Common greenhouse poinsettia production problems

Poinsettias (Euphorbia pulcherrima) are susceptible to a variety of issues when produced in a greenhouse. It is imperative for growers to monitor their crops carefully to avoid such problems. Proper sanitation and cultural control such as removing diseased or insect infested plants debris from the greenhouse, disinfesting benches and equipment, using well-aerated substrate, spacing plants for proper air movement, and venting to maintain low humidity will also help to reduce problems. Once a problem is identified, prompt corrective measures should be taken to avoid major plant losses.

Common insect pests found during greenhouse production of poinsettia include whiteflies, fungus gnats, thrips, shoreflies and spider mites (Photo 1). Monitor insect populations by placing yellow sticky cards – one card just above the crop every 2,000 square feet, replacing weekly – and scouting the crops regularly, randomly picking up pots and searching all portions of plants for problems. This can help growers determine when and how often insecticides should be applied.

Click here to see more tips on common greenhouse poinsettia production problems in an helpfull fact sheet by Michigan State University's Floriculture extension.