How To Get Rid of Bagworms

By Subodh / November 7, 2013

The bagworm whose scientific name is Thyrirlopteryx ephemeraeformis is a destructive pest that will draw your attention as a landscaper. The male and female of this species of insect are quite distinct. The female is wingless and has small but useless legs. The male on the other hand has clear wings and smallish brown body that is hairy. The larvae of this insect pest grows to about five centimeters in length and is pale amber in color at the lower bottom while the head is dark and sclerotized. This insect is common within the eastern parts of the US.

If you grow the sycamore, maple, poplar, oak, boxelder, apple among others you probably should know that the bagworm may be found within your garden. In fact arborvitae is most susceptible to the infestation of this insect pest.

How to Get Rid of Bagworms

Also known as the evergreen bagworm, this insect has become common in most gardens and at very alarming numbers. During the winter close to 1000 eggs remain intact in the bag and the hatching is between May and June with worms falling off suspended on silk threads. By august the worms reach the pupa stage. By September the males emerge from their bags for a mating period.

Generally a single bagworm will do negligible damage. However their colonies run to thousands and since the female do not fly the defoliation effect will affect the conifers and destroy them within two seasons. As such the effect of bagworms is much more noticeable in woodlands and forests.

The first time you see a bagworm it is likely that they are in their larval stage. The common sight is one where you will see a bag spun from plant detritus hanging from the tree. The insect has its head out most of the time and feeding on the tree leaves. Generally the bagworms live within these bags most of the time.

If you live in the region near the Rocky Mountains up to Midwest and south between Texas and Florida you will commonly encounter these insects in their season. Because their breeding time results in thousands of these bags, birds will normally feed on some of the bags that have the eggs. Interestingly though the eggs have a hard shell that will travel through the birds’ digestive system without being digested and soon get egested. It is in this way that the bagworms quickly spread to a very large area and this is how they eventually become a threat to the vegetation cover and particular the host trees.

Because of their large numbers the hatching process may appear as though it is several generations although bagworms only have a single generation every year. It is actually the hatching times that vary and this makes it look like there are several generations.

There is a variation between the bagworms based on their feeding habit. There are those that are monophagaous and this feed on only one kind of plant while there are those that are polyphagous and feed on different types of plants. The commonly occurring bagworm feeds mostly on the arborvitae, junipers and eastern red cedar. Generally if the infestation is on a large scale then the bagworms will feed on other tree types as well.

Having seen an infested area or may be if you have lost a forest or trees in your garden to this menacing insect, it may be important to discuss some of the ways that you can employ to control the bagworm. Certainly the defoliation action of the bagworm is most undesirable and detrimental to the forest cover.

Early detection is the key to better control

Certainly whatever the infestation, early detection serves as a good starting point to controlling the devastation that may result from bagworms infestation. The best time of doing an inspection of your trees is during winter, early spring or fall. At this time all the bagworms that you identify contain the eggs that are going to hatch during spring. You may want to pick these bags and burn them to destroy the eggs.

If you miss out on this season you can still carry out a check in April and get the larvae when they begin the feeding. You can still pick these and destroy them by burning. This is an option for infested areas that you can easily reach. However this may not be practical if you are dealing with matured trees.

Spraying may be an alternative to picking and burning. However you must bear in mind the fact that this method is far less effective on matured bags. However susceptible forest cover can be sprayed as early as June and the process consistently repeated in order to catch the larvae as well.

Generally the most effective way would be to inspect the forest cover for the bagworm eggs and physical destroy them or use chemicals to do the same. The process must be repeated after a time in order to eliminate the whole cycle of the insect pest.

Note that once the bagworms hatch the chances of controlling the infestation becomes more diminished and the cost is higher apart from the damage to the forest cover. Hence the best time to catch these bagworms is the time when the eggs are still in the bags, which is the time that you can use a number of ways to disturb the breeding cycle of the bagworms and reduce or eliminate their undesirable defoliation effects on the forest cover.