Trichoderma as Biological Control Agent

**39**

**Chapter 3**

**Abstract**

*Trichoderma* as a Biocontrol Agent

White Mold on Soybeans in Brazil:

Biological control agents are alternatives to chemical pesticides in the manage-

**Keywords:** biological control, *Sclerotinia sclerotiorum*, *Glycine max*, hyperparasitism,

*The white mold or Sclerotinia stem rot* (*Sclerotinia sclerotiorum*) is an important disease in Brazil and in the fields is founded more than 7 million ha with the disease on soybeans in populations of the sclerotia between 1 and 500 per meter square (**Figure 1**). The evolution of agricultural practices over the years undoubtedly increased global food production [1, 2]. Those practices included the use of fertilizers, machinery, improved genetic plant materials, adoption of different cropping systems (no-tillage, crop rotation, intercropping), and intensive use of chemicals. In this scenario, pests coevolved with crops demanding new management strategies,

ment of plant diseases. Currently, hundreds of bioproducts are commercially available in international market varying mainly in antagonistic microorganisms and formulation. We screened four *Trichoderma*-based products as to their efficacy in controlling *Sclerotinia* stem rot (SSR) under protected and field environments and their effect on soybean seeds' sanity and physiological qualities. We also tested application technologies through seed microbiolization and foliar spraying to deliver the microorganisms, and their compatibility with chemical fungicides. In vitro assays showed that all Trichoderma strains were antagonistic to *S. sclerotiorum* evidencing hyperparasitic activity. Moreover, the bioproducts reduced fungi incidence on soybean seeds, promoted faster seedling emergence and did not hamper seeds' vigor. Increases of 14 and 37% were registered for root length and shoot fresh weight over that of the untreated control indicating potential application of the bioproducts as soybean growth promoters. Thiophanate-methyl and procymidone were the most compatible, without drastically affecting spore germination or mycelium growth. Under field conditions, all *Trichoderma* strains reduced SSR incidence and increased soybean grain yield. Formulation interferes on bioproducts' viability

against *Sclerotinia* Stem Rot or

*Breno Cezar Marinho Juliatti and Tâmara P. Morais*

Usage and Technology

*Fernando C. Juliatti, Anakely A. Rezende,* 

and efficacy deserving special attention upon development.

**1. Situation of** *Sclerotinia* **stem rot in Brazil**

physiological seed quality

### **Chapter 3**
