Although the word "larder" is essentially the same thing as a cabinet where food is stored, larder beetles and cabinet beetles are quite different in appearance. Both of these dermestid beetles invade kitchens and anywhere else that you happen to stash food. If you see an adult beetle or the husks of molting larvae, you will want to get rid of these pests as quickly as you can before they infest a lot of your foodstuffs. Here is how to tell the difference between the two beetles and their larvae and what pest control methods work best.
Larder beetles prefer meats, blood and fats, unlike their cabinet beetle cousins who would rather eat grain products. If you store a bag of fried pig skins in your nightstand, do not be too surprised when you start noticing these beetles hanging around or their fuzzy larvae crawling all over the bag. The beetles themselves are oval-shaped and black, with a wide brown stripe through their middles.
Kids and teens who sneak food into their bedrooms will often start an infestation of these pests, and then you will be vacuuming larder beetles, molting shells and larvae out of your bedroom carpets and soft furniture for weeks. If you failed to prevent them (because kids will be kids and hoard snacks in their rooms) then your only recourse is to vacuum several times a week, have the mattress and any soft chairs professionally cleaned, and wash and bleach all hard surfaces. If the beetles still come wiggling around, you will have to call a pest control expert.
The larvae of cabinet beetles and larder beetles look a lot alike. They are both long and fuzzy in appearance and very wiggly. Bags of food infected with the larvae will have them wiggling in giant nests all over the food products. Unlike their larder cousins, they love plant and grain foods. They will invade your cereal products, your boxed pancake mixes, your boxed mashed potatoes, and sometimes even spices. The adults are oval with a mottled appearance on their upper shells.
You can use commercial traps to collect adult cabinet beetles and prevent them from mating. As for their eggs and larvae, the adults will attempt to lay eggs in a dark corner of your cupboard near one of their favorite foods. If you see the larvae, which is more probable than seeing a live adult, you will want to clean out your cupboards, bleach them, spray a strong disinfectant or pest control into the cracks of your cupboards and throw away any plant- or grain-based foods that were not in tightly-sealed containers.