It’s one thing to use biocontrol to manage pests in a greenhouse but it’s even better not to welcome them into the facility in the first place. Growers are catching onto that idea thanks to Vineland Research and Innovation Centre (Vineland).
In a 2018 survey conducted by Vineland, two-thirds of growers who participated said they are using cutting dips to eradicate pests before new ornamental crops take root in their greenhouses. More than 80 per cent also said it is a practice they will continue using to keep bugs at bay.
Vineland has been instrumental in selling the idea of dipping imported plant cuttings (which greenhouse flower growers typically use to start new flower crops) in insecticidal oils or soaps, or biopesticides to kill pests. It is also working with product manufacturers and Flowers Canada (Ontario) Inc. to change labelling on existing pest control products to include cuttings dips as an approved use.
Dipping ornamental cuttings in a greenhouse to eradicate pests
“A lot of cuttings are not as clean as you would like them to be,” said Rose Buitenhuis, PhD, Vineland’s Research Scientist, Biological Control. “Cutting producers do spray for pests during production, however, low levels of whiteflies and thrips can survive and are difficult to detect when they arrive in a facility.”
Between July 2017 and March 2018, Vineland sampled chrysanthemum cuttings and found 84 per cent of them contained one or two thrips per batch of 20 cuttings. Given the fact that thrips can lay up to 300 eggs in their lifetime, those small numbers can quickly get out of control. Dipping cuttings into an oil, soap or biopesticide significantly reduces the risk of pests hitching a ride onto planting stock.
“Our three-year research project showed that this technique will take care of 70 to 80 per cent of whiteflies and thrips that come in and basically sets the clock back on pest population development for weeks, so growers can implement a biocontrol program,” said Buitenhuis.
What’s next? Vineland will begin commercial trials of dips against thrips this fall following testing that was effective in its own greenhouse.
The whitefly project was funded in part through Growing Forward 2 (GF2), a federal-provincial-territorial initiative. The Agricultural Adaptation Council assists in the delivery of GF2 in Ontario. Additional support was provided by Dümmen Orange, BioWorks, Koppert Canada and Flowers Canada (Ontario) Inc.
The thrips research was funded by the American Floral Endowment in collaboration with BioWorks, Neudorff and greenhouses in Niagara, ON.