A topic that comes up frequently by our customers is bagworms. The topic is normally posed as a question such as "what are those small pine cone looking bags that are either gray or brown in color and are on the underside of the leaves of my tree?". One customer stated that she opened the cone up and it had a grub or caterpillar like creature in it. I believe the next word out of her mouth was "gross looking".

Well, she and many others had just encountered their first bagworm infestation. In fact, if there is one pine cone looking bag, you will find others in the same vicinity. Adult bagworms actually are moths and the females lay their eggs in these pine cone silky bags. When the larvae emerge they eat the foliage on the host plant.

To rid your plants of these pests you can treat the with Bacillus thuringiensis (Bt) sold under trade names such as Dipel and Thuricide. This is an organic remedy that will not harm the plants, trees, birds and other insects in your yard or garden. You will need to wait until the bagworms are present to use as it must be consumed by the pests. Another treatment is to spray a dormant season oil to ward off infestations. This technique can only be used when the subject plants are dormant. The oil spray smothers overwintering insect eggs; this process is safe for the plants.