Dioryctria abietivorella (D. abietella) (Pyralidae (Phycitidae))

fir coneworm


Insect:

Dioryctria abietivorella adult moth. Medium-sized greyish moth, wingspan 28 mm. This is not the injurious stage. Forewings are narrow blended dark and light grey, with diffuse, white 'w' shaped cross bands near midpoint and wing tip.

Larvae:

Dioryctria abietivorella later instar larva. Mature larva is reddish with a brown head, extremely active when disturbed. Feed from June to September. Pupate in cocoons on the ground.



Damage:

Douglas-fir cone damaged by Dioryctria larval feeding; notice the holes and frass. Larva feeds voraciously, tunnelling indiscriminately through scales and seeds. It leaves round holes and considerable amounts of coarse frass on the surface of the cones that is held together by webbing. One larva can destry a whole cone. A heavy infestation can destry 100% of a cone (and seed) crop.



Principal Hosts:

Douglas-fir and Abies spp. primarily, but will attack cones of many coniferous species.

Economic Importance:

Very significant damage in Douglas-fir cones.

References and Links:

EAG: 545, 547-549;

Fact sheet.

Additional Images:



Sliced cone showing heavy feeding on seeds and scales. Coarse frass held on the outside of cone by silk spun by fir coneworm caterpillar. Egg on dissected cone.