*Trichoderma*: A Biofertilizer and a Bio-Fungicide for Sustainable Crop Production

*Bongani Petros Kubheka and Luwam Weldegabir Ziena*

## **Abstract**

*Trichoderma* has been studied widely. It has been found to play a major role in agricultural production. Around the world scientists and farmers have taken advantage of this knowledge. It is reported to improve plant growth of many crops such as tomato, lettuce, maize, beans, cabbage sugarcane and many more crops. There are two broad categories where *Trichoderma* plays a major role which is its use as a biofertilizer as well as a biofungicide. Its use as a biofertilizer has been aggravated by its ability to produce volatile compounds, ability to solubilize phosphates making them available to the plant. Moreover, farmers use it as a biofertilizer because it improves the uptake of macro and micro nutrients by the plant. As a biofungicide, *Trichoderma* is not to control many pathogens from various crops. This includes the control of pathogens such as *Rhizoctonia, Phytophthora, Rhizoctonia, Sclerotinia, Phythium, Fusarium, Sclerotinia* species *and Galumannomyces*. The mechanisms used by *Trichoderma* as a biofungicide includes, antibiosis, mycoparasitism, competitive advantage in the rhizosphere as well as priming of the crop self-defense mechanisms. The purpose of this book chapter is to highlight the importance of *Trichoderma* in agriculture as a biofertilizer and biofungicide.

**Keywords:** biofertilizer, biofungicide, phytohormones, volatile compounds, phosphates, nutrient uptake, antibiosis, mycoparasitism, competition, resistance

### **1. Introduction**

The increase in the human population around the world has pushed farmers to produce more food. This pressure forced some farmers to use more chemicals in their operations, which led to concerns raised by environmentalists and health officials as some chemicals were damaging the environment and people's health. This has raised a necessity of exploring alternative methods to improve fertilization, and manage pests and diseases.

Biofertilizer became an option as it is friendlier to the environment as well as on human health. *Trichoderma* is one of the fungal cultures that has been studied for this purpose [1]. It has been found that *Trichoderma* can produce various plant growthpromoting compounds such as enzymes and phytohormones [2]. Some enzymes

produced, helps the plant to access nutrients that are not accessible by the plant due to their form. For example acid soils tend to bind phosphorus forming toxic complexes rendering the phosphorus unavailable to the crop. This results in the crop not getting the nutrients that were meant for it, thus reducing the crop yields. Some enzymes produced by *Trichoderma* solubilize phosphates making the phosphorus available again to the crop [3].

Phytohormones on the other hand are compounds that are responsible for the growth and development of the plant. Some are responsible for plant elongation, shoot and root developments, others are involved in plant pests and disease control [4]. *Trichoderma* has been reported to produce some of the plant growth hormones such as indole-3-acetic acid (IAA), Auxins, gibberellic acid [5–7]. Scientists and farmers exploit these properties by developing biofertilizers, in this case using *Trichoderma* as the organism that can produce multiple phytohormones [8].

Biofungicides also became an alternative to chemical or synthetic fungicides to minimize the damage caused by chemical fungicides to the environment, animals and human beings. *Trichoderma* is one of the fungi that is also used as biofungicides by farmers as it has various mechanisms for controlling growth and development of several plant pathogens. *Trichoderma* is reported to produce antibiotics [9, 10], volatile compounds [11, 12], induce or prime plant resistance [13]. Moreover, it is reported to compete better than other microorganisms in the rhizosphere and has mycoparasitism behavior [14].

The objective of this book chapter is to prove that *Trichoderma* may be used as both a biofertilizer and biofungicide providing a sustainable alternative to chemical methods of fertilization and controlling plant pathogens.
