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Biological Control Agents (BCAs): A Grower’s Guide to Getting Started

Have you noticed how often you pick up a trade magazine and find articles touting the upside of using biological control agents (BCAs) to control insect and mite pests in greenhouses? Grower interest in biological controls continues to increase for several compelling reasons. Among them, pesticide resistance, bee safety concerns, a sharp increase in greenhouse production of edible crops and a general desire for a “greener” approach to pest control lead the way.

The initial transition to BCAs requires commitment and a bit of learning with solid support from an informed supplier. GGSPro partners with specialists from BASF, Beneficial Insectary, Bioline Agrosciences, BioWorks and others to support growers with the latest and most accurate biocontrol information. Success stories are increasingly common as the industry becomes more educated about how to utilize this approach to pest control.

Implementing a BCA program involves a significant shift in how managers think about pest control and crop management. It may help to think of implementing BCAs as you would growing a new crop for the first time: You’re already an expert in growing so, with some technical assistance and a healthy dose of perseverance, you can succeed.

While this can feel daunting, those who are committed to the approach often find there’s more and better information available to assist growers than ever before. Techniques have been created or improved upon to enhance the performance of biocontrols. For years, growers have used banker plants to support Aphidius colemani and Orius insidiosus; updated techniques have decreased cost and boosted performance. Breeder buckets for mass production of rove beetles (e.g., Atheta or Dalotia coriara), are affordable and easy to maintain. The quality and selection of the BCAs themselves have also grown, contributing to increased success rates.

Start small

If you’re unsure about trying BCAs, consider starting small. Really small! Nematodes are a great entry point into biocontrol. They provide tried-and-true control for fungus gnats as well as effectively reducing thrips populations by attacking soil-borne pupal stages. Nematodes can be paired up with soil-dwelling predators such as Stratiolaelaps scimitus (aka Hypoaspis miles) and the previously mentioned rove beetles to further enhance fungus gnat, shorefly and thrips control.

Nematodes are compatible with most traditional pesticide programs, further easing the transition. It’s critical to know which pesticides can be paired with BCAs, since beginning a BCA program rarely means that no more pesticides are used. Your supplier should be able to offer details regarding pesticides that are compatible with one or more BCAs. With careful guidance, you may be able to use certain pesticides to keep pests below damaging thresholds without unraveling the biocontrol program.

One step at a time

Another way to start small is to begin with BCAs in just one greenhouse. This approach also gives you a chance to step into this new endeavor with less risk. A house full of vegetables and herbs would be a prime candidate since there are fewer effective pesticides labeled for edible crops in greenhouses. Build on your success and expand into the rest of the range as your confidence grows.

Last but not least, be sure to enlist your supplier’s help. Work together to review your pesticide application records for the previous three months to determine if any may interfere with starting your program. Sometimes a transition period to "softer," shorter-residual pesticides may be needed before BCAs can be safely introduced. From here, you’ll be on your way to success with BCAs.

Simplified delivery

Delivering biocontrols where they’re needed has always been challenging, especially with predatory mites that are usually distributed in bulk by hand. The development and improvement of sachets has come to the rescue for many growers.

Think of sachets as individual breeding colonies typically consisting of bran, prey mites and the predator mites in an ideal balance to provide four weeks or more of consistent release of predators into the crop. Mini-sachets are among the most popular and are placed in the crop canopy by way of a hook built into the sachet or on sticks that allow for easy placement just above the soil surface. Currently, Amblyseius species of mites are available in sachets include andersoni, californicus, cucumeris and swirski. In the near future the spider mites predator Phytoseiulus persimilis is expected to be available as a sachet as well.

8 steps to a bright beginning

Here's a checklist to help you evaluate your readiness to begin using BCAs. If some criteria aren't currently being met, tend to those before taking the plunge.

  1. Have a good understanding of pest and BCA life cycles. Understanding the biology of insect and mite pests is crucial for all types of pest control programs.
  2. Reduce incoming pest pressure. Segregate incoming shipments for careful scouting and treating with BCA-friendly pesticides if needed.
  3. Practice strong sanitation. Sanitation is crucial! Weeds and “pet plants” can hobble a biocontrol program by providing safe haven for insects and mites.
  4. Work with your biocontrol advisor to schedule BCA orders in advance. Unlike pesticides, BCAs are alive and cannot be warehoused to anticipate your needs. Forecasting becomes easier as you gain experience.
  5. Practice vigilant scouting using sticky cards and plant inspections. Remember to track pests and beneficial organisms. Early detection of pests is critical because few BCAs are capable of controlling high pest populations.
  6. Understand chemical compatibility. Know which pesticides are compatible with the BCAs that you intend to use before you release them. Quick action may be needed to save a biocontrol program, so be prepared in advance.
  7. Ensure full team support. Everyone involved in the production of the crops needs to be on board with utilizing BCAs, including managers and ownership. Biocontrol is a team sport!
  8. Have a realistic attitude. BCAs can be very effective, but they are not a simple solution. Learning requires commitment and some trial and error. (How did your first crop of poinsettias turn out?) Failures are not permanent. Clean it up and try again!