For some companies, a switch to biocontrols is an easy decision to make.
Parkway Gardens of Ontario, Canada, began using biocontrols nine years ago after Erik Jacobsen, the company’s owner, wanted to expose Parkway, its customers and the environment to fewer pesticide products.
“Many pesticides were increasingly ineffective, and in Canada, new product registration moves with glacial slowness,” Jacobsen says. “The labor cost of applying pesticides is much greater than using biocontrols.”
In addition, it was also an opportunity to market the company’s eco-friendliness to a younger demographic, he says.
In a Q & A with Greenhouse Grower, Jacobsen explains what biocontrols and methods have proved effective for Parkway Gardens
GG: In what types of greenhouse structures are you using biocontrols?
Jacobsen: Our greenhouses are all poly covered. About half the range is a Westbrook 14-foot at peak gutter-connected block, and the remaining half a mix of quonset-style houses from various manufacturers.
GG: Who are your suppliers for biocontrols?
Jacobsen: Biobest through Plant Product (MGS) and NIC
GG: What are your application methods? Sachets or any equipment?
Jacobsen: A mixture of techniques are used: sachets, egg cards, shaker canister (with and without medium) and injection into irrigation lines (nematodes).
GG: What pests are you controlling with biocontrols? Which ones aren’t well controlled with biocontrols?
Jacobsen: Codling moth, white fly, shore fly, fungus gnat and spider mite are controlled extremely well, aphids, broad mites and western flower thrips are controlled moderately well and scale insects and mealybugs have poor or no biocontrol.
GG: Have you had to come in to fight outbreaks with traditional controls?
Jacobsen: Yes, especially when reproduction rates of predators are out of sync with pests at lower temperatures early in the season.
GG: What are the challenges with using biocontrols?
Jacobsen: Monitoring for pests is incredibly important. Knowing when populations are rising at an early stage is critical to a timely response, whether it involves increased releases, or chemical intervention. Understanding pest lifecycles, and how biocontrols interact with them is also essential. Not all pests have useful or effective biocontrols — scale insect as an example. It’s about knowing when to intervene before populations reach crop-damaging levels. It won’t save you money, but it probably won’t cost more either.
GG: Are there special considerations when dealing with flowering potted vs. bedding plants when it comes to biocontrols?
Jacobsen: Understanding the insect lifecycle and what their feeding preferences are will direct where and when biocontrols are used. Since bedding plants are in the greenhouse for shorter periods, outbreaks are less common than say on a hanging basket crop that is growing longer and often warmer, creating more opportunity for outbreaks. Application of non-flying predators is more difficult on spaced potted plants since crawling predators may have difficulty travelling between plants.
GG: What resources do you use for questions about biocontrols (people vs. websites)?
Jacobsen: We use both. There is a wealth of information available from companies like Biobest and Koppert, but talking to your suppliers’ sales reps often gives you useful tips based on others experience. We also talk to other growers using biocontrols to hear about their methods and results, and we attend conferences like the Canadian Greenhouse Conference where talks on biocontrols give us information on the latest methods.
GG: Any tips or advice to others using biocontrols?
Jacobsen: Be persistent — you won’t get it right the first year. Read. Read more — and keep learning. Remember that biocontrols are another tool to be used, but they are not a magic bullet. We went from having an uncontrollable whitefly population that was seriously affecting our plant quality and sales to having zero whiteflies. Biocontrols can be very effective when the greenhouse operator makes a serious commitment.