Biodiversity of Fusarium species causing ear rot of maize in Germany

In Germany, maize is one of the most important agriculture commodities, a major component in animal feed as well as an essential substrate producing biogas. Maize ear rot poses a major impact worldwide as it is caused by several Fusarium spp., most of which have the ability to produce mycotoxins. Despite of the expansion of the maize acreage in recent years, limited information is available concerning the incidence of Fusarium ear rot in Germany. Therefore, in a two-year survey maize crops were sampled in the major maizeproducing areas in Germany to establish the severity of Fusarium ear rot and the biodiversity of Fusarium species. In 2006, the frequency of kernels infected by Fusarium spp. ranged from 0.7 % to 99.7 %; the average incidence was 32.4 %. Thirteen Fusarium species were isolated from maize kernels, with F. verticillioides, F. graminearum and F. proliferatum being the predominant species. In 2007, the highest incidence of Fusarium ear rot was 64 %; the mean level of infection was 21.7 %. F. graminearum was by far the most frequent species isolated from all sampled fields in 2007. In addition, F. crookwellense, F. subglutinans and F. avenaceum were also frequently isolated. In particular, the fumonisin-producing species F. verticillioides an F. proliferatum were less frequent than in 2006. The year-to-year variability in the frequency of Fusarium species and in the overall infection rate may be explained by significant differences in temperature and precipitation during the growth periods.