Trichoderma: A biopesticide with multiple modes of action and more besides

Radial growth of Trichoderma stromaticum with characteristic sporulation on an agar plate

Trichoderma is a fungal group which contains a wealth of species used as commercial biopesticides. It is one of the most commonly used microbial biopesticides, with nearly 200 commercial products in the Americas, Europe, Asia and Africa. However, its use is much greater than the commercial sector with many local informal production facilities producing Trichoderma at a farm or community level.

Why is Trichoderma so successful?

A direct approach

Trichoderma spp. are primarily recognized for their direct biocontrol action against a wide range of pathogens, both soilborne and those on the aerial parts of crop plants. These pathogens include fungal and oomycete pathogens, such as Rhizoctonia, Fusarium, Verticillium, Pythium and Phytophthora. Although Trichoderma usually attack a wide range of pathogens, there are also those which have evolved to target a particular pathogen, such as T. stromaticum, which is effective against the witches’ broom pathogen in Brazilian cocoa orchards. These direct actions include;

  • Mycoparasitism; where the fungus colonizes and feeds on the mycelium of the host fungus
  • Antibiosis; where its metabolites directly act against the target pathogen
  • Competitive exclusion; where the physical presence of the Trichoderma actively prevents access to a host plant.
An indirect approach

In addition to these direct methods of antagonism towards a pathogen or group of pathogens, Trichoderma has other more subtle means by which it can aid a crop in combating pathogen attack. Close association of the Trichoderma within the rhizosphere, around the roots or within the roots, or even as an endophyte within other aerial tissues of the plant, can have a profound effect on the host plant. This includes;

  • Increasing the solubilization and uptake of nutrients, thus improving the general health and fitness of the crop
  • Activating the host plant’s defence system, priming it for a more effective response to the presence of a pathogen; analogous to human vaccination and subsequent immune response! This maybe local – or systemic – (throughout the host plant) induced resistance.
  • Providing tolerance to abiotic stress such as drought, which in turn will provide resilience to a pathogen attack.

The extent to which these more subtle effects are expressed may be highly dependent on the Trichoderma spp. or strain selection for a given crop.

 

Trichoderma spp. colonising, and sporulating on, mycelium of Moniliophthora roreri (frosty pod rot pathogen) on a cacao pod
Trichoderma spp. colonising, and sporulating on, mycelium of Moniliophthora roreri (frosty pod rot pathogen) on a cacao pod

Where can Trichoderma be used?

Trichoderma can be used for crop protection in a wide range of production systems. It can be effectively used, dependant on manufacturers’ recommendations and national registration for;

  • Covered crops, greenhouse or polytunnels
  • Field crops
  • Orchard crops

It can also be used in forestry, in nurseries for seedling production, but can also be used to manage the more rapid destruction of inoculum such as Armillaria spp. (in tree crops) and also Ganoderma spp. (in Oil Palm) by application to diseased material in the field.

Want to find out more about Trichoderma and its role in crop protection?

See how Trichoderma has been successfully applied in Spain for lettuce production in the field.

How can Trichoderma help you?

To take advantage of this remarkable group of fungi for your management of pathogens, review products for your country on the CABI BioProtection Portal.