What's eating my mountain pine?

Mountain Pine (Pinus mugo) commonly suffers from pine needle scale, Mugo pine aphid, and pine sawfly. In exposed garden and bonsai settings, spider mites cause summer browning. Rabbits and deer browse young trees. Scale insects are the most damaging persistent threat on established specimens.

White crusty scale on needles causes yellowing, premature needle drop, and weakening of whole branches Apply horticultural oil in late winter or early spring; remove heavily encrusted branches; use systemic insecticide if widespread

Large brown aphids cluster on bark and stems, producing copious sticky honeydew and sooty mold Hose off colonies with water; apply insecticidal soap in spring; encourage parasitic wasps by avoiding broad-spectrum insecticides

Larvae strip needles from outer branches in groups; severe defoliation weakens compact cultivars rapidly Hand-pick egg masses and larval clusters; apply Bt or spinosad to young larvae; check undersides of needles in late spring