Pine Diseases Chart

Needle Blight
Dothistroma sp.		 Brown Spot
Mycosphaerella dearnesii
(Sricca acicola)
 
Time of infection

New needles – midsummer to Oct., older needles- May to Oct (worse in Sept & Oct)

Usually early in growing season, June - July – as new growth develops (occasionally into early fall).

Time from infection to symptoms

5 weeks to 6 months

One month to 6 months depending on pine and age of pine (young plants show symptoms quickly as do Scots pine and developing needles).

Symptoms

Water soaked lesions that become tan to light brown spots – needles may break off or fold at the infection site. Young trees more than older trees and more often on the lower branches.

Brown spots with yellow halos - other coloring of spots possible. Eventually needles turn all brown. New shoots & needles may die by winter. If shoots stay alive then older needle die earlier in succeeding years. Needles may or may not fall off by late fall. Occurs more often on lower branches.

Time to look for symptoms

Throughout the year

Summer (June – August)

Some susceptible hosts

Austrian & Ponderosa -mostly, lodgepole, mugo, Japanese red –often, Scots and red usually resistant

Ponderosa, Scots & red - most, Jack, mugo, pitch, eastern & western white & black -sometimes

Disease growing conditions best for severe infection

Several days of cool and wet or cloudy days. Growing the trees outside their native habitat makes them more susceptible.

Warm/hot and wet and may take 3 years to reach epidemic conditions

Suggested cultural practices

Good air circulation, plant native species of pine.

Grow resistant varieties, plant disease-free trees, allow for good air circulation, do not prune when trees are wet.

Over wintering site of disease

In lesions of infected needles

On dead needles

 

Needle Cast
Lophodermium seditiosum		 Tip Blight
Sphaeropsis sapinea
(Diplodia pinea)

Time of infection
Usually mid to late summer – after new growth hardens off.

As new growth emerges some research indicates fungus may be in plant tissue the previous year but does not cause infection till following year.

Time from infection to symptoms
Several weeks to following spring.

3 – 4 days (in warm weather) to several weeks

Symptoms
Brown spots with yellow halos. Eventually needles turn all brown in April & May and fall off leaving only new growth in June & July. Lower branches most affected.

Bleeding at base of branch tip & yellow- browning of foliage, internally the tissue is reddish brown and resinous (can be a severe canker problem on branches and trunk producing large globs of oozing sap over the infected tissue, xylem may turn gray to black in canker area – tree can be killed).

Time to look for symptoms
Fall through winter into summer

Late spring to fall

Some susceptible hosts
Red (as seedlings mostly), Austrian & Scots -most. Jack & White - almost never

Austrian, Ponderosa, Scots– most. Red, mugo, & other 2 & 3 needle pines -sometimes

Disease growing conditions best for severe infection
Cool and moist –

Temperatures between 55 and 100° F. & 12 hours of wet weather during bud break and candle growth for tip blight. Planting pines outside the native range and habitat.

Suggested cultural practices
Maintain good air circulation.

Plant less susceptible pines. Use only native pines.

Over wintering site of disease
On dead 1 year old needles on ground or on tree & occasionally on cones

Infected needles on tree and ground, infected cones (green or brown), shoots, needle sheaths and canker areas

Written by James Schuster, Extension Educator, Horticulture, and reviewed by Bruce Paulsrud, Extension Specialist, Pesticide Applicator Training and Plant Pathology, University of Illinois at Urbana-Champaign.