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Corn Rootworm IPM

Regional Working Group


  • corn rootworm root injury Erin Hodgson

    Assess roots now to evaluate corn rootworm management strategies

    Western and northern corn rootworm are serious pests of corn throughout the Corn Belt. We recommend that farmers scout every cornfield every year, regardless of the management tactic(s) used, to evaluate management decisions and prepare for next year. It is a good idea to scout for larvae early in the season, assess root injury when larval feeding wraps up, and monitor adults later in the season. Corn rootworm adults have started emerging throughout Iowa, which is an excellent time to evaluate root injury.

  • corn rootworm management field day location flyer

    Corn Rootworm Demonstrations in Iowa this Summer

    Last year, entomologists and field specialists with Iowa State University Extension and Outreach received many questions about effective management of corn rootworms as populations have increased in the past two years and farmers have experienced enhanced root injury during drought conditions. We teamed up with the ISU extension field agronomists to host corn rootworm management field days at 7 ISU Research and Demonstration Farms in 2022. Come join us this summer to learn about corn rootworm identification, sampling, management, and resistance.

  • Journal Article: Characterizing the sublethal effects of SmartStax PRO dietary exposure on life history traits of the western corn rootworm, Diabrotica virgifera virgifera LeConte

    Results summary from abstract: "Results from this study collectively suggest that SmartStax® PRO may negatively impact WCR life history traits, which may lead to reduced population growth when deployed in an area with WCR resistance to Bt traits."

  • Illinois 2021 applied research results

    2021 Applied Research Results: Field Crop Disease and Insect Management

    The 2021 Field Crop Insect and Disease Applied Research Report provides farmers with updated control efficacy and pest distribution information for major pests of corn and soybean. Use these evaluations to guide control decisions, track performance over time, and see trends in pest populations.

  • Handy Bt trait table March 2022

    The Handy Bt Trait Table - Field Corn March 2022 PDF

    The Handy Bt Trait Table provides a helpful list of trait names and details of trait packages to make it easier to understand company seed guides, sales materials, and bag tags.

  • Wisconsin seed treatment guide

    What's on your seed? Wisconsin seed treatment guide updated for 2022

    The purpose of this publication is to take some of the confusion of seed treatments away, giving you a better understanding of what is on your seed. The list covers seed treatments registered in the state of Wisconsin for use on field corn, soybean, small grain and/or alfalfa seed.

  • Ontario trap sites with 2+ beetles/trap/day

    Ontario corn rootworm trapping network results 2021

    Results from the 2021 Ontario trap sites participating in the Adult Corn Rootworm Trap Monitoring Network have been summarized in the infographic. 

  • CRW monitoring network locations

    Regional Corn Rootworm Monitoring Network Report - 2021

    Western corn rootworm (WCR) and northern corn rootworm (NCR) continue to dominate as economic pests throughout the U.S. and Canada. In response, the Corn Rootworm IPM Regional Working Group was formed during the spring of 2021 and continues to grow. Currently, we are made up of university, industry, and government personnel from at least 12 U.S. states and 5 Canadian provinces. Recently, high corn rootworm populations and the development of resistance to Bt corn hybrids in some areas has sparked greater interest in scouting and alternative management of corn rootworms.

  • Journal Article: Evidence of western corn rootworm (Diabrotica virgifera virgifera LeConte) field-evolved resistance to Cry3Bb1 + Cry34/35Ab1 maize in Nebraska

    Results summary from abstract: "The present study confirms the first cases of field-evolved resistance to Cry3Bb1 + Cry34/35Ab1 maize in Nebraska and documents a landscape-wide WCR Cry3Bb1 resistance pattern in areas characterized by long-term continuous maize production and associated planting of Cry3Bb1 hybrids. Use of a multi-tactic integrated pest management approach is needed in areas of continuous maize production to slow or mitigate resistance evolution to Bt maize."

  • Journal Article: Characterizing the Relationship Between Western Corn Rootworm (Coleoptera: Chrysomelidae) Larval Survival on Cry3Bb1-Expressing Corn and Larval Development Metrics

    Summary of results from abstract: "Results indicate that as the level of resistance to Cry3Bb1 within field populations increases, mean head capsule width and larval fresh weight also increase. This increases our understanding of western corn rootworm population dynamics and age structure variability present in the transgenic landscape that is part of the complex interaction of factors that drives resistance evolution. This collective variability and complexity within the landscape reinforces the importance of making corn rootworm management decisions based on information collected at the local level."

  • Thumbnail from the video in French

    Video (French): How to manage corn rootworm in grain and silage corn

    Corn rootworms are important pests for this crop, especially the larvae that attach to the roots and can indirectly induce yield losses. Good integrated crop management reduces the risk of damage. In this video, you will be able to learn more about: corn rootworms and their biology, the damage caused to corn by these pests, and the different methods of integrated management. This explanatory video is a project of the Grain Research Center (CÉROM). It was funded by the Ministry of Agriculture, Fisheries and Food as part of component 3 of the Prime-Vert program and is linked to the Quebec Phytosanitary Strategy in Agriculture 2011-2021. This video is in French.

  • Representative roots for each treatment. Left to right: no management, Aztec, SmartStax®, and SmartStax® Pro. Photo by Rebecca Vittetoe.

    Summary of Corn Root Injury Evaluation in Southeast Iowa

    Last week, a team of us met up at the Iowa State University Southeast Research Farm (SERF) to evaluate root injury in a small trial for corn rootworm management. The trial had four treatments replicated eight times. The treatments included no management (glyphosate-tolerant only; no Bt traits or insecticide), granular soil-applied insecticide (Aztec), SmartStax®, and SmartStax® Pro (RNAi).

  • Japanese beetles clustered on a corn plant.

    Corn Silks (and Feeders) are Out – Assess Pollination in Fields

    Cornfields are starting to tassle and silk all over Iowa.  Many insects like to feed on silks, so it is a critical time to assess pollination rates. This article highlights a few of the most common silk feeders of importance.

  • Accumulated soil degree days (base 50°F) in Iowa as of June 11, 2021

    Corn Rootworm Egg Hatch Peaking in Iowa

    Corn rootworm egg hatch in Iowa occurs from late May to the middle of June, with an average peak hatching date of June 6 in central Iowa. Even with recent warm temperatures, hatching is a bit delayed this year due to cool spring temperatures.

  • Canadian Bt trait table French

    Canadian Bt Corn Trait Table April 2021 - French (PDF)

    The Canadian Bt Corn Trait Tables have been updated for April 2021. The tables list information about trade names, Bt proteins, refuge requirements, and more for products approved in Canada in French.

  • Canadian Bt trait table

    Canadian Bt Corn Trait Table April 2021 - English (PDF)

    The Canadian Bt Corn Trait Tables have been updated for April 2021. The tables list information about trade names, Bt proteins, refuge requirements, and more for products approved in Canada. 

  • Assembling black cutworm barriers at Johnson Research Farm located near Ames, Iowa. From left to right Leslie Du, Ryan Meehan, and Lydia Holmes

    2020 Evaluation of Insecticides and PIPs PDF

    In Iowa, the species of corn rootworm (CRW) that are of economic importance include western corn rootworm Diabrotica virgifera virgifera LeConte and northern corn rootworm D. barberi Smith and Lawrence, and these two species are the most damaging pests of corn, Zea mays, in the United States Corn Belt. Eggs are laid in the soil during the summer and hatch the following spring. Larval feeding on corn roots in June may diminish yield by reducing plant growth and drought tolerance, and by imposing harvest losses due to plant lodging. Adult emergence from the soil is underway by early July, with most adult emergence completed by mid-August. Additional crop losses may be caused by adult beetles feeding on corn silk and soft doughy kernels. In Iowa, crop rotation, where it fits cropping practices, remains the preferred method of management.

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