Skip to main content

Biological control of plant diseases gaining momentum

Over the last few decades, indiscriminate use of synthetic pesticides has created concerns due to its detrimental effect on the environment and human health. These concerns, however, generated a continued and increased interest in finding environmentally friendly pest management tools.

A significant global effort is underway to generate low-cost, biorational, natural pest control products. Besides crop plant resistance, various biological control methods based on natural pest suppressing organisms are regarded as main alternatives. More specifically, biological control of plant disease has been gaining momentum in recent years because it offers an alternative and supplement to synthetic chemicals. Microorganisms from diverse groups have successfully been used as biocontrol agents due to their ability to suppress harmful microbes using a variety of mechanisms, such as competition, antibiosis (production of antimicrobial compounds) and resistance induction in the host plant.

History of Biological Control

Since the inception of agriculture, the biological control of plant disease has played a significant role in integrated disease management by balancing harmful and beneficial microbes. Although it took scientists and pathologists a long time to discover and characterize these beneficial microbes, current knowledge and the availability of beneficial microbe-based commercial products has changed growers’ perceptions of biological control of plant diseases. As a result, biocontrol is becoming a more regular part of many growers’ integrated disease management programs.

As consumers demand more sustainable production methods utilizing biorational products, biological control has found its place in the form of augmentative releases, particularly for the management of pests that are difficult to control with pesticides or are prone to developing resistance against chemicals. Retailers have taken notice and many are beginning to set expectations for what they want to see from growers.

Due to increased investment in research and education on multiple aspects, including new products, application techniques and supply chain considerations, biocontrol has proven a good fit for growers looking to add more sustainable tools in their production.

Considerations for Biological Controls

A few applied considerations can help improve efficacy of products at the growers’ level.

  • Biocontrol agents are living organisms that interact with environmental factors and other living organisms in the application sites; therefore, application of biocontrol products should be done in a cool, moist environment.
  • Proactively apply biocontrol agents at the very early stage of disease as opposed to when the disease has already set in.
  • Biocontrol agents should be in place to colonize the plant surface before encountering harmful microbes. For example, treat seed and planting mix with biocontrol agents to facilitate root colonization. A recent study showed that pasteurized planting mix treatment with biocontrol agents followed by seeding provided maximum colonization of seedling root systems and enhanced seedling vigor compared with non-pasteurized planting mix treatment shown here. This application method is especially important for biocontrol agents that do not flourish in a competitive environment.
Difference in tomato seedling vigor
  • Application of biocontrol agents on an augmentative basis may need more frequent applications early in the season until a significant amount of the biocontrol agent has built up.
  • Producers of agricultural commodities who are willing to integrate biocontrol agents into their crop protection package should look for products listed on the Organic Material Review Institute website. Because efficacy of products has not been verified by university scientists, it is imperative to retrieve efficacy data from university scientists before using a specific product.