Rootworm Beetles Emerge - Protect Corn Yields Early

Jul 17, 2026
By Farms.com

Crop Rotation Remains the Most Effective Defense Against Rootworm

As western corn rootworm beetles begin emerging from the soil, corn growers are encouraged to closely monitor fields for warning signs that could indicate rising pest pressure.

Curved or "goosenecked" corn plants and increasing numbers of adult beetles may signal a strong rootworm population and the possibility that some insects are becoming resistant to Bt corn traits.

Penn State Extension specialists John Tooker and Adriana Murillo-Williams advise producers to stay alert during this period, as western corn rootworm remains one of the most damaging insect pests affecting U.S. corn production.

The larvae feed on corn roots, limiting the plant's ability to absorb water and nutrients. Severe root injury can cause plants to lodge, lower yields, and complicate harvesting.

Experts emphasize that crop rotation continues to be the most reliable strategy for reducing rootworm populations in Pennsylvania and nearby states. Because the larvae cannot survive on crops such as soybeans, alfalfa, sorghum, or sorghum-sudangrass, rotating fields out of corn disrupts the pest's life cycle and helps prevent infestations.

For growers producing continuous corn, Bt hybrids with belowground insect protection remain an important tool. However, relying on the same Bt traits year after year can encourage resistance. Cases of Bt-resistant western corn rootworm have already been confirmed in several Midwestern states and have also been identified in Pennsylvania.

Producers observing high beetle populations or lodged corn should inspect root systems for feeding damage. While insecticide applications against adult beetles generally do not reduce next season's populations, treatment may be warranted if beetles are clipping corn silks and interfering with pollination.

Extension experts recommend diversifying pest management practices by rotating crops, selecting hybrids with different rootworm-control traits, using soil-applied insecticides when appropriate, and adjusting planting dates.

Farmers experiencing unexpected damage should notify their seed company and contact their local Extension office for management recommendations.

Photo Credit: gettyimages-songdech17

Video: Western Canadian Agriculture: Hard Times Made the World's Best Farmers

Western Canadian agriculture produced the most advanced farmers in the world not through abundance but through adversity. The crow rate fell. The wheat price went nowhere. The brown envelopes stopped.

When the subsidies disappeared, the bad farmers left and the good ones stayed. And the ones who stayed could not just grow wheat anymore. They started growing lentils and canola and peas and flax and faba beans. They built crop rotation. They got serious about agronomy because there was no government backstop. That process produced the Western Canadian agriculture Dennis Bulani describes in this clip: the most advanced, most educated farming culture in the world.

His contrast with Iowa corn and soybean farmers is sharp. At a DeKalb farmer meeting in Okoboji, Iowa, he asked what crop rotation they ran. Beans on corn stubble, corn on bean stubble. How do you fertilize? The co-op agronomist handles it. Have you considered other crops? No need. We make so much money on corn and soybeans. Western Canadian agriculture was never allowed that comfort. And now those Iowa farmers are watching soybean markets lock up with China and corn prices slide, and they do not have the agronomy knowledge or the research base to pivot. Western Canadian farmers adapted on a dime because they had done it before.

Dennis also makes the case that Western Canadian agriculture keeps adapting in real time. Low commodity prices over the past year have pushed growers to look seriously at precision spot-spray technology. He knows a neighbor who bought a sprayer with the seeing-eye system and sprayed only 80 out of 320 acres. As a chemical retailer Dennis acknowledges that will affect his sales. He supports it anyway, because if it advances Canadian agriculture and makes farmers money, that is a good outcome.

The lesson Dennis draws from the tale of two farms: continuous improvement is the only durable strategy. When canola was $22 a bushel some growers went to Arizona instead of the Crop Production Show. When the price came down those same growers came back to the research and the discipline. Products do not go on Rack Petroleum's shelves unless they pass a replicated trial first. That is what Western Canadian agriculture built through hard times: farmers who do the work whether the times demand it or not.

Dennis Bulani is CEO of Rack Petroleum and Ultimate Yield in Biggar, Saskatchewan. Dan Aberhart hosts GTF Productions, Western Canadian Agriculture's foremost live briefing platform and its foremost AI training platform for ag operators