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.