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Vegetable production: The basics of biological control

The huge variety of biological pest control products now available is enough to confuse any farmer.

The increased demand for biological control products can largely be ascribed to problems developed from the use of chemical pesticides. These problems include pest resurgence, resistance, environmental pollution and risks to human health.

The biological control of plant pests and pathogens continues to inspire research, and there have been developments in many fields. Biological control is designed to reduce plant pathogens and limit pests such as insects, parasitic nematodes and weeds.

In the narrowest sense, biocontrol involves the suppression of pest organisms by other organisms. However, the interrelationships of many environmental variables can result in multiple interactions among organisms and their environment, several of which might contribute to effective biological control.


Biological products may be single ingredients or blends of several materials. Some ingredients are recognised by the scientific and farming communities as having the ability to improve crop yields and/or quality. The value of others is often unknown and should first be evaluated for their ability to deliver upon the manufacturers’ claims.

Farmers more often than not, find themselves in a situation where they need to make decisions about purchasing such products.

The following guidelines can help farmers make informed decisions:

  • Be aware of the specific disease problems you experience on your farm. Biological products can be very specific with regard to disease control.
  • Find out if the proposed product has been registered in terms of your country’s relevant legislation.
  • Look for a label on the packaging that contains specific information about the product, such as shelf life, application rate, active organisms and compatibility with other biological control products.
  • Find out at what pH and temperature range the biological agent is active. This information is very useful for the effective storing and application of these products.
  • Find out if the biological control product is compatible with the chemicals you apply during a growing season.
  • Biological products contain living organisms that can be deactivated or killed by agrochemicals.
  • Can the company selling the product provide you with a professional consulting service for setting up an Integrated
  • Pest Management control programme before selling the biological control products? This should include a thorough investigation of the disease problem situation on your farm and current crop management practices.
  • Does the company provide detailed instructions on how to handle and apply biological control products?
  • Is there any measure of the quality and purity of the biological control product you received? For example: Does the company tell you exactly which organisms are contained in the product and who made the species determination? This should have been done by a recognised taxonomic expert, not necessarily someone at the company. Does the company offer reasonable solutions for any difficulties you may encounter and does it follow up to determine the success or failure of your programme?

Instead of jumping right in to using the product on your entire farm, first test it to see whether it actually yields results in your production environment.

Also read:
Potato production: Biology kicks rhizoctonia in the teeth
Crop production: Beating bollworm with biological products

  • This article was written by Reinette Gouws and first appeared in Farming SA.

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