Plants could be dangerous to the health of your business As one university horticulture professor so succinctly wrote in an e-mail to me, "It is not a nice spring." He wasn't referring to the weather at the time. What he was commenting on was the mounting disease problems growers are facing across the country. Ralstonia solanaceurum on geraniums, tobacco mosaic virus on New Guinea impatiens and Puccinia hemerocallidis on daylilies were some of the most serious problems growers were dealing with. A common factor for these disease problems is their source originated outside the United States and hitchhiked in on imported plant material. Although the Ralstonia pathogen originated on only a few geranium cuttings from Kenya, the seriousness of the problem increased after the cuttings were shipped to rooting facilities in Michigan and New Hampshire. Further propagation led to infected cuttings being shipped to growers in nearly 20 states. Detection of this specific Ralstonia bacterium, which is listed in the Agricultural Bioterrorism Protection Act of 2002, resulted in the quarantine of 800 operations by USDA-Animal and Plant Health Inspection Service. Growers were required to not only destroy infected geraniums, but also any plants that had been commingled within 1 meter of positive-tested plants. While this pathogen can be a major problem with geraniums, it is of even more concern because of the impact it could have on other agricultural crops including potato, tomato, tobacco, pepper and eggplant. That is why USDA-APHIS officials stepped in to identify and eliminate infected plants. USDA-APHIS released an Action Plan in February which detailed the procedures growers should follow to identify and dispose of plants in which the pathogen was confirmed. Protect yourself Vegetatively propagated plants are the hot crops that are currently driving sales in the floral industry. More of this vegetative material is being produced offshore, resulting in fewer American growers propagating their own stock plants and cuttings. In most cases, with the newer vegetative material, it is illegal for growers to propagate their own cuttings. So what can growers do to protect their operations from acquiring an unwanted pest or disease? Tom Dudek, Michigan State University extension horticulture agent, suggested a little common sense and a comprehensive sanitation program will go a long way in avoiding these kind of problems. Here are some of Dudek's suggestions: * Remove and discard from your property old and/or "pet" plants, crop debris and weeds before filling a greenhouse with new plants. * Thoroughly clean benches, floors, tools and irrigation systems with a disinfectant between crops. * Restrict entry into production areas to necessary personnel. Monitor all visitors. * Require employees to wash hands at regular intervals during the day -- especially after eating -- if they are handling plants. * Quarantine newly received plant material in a separate greenhouse or keep it isolated from other plants. Inspect for disease or insect problems. Send samples of the new plants to a diagnostic testing lab and conduct your own in-house tests. Following a preventive program before bringing plant material in from an outside propagator could save you a lot of time, money and worries later. For more: Tom Dudek, Michigan State University Extension-Ottawa County, 333 Clinton St., Grand Haven, MI 49417-1429; (616) 846-8250; fax (616) 846-0655; dudek@msue.msu.edu; www.msue.msu.edu/ipm/grnhouse03/ G03-07-03.htm. Send this article to a friend Enter your e-mail address: Enter your friend's e-mail address: Click the image below to send: © 2002 Branch-Smith Publishing