Pine Coneworm
Dioryctria auranticella (Groté)

Host:  Ponderosa pine

Symptoms/Signs:  Entire cones are usually killed by pine coneworms; partially killed cones become distorted and do not open. Larval feeding cavities inside cones are filled with frass and webbing.

Biology:  Larvae begin feeding in ponderosa pine cones in late spring. They make an entry hole in the basal portion of the cone and consume seeds and scale tissues. Mature larvae pupate in the cavities in the cones created by feeding activity of the larvae. Adults emerge in middle to late summer.

Effects:  This obligate seed and cone insect can be destructive when populations are high. Up to 80 percent of cones can be damaged per year in the Southwest. Coneworms feed on seeds and scales from a cavity inside the cone, severely distorting the cone and preventing extraction.

Similar Insects and Diseases:  There are a variety of cone and seed feeding insects in the West. Other species of insects that feed in seeds and cones of ponderosa pine in the Southwest include pine seed chalcid (Megastigmus albifrons), ponderosa pine cone beetle (Conophthorus ponderosae), and the ponderosa pine seed moth (Laspeyresia piperana). This conophyte is distinguished by the entry hole in the basal portion of the cone and larval feeding cavities filled with frass and webbing.

References:  5, 87