The mealworm beetle is a black to black-brown beetle with grooved elytra and a length of 13 to 18 mm. The bottom is red-brown. The larvae, that can reach 28 mm in size (meal worms) are yellow-brown and have three well-developed legs.
Both the adult mealworm beetles and the larvae prefer to feed on vegetable material, but they can also eat animal material, such as flour products, bread, feed, tatters etc. The female beetle lays about 400 eggs that hatch after 10 to 20 days. Depending on temperature, the larvae stage takes 1 to 1.5 years, after which they develop into fully grown beetles in about 14 days. Because of this long life cycle, Mealworm beetles hardly ever form a plague. Only in poorly inspected, supplies stored for a long period of time, they can cause damage due to contamination. When mealworm beetles are found in a house, they almost always come from bird nests. They are taken to the nest by the birds, after which they enter the house via the roof.
Remove old supplies
Remove abandoned bird nests
Since mealworm beetles hardly ever exist in large numbers and it is easy to trace the source, chemical extermination is not required.