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SPECIAL SESSION: Propagate Plants, not Pests and Pathogens

Tracing the Production of Young Plants from Stock Plants to Rooting of Cuttings
Roberto G. Lopez - Michigan State University.

Over 4 billion stem tip or terminal vegetative cuttings are harvested annually from stock plants for the international floriculture industry. These stock plants are grown in 400 ha. of greenhouses primarily located in Central and South America, Israel, and Africa. In order to prevent the risk of pathogen transmission, the industry begins with true-to-type plants that become the clean and elite stock. This requires extensive efforts to test, identify, and prevent pathogen infection and insect exposure during the build-up and production phases of stock plant management and cutting production and harvest. Time of harvest and post-harvest protocols, proper packaging, cold-chain management, and timely USDA-APHIS port-of-entry inspections are essential for effective international transportation of cuttings, which typically takes 48 to 72 hours. Upon receipt, the unrooted cuttings are rooted in propagation greenhouses to produce rooted liners. Root initiation typically begins in 1 to 3 weeks, and fully rooted cuttings are ready to be shipped to other greenhouse growers or transplanted after 2 to 8 weeks depending on the species.