|The impact of bacterial and viral diseases in hybrid seed production: the human factor|
C. J. KUROWSKI (1). (1) Monsanto Company, Woodland, CA, U.S.A.
Insects are the most common vectors of bacterial and viral pathogens. Bacterial and viral pathogens are the most prevalent seed-borne and seed-transmitted pathogens encountered by the vegetable seed industry, complicating the management of the diseases they cause. Historically, in the literature seed has been implicated as a pathway for many plant pathogens, and in the further spread of the diseases they cause. While some of these claims are supported by strong scientific evidence, others are not. Such unsupported claims have major cost and time ramifications for the seed industry. Worldwide movement of commercial seed is impeded by countries that use these unsubstantiated claims to mandate unwarranted seed health testing. New and existing diagnostic methods are used for seed testing, at times without proper validation, which can lead to erroneous conclusions. The criteria for a rigorous and effective seed health test, as well as why seed health testing has not moved away from traditional techniques in favor of the more sensitive molecular techniques will be discussed from an industry perspective. Currently, a zero tolerance threshold is imposed for many seed-borne pathogens, which may not be attainable, nor may such a goal be reasonable or necessary. In an effort to address unsupported seed-borne/transmission claims, the vegetable seed industry, in collaboration with the International Seed Federation, is developing science-based, pest lists for vegetable crops.