Seedcorn Maggots: What You Need to Know

Below-ground pests like seedcorn maggots usually strike early in the season. By the time they’re detected, it’s often too late to salvage your pulse crops. However, with effective prevention strategies, you can protect your fields from planting through emergence, ensuring a healthy start.

How Seedcorn Maggots Impact Pulse Crops

Seedcorn maggots are the larvae of adult flies that resemble common houseflies with dark gray bodies, black legs and transparent wings. In late April, adult flies lay their eggs in the soil where they hatch into small, pale maggots about 1/4 inch long within 2 to 4 days. The maggots’ lifecycle lasts 2 to 3 weeks.

These maggots move easily in cool, wet conditions, feeding on developing seed and seedlings. This can lead to stunted plant development and impact pulse crop yield potential. Adult flies prefer fields with decaying vegetation or high organic matter, making untilled fields more vulnerable to infestation. Fields with a history of infestations are more susceptible to future damage from seedcorn maggots.

Seedcorn maggots harm young pulse crops by feeding on the seed germ and burrowing into seeds, eating the inside and leaving behind empty shells. They also feed on the stems of the seedlings, weakening and wilting the plants — sometimes leading to plant death.

This damage creates bare spots in the field, prevents seed germination and reduces plant emergence. No rescue treatments are available, so it’s too late to save affected crops once seedcorn maggots are established.

How to Prevent Seedcorn Maggots

Check for seedcorn maggots when preparing to plant your pulse crops. As you scout, look for eggs in the soil. Seedcorn maggot eggs appear as small, brown cylinders resembling tiny footballs. Early detection can help prevent an infestation before it affects your crop.

To avoid a seedcorn maggot infestation, consider delaying planting until the soil dries out and warms up. These pests thrive in cool, moist conditions, so warmer, drier soil conditions are less favorable for maggot development. Additionally, planting treated seeds can suppress these pests and be an effective preventive measure.

Coming Soon: A New Option to Suppress Seedcorn Maggots

A new seed treatment featuring the active ingredient isocycloseram is coming soon for use on cereal and pulse crops. This seed treatment will help suppress seedcorn maggots and other belowground pests and will be lethal to wireworms, helping protect crops from early-season damage. Isocycloseram will belong to Insecticide Resistance Action Committee (IRAC) Group 30, which will act through contact and ingestion and has no known cross resistance to other insecticides.

Be the first to learn more about isocycloseram.

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