Until this year, thrips was not considered to be a major pest of poinsettia in Ontario. Observation of thrips damage in poinsettia has been rare in Ontario except occasionally in the spring during bedding plant season. However with the changing pesticide use patterns for the control of Silver Leaf Whitefly, the pesticide pressure on the thrips has been reduced considerably. As with other crops, the thrips are usually found in the young growing tips where the tissues are succulent and protection is provided. Feeding injury symptoms include white streaking or stippling on the upper leaf surface or as small areas in the expanded leaf where the tissue appears knotted because the young cells have failed to expand.
Many leaves can have a deformed leaf shape because of feeding injury while still quite immature.
The symptoms are most obvious on young fully expanded leaves. See accompanying photo. Control should be achieved using a typical thrips spray programme or consult your Greenhouse Crops Specialist for further information. This information is provided as a public service, but we cannot guarantee that the information is current or accurate. Readers should verify the information before acting on it.