Small Pest, Potentially Big Threat

Insect pests, mainly stored product pests, are estimated to destroy roughly 10 percent of the United States grain production annually.

What does that equate to in financial terms? Grain producers and food processors relying on this valuable commodity to bake bread, brew beer and numerous other food products, take a USD3 billion hit.

While Indian meal moths, cigarette beetles and granary weevils grab most of the “headlines” there is another insect – albeit one that is small in stature – that poses a threat to the tons of unprocessed grain products that are stored and transported annually.

Psocids are very small insects that have been a problem in grain storage and processing facilities for some time but have experienced a resurgence much to the chagrin of QA and plant managers.

These tiny pests can spoil grains and seeds, and cause allergic reactions to sensitive consumers that eat tainted products.

“Psocids are very unique pests that have been somewhat overlooked because they are hard to detect and out of sight is out of mind,” says Lance Gray, Oregon-California district manager for Sprague. “Inspecting for them can be difficult because of their size and since they reproduce rapidly you can have millions of them in your facility before you even know they’re present.”

Gray says a variety of Psocid species can be found within food or seed processing facilities, each possessing unique behavior and biology traits. Different species also require different treatment approaches as there is not a one-size fits all solution.

Psocids are attracted to wet, damp conditions, typically on the north and east sides of buildings where the winter sunlight is in short supply. Gray says this winter’s heavy rains up and down the West Coast could set the table for an active spring and summer.

“Psocids are very fickle insects and if recent trends continue and there is a warm, humid spring, we could see them in abundance,” says Gray.

He advises now is the time for facility and QA managers to get ahead of Psocids and take steps to mitigate their risk.

Reducing Your Risk

There are several steps food and seed processing and storage facilities can take to deal with Psocids. Work jointly with your pest management service provider to:

  • Monitor and inspect to see where the Psocids are coming from
  • Make a proper identification of the species you are dealing with
  • Address and eliminate the conducive conditions that are supporting the infestation

Monitor and Inspect Frequently

Regular inspections of grain and seed storage areas, including product packaging, are the first steps. This is easier said than done considering the Psocids’ small size and ability to avoid detection.

Gray says Psocids can collect on cardboard packaging of finished product appearing as a layer of fine dust and are only identifiable under a handheld microscope. He recalls visiting a nut processing plant and seeing ‘dust’ stirring around his feet as he walked. That ‘dust’ was Psocids.

“Like other pests, Psocids can be introduced into a facility via incoming shipments of seed and grains,” says Gray. “Initial inspections are important to stop them at the loading dock.”

To detect Psocids, Gray uses a relatively low-tech but effective technique. He places a sheet of white paper or cardboard on top of grain or seed piles inside storage bins, rail cars or truck beds, and waits to see if Psocids collect on the paper’s surface.

Make Correct Identification

Correctly identifying Psocids – they can sometimes be mistaken for springtails – is a critical component to gaining control.  A misidentification can lead to the wrong treatment program being applied, failed results and continuing headaches.

Eliminate Conducive Conditions

Since Psocids are attracted to moisture and are susceptible to changes in humidity (i.e. the drier the less likely they survive), make sure to establish a solid vapor barrier around structures. Seal cracks in the floor and openings in the roof to keep Psocids and other pests out.

Don’t allow excess moisture to gather on the interior or exterior. Use fans to dry areas where moisture may have accumulated – Psocids do not need a lot of moisture to survive.

Maintain landscape plants and trees, do not allow vegetation to become overgrown since it provides a natural habit for pests right outside your front door. Have landscapers blow grass clippings away from a structure. If clippings are blown near the foundation it could literally blow Psocids into cracks and crevices and inside.

Gray says he’s had success with barrier crack and crevice treatments to stop Psocids and other occasional invaders on the outside before they get in.

“It only takes a few Psocids gaining access to become a real headache for facility and plant managers,” says Gray. “Because of their ability to reproduce rapidly and in great numbers they can quickly contaminate products and cost the company significant dollars in lost inventory.”

Seven Things You Should Know About Psocids

Jeff Weier, technical director for Sprague, offers the following insights:

  1. Psocids can be found in a variety of facilities including bulk commodity storage warehouses (pet food plants are common), grain storage facilities and even canning plants.
  2. Eliminating sources of excess moisture is the key to preventing Psocids.
  3. Psocids are attracted to products with high moisture content and won’t develop in temperatures below 49 degrees Fahrenheit.
  4. Psocids mainly feed on moldy grains and grain dust.
  5. Psocids can be introduced into facilities on wet storage pallets or incoming shipments of bulk materials.
  6. Psocid ‘hot spots’ inside facilities include the cracks and crevices, and expansion joints in floors and on bagged products.
  7. Psocids are primarily a summertime pest.