Photos courtesy of Orkin.
The bad news: as essential as your ingredients are to your business, they’re also an attractive food source for stored product pests. The good news: these pests leave behind signs of their presence, which — if noticed early — can be acted on and precautions can be made to avoid a pest infestation.
Stored product pests can cause major problems when they find their way into grains and products and are allowed to feed and reproduce over time. Insects like weevils develop inside the grains, making them difficult to detect and manage. Some insects, like warehouse beetle larvae, can cause health concerns such as digestive irritation due to the small hairs that cover their bodies. This is not only a concern for your business’s reputation and bottom line, but could cost you major points on your next audit.
Under the Food Safety Modernization Act (FSMA) regulations, prevention is the emphasis in all U.S. facilities. Prevention requires a myriad of proactive exclusion and sanitation tactics to make your facility less attractive to pests and help block them from getting inside your facility in the first place.
To successfully prevent stored product pests, you need to understand what they are, how to identify them and why they are attracted to your facility.
Types of stored products pests
There are many different species of stored product pests, but they can be classified into three main categories based on their biology and habits.
Internal feeders: Internal feeders lay eggs inside or outside the grain kernels but develop entirely inside the kernel.
Some of the commonly encountered internal feeders are lesser grain borers, as well as rice, maize and granary weevils. Weevils are typically brown in color and have a distinctive elongated “snout.” They measure up to 5 millimeters in length. Lesser grain borers, the most common across the United States, are a bit smaller and don’t have the snout that weevils do. Both weevils and lesser grain borers feature pitted patterns on their bodies, and all of them can fly with the exception of the granary weevil. Since the larvae and pupae develop inside the individual grains, damage becomes especially evident when the adult chews out of the now hollow kernel, leaving a distinctive round exit hole.
External feeders: External feeders eat and damage broken grains and processed grain-based products. Some are considered scavengers and will eat just about anything, even if other pests have been there first.
Common pests in this category include Indian meal moths, flour beetles and saw-toothed grain beetles.
An adult Indian meal moth is about 9 millimeters long with a wingspan of 14 to 20 millimeters. The front wings are two-toned: reddish brown at the wing tip and silver grey at the base. The larvae are small and cream colored. If you don’t see the pest itself, know that it spins a messy silk webbing that gets gummed up with frass and food particles.
Flour beetles (both red and confused) are 3 to 4 millimeters in length and are a reddish-brown rectangular-shaped beetle. These insects often may be found in grain bins infested with internal feeders; they feed on the kernels the borers have broken up.
Saw-toothed grain beetles are smaller than flour beetles (3 millimeters) and have distinctive “teeth” on the margins of the thorax. While they will feed on any type of broken grain, they prefer oats.
Secondary feeders: Secondary feeders typically feed on the mold and fungus that can grow on out-of-condition grain and damp areas.
One of the common mold-feeders is the foreign grain beetle. These resemble flour beetles in size and color but have two “bumps” on the top corners of the thorax. Eliminating the molds and damp conditions that promote mold growth is often enough to prevent large infestations of foreign grain beetles.
If you’re ever unsure about the pest problems in your facility, a trained professional can help correctly identify the species and recommend the best course of action to resolve the problem.
But with any prevention strategy you implement, it’s going to take a team effort from employees, management, and your pest control specialist.
To help prevent stored product pests, a variety of tactics should be incorporated as part of your IPM program.
First, closely inspect incoming shipments for signs of stored product pests like live insects, webbing and damaged kernels. To help monitor, take a sample and place in a closed, labeled container for later observations to see if any activity is noticed.
Second, place pheromone traps in your facility to monitor for insects. Once placed, these will offer insight as to which areas in your facility are most at-risk for pest problems.
Third, use temperature as a tactic. Stored product pests cannot live in extreme temperatures, so, if possible, keep grains aerated and cooled. Most stored product insects can’t develop below 15oC (60oF).
Finally, create a sanitation schedule with daily, weekly, and monthly duties. Clean up product spills immediately, and watch for damp or wet spots that may encourage mold. While it’s impossible to clean up everything, the more you can limit the amount and access to food, the fewer insects can get established.
As part of your sanitation schedule, inform employees about the signs of stored product pests and assign specific areas around your facility for them to inspect.
The bigger the facility, the more important it is to have your whole team working to prevent pest infestations. If you catch pests early, issues will be quicker and cheaper to fix.
Being proactive is an important part of this entire process, so forming a strong partnership with your pest management provider is crucial. They can help with training and ensure you and all your staff know what to look for and how to help manage pests. Reach out to them early and often if you suspect any issues.