What's eating my mugo pine?

Mugo Pine 'Mops' is most threatened by pine needle scale and Zimmermann pine moth, whose larvae tunnel into branch bases causing resin-soaked dieback. Pine sawfly larvae can strip needles rapidly in late spring. Mugo tip blight (Diplodia) often follows insect stress in humid summers. Deer occasionally browse in winter.

White, oyster-shell-shaped scales encrust needles; heavily infested needles yellow and drop, weakening the plant. Apply dormant oil in early spring to smother overwintering eggs; spray with horticultural oil or insecticidal soap when crawlers emerge in late spring.

Larvae skeletonize old needles in groups in late spring, leaving straw-colored stubs; rarely kill the plant but cause unsightly defoliation. Hand-pick small larval colonies; spray insecticidal soap, spinosad, or neem oil on larger infestations; remove egg-laden shoots in winter.

Masses of resin (pitch tubes) at branch whorls and the main trunk; branches droop and die back above the entry point. Prune and destroy infested branches; apply a preventive pyrethroid to branch whorls in early spring and midsummer to target egg-laying adults.

Browsed and shredded shoot tips and needles in fall and winter, especially on young or low-growing plants. Use wire caging or deer fencing around young plants; apply deer repellent sprays, reapplying after rain.