Stored Product Pests: How to Tell Them Apart

Stored product pests are one of the most commonly misdiagnosed jobs in pest control. A quick glance and a general spray rarely touches them, because they live inside the food. Getting the identification right is half the job, so here is a field guide to the ones we see most.

Weevils (rice and maize weevils)

Small dark-brown beetles with a distinct snout. The female chews a hole in a whole grain, lays an egg inside and seals it. The larva eats the grain from the inside out, so a bag of rice can look perfect and still be infested. Found in rice, maize, whole grains and pasta. See weevil control in Cape Town.

Flour or grain mites

Too small to see one at a time. In numbers they look like pale, cream-coloured dust that moves, often with a slightly sweet, musty smell. They love damp flour and animal feed and make it unpalatable.

Indian meal moth (pantry moth)

A small moth with two-tone wings, copper at the tips and pale near the body. The damage is done by the caterpillars, which leave silk webbing in cereals, nuts, dried fruit and pet food. In a home pantry this is usually a quick fix once the infested packets are found. More on moth control.

Confused and red flour beetles

Slim, reddish-brown beetles about 3 to 4 mm long. They can't eat whole grain, so they follow damage done by other pests and infest flour, broken grain and silos. In bulk storage they cause serious losses.

Drugstore (biscuit) beetle and tobacco beetle

Tiny, rounded, brown beetles that look almost identical. The drugstore beetle is the one most often found in homes, in spices, biscuits, dry pet food and even paper. The tobacco beetle (Lasioderma serricorne) prefers dried tobacco, spices and dried plant material.

Who gets them, and why

At home it usually starts with one infested packet from the shop. In supermarkets, warehouses and feed stores the risk is higher: slow stock rotation, spillages left under racking and bags against walls give these insects everything they need.

How we deal with them

1. Find and remove the source: every infested product, not just the obvious one.
2. Vacuum and clean shelves, cracks and corners where larvae and eggs hide.
3. Apply a targeted residual or insect growth regulator in cracks and crevices away from food.
4. Set pheromone or food traps to monitor moths and beetles afterwards.
5. For businesses, recommend stock rotation, spill control and storage changes in the written report.

Need help now? Our main stored product pest control service page covers treatment and pricing factors, or call 021 012 5825.

Where stored product infestations usually start

In a home pantry

Rarely in the packet you use every day. Look at the back of the top shelf: the half-used bag of cake flour from months ago, spices you bought for one recipe, a box of birdseed, dry dog food in its original bag. Dried flower arrangements and potpourri can hold drugstore beetles too. Shelf lining paper and the gap behind shelf supports collect spilt grain, which keeps a small population going after the food itself is gone.

In a shop or warehouse

Start with the bottom rack and the floor beneath it, where spillage builds up out of sight. Then the damaged-goods and returns area, slow-moving lines, bags stacked against walls and the dust in corners of bulk stores. Wooden pallets that have carried grain can bring insects in with them.

A quick pantry check routine

1. Take everything out of one shelf at a time.
2. Look at packet seams and folds for webbing, small holes or fine powder.
3. Tip a little of each dry product onto a white plate and watch it for a minute.
4. Check the shelf corners and the underside of the shelf above.
5. Vacuum, wipe, let it dry, then repack.

Doing this every couple of months, especially through Cape Town's warm summer, catches most problems while they are one packet big.

What to throw out and what can be saved

Bin anything with live insects, webbing or holes in the packaging. Bin opened packets that were sitting next to it as well, unless they were in a properly sealed container. Sifting weevils out of flour is not worth it. Sealed tins, unopened glass jars and food in tight-lidded containers can usually stay, once you have wiped the outsides. Wash reusable containers in hot, soapy water and dry them completely before refilling, as damp flour is exactly what mites like.

When to call us

Call if they come back within a few weeks of a thorough clear-out, if you find them in more than one room, or if you can't find the source at all. Businesses should call at the first sign, because it is stock and reputation on the line. Send a photo on WhatsApp first and we will tell you which pest it is, or contact us for a free quote.

Frequently asked questions