**2.3. Gordon**

taxonomy of *Fusarium*, but none of them received a global agreement. During 1980s, *Fusarium* taxonomists in the world collaborated to offer a unique agreement on *Fusarium* taxonomy. In 1990s, however, the application of phylogenic species concept based on the DNA sequencing resulted in introducing new species of *Fusarium* that often cannot be distinguished morphologically. In 2006, Leslie and Summerell published "The *Fusarium* Laboratory Manual" and

14 Fusarium - Plant Diseases, Pathogen Diversity, Genetic Diversity, Resistance and Molecular Markers

*Fusarium* species are among the most common and widespread plant pathogens in the world and are of great economic importance [4]. Every plant pathologist, mycologist, agronomist, and horticulturist encounters them in the course of work. They are serious pathogens on a wide range of crops. In spite of worldwide investigations on *Fusarium* in the past 200 years, *Fusarium* diseases continue to be among most important plant diseases and cause widespread

Several *Fusarium* species produce mycotoxins, which cause various disorders, including cancer in animals and humans [5]. Zearalenone, fumonisin, moniliformin, and trichothecenes are among most important *Fusarium* mycotoxins, especially in grains [5]. The objective of this

The genus *Fusarium* was introduced in 1809 [1]. During 1809–1935, much of the works on *Fusarium* were focused on identification of *Fusarium* species and diagnosis of *Fusarium* diseases. In the past 100 years, the taxonomy of *Fusarium* has undergone a number of changes,

The basis for all modern taxonomic systems of *Fusarium* species is the work of Wollenweber and Reinking, which was published in "Die Fusarien" in Germany. In this publication, 16 sections, 65 species, 55 varieties, and 22 forms of *Fusarium* were introduced, which were separated based on the morphological differences [2]. Prior to this publication, about a thousand *Fusarium* species had been described, often a different species for every host. Wollenweber and Reinking offered an order to a chaotic situation of *Fusarium* taxonomy. In their taxonomic system, each section contained species that were united by critical morphological characteristics (e.g., macroconidia morphology and pigment). Each section contained only a few species. Other taxonomists used

the sections created by Wollenweber and Reinking to develop their taxonomic systems.

taxonomy was easy to use and identify any *Fusarium* isolate to species level.

During 1940s and 1950s, Snyder and Hansen in the United Sates (US) developed a new taxonomy system and reduced number of species of *Fusarium* to nine [6, 8, 9]. Their identification was based on using cultures derived from single spores. The Snyder and Hansen species

chapter is to provide details of *Fusarium* taxonomy, pathology, and mycotoxins.

which is adapted and "The *Fusarium* Laboratory Manual" [3].

described 70 *Fusarium* species [3].

crop losses throughout the world [4, 7].

**2.1. Wollenweber and Reinking**

**2.2. Snyder and Hansen**

**2. Taxonomy**

Gordon published a number of papers on *Fusarium* species collected from Canada [10–12]. He used *Fusarium* taxonomy system developed by Wollenweber and Reinking with some concepts of Snyder and Hansen system.
