CAN: The case for new biocontrol agents

Greenhouse production in Canada is growing and evolving. Tomatoes, cucumbers and peppers have traditionally been the primary crops grown in Canadian vegetable greenhouses, while the floriculture sector has been producing a wide range of potted plants, bedding plants and cut flowers.

In recent years, the diversity of food crops has expanded to include lettuce, green beans, eggplant, various herbs and microgreens, strawberries and raspberries, along with an increased diversity within each vegetable category. Over the last two years we have also seen tremendous growth in the production of ‘medicinal’ crops. Market demand has stimulated some of these developments, and greater unpredictability in weather events as a result of climate change has also prompted moves toward production in protected structures.

The greenhouse environment, while ideal for crops, also favours many arthropod pests and plant diseases, which in turn have to be managed. Aided by international movement of plant material (finished and propagative) and a changing climate, the risks of pest incursions - both new and known - have never been greater. Resistance within these pest populations is widespread, and we are faced with declining access to new chemistries. Market forces are also influencing the agricultural landscape with rising demands (driven by consumers) around agri-environmental sustainability and food provenance. To meet these challenges, the greenhouse sector has embraced the use of biological control within integrated crop management programs and biocontrol is now successfully practiced in Canada over a diverse variety of ornamental and vegetable crops.

This evolution in crop management is not unique to Canada though, and demands for biocontrol services are growing worldwide. This has placed an enormous stress on biocontrol companies just to keep up with orders for their existing products, let alone develop products for new pests on new crops. The challenge to researchers and the biocontrol industry is to devise ways in which biocontrol strategies can evolve to meet these growing demands.


Biocontrol strategies largely rely on regular releases of natural enemies, including specialist predators or parasitoids, and applications of microbial biopesticides or nematodes. Despite the development of sophisticated biocontrol programs, pests such as whiteflies, spider mites, thrips and aphids remain an ongoing challenge. Biologicals do not work equally well in all crops or jurisdictions. Moreover, some pests currently have no biological solutions and changes in the prevalence of closely related species, e.g., onion thrips vs. western flower thrips, undermine the efficacy of established biocontrol programs. As a result, growers are periodically forced to use pesticides and few of them are truly compatible with natural enemies. How can we eliminate the need for pesticide intervention, preserve the integrity of biocontrol systems, and conform to market demands for ‘pesticide-free’ produce? Part of the solution lies in the development of new natural enemies that will strengthen bioprograms and expand the range of pests that can be successfully managed in this manner.

Click here to read the full article at Greenhouse Canada.

Photo credit: Dr. Gerben Messelink

01/09/2019 - Greenhouse Canada

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