Investigation and Research on Influencing Factors of Leaf Spot of Amomum villosum Lour. in Open Field

The leaf spot of Amomum villosum Lour.in open field were surveyed between 2008-2009 in Xishuangbanna aera.It demonstrated that leaf spot was one of the major diseases on Amomum villosum Lour.The occurrence regularity was that it began to occur at the beginning of October,January was the peak season and August was the trough season.The characteristic was that it became epidemic in winter and got into slight state in summer.The influencing factors of leaf spot included the temperature,rainfall,planting density,environment,variety and so on.According to the analysis of the relativity between the month average temperature,rainfall and field disease index,the correlation coefficient was 0.8413 and 0.9358 respectively,which showed that the more environment temperature was higher(10-30 ℃) and rainfall increased(10-250 mm),the lower field disease index occurred,and there were negative relevant relations between them.