Bagworms are a common pest in North Texas, particularly affecting evergreen species such as cedars, junipers, and cypress trees. However, it is not uncommon to observe them infesting broad-leaf trees like oaks, maples, and elms as well. While bagworms are widespread, they may not always be noticeable, especially on evergreens, as they use material from the trees they infest to camouflage their casings. Like other insects, bagworms have a year-long life cycle, and control measures depend on the growth stage of the pest.
The Impact of Bagworms on Cypress Trees and Other Texas Species
Bagworms, if left uncontrolled, can be quite devastating and defoliate major portions of an infested tree’s canopy quickly. We typically begin to see the impacts of these pests in mid-to-late summer, with infestations peaking into fall. Recognizing and addressing these infestations early is crucial to maintaining the health of your trees.
Identifying Caterpillars and Worms on Trees in Texas
TreeTech would like to offer some basic information to assist in the identification and control of these persistent pests. Understanding what bagworms are and how they behave is the first step in protecting your trees.
What Are Bagworms and How Do They Behave?
Bagworm is the common name for several different species of insects, which are actually a type of moth (order Lepidoptera, family Psychidae). T
he bagworm caterpillars are very small (about 1/25 of an inch long) and spin silk thread, which they use to attach themselves to plants and to weave into their bags.
Unlike a typical cocoon, the bagworm’s casing functions as a moveable shelter, with the caterpillars exiting to find food and climb up the plant.
Once the caterpillar has matured, it undergoes a metamorphosis period before emerging as an adult. Male bagworms resemble small moths, while the females are flightless.
Male bagworm moths seek out females during mating season, and the female uses her bag to lay eggs. The exact times of caterpillar and adult emergence vary from species to species and are dependent upon the weather.
Image of a typical casing of bagworms on a cypress.
How to Control Bagworms and Protect Your Trees
While bagworms are not prevalent every year, once they have infested a tree, they will continue to live there unless controlled.
Simple Methods for Managing Bagworms on Your Trees
The simplest control method is to manually remove the bags. They can be pulled off by hand or sprayed off with high-powered water. It is important to dispose of or destroy the bags, and not just leave them lying on the ground, as the eggs they contain can hatch and re-infest the tree.
When to Use Insecticides for Bagworm Control
Insecticide sprays can be used to control bagworms but are most effective in early summer (June) when the caterpillars are small and can be completely ineffective by late summer (August). Systemic insecticides applied as a soil drench may be used as a preventative measure to control infestations the following year.
Consult a Certified Arborist in Dallas for Professional Tree Care
Consulting a certified arborist is essential to determine the best course of action for bagworm infestations and overall tree health. A certified arborist in Dallas can assess your trees, recommend treatment options, and provide expert care to keep your trees healthy year-round.
Image of the optimum time for spray control for and damage from bagworms. Credit: Kansas State
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