Quiz Answers: Pantry Pests

Here are the answers to yesterday's quiz on pantry pests. As the weather gets colder, there are fewer outdoor bugs and our attention is turned to household invaders. But pantry pests can and do infest during all seasons. 

1. The best way to find the source of a grain moth infestation is (d) inspect all dry goods. Pheromone traps will catch adult moths and may help you target a particular area, but the best way to find infested product is to look in every bag, box and package - whether opened or not. If you find frass, the silky webbing pantry moths leave behind, discard the dry goods in which the frass is found. Usually one box or bag will contain the primary source, and you will know it when you find it. But secondary sources may be present. Don't stop until all dry goods are inspected. And check also for webbing on the under side of stored canned goods!

2. Cigarette beetles are most commonly found in (c) dog food and paprika. When checking for the source of pantry pests, don't forget the spices and dry pet food. If you have decorative items like wreaths that are made out of natural products, check these too.

3. Pantry moths develop from egg to adult in (b) around 10-14 days, depending on temperature. If you have removed all the adult moths and their larvae, but find more in 10-14 days, there was a source you missed. Check dry goods again, and clean the shelves with a disinfectant cleaner to kill any remaining eggs.

4. Meal worms usually spend the winter (b) as larvae. It is difficult if not impossible to determine what the adult bug will be just by inspecting larvae. And larvae are not commonly susceptible to pesticide sprays. But boric acid will stop them in their tracks. If you find any kind of larvae, clean the area with a good disinfectant cleaner and look for the source. These pests love to hang out in bird feeders too.

5. It is rarely effective to use insecticides against pantry moths because (a) larvae and pupae are not controlled with insecticides. As noted above, larvae crawl right through liquid chemicals. And if the larvae are not controlled, the problem will persist.

6. (B) Larval Indian meal moths leave webbing, or frass. They spin the web as they become fully grown and leave behind silken threads wherever they crawl. This is the frass mentioned above - and is easily noticed as it caused clumping in rice, oatmeal or cornmeal and is sometimes apparent on the outside of a box or bag of infested product. Since the frass usually contains excrement, it should be disposed of immediately.

7. Small, wormlike bugs in the pantry are usually (c) larval moths. But as mentioned, larvae are difficult to identify. Any larvae found should be taken seriously as a pantry infestation. They can (and will!) chew holes through cardboard or plastic packaging materials to get to the food inside. One method of killing pantry pests before they hatch is to store dry goods in the freezer for a couple of weeks. Since the product may be infested when you bring it home from the store, storing it in heavy plastic or glass containers may not be sufficient.

We hope you've learned something useful about common pantry pests. As with all pests, if you cannot solve the problem yourself, contact a pest professional. But in the case of pantry pests, what you can do yourself is really the best solution to the problem.

Tuesday's Quiz: Pantry Pests

Today's quiz asks you to test your knowledge of common pantry pests. These are stored product pests that infest dry goods in your pantry - including moths and weevils. See how much you know about these uninvited guests.

1. Grain moths often come in pre-packaged food from the store. What is the best way to find the source of infestation?

a. Put out traps.

b. Look in whole grain foods like rice and oatmeal.

c. Call a pest professional to check your cabinets.

d. Inspect all dry goods.

2. Cigarette beetles are a common stored product pest (see illustration above). In which stored products are they most commonly found?

a. sugar and flour

b. cornmeal and oatmeal

c. dog food and paprika

d. rice and coffee

3. Pantry moths develop from egg to adult in about

a. 3-5 days

b. 10-14 days

c. 16-20 days

d. 3-4 weeks

4. How do meal worms usually spend the winter?

a. in hibernation

b. as larvae

c. as pupae

d. under ground

5. It is rarely effective to use insecticides against pantry moths because

a. the larvae and pupae are not controlled with insecticide

b. the moths actually feed on insecticides

c. insecticides have little or no residual effect

d. moths can fly away from the poison

6. Indian meal moths are one of the most common of stored product pests. The "webbing" or silk mat that identifies their feeding area is left by

a. the adult moths

b. the larvae

c. the pupae

d. all of the above

7. Small, wormlike bugs in the pantry are usually

a. parasites that feed on moths

b. undeveloped beetles

c. larval moths

d. worker moths

Answers to today's quiz will be published in tomorrow's blog.

Butterflies are Free...

... but moths can cost you! Common pantry pests in San Diego County include Indianmeal moths and the Angoumois Grain moth, stored product pests that can invade dry goods in the kitchen. You may bring them home in a bag of rice or a box of oatmeal from the store. Once in the door they cause all kinds of trouble. We are often asked if the moths in our customers' pantries will also invade closets and damage clothing. The answer is no. Although similar in appearance, clothes moths have different eating and living habits. Grain moths are much more visible -  you will see the adult moths in greater numbers, and usually in the kitchen area. But getting rid of them can be time consuming and frustrating. In order to avoid pantry moths, freeze all grain-based products you buy for 4 days before storing them in airtight containers. This is especially important if you buy grain products from bulk bins. Be aware that moth larvae can bore through plastic bags and cardboard boxes. 

If you already have an infestation, go through all grain based stored products. This includes bird seed and dog food, spices, nuts, raisins, cereals, pastas, even chocolate - look through everything! If you find webbing, clumping or larvae in a box or bag, throw it out. Clear off pantry shelves and clean with a good disinfectant cleaner or vinegar solution. This process should eliminate most infestations. Occasionally moth larvae still hatch out from eggs left in the cracks and crevices of pantry shelves. If all your grain-based products are in air tight containers, you can safely put out a moth trap , available at some local retail outlets or online here, to catch ambient adults as they hatch.