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Plan ahead and prevent yield loss due to slugs.

Agronomy Bulletin 30 ─ Managing Slugs

Manage slug pressure by ensuring crops can outgrow feeding pressure early in the season.

Situation

Slug damage in corn and soybeans has increased with the adoption of no-till and minimum-till practices. Because rescue treatment options are limited, growers should take steps to prevent slug damage.

Factors to Consider

  • Weather and soil conditions
  • Crop vigor
  • Tillage
  • Planting conditions
  • Control options

Action Plan

  1. Observe slug activity. Track slug activity by looking for the characteristic trail of slime. Slugs favor cool, moist conditions and available plant residue. Damage in corn and small grains is caused by slugs scraping along leaves, first causing a window pane appearance and then tattered leaves. Damage in soybeans starts with deep feeding scars in the cotyledons and is followed by irregular holes in the leaves. Because the growing point of the soybean plant is above ground, damage can result in stand loss.
  2. Promote early season vigor. Young plants can tolerate some defoliation without a yield penalty. Manage slug pressure by ensuring crops can outgrow feeding pressure early in the growing season. Select corn hybrids and soybean varieties with good emergence and vigor. Manage weed pressure and fertility to promote early growth.
  3. Manage residue. Conventional tillage is most effective at reducing slugs but is not always an option. Row cleaners and strip tillage can warm the soil, creating an unfavorable environment for slugs while young plants have a favorable growing condition.
  4. Choose an optimum planting date. Plant early to give plants a head start against the worst slug feeding. Don’t plant into soils that are so wet that the seed trench does not close behind the planter, as this allows slugs to have protected access to growing seedlings night and day.
  5. Consider chemical control. Metaldehyde-based chemicals provide effective control but are expensive to apply at field scale. Foliar application of a 30 percent urea-based nitrogen solution also can be effective under certain conditions. It works as a direct contact irritant so slugs must be active on leaf surfaces to be effective. Apply at night for best results. When weighing management options, seek advice from your local agronomic professional or adviser.

Summary

Slugs can be difficult to manage in no-till systems, but planning ahead and using a coordinated integrated pest management approach can prevent damaging yield loss. For more information, contact your local Mycogen Seeds commercial agronomist or trusted agronomic adviser.

Resources

Published on Thursday, August 15, 2013