*Trchoderma* Spp.: Their Impact in Crops Diseases Management

*Amar Bahadur and Pranab Dutta*

#### **Abstract**

*Trichoderma* species, a cosmopolitan fungi, present in all types of soil, manure, and decaying plant tissues that can degrade domestic waste relatively quickly without emitting bad odors. *Trichoderma* is recognized worldwide as potential fungal biocontrol agents for the management of various foliar and soil-borne plant pathogens, highly compatible with sustainable agriculture and play major role as a component of integrated pest management. Bio-control agents are an antagonism and eco-friendly approach for managing plant diseases. *Trichoderma* as bioagent area effective not only against soil-borne plant pathogens, but also against nematodes without any adverse effect on beneficial microbes. *Trichoderma* is capable of growth promotions in crops. There are two major mass production methods of *Trichoderma* spp. *viz*., solid state fermentation and liquid state fermentation. In solid, fungus is grown on various cereal grains, agricultural wastes, and byproducts, and these products are used mainly for direct soil application to suppress the soil-borne inoculums. In a liquid state, *Trichoderma* is grown on media such as molasses and yeast in deep tanks and fermentation can be made into different formulations such as dusts, granules, pellets, wettable powders. As seed-treating agents or bio-priming agents, *Trichoderma* formulations can be successfully used against several soil-borne diseases caused by *Pythium, Phytophthora, Rhizoctonia, Fusarium and Sclerotium, spp*. in several crops.

**Keywords:** *Trchoderma* spp. formulation, multiplication, mechanisms, management

### **1. Introduction**

The genus *Trichoderma* strains are versatile, highly competent, root colonizers, cosmopolitan in nature, fast growing in culture; produce numerous green spores and chlamydospores as used for eco-friendly disease management which is important in organic agriculture. *Trichoderma* species have been used as a biological control, biofertilizers, source of enzymes and protein producers. *Trichoderma* increase the fertility of soils and improved plant growth beyond disease control [1, 2]. *Trichoderma* strains colonization on root and enhances root growth, root area, root length, increases in dry weight, shoot length and leaf area [3]. Plant growth promotion is due to the production of plant hormones and the uptake of nutrients by the plant [4]. They promote root growth, nutrient availability and release plant growth regulators [5]. Application in plants and can prevent the infection

of diseases through induced resistance, competition for nutrients and space, antibiosis, hyperparasitism. Induced resistance may be local or systemic. *Trichoderma* species are cosmopolitan fungi, frequently present in all types of soil, manure and decaying plant tissues [6]. *Trichoderma* species are a well known bio-control agent, utilize chitinolytic enzymes to disintegrate and degrade the pathogen's cell walls and colonize on the root, soil and foliar environments suppressing phytopathogens [7–9]. *Trichoderma* spp. is highly interactive in root, soil and foliar in the environment, parasitize other fungi [10]. *Trichoderma* was first described in 1794 and its perfect stage (*Hypocrea*). Morphological characters and an online identification tool are available for identification of species within the genus *Trichoderma* and recognized from long back as biological agents, control of plant disease and also their ability to increase root growth and development, crop productivity, resistance to abiotic stresses, and uptake and use of nutrients. Application of *Trichoderma harzianum* to plants resulted in improved seed germination, increased plant size, and augment of leaf area and weight [11]. *Trichoderma* spp. is well documented and effective biological control agent of soil-borne diseases by secreting several cell wall degrading enzymes, antibiotics [12, 13]. They have produced extracellular proteins and fungi toxic substances for understanding the role in antagonistic as playing in biological interactions [14]. *Trichoderma reesei* and *Trichoderma harzianum* are capable of producing proteinase, mananase, laminarinase and chitinase that the nature of antagonism by mycoparasitism [15]. *Trichoderma*, a soil-borne mycoparasitic fungus has been shown effective against many.soil borne phytopathogens [16–19]. *Trichoderma viride* and *Trichoderma harzianum* found to highly antagonistic against *Sclerotium rolfsii* and management of diseases in vegetables and legumes [20–29]. *Trichoderma harzianum* is an antagonist probably their ability to fight for cellulose in the mucilage layer at the root surface [30]. *Trichoderma* spp. have been reported to control soil-borne plant pathogens viz., *Rhizoctonia solani* Khun., *Sclerotium rolfsii* (Sacc.) Curzi., *Pythium* and *Fusarium* spp. [31–36] and *Botrytis* rot of fruits on grape. *Trichoderma harzianum*, widely tested as potential biological control agents many soil-borne plant pathogens [10, 37–39]. *Trichoderma hamatum* produced inhibitory volatiles compounds that reduced the gray mold of snap bean pods and blossom [40, 41]. *Trichoderma harzianum* T39 less effective in cucumber fruit and stem gray mold under wet and below 20°C compare to elevated temperatures [42]. *Trichoderma harzianum* inoculated in root increased peroxidase and chitinase activities in leaves of cucumber seedlings [43]. *Trichoderma harzianum* T39 effectively controlled *Botrytis* diseases, white mold (*Sclerotinia sclerotiorum*), leaf mold (*Cladosporium fulvum*) and powdery mildew (*Sphaerotheca fusca*) [42, 44–47]. *Trichoderma* bio-control agents are used against fungal phyto-pathogens such as *Phythium, Phytophthora*, Macrophomina*, Aspergillus*, *Rhizoctonia* and *Fusarium* through the mechanism of mycoparasitism, antibiotics and competition for food and space [5, 48]. Induced resistance is an important mode of bio-control in vegetative tissues [49, 50]. *T. harzianum* induced systemic resistance in the plant against fungal and bacterial pathogens [8, 9]. Induced systemic resistance caused by various micro-organisms and protects plants against the soil or foliar pathogens [51]. *Trichoderma*, *Gliocladium* and *Pythium* spp. are known as mycoparasites [46]. *Pythium* spp. is non specific mycoparasites and interact with many soil borne fungi [52]. *Trichoderma virens* produces two major antifungal antibiotics- gliotoxin (toxic to Rhizoctonia *solani* and *Pythium ultimum*) and gliovirin (toxic to *Pythium* spp.) [53]. *Trichoderma virens*, produce the antibiotics gliovirin and gliotoxin

Trchoderma *Spp.: Their Impact in Crops Diseases Management DOI: http://dx.doi.org/10.5772/intechopen.101846*

as mycoparasite. *Trichoderma harzianum* T39 is competition for nutrients and interference with the production of pectolytic enzymes against the pathogen, and also prevents the penetration of the host tissue and is shown to induce resistance [54–56]. *Trichoderma harzianum* T39 produces protease on leaves against *Botrytis cinerea* disease development [57]. Secretion of proteolytic enzymes that deactivate pathogenicity related hydrolytic enzymes of pathogenic fungi [58]. *Trichoderma viride* is involved in bio-control management *Sclerotium rolfsii* through the proteolytic activity as reported [59]. *Trichoderma* species can degrade domestic waste quickly without emitting bad odors [60]. The genus Trichoderma has the potential to control plant-parasitic nematodes [7, 61]. *Trichoderma harzianum* is associated with a reduction in nematode population by parasitizing and killing in the rhizosphere [62]. *T. harzianum* has a rich source of chitinolytic enzymes which might degrade the eggshell during parasitism of eggs and juveniles [39, 62]. *Trichoderma* promotes crop productivity, resistance to abiotic stresses and uptake of nutrients [63]. *Trichoderma* colonization in the roots and soil helps insolubilization of minerals viz.; rock phosphate, Fe, Mn, Cu and Zn and also enhances N-used efficiency [1]. *Trichoderma* based commercial products are manufactured and marketed worldwide for the management of plant diseases [10, 17].

#### **2. Characters and isolation techniques**

*Trichoderma* is a good bio-control agent as well as a fertility promoter. *Trichoderma* fungi can produce antibiotics, enzymes that antagonize plant pathogens and hormones that regulate root architecture and promote plant growth. *Trichoderma* protects a wide range of foliar pathogens. *Trichoderma* strains have numerous mechanisms for attacking other fungi and enhancing plant and root growth [1]. *Trichoderma* is colonizing in the rhizosphere and resulted in the increased root, aerial systems and crop yields [64, 65]. *Trichoderma* has a strong capacity to mobilize and take up soil nutrients and making it more efficient and competitive. Competition for nutrients is the major mechanism used by *Trichoderma harzianum* to control *Fusarium oxysporum* f. sp. *melonis. Trichoderma* spp. produces three kinds of propagules; hyphae, chlamydospores, and conidia [18]. The main propagules of *Trichoderma* spp. is hyphae and during the drying process losing viability. Chlamydospores and conidia have been used as the active ingredients of *Trichoderma* spp. based production [66–68]. *Trichoderma* fungal conidiophores are highly branched, not verticilate, 1-celled, ovoid, borne in small terminal clusters, loosely or compactly tufted, and often formed in distinct concentric rings (**Figure 1**). The conidiophore branches with paired and assume a pyramidal feature, chlamydospores produced by all species. *Trichoderma* strains produce only asexual spores, the sexual stage of *Trichoderma* belong to the ascomycete genus *Hypocrea* [69]. *Trichoderma* is one of the common fungal biocontrol agents used worldwide for the management of various foliar and soil borne plant pathogens. *Trichoderma* fungi are present in most of all types of soils can be isolated from forest and agriculture soils and wood. Several species are beneficial in agriculture. The fungus grows a range between 25 and 30°C of optimal. The most suitable culture media for its cultivation are cornmeal dextrose agar whereas colonies appear transparent, and on potato dextrose agar the colonies appear initially white and then green (**Figure 2**). *Trichoderma* can be produced in a liquid or solid fermentation medium.

#### **Figure 1.**

*Phialid showing production of conidia in highly branched conidiophore (photo credit: Dr. Pranab Dutta & Lipa deb, CPGSAS, CAU (Imphal), Umiam, Meghalaya.*

#### **Figure 2.**

*Pure culture of Trichoderma harzianum in PDA plate (photo credit: Dr. Pranab Dutta, CPGSAS, CAU (Imphal), Umiam, Meghalaya.*
