Nicole Ward and Don Hershman, University of Kentucky Department of Plant Pathology
Win Dunwell, University of Kentucky Department of Horticulture
Soybean cyst nematode (SCN) is the most serious disease pest of soybean in the United States and results in an estimated $1 billion in losses annually. SCN is a microscopic roundworm (Heterodera glycines) that feeds on root of soybean and reduces its capacity to absorb water and nutrients. Yield losses of 30% or more are common where SCN-susceptible soybean varieties are grown and SCN levels are high. SCN was first discovered in Kentucky in 1957 in Fulton County but is now found in every Kentucky county in which soybean is grown commercially.
SCN causes a problem for field production nurseries because Canada and some states—for example, California— do not allow soils (in ball-andburlapped materials) to be imported without proof that the nursery stock comes from SCN-free counties. Other states, including Pennsylvania and New York, assume that the blanket statement “free from all pests” includes SCN. SCN survives in soil as long-lived cysts (Figure 1). The cysts can be spread by any means that spreads soil particles, including windblown soil; soil attached to roots of host or non-host plants; soil peds in bird droppings, seed bags, or stock feed; flood water; or farm and construction equipment.
Essentially anything that causes soil to be moved from one place to another can spread SCN cysts into previously un-infested soil. Quarantine restrictions are an attempt to limit the continued spread of the nematode or more aggressive types of SCN in places like Ontario, Canada, that already have an SCN problem.
To learn more – check out the following website:
Soybean Cyst Nematode: A Potential Problem for Nursuries
PDF: 368 kb, 4 pages