What's eating my tamarack?

Tamarack's most damaging pest is the larch casebearer, a moth larva that mines needles causing widespread browning. The larch sawfly can completely defoliate trees over several consecutive years. Woolly larch aphid coats needles in white wax. Deer and moose browse young trees in their boggy native habitats.

Larvae mine individual needles from inside a portable silken case; infested needles turn brown and dry from the tip; heavy infestations make crowns look scorched Apply carbaryl or spinosad when adults emerge in late spring before eggs hatch; encourage parasitic wasps (Agathis pumila was released as biocontrol); single-year mining rarely kills trees

Larvae feed in groups stripping entire needles; repeated defoliation over 3–5 years kills branches and eventually the whole tree; frass and skeleton needles visible Apply Bt or spinosad targeting young larvae in late spring; destroy cocoons in litter below trees; diapause parasite Mesoleius tenthredinis provides biocontrol in established populations

White waxy wool coating on needles and shoots; sticky honeydew drip; sooty mold growth; heavy infestations cause yellowing and early needle shed Horticultural oil in late winter targets overwintering stages; insecticidal soap on active woolly colonies; beneficial insects including lacewings provide natural suppression