Bartlett Tree Experts - Lancaster, PA & Lebanon, PA

10/22/2026

The bagworm, a serious defoliating pest

The bagworm, Thyridopteryx ephemeraeformis, is an unusual caterpillar that defoliates many ornamental trees and shrubs throughout the eastern half of the United States. The name comes from the bag-like structure made of leaf fragments bound together with silk produced by the larva. Most of this insect’s life is spent within this protective bag. Bagworms blend in and often go unnoticed until significant defoliation has occurred.

Host Plants Bagworms feed on more than 125 species of plants. Conifers such as arborvitae, juniper, cedar, cypress and white pine are preferred hosts, and in parts of the Midwest, deciduous trees, particularly maple, sycamore and locust, are frequently infested. Favored species are identified readily in the dormant season by the presence of bags on the plant.

Description The spindle-shaped bag structures are the principal evidence of a bagworm infestation. Bags are approximately 1/8 inch long when first visible and can reach approximately

2 inches long and 1/2 inch in diameter when fully developed. Larvae are approximately 1 inch long when fully grown. The body is dark brown with a yellow head region and is hairless. The female moth is worm-like and lacks wings, legs, antennae, and eyes; it is yellowish white and nearly hairless. The male moth resembles a wasp with a black body and dense hairs; its wings are clear and approximately 1 inch across.

Life Cycle Bagworms overwinter as yellowish eggs within the bag. Some bags contain only male larvae, so eggs will not be found in every bag. Eggs hatch from late-May through mid-June, and as larvae emerge they begin feeding and constructing new bags. As larvae continue to feed and grow, they enlarge the bag to accommodate their increased body size. In late-July through early August, fully grown larvae secure their bags to a twig with silk and pupate within the bag. Male moths emerge in about one month and fly to a bag containing a female. Mating occurs and eggs are deposited in the protective bag so larvae can emerge the next year.

Control Removing and destroying the bags can reduce light bagworm infestations on shrubs and small trees. This should be done in the dormant season before eggs hatch.

On conifers and other plants with heavy infestations, management is frequently necessary. Please contact your Bartlett Arborist Representative for information on effective control of this pest.

10/20/2026

Preparing your trees and shrubs for winter

Extreme weather events and changing climate conditions result in chronic stress to our woody plants. In many areas, we have seen decline and death of even well-established mature trees. Here are suggestions to promote the health of trees and shrubs, and to protect them from temperature extremes.

Apply and maintain a 2- to 4-inch layer of organic mulch at the base of woody plants, extending out to the drip line if possible. Wood chips are one of the best materials to use. The combination of leaves, twigs, bark and wood is similar to the natural mulch found in a forest setting. This layer of mulch allows water pe*******on and decreases evaporation, and protects roots from extreme temperature changes. Mulch should be left to decompose in place rather than removing and replacing with new mulch each year.

Providing water during drought is very important. Trees and shrubs, especially evergreens, are at a great disadvantage going into the winter months, suffering drought stress. Be sure to continue irrigation until cold temperatures arrive.

Ask your Bartlett Arborist Representative to sample your soil for nutrient content and pH level. Fertilize only if your soils are nutrient deficient. Adjusting soil pH may be necessary to improve availability of some nutrients. Multiple treatments may be needed to make adjustments in soil pH. Fall is the perfect time to begin these services.

10/16/2026

10/08/2026

Fall🍂 is a great time to plant new trees🌳 in your landscape. With cooling temperatures and increased rain🌧, there is less drying out of newly transplanted trees. This increases the likelihood of tree survival. 👍 Root growth increases in the fall, so tree stability is improved, and more water and nutrients can be absorbed to prepare for next spring’s growth spurt.

Be aware, though, that depending on your zone, certain trees including some maple, birch, beech and dogwood species are considered ‘fall planting hazards.’ These trees can more easily be damaged by cold winter temperatures and should not be planted now so be sure to research what works in your area.

New transplants should be mulched with wood chips or other organic material to insulate the soil and maintain soil moisture levels. Mulch should be applied from just off the trunk to the outer dripline whenever possible. If there is dry weather, irrigate the root zone deeply, but do not apply water directly to the trunk.

10/06/2026

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10/01/2026

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