What are they? Tiny worm-like insects (from grain/rice weevil larvae) and web-like silken threads (produced by the meal or weevil moth) that appear in our produce in the pantry are commonly referred to as weevils. The most common pests we find in our pantry here in Australia are Indian meal (or weevil) moths and grain/rice weevils. Grain weevils attack hard cereal products such as macaroni and spaghetti, whilst rice weevils attack grain and seeds. Indian meal moth larvae can be found in grain products as well as dried fruits, nuts, seed, biscuits, chocolate and dry dog food.
There are, in fact over 60,000 species of weevils and they can range in size from 3mm to 10mm in length.
Where do they come from? Weevils have been known to find their way into the home from outside (in the form of adult beetles or moths depositing their eggs in a food source). However in most cases, they are already present in produce, originating at the processing plant, a warehouse, in a delivery vehicle or even at the store of purchase.
What to do in the case of an infestation
The first signs of rice or grain weevil infestation is the presence of tiny, squirming larvae, which is most likely going to be found in produce such as grains, cereals, pastas, nuts, tea bags and pulses. In the case of meal moth infestation, it will usually be in the form of silken threads throughout the produce and possibly signs of larvae. Unfortunately, you will have to dispose of the produce, and most importantly, find the source of the contamination, which could be in another container. Finding the original source is the key to eliminating further problems and food spoilage. Until you find the source, you will continue to have pantry pests.
Once you've identified and removed the infestation, take everything out of the pantry, give it a vacuum and wipe down all the cupboards, pantry shelves and surrounding areas. Make sure you get into every corner and crevice. Rather than using chemicals, use natural cleaners such as eucalyptus oil, tea-tree oil or vinegar to wipe down the shelves.
Tips to prevent further infestations:
• Ideally, if you have room in your freezer, place items such as flour, grains, cereals and pulses in freezer bags and place the items in the freezer for a minimum of four days. This will kill any eggs that may be present in the produce. Once removed from the freezer, keep the items in airtight containers.
• Dried bay leaves discourage grain and rice weevil infestation, so place one in each airtight container.
• Purchase non-toxic, pesticide-free pantry moth traps if you continue to have pantry moth infestations. Lures can last for up to three months.