Lesser grain Borers can be found in most any part of the home. There are two main species of this insect; the Lesser Grain Borer and the Larger Grain Borer. As their name indicates, they like to “bore” into grain and grain based products. This boring will many times leave nothing but empty grain shells in their wake. Grain bins, storage bags, boxes and just about anywhere pantry type food is processed are all environments where lesser grain borers will thrive.



Once established in food processing facilities, lesser grain borers will be packaged and shipped to stores where consumers will unknowingly purchase them. And when you bring them home in your grocery bag, adults will migrate looking for anything on which to lay eggs.

Since lesser grain borers can eat just about anything in the home, it is not likely they will “starve” to death and disappear if you bring some home. If lesser grain borer activity is found in any part of the home, control measures must be taken to insure active populations are eliminated as soon as possible.



Lesser grain borers are found all over the world. Closely related to Powder Post Beetles, lesser grain borers are able to eat cellulose products like books, boxes, furniture and anything made of wood. However, they prefer grain like wheat, corn and sorghum. The two species (lessor and larger) are very similar in look and biology. The main difference between the two is their size. Lesser Grain Borers are about 1/8 of an inch long; Larger Grain Borers are about 1/4 of an inch long (about twice as long). Both will readily infest and thrive on the same types of food.



Grain borers will eat a wide range of food including nuts, wheat products, pasta, rice, cookies, dried fruit, corn, books, boxes, dried flowers and many other “natural” products. If brought home in a package, adults will most likely stay if the food is good. However, some are sure to relocate and lay eggs on anything their babies can eat.



Adult female lesser grain borers will lay 300-500 eggs over her life. And since she can fly well, its common for infestations to appear randomly throughout the home.

Eggs will hatch in a week or two after being laid and larva will immediately begin to feed on whatever they can find as they crawl about.

Larvae will go through 2-4 molts before pupating into adults and though the average time this process will take is about 60 days, it can happen in 30 days or less. This ability to populate rapidly and the random nature in which it can occur is why you must take measures to control any activity as soon as it is identified.



Here are guidelines and treatment schedules to follow when lesser grain borers are found in the home.

First, empty all cabinets, shelves and closets where they’ve been seen or where you think they might exist. Any food stuff which has active borers must be discarded in sealed plastic bags. This will help contain them until the garbage is picked up.

If you are not sure if something has activity, store it in a plastic bag and check it every few days. If the item you’re storing has lesser grain borers in it, at some point they’ll try to get out and will be visible in the bag. And if you ever find them active in the bag, throw away the item immediately. If you never find an insect after 60 days, the item is most likely pest free and can be saved.

Since lessor grain borers are temperature tolerant, don’t waste your time trying to freeze adults, eggs or larva. Though you can kill some, too many will live prepared to continue their cycle.

Once any food item which is thought to have activity is properly discarded, you’ll be ready to prepare for a treatment.

However, before you treat, vacuum all closets, shelves and baseboards. This will help by removing some eggs which are typically too small to see.

Lesser grain borers lay eggs with a glue like excretion which helps to protect the egg and keep it secured to surfaces where food is likely to be available. For this reason, wiping or washing won’t remove them but a vacuum should get some.



Once everything has been removed from the cabinets and you vacuum them out, treatments can start.

The one product most commonly used for this pest is DFORCE AEROSOL. It comes in a spray can with a straw attachment making it ideal for applying to cracks and crevices where both adults and larva like to reside.

D-Force Aerosol




Be sure to treat all cabinets – not just where you think they may be hiding. Lesser Grain Borers are small, fast and quick to hide when ever people are around disturbing where they’ve been feeding. Many will go unnoticed and missed so it is best to treat every cabinet and be sure you get proper coverage.

Now if you’re unsure where they might be focused, use PT-PHANTOM. It’s used like the Dforce but has virtually no odor. But the real advantage is that Phantom is undetectable by insects so they’ll readily walk on treated surfaces. And it takes 3-4 days to kill the target pest. But this is very much by design.

Basically because it takes that long to work, affected insects will be picking up some chemical and in turn sharing it with others. So when it eventually kicks in and starts killing them, it will kill many more than what originally touched the treatment. So if you’re unsure where they might be nesting or hiding but have a few areas you know to treat, go with Phantom. It will surely get them no matte where they’re located.






Now with the cabinets and pantry areas properly treated with an aerosol, you may want to treat other areas of the home too. Laundry rooms, garages, basements and other areas where pet food and lesser grain food stuff like grass seed are kept will be prime locations for nests. The only problem is using an aerosol for all these other areas isn’t the best approach.

What is better suited for more expansive areas is D-FENSE SC. This odorless concentrate is mixed with water and can be sprayed on carpeting, baseboards and other areas where lesser grain borers might be hiding.

Mix .5 to 1 oz of D-Fense per gallon of water and apply the mixed gallon over 800 sq/ft of area. Treat once a month until the problem is gone; once every 3 months to make sure they don’t come back.





To properly apply the mixed solution, you’ll need a good PUMP SPRAYER. Our model is built to our specifications and will provide an ideal fan spray pattern for open areas, baseboards and spot treatments.





Focus the application on baseboards, moldings and floor joists (if visible – especially in crawl spaces or basements). Since rodenticide is one of their favorite foods, be sure to check any bait placements you’ve done in the last couple of years for rats or mice. We have found old forgotten bait blocks and seed infested with grain borers so it’s important you’re thorough during your inspection.

Another area not to ignore is the attic. In fact attics are common areas where lesser grain borers thrive. From there they can easily find their way inside living spaces. So if you’ve got an attic with some kind of rodenticide placement, be sure to inspect it and if borers are found, throw it away and treat with D-Fense to insure migrating adults won’t be able to find their way back to living areas.


Now that you’ve treated cabinets, pantries, rooms and baseboards where adults may be hiding, install some LESSER GRAIN BORER PHEROMONE TRAPS. These traps use strong pheromones or sex attractants to lure adults. Once borers crawl or fly inside, they’ll get stuck on the non-drying glue distributed throughout the traps inside walls.






Set low profile traps in the back corner of any shelf or cabinet area. They’re discreet and easy to conceal. As a general rule, try to get at least one cabinet space. For open areas in surrounding rooms, install the hanging style. Traps will remain active for 2-3 months and should be replaced after 3 months; replace them sooner if they get filled with borers.

Now if you’ve been seeing lesser grain borers out in the open foraging on kitchen counter tops, the floor, around wall units, etc., the XLURE TRAP will be better suited for these “out in the open” problem spots.

The Xlure trap has a protective, hard plastic body encasing the trap. Inside the station is a unique catching gel, bait and pheromone which is well protected and safe inside this case. Lesser grain borers will readily find their way inside but will get caught because of it’s design.

XLure Beetle Trap




Lesser grain borers can be a persistent pest once established in the home. To break their cycle, you’ll need to remove any food which is infested. Next, clean and vacuum all cabinets or closets where they’ve been found. Treat with Dforce Aerosol to kill off hatching larva and migrating adults. Dforce will provide several weeks of protection should new eggs hatch or if new adults come to the area.

If you have them throughout the home, treat with D-Fense. Its more efficient and will cost less in the long run compared to using just an aerosol.

Finally, set out some Pheromone based traps in cabinets and pantries where activity has been noted. Be sure to keep the traps fresh so they’re always helping by catching adults before they mate and try to reproduce. This program will break the cycle and usually within 1-2 months, the problem will disappear.


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