Pine Diseases
Gary W. Moorman, Professor of Plant Pathology
| Disease | Symptoms | Pathogen/Cause | Management |
|---|---|---|---|
| Cyclaneusma needlecast | Needles on Scots and Austrian pines yellow and have dark-brown bands from September through December the year after infection or from April through June, 2 years after infection. The brown bars become filled with a tan fungal fruiting structure, which opens wide under very moist conditions. | Cyclaneusma minus | Space plants and control weeds to ensure good air circulation around the tree. Apply chlorothalonil first in mid-March and again in early May, mid-June, mid-August, and mid-October to protect the needles since they can be attacked any time the temperature is above 32°F and water is on the needle. |
| Sphaeropsis tip blight | Shoot tips are attacked in the spring and a canker forms at the base of the new shoot. Resin oozes from the canker. This often occurs on scattered branches low on the tree at first. Close examination of the dead and dying tips reveals that the tissue was killed before the needles reached full size. Lower branches are killed in succeeding years. Old cones and dead needles persist on the tree and have small, dark-brown to black, pimple-like fruiting structures peppering their surface. | Sphaeropsis sapinae (formerly Diplodia) | Do not plant young, healthy two- and three-needled pines near older, infected pines. Remove infected twigs to reduce the amount of fungus in the tree. Apply azoxystrobin, thiophanate methyl, or copper salts beginning as the buds swell in the spring and repeat application until the needles reach full size. Spraying at other times is not effective. Do not apply high-nitrogen fertilizer. |
| Ploioderma needlecast | From March through May the year following infection, red-brown spots develop on needles. Tips of needles girdled by spots die while needle bases remain green and needles remain attached to twig. Black fungal fruiting structures that look like lines in the dead area of the needle form. Needles are cast in May through June the year after infection. | Ploioderma lethale (formerly Hypoderma) | Space plants and control weeds to ensure good air circulation around the tree. Apply chlorothalonil or mancozeb three times at 3-week intervals beginning in late May. |
| Lophodermium needlecast | From March through May the year following infection, needles on lower branches turn completely brown and fall. Black fungal fruiting structures that look like lines in the dead area of the needle form on the cast needles. | Lophodermium | Space plants and control weeds to ensure good air circulation around the tree. Apply chlorothalonil, azoxystrobin, or mancozeb three times beginning in mid-July and at 3-week intervals. However, if early summer is warm, begin in mid-June. |
| Needle rust | Two- and three-needled pines develop small, cream-colored, bag-like pustules on the needles. These rupture and release orange spores that blow to and infect goldenrod and asters where the fungus overwinters. Pines are infected the following summer by spores from asters and goldenrod. | Coleosporium asterum | Little damage occurs, and no control measures are recommended. |
| Pine-pine gall rust | Many round galls form on the branches and enlarge up to several inches in diameter. Approximately 15 months after infection, masses of yellow spores erupt from the galls and infect new pine shoots. | Endocronartium harknessii | Inspect plants very carefully and prune all galls. Inspect all newly purchased seedlings carefully for galls. Destroy infected seedlings. Apply mancozeb as new needles emerge and again 2 weeks later. |
| Pine-oak gall rust | A few galls, which may swell to 10 inches in diameter, form on two- and three-needled pines. Masses of yellow-orange spores erupt from the galls about a year after infection and blow to red oaks. Small areas of yellow-orange spores develop on the underside of oak leaves in the summer. These spores reinfect oak. Small, brown, hair-like fungal structures, where the fungus overwinters, develop on the underside of oak leaves late in the growing season. | Cronartium quercuum | Inspect plants very carefully and prune all galls. Do not establish a two- and three-needled pine nursery close to or within a red oak stand. Inspect all newly purchased seedlings carefully for galls. Destroy infected seedlings. |
| Root rot | Trees, particularly white pines, are stunted before any other symptoms appear. Infected trees decline, yellow, wilt, and die. Dead needles remain attached. Resin oozes from a girdling canker at the soil line or several inches above the soil. Wood beneath the bark where resin is oozing is chocolate brown to black. | Verticicladiella procera | Trees most susceptible are ones growing on poor sites for pines. Remove infected trees and do not replace them with pine. |
| White pine blister rust | White pines develop swollen cankers on the trunk or branches. Resin flows from the cankers. Powdery, yellow to cream-colored spores erupt from the cankers in May through July, two to three seasons after infection. Branches and entire trees are girdled and die. Spores formed on the pine infect the leaves of currants and gooseberries (Ribes). Spores formed on currants and gooseberries infect pines through the needle. The fungus then grows into twigs, branches, and the main trunk. | Cronartium ribicola | Destroy currants and gooseberries in and around nurseries. Purchase and plant only rust-free plants. Inspect pines frequently and prune out any infected branches, cutting 12 inches below the canker. |
Sphaeropsis symptoms on tree and twig.
Fruiting bodies on cone scales
Lophodermium fruiting structures. Cyclaneusma fruiting structures.
Pine needle rust (Photo courtesy, M. Masiuk).
Pine-pine gall rust. Needlecast infection and symptom timing.
Active Ingredients and Trade Names of the Chemicals
| FRAC Group No. | Risk Level | Class | Active ingredient | REI Restricted Entty Interval | Trade names (EPA Reg. No) |
|---|---|---|---|---|---|
| 1 | 3 | Benzimidazole | thiophanate methyl | 12 | 3336 (1001-69), OHP 6672 (51036-329-59807), Fungo Flo (51036-329-59807), Systec 1998 (48234-12) |
| 11 | 3 | Strobilurin | azoxystrobin | 4 | Heritage (10182-408) |
| M | 1 | Chloronitrile | chlorothalonil | 48 | Daconil (50534-9) |
| 12 | Echo (60063-7), PathGuard (60063-7-499), Concorde (72167-24-1812), Pegasus (72167-24-1812) | ||||
| Copper, fixed | copper hydroxide | 48 | Kocide (352-656), Champion (55146-1) | ||
| Dithiocarbamate | mancozeb | 24 | Dithane (707-180), FORE (707-87), Pentathlon (1818-251) | ||
| manganese + zinc | 24 | Protect T/O (1001-65) | |||
| M + M | 1 | mancozeb + copper | Junction Fungicide (1812-360) |
Fungicides and Fungicide Resistance Management - Certain fungicides, usually systemic fungicides, are said to be 'at risk' to the development of resistance if they are used repeatedly. See the Risk Level in the above table (1 = low risk; 3 = high risk). The Fungicide Resistance Action Committee has developed a numbering system in which chemicals with the same FRAC Group number have the same mode of action (See http://www.frac.info/frac/index.htm ). It is recommended that chemicals at high risk be used sparingly and in rotation or mixed with chemicals with different modes of actions (different FRAC number).
DISCLAIMER
Notice: The user of this information assumes all risks for personal injury or property damage.
Warning! Pesticides are poisonous. Read and follow all directions and safety precautions on labels. Handle carefully and store in original labeled containers out of the reach of children, pets, and livestock. Dispose of empty containers right away, in a safe manner and place. Do not contaminate forage, streams or ponds.
Issued in furtherance of Cooperative Extension work, Acts of Congress, May 8 and June 30, 1914, in cooperation with the U. S. Department of Penn State College of Agricultural Sciences research and extension programs are funded in part by Pennsylvania counties, the Commonwealth of Pennsylvania, and the U.S. Department of Agriculture.
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