Western Corn Rootworm

What it looks like

Adult western corn rootworm beetles are black and yellow. Males usually have mostly black wing covers, while females have more even black and yellow stripes. The larvae are slender and yellowish white with dark heads.

The eggs spend the winter in the soil and hatch in late spring or early summer. The larvae feed on roots for about 4 to 6 weeks before changing into pupae, and the adults come out about a week later, in mid to late summer. Western corn rootworms usually have 1 generation per year.

Damage

Western corn rootworms are a major pest of corn. Both the larvae and the adults can badly damage plants and roots. The larvae do the most harm as they feed on the roots, while the adult beetles attack every part of the corn plant, including the leaves and silks.

The damage can keep plants from taking up nutrients, leaving them stunted and misshapen, and makes them more likely to get diseases.

How nematodes help

The beneficial nematodes in BioLogic's products hunt down and kill corn rootworm larvae in the soil. Killing the rootworms as larvae stops the life cycle, so new adults don't emerge.

How to apply

Treat with Scanmask from late May to mid-July, applying it to the soil around your crops. Ecomask also works. The larvae hatch from late May to mid-June and spend 4 to 6 weeks in the soil, and that is when nematodes can kill them. The Garden Pack includes Scanmask Spray and the Nema-Jet Sprayer.

Also see the northern corn rootworm and southern corn rootworm.

See How to apply for step-by-step directions, or use the calculator on the Scanmask Spray page to see how much you need.