Bagworm alert

Be on a bagworm alert.

Within the next two to three weeks, bagworms will be hatching and begin to feed on plant tissue. I mention this now because most gardeners only notice bagworms when they are large and after extensive damage has occurred.

Each overwintered female bagworm bag will have an average of 300 to 1,000 eggs in it. These eggs will soon hatch into larvae and then immediately begin to feed on plant material.

As the larvae feed, they form a protective bag around themselves. The appearance of the bag will be determined by the kind of foliage they are feeding on. Initially the feeding bagworm will look like a little cone attached to green foliage.

The preferred host plants are arborvitae and juniper. But, don't be surprised if you find them feeding on any plant in your landscape. I have also seen them on telephone poles and house gutters.

These products can be used to rid vegetation of bagworms and other insects. (Laura Simon)

As the summer progresses, the feeding bagworms will increase the size of the protective bag around themselves. The mature bag will be spindle shaped and about 2 inches long.

Toward the end of the summer the larvae change into adults. The females are wingless and continue to live in their bag. The males are winged and mobile. They emerge and find a female and mate. The female then lays her eggs in her bag and dies. Overwinter eggs are protected from the environment by the bag. No chemical application at this time will control them.

Bagworms can cause extensive damage on evergreens if left untouched. I suggest that you tour your landscape every few days around Memorial Day each year and look for the presence of bagworms.

If you find bagworms when they have just hatched, you can control them easily with an application of most general-use insecticides such as spinosad, bifenthrin or carbaryl. They are easily controlled during the summer as they are feeding.

Many gardeners find bagworms early in the spring or late in the fall and want to spray for bagworm control at that time. The only effective control at that time is to pull the bags off the plants and dispose of them.

So spend a little time in your landscape around Memorial Day to determine if bagworms are present. If they are, apply an insecticide immediately. They are easy to control when they are small.