Spruce Needle Miner
- Eggs: The female deposits a group of pale-green eggs, shingle fashion, at the base of needles.
- Larvae: Larvae are green with dark brown heads and can grow up to 8 mm long. Upon hatching, the larvae cut a hole at the base of a needle to begin eating the needles interior. Larvae eat all summer, then go dormant to overwinter inside a hollow needle.
- Pupae: In early spring, larvae resume feeding until they are ready to pupate in mid-April.
- Adults: Adults are smoky brown moths with blunt wings. They emerge in late May and June to mate.
- Clusters of dead needles enclosed by silk strands: As feeding larvae often cut off the needle they ate, which remains attached to other dead needles by silk strands.
- Preventive tools:
- Follow a regular watering, fertilizing, and pruning schedule to keep your trees as healthy as possible to resist attack.
- Physical tools:
- Wash away nests with a strong blast of water before bud break in spring.
- Prune and destroy infected needles and branches where nests are located.
- Biological tools: Not applicable.
- Least toxic chemical tools:
- Apply Bacillus thuringensis var. kurstaki ( also known as Organic Insect Killer, Bt.k.) according to label directions to treat infestations when larvae are young.