GIS Park

Downy mildews is a kind of serious disease on maize,caused by 9 kinds of pathogen in 3 genus,among them Peronosclerospora maydis,P.sacchari,P.philippinensis,P. sorghi and Sclerophthora rayssiae var.zeae were important quarantine pathogens in China. So it is of important significance in theory and application for risk assessment,potential distribution prediction and proposal of risk management measures in China.In this paper,model variables included environment factors(weather condition, terrain environment,vegetation information) concerned with biological distribution,and the potential risks of these 5 kinds of pathogens in China were analyzed by using ecological niche models,Maxent and GARP software.The results of two models were compared according to AUC values.Then the suitable distribution areas were zoned,and the potential suitable areas was divided into different levels produced by Geographical Information System(GIS) based on the suitability values.The comparison of two model results indicated that the prediction values of suitability of 5 kinds of pathogens of maize downy mildew by using Maxent were better than those by GARP.The results of Maxent showed that maize downy mildew has a broad suitable distribution areas in China,and South of the Yangtze River area is the main region for suitable to maize downy mildews.P.sorghi has the maximum suitable areas among the 5 kinds of pathogens in China,areas of moderate and high risk covered northern China Plain, middle and lower Plain of Yangtze River,central northeastern regions of China,Guangxi Province and Guangdong Province,Fujian Province as well as western Yunnan Province. While S.rayssiae has the minimum suitable areas,mainly in south of South China.There are large areas of maize planted in these regions,which could provide available host for maize downy mildew infection,colonization,occurrence and epidemics.So,it is necessary for maize production of China to quarantine and monitor maize downy mildews.