Seed Facility Fumigations

June 2025 Edition: Seed Facility Fumigation by: Jerry Skordjal

Were you like me when I was a kid? Sitting in the back seat of your parent’s car, watching field after field of corn pass you by and wondering, how did it get there? You saw the farmer and his tractor and his plow in the early spring, maybe you even got stuck behind one on the road, but where did the farmer get the seed? Alright, I never gave it much thought as a child. Instead, I just spent hours in the neighbor’s field playing hide and seek and coming home with corn leaf cuts head to toe. I had no idea how much thought and testing went into each kernel, nor the extensive impact the business of farming had on our economy. It wasn’t until I grew older did I find myself intrigued by the process of how wheat makes it to our bread or how corn makes it to our chickens. Starting my pest management journey in 2010, shortly after high school, I gained a passion for the ‘where’ and the ‘how’ of the grain and seed industry.

Production of seed is an important, yet complex process. Seeds such as corn, soybeans, cotton and many more play an important role in our everyday lives. Most people not familiar with the process, would be surprised to learn how many steps it takes for one kernel of corn to grow into the very corn stalks they drive by each day. These steps create challenging pest situations that require pest management professionals to practice and execute a variety of control methods. Most all seed producers have sites in South America, Hawaii, France and other sites to provide off season growing capabilities and to keep up with demand. That seed, then must make its way here to the Midwest via plane, ocean and roadway.

When seed is processed and sold to the farmer, it is common practice for the seed producer to accept returns on the unplanted seed from the farmer. This is due to the extreme value of seed and the need to maintain good relationships with farmers. Seed can range from $75 per bag for soybeans to north of $400 per bag for corn. This makes a standard pallet of seed worth nearly $4,000 to over $20,000. The seed producer will bring these returns in for testing and resale at a later date. This practice increases the risk of rodent or insect activity being introduced into the facility and potentially to other new seed.

To further the complication in managing these incoming pests, rodents have the advanced ability to live on consuming corn seed alone. Seed, such as corn, can provide all the nutrients needed for mice to not only survive but thrive and multiply. The biology of the rodents allows them to pull the water requirements for survival from the seed they are eating. This means, once a pregnant female has found her way into a pallet of seed, she has potentially claimed herself a home valued at $20,000 and has everything she needs to grow her family. With pallets coming in from farmers and being placed next to each other by the 1,000’s, this risk starts to multiply.

Insects, most commonly the Indian meal moth, benefit from common storage habits of seed facilities. Despite the common seed facility having large warehouses for their products, they never fail to fill, if not, overfill the space. When pallets and boxes of seed start to flood in and are placed tight alongside each other, inspection can be difficult. While devices, such as hanging pheromone traps, can aid a pest management professional in locating pests. They can only assist in narrowing down an area of interest. It can still be a challenge to coordinate with the customer to remove rows of product to inspect for these pesky fliers. Usually, by the time the larva is easily visible along the outside of the seed box, several other boxes in that same row have been compromised.

While Integrated Pest Management tools such as traps, rodenticides, sanitation and exclusion are vital steps to a quality program, there are times when the fumigation tool becomes a necessity to ensure product and brand protection. No farmer wants to return to his field for the first plant of the spring and find the center of his pallet decimated by the mighty House Mouse, Mus Musculus.  

This is where fumigation can ease concerns of product contamination by pests. A fumigant is a pesticide that targets the pest in the form of a gas, giving this process a benefit in penetrating the pallets, boxes, bags and wall voids needed in a seed facility. This method is a proven choice due to the journey a bag of seed takes from production to a farmer to be planted and back to the seed facility year after year. There is a unique combination of components to a fumigation after a target pest is found. By applying the right concentration of gas over a given period of time and as required, maintaining certain temperatures, fumigating can be used to target a specific pest.

Over the decades, two major fumigants have been used and are currently being used to treat pests in seed facilities. Phosphine, being the first and oldest of the two. This fumigant comes in a variety of formulations all with unique purposes and goals. While still heavily used today, it has been phased out of structural fumigations. Advancements in seed facilities such as electric forklifts, bagging equipment and automation technologies have pushed Phosphine to the side.

Phosphine and its corrosive nature to metals and electronics has been replaced by Sulfuryl Fluoride for these fumigation needs. This fumigant has become the more popular choice for these fumigations due to the non-corrosive nature. Another benefit to Sulfuryl Fluoride can be the lower downtime. Phosphine has longer exposure times due to the mode of action and depending on the formulation needed to complete the job. Sulfuryl Fluoride uses a program provided by the manufacturer to ensure efficacy is reached based on the target pest using time and temperature. This allows the pest management professional to work with the customer to meet the required deadline for reentry while also using a more precise amount of fumigant. With Sulfuryl Fluoride, most rodent target fumigations and even some insect target fumigations, can begin by the end of a shift shutdown Friday evening and be cleared for reentry by 6:00am Monday morning.

Understanding how seed is produced, moved and stored, is how a good pest management professional is able to advise their client in regard to minimizing pest damage to their product. While we stay strong in the belief of start with the pest first, understanding our customer’s business is key. Knowing how they handle their products will provide a pest management professional with the knowledge needed to handle any pest in the most cost-effective and timely manner possible.