How to Manage Pests

Pests in Gardens and Landscapes

Pine tip or shoot moths—Rhyacionia spp.

About two dozen Rhyacionia species feed on pine terminals in the United States. Nantucket pine tip moth is the major pest species in California. Other species include the Monterey pine tip moth, Ponderosa pine tip moth, and European pine tip moth. Adult moths are reddish brown with silver gray markings; some adults begin emerging in January. Females lay tiny eggs singly on the new growth tips. Eggs hatch in 1 to 2 weeks and the larvae feed on or in the base of needles or buds. Mature larvae are yellow to pale brown with a dark head. Summer-generation larvae pupate in the tips; overwintering pupae commonly occur in the litter. The annual generations range from one in Massachusetts to about four in the southern United States, including Southern California.

Damage

The most obvious symptoms of a pine tip moth infestation are dead shoots that are very noticeable from a distance. Shoots may be brown or reddish. Silk webbing and boring frass are visible during close inspection of infused terminals. The webbing becomes covered with pitch as larvae bore into the shoots and feed. Tip moth damage to the central growing terminal can significantly alter tree shape, causing crooked or forked stems and reducing the marketability of Christmas trees.

Solutions

Provide trees with proper cultural care, especially appropriate irrigation, to increase their tolerance to damage. Prune infested tips from October through January to prevent overwintering moths from emerging. Remove and dispose of clipped foliage to eliminate developing larvae and pupae on pruned tips. Consider planting species not susceptible to pine tip moth. High Nantucket pine tip moth populations can be reduced by applying a broad-spectrum insecticide to foliage to kill young larvae. The repeated spraying necessary to provide good control is not justified unless trees are of especially high aesthetic value, such as in Christmas tree plantations. Spraying can also interfere with the effectiveness of the parasite Campoplex frustranae, an introduced wasp parasitic on Nantucket pine tip moth larvae and pupae in California.

Nantucket pine tip moth adult
Nantucket pine tip moth adult

Pine tip moth pupa in damaged terminal
Pine tip moth pupa in damaged terminal


Statewide IPM Program, Agriculture and Natural Resources, University of California
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