Pest Types

All information in this section of our website is taken from the Pest Fact Sheets which are published on the Harrow County Council website. We would like to thank the Harrow County Council Web Team for their kind permission allowing us to reproduce these fact sheets.

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Mealworm Beetle

The Mealworm beetle (Tenebrio molitor) is commonly known in its larvae form, known as mealworms, which are a favourite food for caged birds and pet lizards etc. Mealworm beetles are most commonly seen in summer. They normally spend the winter as larvae, changing to beetles during the following summer and die in the autumn. Although they are seen wandering in many areas, they prefer dark and damp conditions. Mealworms often feed on corn or flour, and are sometimes found in birds nests feeding on the birds' droppings. Being omnivorous, they will also feed on the bodies of dead rats or mice if they are old and dry.

Life Cycle
The female beetle lays up to 500 eggs over a period of weeks, which are soon covered with dust and debris. Two weeks later, the larvae hatch and immediately start feeding on any suitable material. These larvae are bright yellow with each segment shading to yellowish brown and have a shiny, waxy appearance. This is a slow breeding species and the larvae may take up to one and a half years to reach maximum size (around 28 to 30mm) passing through 10 to 20 moults.

When about to pupate, the larva moves away from the food source, thickens and assumes a curved posture. The pupal stage lasts about 3 to 4 weeks, depending on temperature and the adults live for 2 to 3 months. The adults will feed on the same foodstuffs as the larvae but are less voracious and do less damage. The adult beetles are shiny reddish black in colour. Adult beetles found indoors in domestic premises in ones and twos, may have come from a nearby bird’s nest and have been attracted in through an open window by the lights whilst flying on a warm summer evening. They do no harm in the living rooms of a house but can sometimes become a nuisance in the kitchen if they get into containers of food and start breeding.

Control
If lots of these beetles are found indoors, then check all the kitchen cupboards for spilled foods or infested bags of flour, etc. Check in the bases of cupboards and behind appliances for any old food residues of which you may be unaware. Check in lofts and roof spaces for old bird’s nests. If you have recently had a pest control treatment for rats or mice, it might be worth checking under the floorboards for old corpses. Clean up thoroughly and throw away any very old or infested stocks of food.

Use an insecticidal spray sold for crawling insects that is labelled as safe for use in kitchens. Use it on areas that food will not touch directly, eg inside cupboards but not on worktops. Bearing in mind the long life span of the mealworm larvae, it may be necessary to carry out follow up treatments for several months. After you have treated the current infestation, be aware that further mealworms may hatch out into beetles later on, so you may need to keep treating until all the eggs have hatched out and the infestation is completely gone. Because of the beetle’s long development period, an infestation is often indicative of poor hygiene and the presence of old food residues.

If you are unable to deal with a common pest problem satisfactorily, then contact Commercial Pest Control London. Our rates are competitive and we will get the job done fast and efficiently. For a professional service call Commercial Pest Control London today on freephone 0800 043 2056

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