Insects

Insects may attack conifer cones or seeds at any time from the formation of the cone bud through seed maturity. Cone and seed insects (moths, wasps, beetles, true bugs, and some flies) can destroy whole crops or reduce the seed production so much that collection would not be cost effective. Often, you will see indicators of the insect’s presence, such as brown or discolored spots on the cone, fresh pitch exuding from the cone, frass (insect droppings), deformed cones, stunted cones, dead conelets, or cones that ripen early. You may see larval galleries or larvae while examining a cone’s cut face.

Hundreds of seed and cone insects feed on western conifers. Many of them have complicated life cycles. Use local references and rely on the forest health management staff assigned to your forest to help you identify insects and develop management strategies.

Insecticides are the main control techniques for seed and cone insects, although their use may be practical only in seed orchards or when a cone collection is critical. Long-lasting (residual) sprays have been applied to developing cones. Systemic insecticides have been injected into a tree’s vascular system or placed in the soil to be absorbed by the tree’s roots and transferred to the cones. Contact your local forest health management staff for help in selecting an appropriate insecticide.

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