1) SUMMARY

Large populations of rodents, mostly meadow vole (Microtus spp.) and to a lesser degree ground squirrels (Spermophilus spp.), cause severe damage to emerging beets.  This causes loss of stands and occasionally leads to replanting.  The greatest damage occurs later in the year to the developing sugarbeet root.

Evidences of vole infestations are hollowed out portions of roots, a nearby burrow, or a mound of soil with near dead or dying plants.  Overwintered sugarbeets are an attractive habitat for meadow voles, providing cover, source of food, and protection from predators.  Vole damage is most severe in overwintered beets where the populations have reached numbers between 1,000 and 3,000 animals per acre.  Damage is usually concentrated at the edge of fields.  Later, when populations increase, the area of damage expands, as does yield losses.  Root feeding will also allow secondary root rot pathogens to enter and deteriorate the entire root, causing an additional loss in production.

Ground squirrels have been less of a problem in sugarbeets.  However, existing populations next to a newly planted field can reduce stands by feeding on emerging plants.  Effective control options exist for squirrels, including fumigants, traps, and poison baits.  The use of PVC pipe with baits inside, placed near the area of activity, has been a successful management tool.

 2) CURRENT PEST MANAGEMENT PRACTICES

Control of meadow voles is only effective with zinc phosphide bait applied to the populated areas of the field.  If applied by air, the agricultural commissioner must make an inspection to verify vole population and must be present during the application of zinc phosphide.  Regulatory personnel need not supervise ground applications.  Little impact on populations have been made by natural predators or other non-chemical strategies.

 3) REDUCED-RISK OPTIONS

  No information available.

 4) CHALLENGES

  No information available.

 5) INNOVATIVE FEATURES IN REDUCED-RISK PROGRAM

  No information available.

  6) BARRIERS TO ADOPTION OF REDUCED-RISK METHODS

  No information available.