For poinsettias, prevention is better than cure

With their red and white bracts, poinsettias are a Canadian Christmas favourite. They’re the second-largest potted ornamental crop in Canada, half of which – approximately 4.2 million pots per year – is grown in Ontario.

When it comes to potted plants and flowers, consumers demand an aesthetically perfect crop, free of pests and blemishes. That led Flowers Canada (Ontario) to access funding from Growing Forward 2, for a project led by Dr. Rose Buitenhuis, of the Vineland Research and Innovation Centre, to provide growers with tools to respond to emerging pest issues.

Her goal is to identify an effective control to reduce infestation levels of whitefly, a pest that can enter a greenhouse on imported poinsettia cuttings, at the beginning of the production cycle. This will allow biocontrol strategies – using a natural predator to control a pest – to work more effectively and keep pest populations from developing and ultimately damaging the plants.

Earlier research has shown that dips for poinsettia cuttings which contain products like fungi, insecticidal soap or horticultural oils can significantly reduce whitefly numbers on affected cuttings.

In the current project, Buitenhuis is applying the “clean start” principle to poinsettia production by making cutting dips part of an integrated pest management program for the holiday crop. She is evaluating the effectiveness of the combined approach and determining the risk of plant pathogen build-up and transfer through the dipping technique.

Results are positive, showing that whitefly numbers are lower on dipped plants than plants that didn’t receive the dip. The risk of plant pathogen transfer was low and a cost-benefit analysis shows the approach makes economic sense too – dips followed by biocontrol is the preferred option for reducing whitefly infestation in poinsettia production in Ontario.

Funding for this project was provided by Growing Forward 2 (GF2) a federal-provincial-territorial initiative. The Agricultural Adaptation Council assists with the delivery of GF2 programming in Ontario.

Source: AAC