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Pine Diseases: Needlecasts, Tip Blights, Gall Rusts, and Root Rots

Disease Reference Table

Disease	Symptoms	Pathogen/Cause	Management
Cyclaneusma Needlecast	Needles on Mugho, Scots, Austrian pines yellow with dark-brown bands Sept–Dec year after infection or Apr–Jun 2 years after. Brown bars fill with tan fruiting structure opening wide under moist conditions.	Cyclaneusma minus	Space plants, control weeds for good air circulation. Apply fungicide: mid-March, early May, mid-June, mid-August, mid-October (needles attacked any time temp >32°F and water on needle).
Diplodia Tip Blight	Shoot tips attacked in spring; canker at base of new shoot. Resin oozes from canker. Often on scattered low branches first. Dead/dying tips: tissue killed before needles full size. Lower branches killed in succeeding years. Old cones/dead needles persist with small dark-brown/black pimple-like fruiting structures.	Diplodia (formerly Sphaeropsis)	Don't plant young healthy 2-3 needle pines near older infected pines. Remove infected twigs to reduce fungus. Apply fungicide as buds swell in spring, repeat until needles full size. Spraying other times ineffective. Don't apply high-nitrogen fertilizer.
Ploioderma Needlecast	Mar–May year after infection: red-brown spots on needles. Tips girdled by spots die; bases remain green, needles attached. Black fruiting structures like lines in dead needle area. Needles cast May–Jun year after infection.	Ploioderma lethale (formerly Hypoderma)	Space plants, control weeds for air circulation. Apply fungicide 3 times at 3-week intervals starting late May.
Lophodermium Needlecast	Mar–May year after infection: needles on lower branches turn completely brown and fall. Black fruiting structures like lines in dead needle area on cast needles.	Lophodermium	Space plants, control weeds. Apply fungicide 3 times starting mid-July at 3-week intervals. If early summer warm, start mid-June.
Needle Rust	2-3 needle pines: small cream-colored bag-like pustules on needles. Rupture, release orange spores blowing to goldenrod/asters (overwinter). Pines infected next summer by spores from asters/goldenrod.	Coleosporium asterum	Little damage; no control recommended.
Pine-Pine Gall Rust	Many round galls on branches, enlarge to several inches. ~15 months after infection: yellow spores erupt from galls, infect new pine shoots.	Endocronartium harknessii	Inspect carefully, prune all galls. Inspect new seedlings for galls; destroy infected. Apply fungicide as new needles emerge and again 2 weeks later.
Pine-Oak Gall Rust	Few galls, may swell to 10" diameter on 2-3 needle pines. Yellow-orange spores erupt ~1 year after infection, blow to red oaks. Small yellow-orange spore areas on oak leaf undersides in summer; reinfect oak. Small brown hair-like structures (overwinter) on oak leaf undersides late season.	Cronartium quercuum	Inspect carefully, prune all galls. Don't establish 2-3 needle pine nursery near red oak stand. Inspect new seedlings for galls; destroy infected.
Root Rot	Trees, especially white pines, stunted before other symptoms. Decline, yellow, wilt, die. Dead needles remain attached. Resin oozes from girdling canker at soil line or several inches above. Wood beneath bark where resin oozes is chocolate brown to black.	Verticicladiella procera	Most susceptible: trees on poor sites for pines. Remove infected trees; don't replace with pine.
White Pine Blister Rust	White pines: swollen cankers on trunk/branches. Resin flows from cankers. Powdery yellow/cream spores erupt May–Jul, 2-3 seasons after infection. Branches/entire trees girdled and die. Spores on pine infect currant/gooseberry (Ribes) leaves. Spores on Ribes infect pines through needles; fungus grows into twigs, branches, trunk.	Cronartium ribicola	Destroy currants/gooseberries in/around nurseries. Purchase/plant only rust-free plants. Inspect pines frequently; prune infected branches 12" below canker.

Diplodia symptoms on tree and twig; Diplodia fruiting bodies on cone scales; Lophodermium fruiting bodies on needles; Cyclaneusma needlecast fruiting structures; Pine needle rust (photo courtesy M. Masiuk); Pine-pine gall rust.

Plant Disease: Spruce and Pine "Pine Worms": Myth and Free Forester Assessment; Leyland Cypress Needle Blight: Cercospora Identification and Copper Treatment; Pine Needle Mulch: Benefits, Terpene Concerns, and Safe Use; Pine Needles Under Ponderosa Pines: Mulch Benefit vs. Grass Competition; Pine Needle Management: Leave, Rake, or Mulch?; Pine Needles vs. Native Grass: Rake or Keep?; Pines with 5 Needles per Bundle: Species Guide; Managing Pine Needle Duft Under Ponderosa Pines for Native Plants; Removing Pine Needles from Rock Borders: Blower Technique; Common Spruce Diseases: Identification and Management

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