This podcast episode focuses on a few recent pest updates, like soybean aphid, twospotted spider mites, and a mix of defoliators. Matt talks about spider mite activity in some of his research plots and also in fields near Brookings, SD. Erin notes soybean aphid activity is down throughout Iowa and they both revisit the economic threshold for this common pest. To read more information about why the economic threshold for soybean aphid remains consistently at 250 per plant, read this webpage co-authored by many university entomologists. Finally, Matt shares a research update on the release of parasitic wasps that like to feed on soybean aphid.
Today, Matt and Erin talk about noteworthy news items related to field crop pest management. But first, they talk about upcoming meetings they plan to attend. Both are attending the ICE (International Congress of Entomology) meeting in Orlando next week. And both plan on speaking at the annual ISU Integrated Crop Management Conference in Ames (Nov 29 - Dec 1). Erin will talk about a management plan for soybean aphid, particularly with suspected pyrethroid resistance in Iowa. Matt plans to talk about pollinators in field crops. In Minnesota, the governor proposes restrictions on neonicotinoids in agriculture and the implications for that are largely not understood. Also, the recent merger discussions between Bayer Crop Science and Monsanto also could change the ag industry in the U.S. and around the world.
It's a new beginning for the podcast - Season 8 starts today! Matt and Erin have a bit of random conversation at the beginning like usual. But they eventually provide a summary of the recent new of an organophosphate, chlorpyrifos. The EPA has been dealing with a petition to revoke tolerances for this widely-used insecticide. The EPA will not move forward with restricting chlorpyrifos in any crop; this could be important as farmers make product choices for 2017. Erin wrote a recent ICM Blog about it. Matt shared updates about his recent travels to the S1055 Soybean Entomology Working Group meeting in Memphis where he compares soybean production in the North Central Region to the South. Surprise - it's a lot different! Erin wraps up by providing overwintering mortality predictions for bean leaf beetle. The 2016-2017 winter was moderate and about half of the beetles are expected to survive. Read more in her recent ICM News article.
Bean leaf beetle adult. Photo by Winston Beck, ISU.
It's been a few weeks, but Matt and Erin have a new episode out today! Erin starts off by providing a statewide update on soybean pest populations in August. Good news is that most fields had low pest pressure in 2018. Matt shares his impressions of a recent court ruling that will ban chlorpyrifos use in the U.S. The episode title is a play off of Warren Zevon's song, "Lawyers, Guns and Money" from 1978.
Soybean aphid management has relied heavily on foliar insecticides to protect yield since 2000. In 2016, performance issues have been documented in commercial fields and research plots in northern Iowa counties. With support from the Iowa Soybean Association, we are exploring insecticide resistance for soybean aphid in Iowa and describing the mechanism of resistance. Laboratory bioassays identified field-collected population’s evolved resistance to pyrethroids. Read more about Monitoring soybean aphid resistance to lambda-cyhalothrin and identification of mutation associated with insecticide resistance
The use of insecticides to control the soybean aphid has become a predominant management practice for growers. Before the confirmation of the soybean aphid in 2000, less than 0.1% of soybean was treated with insecticides. However, soybean aphid management has resulted in a 130-fold increase of insecticide applications in less than a decade. An estimated 1,400% increase of Iowa soybean acres were treated with a foliar insecticide in 2009 compared to 2000. Growers are also increasing the use of insecticidal seed treatments to control early-season establishment of insects on soybean. Read more about Insecticide Evaluations
Our extension program is led by Dr. Erin Hodgson, and Dr. O’Neal and many lab members also participate in programs throughout the year. We are focused on delivering research-based information to a variety of clientele. Our group serves farmers, crop consultants, agricultural professionals and other university/extension personnel. Most of our programs are within the state of Iowa, but we travel throughout the Midwest to deliver content. Read more about Extension
Erin and Matt welcome Ashley Dean to the podcast to talk about her work tracking and trapping insect pests of corn and soybeans in Iowa, and the breaking news that the EPA has banned chlorpyrifos.
Ashley gives us an update on the low populations of soybean aphids, occurrences of spider mites and grasshoppers, and the slow spread of soybean gall midge into the more central part of Iowa. She also shares her work on trapping corn rootworms and the discovery of a red western corn rootworm. We geek-out a bit about that one.
We discuss the recent announcement that the EPA is reducing the tolerances for chlorpyrifos to zero for all foods. This is a bigger deal than the announcement just over a year ago that Corteva would stop producing chlorpyrifos. Ashley Dean wrote an article about that decision: https://crops.extension.iastate.edu/cropnews/2020/02/corteva%E2%84%A2-en...
We discuss how the removal of chlorpyrifos will reduce the number of insecticides with different modes of action that corn and soybean farmers can use. For details about modes of action, visit this website: https://irac-online.org/modes-of-action/.
There are insecticides that can replace chlorpryifos, but they are more expensive. For soybean aphids, there are also aphid-resistant varieties. Ashley wrote an article about the economic factors related to pest management and soybean production. She developed partial budgets for this article that goes into great detail about the costs of different approaches for managing the soybean aphid: https://onlinelibrary.wiley.com/doi/full/10.1002/ps.6093