Can Genus *Trichoderma* Manage Plant Diseases under Organic Agriculture?

*Kishor Chand Kumhar, Dalvinder Pal Singh and Anil Kumar*

#### **Abstract**

Organic agriculture has been coming up as one of the promising segments of crop production systems in India. There are numerous reasons for it, however; human health, sustainable environment, soil health, etc. are the important ones. As per the latest information, India has about 1.5% of total cultivable land under organic agriculture. The occurrence of plant diseases in this crop production system is one of the limiting factors. For the management of plant diseases in organically grown crops, there are limited resources since there is a restriction on the use of synthetic fungicides. Under such a situation, bio-pesticides have the potency to take care of plant diseases. Although there are certain fungal and bacterial candidates well efficient in controlling diseases, genus *Trichoderma* has occupied a prestigious position among them. It is capable of managing seed and soil-borne plant diseases. Presently it is available in wettable powder (WP) and liquid formulations in variable concentrations for the application.

**Keywords:** *Trichoderma* spp., plant diseases, organic agriculture, mode of action, formulation

#### **1. Introduction**

The interest in organic crop production has been increasing day-by-day since the last decade because of the increased negative impact of conventional agriculture production systems. Production of crops adopting the inorganic agricultural inputs primarily agrochemicals, which has been used starting from seed treatment till harvesting of the crop for providing protective umbrella against various diseases. The frequent and injudicious application of inorganic agrochemical inputs has invited several environmental and health-related problems.

The demand for organic food commodities has been increased tremendously and hence researchers, as well as growers, have been focusing their attention towards organic crop production wherein, the use of inorganic inputs is completely avoided. However, successful crop production through this system faces various biotic and abiotic challenges too.

Organic farming was first initiated by British botanist Sir Albert Howard in 1905. However, in India, it was initiated during the late 90s. The government of India, in the year 2001, implemented the national program for organic production (NPOP) for the promotion of organic farming. Organic farming was started in several states. Sikkim has converted cent percent of the agriculture into an organic state in this country. Presently, India has about 2.3 million hectares under it [1]. with a production of about 1.70 million MT certified organic products with voluminous export of different organic food items [2].

The occurrence of plant diseases is one of the important concerns in organic agriculture. Various fungi are notable/major phytopathogenic fungi causing huge crop losses [3]. For the management of plant diseases, plant protection measures start as early as seed treatment and would continue until crop harvesting in different crops.

In the recent era, organic agriculture is getting huge popularity and adaptability owing to its several beneficial aspects. The organically produced agricultural commodities ensure pesticide-free items which are fit for human consumption. Under such a crop production system, taking care of plant diseases is one of the major challenges. There are limited plant protection options due to the restricted use of synthetic fungicides in it. It emphasises the use of on-farm inputs for almost all requirements. Under such circumstances, the application of *Trichoderma* spp. could be an ideal alternative to handle plant diseases. Since the last couple of decades, genus *Trichoderma* has occupied a reputed position among the microbes possessing disease management potency. As a biocontrol agent, the antagonistic property of *Trichoderma viride* was recognised [4] while working with the damping-off of citrus seedlings caused by *Rhizoctonia*. Various chemical fungicides were the most dominant during the green revolution era in the 60s and 70s and hence *Trichoderma* could not significantly attain popularity among the growers at the grass-root level. Due to excessive usage of chemical fungicides numerous problems related to the environment, soil and human health ecosystem, resistance development, etc. have emerged as a big challenge before everyone, including scientists, consumers, growers, and the overall associated environment. Therefore, majority has been preferring pesticide-free food commodities for the last so many years. It is good news or sign that usage of chemical fungicides has been coming down and usage of biopesticides has been going up nationally as well as internationally [5]. Currently, in India, there are several hundred manufacturers of *Trichoderma* possessing the registration certificate from the Central Insecticide Board and Registration Committee [6]. They are manufacturing and marketing the *Trichoderma*-based products with variable active ingredients, the dose of application in diversified crop avenues. Although there are four-five species of this antagonist suitable for the management of plant diseases, however only two species namely, *T. viride* and *T. harzianum* have been made available to the end-users. The plus point with this antagonist is that it can be used in a wide range of crops, such as cereals, pulses, vegetables, horticultural, and plantation crops [7–11]. Its wettable powder (WP) and liquid formulations are popular in the market; however, the first one is dominant. In addition to managing the phytopathogen, it is capable of promoting the vegetative growth of plants. Being a natural fungus, it is safer for the environment as well as consumers, capable of adjusting and performing under variable conditions. This chapter highlights various important information related to this genus.

This chapter mainly focuses on the application of *Trichoderma* spp. for the management of plant diseases. Organic crop production excludes the use of synthetic/ inorganic fungicides for the control of plant diseases.
