Slug threat to PA corn and soybeans - Scout Now!

By Blake Jackson

Recent heavy rains in parts of Pennsylvania have created ideal conditions for slug populations to surge, putting emerging corn and soybean crops at risk. If you're a farmer in Adams, Columbia, or Montgomery Counties, or suspect slugs in your area, early scouting is crucial.

While options for managing slug damage at this stage are limited, warm and sunny weather provides the best natural defense. Early damage often appears severe, but healthy plants can outgrow it, like hail damage.

However, for heavily damaged areas with dying plants, slug baits containing metaldehyde or iron phosphate can be used. Be aware that these baits are expensive, may be ineffective in wet conditions, and require multiple applications.

Home remedies like spraying nitrogen solutions at night are tempting due to their quick kill effect on slugs. However, this method carries significant drawbacks. The recommended 30% urea-ammonium nitrate solution can burn crops, potentially causing more damage than the slugs themselves. Additionally, repeated applications are needed, and using nitrogen outside a proper management plan can have unintended consequences.

For long-term slug control, planning is key. Diverse crop rotations and incorporating cover crops into your planting strategy are effective methods. While some believe cover crops exacerbate slug issues, research suggests they can be beneficial, even when planting cash crops directly into them (green planting).

Practices that promote rapid early growth, such as row cleaners, pop-up fertilizer, and proper furrow closure, also help crops outpace slug damage.

Another natural defense comes from ground beetles, which feed on slugs. Their populations can be inadvertently suppressed by insecticides, particularly neonicotinoid-coated seeds and pyrethroid or organophosphate sprays. Avoiding unnecessary insecticide use in slug-prone fields can help maintain healthy ground beetle populations.

For a comprehensive guide on scouting and managing slug infestations, refer to the Penn State slug fact sheet. By implementing these strategies, Pennsylvania farmers can better protect their crops from slug damage and ensure a successful growing season.

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