las-fir, cedar, or hemlock.
Dothistroma needlecast is a serious disease of a wide variety of pines, especially Ponderosa (Pinus ponderosa), Austrian (P. nigra), mugo (P. mugo), and lodgepole pines (P. contorta).
Dothistroma is caused by a fungus called Dothistroma pini.
Yellow to tan spots enlarge to form dark reddish bands on the needles in the fall. The ends of the needles beyond the bands die, while the bases of the needles remain green. Small black spots may appear in the dead and discolored areas. Needles shed prematurely, especially second- year needles. Infection is usually worse in the lower half of the tree. Successive years of severe infection result in decreased growth and death.
Diagnosis can be confirmed by a laboratory. See the diagnosis section under pine wilt (above) for the directions.
• Avoid pruning wet trees.
• Keep trees mulched and watered during drought periods.
• Apply a copper fungicide (many products available) when needles are half-grown and again when new needles are expanded.
Lophodermium is a disease commonly found on Scots (Pinus sylvestris) and red pines (P. resinosa). Ponderosa (P. ponderosa) and Austrian pines (P. nigra) are also susceptible.
Lophodermium is caused by the fungus Lophodermium seditiosum. The disease is spread from August through October by winds during rainy weather. Infection will not be noticed until the following spring.
In March and April, brown spots or bands with yellow haloes appear on the previous year’s needles. As the spots enlarge, the entire needle turns yellow and becomes brown by late spring. Defoliation is common on lower plant portions, often leaving only tufts of green current-season needles at the tips. In late summer, small, black, football-shaped fruiting bodies appear as conspicuous protrusions on dead needles (best viewed with a hand lens or magnifying glass). The bodies characteristically have a lengthwise slit down their centers. Current season’s growth will not show damage.
Diagnosis can be confirmed by a laboratory. See the diagnosis section under pine wilt (above) for directions.
- Avoid planting susceptible plants in low areas with poor air drainage.
- Keep trees watered during drought periods and mulch.
- Severely infected limbs as well as all needle litter from the ground should be removed and destroyed to prevent spreading the disease.
Registered fungicides should be sprayed four times beginning in early July when new needles are fully grown.
- Mancozeb (maneb + Zn)
Refer to the Illinois Urban Pest Management Handbook (University of Illinois Extension Service) for a complete listing of chemical recommendations. Use pesticides safely and wisely; read and follow label directions.
The pesticide information presented in this publication is current with federal and state regulations. The user is responsible for determining that the intended use is consistent with the label of the product being used.
The information given here is for educational purposes only. Reference to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement made by The Morton Arboretum.