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Proper grain handling and storage recommended for reduced pest problems

by Wyoming Livestock Roundup

Worland – There are a number of key measures to take for the prevention of pests in farm-stored grain, according to University of Wyoming Extension Assistant Entomologist Scott Schell, who spoke at WESTI Ag Days in Worland on Feb. 19.

“Harvesting grain at the proper moisture level is important. If we put grain into storage and it has too much moisture, the grain could get mold and is also attractive to some of the pests of stored grain,” he commented.

It is recommended to store corn at less than 15 percent moisture, and most other grains should be stored at 12 percent moisture or less.

“We need to maintain the moisture in our target range for as long as we have the grain in storage,” he mentioned, adding that if grains need to be dried, the process should be done in stages to prevent damage.

Handling grain properly during harvest can also help to prevent infestations, as damaged grain is often more desirable to certain pests.

“Grains can be broken or cracked during harvest, handling or in the augers. Even if we dry out a grain too severely, it can sometimes crack and potentially be the start of a problem,” he said.

Special cautions should be taken with malting barley so cracked or damaged hulls do not impact the brewing process.


“We have to store grain in clean, dry, treated bins, meaning that we need to clean the bins out thoroughly and treat them with a preventative spray before we store a new crop,” Schell continued.

New grain should also be put into empty containers if it will be stored long-term, as mixing new and old grain crops can increase the likelihood of pest infestations.

Schell also warns that contract buyers may have specific regulations about which products can be used to treat storage bins for pest prevention before grains are added.

“Keeping bins clean and repaired is very important to prevent problems. Certainly, we can use older bins, but we need to keep them clean, repaired and as tight as possible, except for aeration systems,” he added.

Schell also noted that grain bins should be filled properly to maintain good airflow. If bins are too full or loaded improperly, moisture and temperature levels can be disrupted, and grain can get encrusted within the bin.

“The point of aeration is to maintain the quality of the grain product, managing it at a proper moisture and heat,” he remarked.


Once the crop has been put up, it’s also important to monitor the grain on a regular basis to ensure moisture and temperatures levels are being properly maintained and the aeration system is working well at all times.

“We can put it on our smartphone calendar or write it on the wall in the house, but we need to check and monitor our bins,” Schell stated.

If preventative measures fail and pests appear, he suggested identifying the pest first and foremost.

“Is it one that we brought in from the field? Is it one that is multiplying in the grain? Or do I have an insignificant insect that showed up in my bin by accident?” he asked.

Once the pest is identified, the best way to manage the population can be identified.

“The goal is to keep damages below the economic injury level. In most cases, we can’t always prevent all damage or all pests as it may not be economically feasible to do so,” he commented.


Fumigation, for example, is one control method that may be effective yet costly.

“Most all fumigation takes special equipment, training and licensing to apply. It’s probably not going to be cheap, and it’s probably best left to the people who have been trained. For our safety and because fumigants are quite toxic, we don’t want to make a mistake,” suggested Schell.

Again, it is also important to review any contracts that may exist with buyers as some companies have strict regulations about products applied to their grains.

“If we contract with a company, we need to find out what fumigants are acceptable to use,” he mentioned.

After measures have been taken to control pest populations, the grain should be re-evaluated for infestations.

“After our reentry period, once the treatment has had time to work, we need to resample and see what our results were. We need to make sure we had a good result and determine what steps we can take in the future to prevent the problem from happening again,” he said.

Multiple techniques

Grain pests can include many different kinds of organisms, from rodents, insects and mites to weeds, molds or other pathogens. Schell recommended using multiple methods to reduce pest problems in grain storage.

“We want to combine many approaches to deal with pests and not rely on only one thing because pests have the ability to become resistant to almost any method of control,” he remarked.

Different kinds of pests can also cause different types of damage, such as insects that grow inside of grains and are not immediately visible, pests that prefer to eat damaged grain and even pests that feed on mold growing on grain stored with too much moisture.

“Again, we need to harvest our grain at the proper moisture level, ensure that our machinery isn’t damaging the grain, store our crop only in clean, dry bins, never put new grain in with old grain and bring moisture levels down to recommended levels in stages. Also, monitoring is very important,” stated Schell.

Natasha Wheeler is editor of the Wyoming Livestock Roundup and can be contacted at

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