Arborvitae trees that are covered with cylindrical cones are infested with which pest?

• A. Bagworm
• B. Spider mite
• C. Aphid
• D. Scale insect

Answer: (A)

Bagworms are the pests that create those cylindrical, bag-like cases from silk and bits of foliage that hang on arborvitae branches. When an infestation is present, you’ll see a string of tan, cigar-shaped bags along the needles. The caterpillars inside feed on the foliage, often defoliating sections of the plant. The bags themselves are a clear sign of the problem and are why this pest is the best fit for the description.

Other common pests don’t form these cylindrical bags: spider mites cause fine stippling and webbing, aphids cluster on new growth and produce honeydew, and scale insects appear as small, immobile shells on the twigs.