**2. Fusarium disease of maize**

*Fusarium* is considered as a most devastating agent among prevalent fungus on maize, particularly in USA, Europe, Africa, Asia and Australia [14]. It damages the host plant severely causing decrease in quality and productivity. *Fusarium* spp. are ubiquitous mostly soil borne pathogen which affect the plant development throughout the cultivation period. Infection of maize plant with *Fusarium* spp. such as *F*. *monilifrme* J. Sheld. (=*Fusarium verticillioides* (Sacc.) Nirenberg), and *F*. *roseum* f. sp. *Cerealis* "Graminearum" (Syn. *F*. *graminearum* Schwabe, group II), are believed to be responsible for the diseases like stalk rot, ear rot, seed rot, root rot and seedling blight of maize [15–17]. The different strain of *Fusarium* such as *F*. *verticillioides*, *F. proliferatum*, *F*. *subglutinans*, *F*. *graminearum*, *F*. *oxysporum* and *F*. *temperatum* are important pathogens involved in seedling diseases which interfere the seed germination and emergence and hence affect the seedling development [18, 19]. Brown discolouration of the seedlings, light yellowish discolored and stunted seedlings are major symptoms of seedlings [20]. Seed rot is another important disease occurs in weak and damaged seed which become easily susceptible to the attack of soil and seed borne *Fusarium* spp. Stalk rot is one of the most common and dominated diseases in maize characterized by tan to pink or salmon discoloration and disintegration of the pith caused by many species of *Fusarium* such as *F*. *graminearum*, *F*. *culmorum*, *F*. *verticillioides*, *F*. *proliferatum*, *F*. *equiseti*, *F*. *avenaceum*, *F*. *cerealis*, *F*. *poae*, *F*. *subglutinans* and *F*. *temperatum* [18, 21]*. The Fusarium spp.* belonging to the *Gibberella fujikuroi* species complex (GFSC) and *F. graminearum* (*Gibberella zeae*) like *F. moniliforme*, *F. temperatum* and *F. subglutinans* are very much associated with stalk rot disease in maize [22]. The common symptoms of stalk rot disease of maize include reduced growth, rotted leaf sheaths and internal stalk tissue and brown streaks in the lower internodes whereas at its maturity, it develops pink to salmon discoloration of the internal stalk pith tissues [23]. The *Fusarium* stalk rot disease may cause premature death of host plant hampering the nutrients and

### *Fusarium Disease of Maize and Its Management through Sustainable Approach DOI: http://dx.doi.org/10.5772/intechopen.100575*

water translocation to leaves and ears. The infected maize plant often wilt and appear from a light to a dull color and lower stalk dries (**Figure 1A**) with pith tissues disintegrating to a shredded appearance [24]. Tan to dark brown discolouration of the lower internodes and pink to reddish discolouration of the pith tissue are the distinct symptoms of stalk rot caused by *F*. *graminearum* whereas for *F*. *verticillioides*, brown streaks appear on the lower internodes and the rotted pith tissue may be whitish-pink to salmon in color [24]. The systematic and successful infection of seed and root gradually extends towards the internodes, stalk and ear contributing more and more diseases in plant [15]. Among *Fusarium* maize diseases, ear rots significantly contribute in loss of both quality and quality of the yield. Ear rot disease is basically concerned with corn ears and *F*. *moniliforme* which predominantly now known as *F*. *verticillioides*, has been reported as causal organism of the disease [25]. *Fusarium* ear rot has been reported as most common disease of maize in United States [25]. *F*. *temperatum*, a closely related species to *F*. *subglutinans* and reported form maize in different countries, was recently identified and described as a new pathogen causing ear rot in European maize [26, 27]. *F*. *graminearum* causing ear rot disease is characterized by a pinkish colored mold [24]. Typical symptoms of *Fusarium* ear rot caused by *F*. *verticillioides* include [28, 29]: (1) tan to brown discolouration or white or light pink mold on random kernels; (2) limited ear areas or groups of kernels scattered over the ear (**Figure 1B**). Symptomless kernel infection was also observed through systemic growth of *Fusarium verticillioides* from infected seed, roots or stalks through ear with peduncles maize [20]. Kernel and stalk are not only the susceptible parts of the maize plant to the *Fusarium* spp. but infections may also occur on foliar parts like leaf sheaths and around the blade-sheath boundary and husks, whereas the leaf blades appear visually unaffected throughout the vegetation period [20]. Comparative analysis of leaf sheath and leaf blade contamination with DON (mycotoxin) showed that higher concentrations of DON was in leaf sheath indicating that leaf infection by *Fusarium* spp. may move from primarily infected leaf sheath into the leaf blades [30]. The airborne spores of the fungus during its reproductive stage contributes its richness to maize field [31]. Further, *Fusarium* spp. also infect the husks, leaf sheaths and around the blade-sheath boundary with appearance of whitish mycelium and/or pink spore layers, reddish discoloration zones and necrotic lesions on husk, Leaf sheath and blade/sheath boundary [20].

**Figure 1.** *Major diseases of maize caused by* Fusarium *spp.; (A) stalk rot disease and (B) ear rot disease.*
