Starting with high quality disease and insect free plant material is a critical step in the management of diseases and insect pests in the greenhouse. The first step in reducing pest pressure is to purchase high quality, pest free plant material from reputable producers. When new plant material is brought into the greenhouse it should be inspected thoroughly for any signs or symptoms of pest activity. Inspect incoming plants for key insects, diseases, weeds and cultural problems. Inspect the entire plant - leaves, stems and roots for any indication of pest activity and for general health, and train employees to monitor for and identify diseases and insect pests. If at all possible, do not accept plant shipments with serious insect or disease infestation. Incoming plant materials should also be quarantined from the rest of the crop until you can be sure they are pest free. If possible set a small area in the greenhouse aside as a quarantine area and keep plant material from different suppliers separate.
If isolated evidence of insect activity (such as aphids) is found and you decide to keep the shipment, place plants in the quarantine area. Treat immediately and hold the plants in this area until you are sure they are healthy and free of pest problems. Ask workers to enter this quarantine area at the end of the day to avoid moving pest problems throughout the operation.
For more information see the fact sheet below:
IPM Scouting and Decision-Making, UConn Extension: http://ipm.uconn.edu/documents/view.php?id=232
For more information:
University of Massahussets Amherst