Corn Rootworm

Aug 11, 2017

By Bryan Jensen

Useful corn rootworm management data can, and should be gathered during the month of August. Digging and washing roots will provide insight on efficacy of rootworm management tactics. Scouting for beetles will give you a perspective regarding forthcoming pressure in continuous corn fields.

The window is closing for the best time to observe rootworm feeding. Most larvae have now completed feeding. Root regeneration has started and will only continue to get worse. Especially when soil moisture is adequate. Although root regeneration is good, it does mask larval feeding and may not give you a true picture of efficacy. I don’t hear or see enough people digging roots to validate their management choices. You wouldn’t consider using herbicides in a weed management program without ever checking to see if it worked. Do the same for corn rootworms. Just because the field has not lodged doesn’t mean there isn’t economic damage. Conversely, lodging is not always a definitive sign of rootworm feeding. Dig and wash roots starting in late July through August. This information will validate your management choice but can also provide important information regarding Bt resistance and presence/absence of first-year western corn rootworms.

To quantify root damage, use the Nodal Injury Scale developed by J. Oleson, Y. Park, T. Nowatzki and J. Tollefson at Iowa State University. This is an excellent rating system and more information is available at http://www.ent.iastate.edu/pest/rootworm/nodeinjury/nodeinjury.html . Essentially, the injury scale uses a decimal system. The number to the left of the decimal indicates the number of complete nodes (or equivalent number of nodes) of roots pruned back to within 1 ½ of the stalk. The number to the right of the decimal indicates the % of the next node of roots pruned. A root rating of 1.2 indicates the equivalent on one complete nodes of roots is pruned and 20% of the next.

There are several UW Extension resources available to guide you through the root rating procedure and rating system.

Rating corn roots for rootworm feeding publication.

Scouting for corn rootworm beetles is every bit as important as it was decades ago. Perhaps more so because of the need to diversify management practices that reduce the potential for resistance. The Pest Survey Bulletin has reported low beetle counts in the 2015 and 2016 growing seasons. Several locations did not report finding a single beetle.

Counting adults during the egg laying period (mid-August to early-September) will give a good indication of expected larval damage in next year’s corn. The process is simple and doesn’t take a great amount of time when compared to the overall value. By establishing the level of adult infestation during the current year, you can determine whether preventative treatments will be necessary in the following year’s corn crop. The grower will need to manage corn rootworm larval populations if you find an average of 0.75 beetles per plant during any one of the three field samplings. This data will help you make appropriate management decisions based on observed field populations. Several UW Extension resources are available to help with beetle scouting.

Corn Rootworm Beetle Scouting publication.

Larval damage: notice root pruning on several nodes

Western (L) and Northern (R) corn rootworm beetles

Source: wisc.edu

Video: The FCDC and AgSmart Bring Plant Breeding to a Wider Audience

In the vast prairies of Alberta, Olds College’s Field Crop Development Centre (FCDC) stands as a beacon of innovation and research in the agricultural world. The institution has become a key player in advancing agricultural technologies and practices. The FCDC’s commitment to applied research has driven them to seek effective means of disseminating their findings and creating a positive impact on the farming community.

One such avenue that aligns with their mission is AgSmart, an event dedicated to showcasing cutting-edge agricultural technologies. The coming together of the FCDC’s annual Field Day and Ag Smart has proved to be a natural fit, fostering a synergy that benefits both parties and propels the agriculture industry forward. The FCDC Field Day took part in conjunction with AgSmart for the first time this week on Aug. 1-2 in Olds, Alta. FCDC Program Director Kofi Agblor and Olds College VP of Development Todd Ormann sat down for an interview with Marc Zienkiewicz to discuss the significance of the two events taking part together and what the future holds.

The Intersection of Research and Technology The essence of the FCDC lies in its dedication to plant breeding and new seed varieties, particularly barley and triticale. While conducting research is essential, it becomes meaningful when its benefits are shared with the wider community. This is where AgSmart steps in, providing a key venue for the FCDC to showcase their research. This union between research and technology creates a holistic and enriching experience for farmers, ranchers, and industry professionals, the pair said.

Seeds as Technology For the FCDC, the partnership with AgSmart goes beyond mere event collaboration. It is about creating an environment that bridges the gap between seeds and smart technology, Ormann said. The college believes that for technology to truly revolutionize agriculture, it must begin with a strong foundation — high-quality seeds. As the saying goes, “it all starts with a seed.” To demonstrate this critical aspect, the collaboration aims to showcase the seed value chain as an integral part of the smartphone.

The Birth of a Powerful Alliance The idea of joining forces emerged when staff realized the potential synergy between AgSmart and the FCDC Field Day. With just a few days separating the two events, a proposal was put forward to merge them. The marketing and communications teams from both sides worked seamlessly to ensure the essence of both events remained intact, creating a powerful alliance that leverages the strengths of each, Agblor said.

Driving Advancements in Breeding For Agblor, the partnership with AgSmart has tremendous potential to drive advancements in breeding and other technology. With technologies like drones and imaging becoming integral to phenotyping, breeding is no longer confined to vast fields to assess thousands of plants manually. Instead, it benefits from the data-rich insights brought about by smart technologies. These advancements make breeding more efficient, precise, and instrumental in shaping the future of agriculture.

Overcoming Challenges Together While the partnership between Olds College and Ag Smart has been a resounding success, there are challenges on the horizon. Securing stable funding for long-term breeding initiatives is crucial to sustain progress. The college is committed to navigating these challenges and investing in agriculture’s future sustainably, Agblor said.