple valsa canker （Valsa ceratosperma） in Yantai apple producing area in 2011 and analyze the major causes of the disease. [Method] In May 2011, 21 commercial apple or-chards in Qixia, Haiyang and Laiyang were selected to investigate the outbreak of applevalsa canker. [Result]The results showed that apple canker occurred seriously in Yantai apple producing area in 2011. The ratio of diseased plants with new canker scars was 68.20% and the ratio of dead plants infected with Valsa cer-atosperma was 2.76%. The average ratios of diseased branches and one-year-old dead branches were 23.98% and 10.74%, respectively. The percentage of orchards with more than 50% diseased plants accounted for 25%-30% of the total number of orchards investigated, and the overal prevalence situation was more serious than normal years. In the investigation, 967 new canker scars were observed, with an average of 2.32 canker scars per plant. Specifical y, 80.04% canker scars were de-veloped from pruning wounds; 60.29% canker scars were developed from previous scars. [Conclusion] The long-period precipitation in the autumn of 2010, low temper-ature in the winter of 2010 and the severe drought in the spring of 2011 might be the major factors causing the outbreak of apple valsa canker in Yantai apple pro-ducing area in 2011. Pruning wounds were the main infection entrances of V. cer-atosperma, and the recurrence in previous scars was the main reason for the out-break of apple canker in spring.

[目的]为了解2011年烟台苹果产区腐烂病的发生情况，研究病害的发生规律。[方法]2011年5月，在腐烂病发病较重的栖霞、海阳等地选择21个农户的果园，对腐烂病的发生情况进行了调查。[结果]结果表明，21个果园中具有新病疤的病株率为68.20%，死株率为2.76%，平均受害枝量为23.98%，死枝量10.74%，病株率超过50%的果园占25%～30%，总体发病情况比一般年份严重。调查共发现967块新病疤，平均每株2.32块，其中源自剪锯口的病疤占80.04%，从旧病疤复发的病疤占60.29%。[结论]2010年秋季的连续阴雨、冬季低温和2011年春季干旱可能是导致烟台苹果产区2011年春季腐烂病大发生的主要原因。剪锯口是腐烂病菌侵染的主要途径，旧病疤复发是春季腐烂病发病的主体。