Spruce Budworms

Close up image of a spruce budworm
spruce budworm crawling on the ground
spruce budworm on a branch
spruce budworm and adult

Several species of spruce budworms are responsible for the loss of vast numbers of evergreen trees across the northern United States. The caterpillar larvae of native moths, these extremely destructive pests target cone-bearing, needle-leaved evergreens, such as spruce and fir. Spruce budworms can completely defoliate trees in landscapes and forests in a single season. One generation occurs each year.

Identification: Spruce budworm larvae go through several stages, changing color and growing larger and more destructive with each stage. The tiny, immature larvae measure about 1/12 inch and have yellow-green bodies with light brown heads. Final larval stages grow to 1 inch long with dark brown or black heads. Their dark brown or cinnamon-brown have light-colored spots up and down their back. Adult spruce budworms are grayish brown moths with various markings and wingspans of about 3/4 inch

Signs/Damage: Spruce budworms bore into evergreen needles and buds to feed, focusing on new growth and tips. Needles are often sheared at the base and left hanging on thin, silken threads. Tree tops and branch tips turn brown, and damaged trees appear scorched. Heavily defoliated trees turn gray and die.

Control: Spruce budworm damage starts as soon as weather begins to warm in spring. Effective control targets the emerging larvae before they can damage trees. For large trees more than 10 feet tall, seek professional help. For trees under 10 feet, GardenTech® brand offers highly effective products to kill these leaf-eating caterpillars and keep protecting for up to three months:

  • Sevin® Insect Killer Concentrate, used with a pump-style sprayer, provides thorough coverage for small trees and shrubs. Use the easy-to-use measuring cap, add the appropriate amount of water to your sprayer, and mix well. Spray to cover all leaf surfaces and buds thoroughly, concentrating on new growth that these pests target first.
  • Sevin® Insect Killer Ready to Spray, used with a garden hose, measures and mixes automatically as you spray. Treat to cover all leaf surfaces and buds thoroughly. Give special attention to branch tips and new growth that spruce budworms prefer.

Tip: Healthy trees can withstand infestations that leave weak trees beyond recovery. Keep evergreens pruned, nourished and irrigated well.

Always read product labels and follow the instructions carefully.

GardenTech is a registered trademark of Gulfstream Home and Garden, Inc.

Sevin is a registered trademark of Tessenderlo Kerley, Inc.




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