Kansas, known commonly as the “Wheat State,” generally produces the largest amount of hard red winter wheat in the United States, which is used for flour and bread-making. Many people work to ensure that flour is at its highest standard for consumers.
Just trace the grain from the farmer to the grain elevator, processors and retailers before it makes it into consumers’ homes. Consider the many commodity organizations and governmental agencies involved in grain production and preservation. And, don’t forget about the researchers looking for ways to solve problems and improve the process.
In 1914, entomologist George Dean taught the first stored-product entomology course at Kansas State University. Another early leader, Donald Wilbur, arrived at K-State in 1928, and taught courses and conducted research until the 1960s. A house that still stands on Juliette Street in Manhattan is a place where U.S. Department of Agriculture (USDA) scientists reared colonies of insects related to stored products and researched their control beginning in 1934.
Stored products are agricultural commodities that do not require refrigeration after harvest. Grain, grain products that include flour, dried meats and dried cheeses, as examples, fit the stored-product category.
Grain handlers and those who work in the milling industry have long known that insects can pose a problem to grain and flour quality, even before quality standards and regulations were in place by agencies such as the Environmental Protection Agency, Food and Drug Administration and Federal Grain Inspection Service.
By working with stored-product entomologists at K-State since the early 1900s, the grain industry was on the fast track of learning how to control insects and maintain safety and quality of grains, among other stored commodities. This is especially important in making bread, a main food staple that provides for sustenance of life.
Now, 100 years after the first course, stored-product entomology research and instruction continues at Kansas State, and information is provided to stakeholders in the grain and other food industries through K-State Research and Extension.
An integrated effort
Thomas Phillips, the Don Wilbur endowed professor in stored-product entomology at K-State, has been at the university nearly eight years. When he arrived on campus, he went through old files and found former K-State Department of Entomology faculty member Robert Mills had written about the history of stored-product entomology at the university through the 1980s, when he retired.
“One of the reasons I am here is that Manhattan, Kansas is the leading center for any work—research and application—on grain and stored-grain entomology,” Phillips said.
Phillips, along with David Hagstrum, K-State adjunct professor of entomology, decided to finish the history report started by Mills and published it recently in the journal, American Entomologist. Hagstrum said part of the success of stored-product entomology research and application is due to close interactions among the university and nearby industry and government institutions. Those include the IGP Institute, Kansas Wheat Commission, USDA Center for Grain and Animal Health Research, and AIB International—all of which are located in Manhattan.
Historically, K-State has been known for its strong Department of Grain Science and Industry, Phillips said, so it makes sense for the Department of Entomology to partner with it to address issues related to insects’ role in grain handling and quality. Subramanyam Bhadriraju, who recently held the rotating Wilbur professorship in the grain science department, also works in the area of stored-product entomology.
Collaboration extends to involve agricultural economists.
“From our standpoint, we know grain is in the best condition right at harvest,” Phillips said. “The economic decision for storing grain is to make money, but you can imagine at the time of harvest the supply is high, and the price is low. People store a lot of grain and need it throughout the year. They are storing that and hedging that the price will go up, but pest control, among other things, costs money.”
Additionally, K-State’s Department of Biological and Agricultural Engineering is a close partner, as some people within the department work on storage structures and take into account factors such as cooling the grain.
“Insects are cold-blooded,” Phillips said. “The trick is to cool grain down, because you don’t want to store warm grain. Any moisture or molds can take off.”
“You can’t eliminate insects,” he continued. “The grain is cold, and the insects will be in there, but the infestation is kept in check. We have worked on ways to monitor the insect populations by sampling the grain to determine when pests become a problem.”
George Dean suggested in the early days of stored-product entomology that using heat treatment could be an effective control method in mills. While other methods have been tested over the years, including various pesticide and fumigant applications, heat treatment is still used as a preferred control method today, especially as chemical controls are phased out or not preferred.
Using fluidized-bed dryers is one way to heat moving grain. The grain is transported on a bed, and it bounces as heated air is applied. The heat kills the insects, and the grain has time to cool.
“Fluidization is used to get air space in the grain,” Hagstrum said. “You can put hot air around the grain to kill the insects. We would never heat all the grain in the bin and keep it that way, because you could damage it.”
K-State researchers study ways to use heat treatment as an effective pest management strategy. Further, as wheat in particular becomes flour, more collaboration and research is necessary with cereal chemists and professionals involved in baking quality.
All the way to the grocery store
Entomologists at K-State and beyond work to identify those common insects in both stored grain and stored commodities. While some pests are more common in the grain, others prefer the flour, and many more prefer other stored commodities.
Hagstrum reported more than 1,600 insect species that affect stored commodities, including various types of products—from food products such as wheat, coconuts and cured hams, to other household products made from leather, wool or silk. This makes stored-product entomology a broad discipline.
“A review of the literature shows as you go from the grain to the finished product, there’s an increase in the number of species,” Hagstrum said.
Of the more than 1,600 identified, about a dozen are of concern in wheat, with the most damaging pest being the lesser grain borer.
“At the flour mill, you’ll be hard-pressed to find a lesser grain borer,” Phillips said. “So the insects shift a little bit. The red flour beetle becomes the major pest at the mill. Then you get to the feed mill, it’s the soft toothed grain beetle.”
“We could go all the way to the grocery store,” he continued. “I could walk down the pet food aisle and find pests; it is not uncommon to find infested bird seed. The insects could still be in products and get into people’s homes. I get several calls from homeowners.”
Consumers shouldn’t panic about insects, however, because inspectors ensure a certain standard is met at all times. In cooked commodities such as baked goods, the heating process will kill the insects.
For more about 100 Years of Stored-Product Entomology at Kansas State University, published recently in American Entomologist, visit the Entomological Society of America website (http://www.entsoc.org/pubs/periodicals/ae).
Other resources on stored product management are available on the K-State Department of Entomology website (http://entomology.k-state.edu/department-info/publications/stored-product-protection.html). The book “Stored Product Protection,” co-authored by Hagstrum and Phillips, can also be accessed online through the K-State Research and Extension Bookstore (http://www.ksre.k-state.edu/bookstore/Item.aspx?catId=522&pubId=15479) or at your local extension office.