Corn has become an increasingly important crop within the state of North Dakota, where it is currently grown in every county; though the productivity and risk of production varies considerably from region to region (Ransom, 2004). Stalk and ear rot diseases of corn can be caused by many fungi and bacteria. Most of these pathogens occur commonly in the fields and behave opportunistically by primarily infecting senescing, injured or stressed plants. Several fungal species in the genus Fusarium are responsible for diseases such as root rot, stalk rot, ear rot, seedling blight and sudden death syndrome (Wang et al., 2015). Ear rot affects grain quality, limits the use of certain cultivars, and causes concern about toxins (fumonisin and trichothecene) in corn used for feed.
Fusarium verticillioides is reported to be the primary fungus species that causes Fusarium ear rot in the United States, but two other Fusarium species (F. proliferatum and F. subglutanins) also infect corn and cause ear rot disease. In all three species, the disease symptoms are similar, but only F. verticillioides and F. proliferatum produce fumonisins (Beck et al., 2005). The most agriculturally important Fusarium species that produce trichothecenes are F. graminearum, F. culmorum, F. sporotrichioides, F. poae and F. equiseti (Bluhm, 2002; Jurado et al., 2005). All of these Fusarium species are also common fungal pathogens in cereals, particularly, head blight in small-grain crops. Thus, there is a strong need for rapid detection and identification of the Fusarium species, to provide guidance for corn producers on the use of fungicides either to pre-treat fields or as seed treatments.
Given the complex diversity of species and often confusing taxonomy, conventional methods to identify Fusarium are both labor intensive and time consuming (Bluhm et al., 2004; Demeke et al., 2005). As an alternative to conventional microbiological procedures in diagnosis, a molecular based technology offered by NAGC is a rapid and sensitive method to detect target DNA molecules.
NAGC has begun the development of a pathogen screening assay to detect Fusarium species in both seed and soil samples. The development of this high throughput, real-time PCR method would ultimately help establish a cost-effective monitoring regime for producers, which will help them proactively safeguard and manage their crops against future Fusarium outbreaks.