Hosts: Ponderosa pine and piñon
Symptoms/Signs: Adults of pine-feeding needleminers are small, narrow-winged, mottled,
silvery-gray moths with a wingspan of about 10 mm. Eggs are too small,
0.2 mm in diameter, to be noticeable. Larvae are brown, 8 mm long when
fully developed, and usually found mining within current year’s
needles. The pupae are elongate, cylindrical black, and about 6 mm long.
Needles inhabited by third and fourth instar larvae turn a faded yellow-brown
in color and have several tiny holes in them for frass disposal and larval
Biology: Adult moths emerge and fly in June and July. Eggs are laid inside
previously mined needles. Larvae begin hatching in July, crawl to and
mine into previously uninfested needles and overwinter. Pupation occurs
in late spring.
Effects: Persistent infestations can cause severe
discoloration, defoliation, and reduced growth of stems, shoots, and needles.
Insects and Diseases: Similar symptoms, i.e., discoloration and
defoliation, can result from scale insects, aphids, and needle cast diseases.
However, only the needleminers leave telltale holes in the mined