Lophodermium needle cast, the “spring reddener,” infection on a field of pine. Courtesy of Edward L. Barnard, Florida Department of Agriculture and Consumer Services, Bugwood.or (#4823057)
Lophodermium seditiosum Minter, Staley, and Millar
Spores released from mature fruiting bodies (Figure 1) are dispersed by wind or water to the new growth or to other trees.
- Scotch, Austrian, and red pines most susceptible
- Most two- and three-needled pines
- Moderate on field-grown trees
- High on seedlings
Symptoms and Signs
- May first develop in needles on lower branches
Late Winter Through Early Spring
- Infected needles develop yellow or reddish-brown spots
- Current season’s infected needles redden by early spring
Late Spring Through Midsummer
- Needles brown and may fall from tree, leaving only new, healthy-appearing growth
- Raised, black, football-shaped fruiting bodies appear on dead needles still attached to the tree and those on the ground
Causes of Similar Symptoms
- Winter burn
- Dothistroma needle blight
- Lethale needle cast
- Cyclaneusma needle cast
- Pine needle scale
The most accurate and easiest identification period for Lophodermium needle cast is in mid- to late summer when the fruiting bodies are present on needles infected the previous year. The shiny, black, football-shaped fruiting bodies are 1⁄32 inch (0.8 mm) long. They are slightly raised and aligned lengthwise on the needle. When mature, they have a longitudinal slit through which spores will be released. To see if fruiting bodies are mature, wrap some symptomatic needles in a moist paper towel for about 20 minutes to see if they open and release spores. Fruiting bodies occur on dead needles remaining on the tree or those already on the ground.
This common fungal disease is often referred to as the “spring reddener” of Scotch pines. In spring, needles infected the previous year will have small, brown spots, often with yellow margins. The most noticeable symptoms occur as the season progresses and needles turn yellow and eventually reddish brown. They may be cast anytime after symptoms appear. Fruiting bodies are required to confirm a diagnosis.
Biology and Life Cycle
Needle infection starts in mid- to late summer and only the current year’s growth is susceptible. Spores released from mature fruiting bodies (Figure 1) are dispersed by wind or water to the new growth or to other trees. The fungus enters the healthy needles through stomata and begins to disrupt the moisture-distribution mechanism in the needles. Symptoms are generally not apparent until early spring of the year following infection. At this time, infected needles begin to change color, first yellowing and then turning reddish brown by the time shoots are elongating (Figure 2). Severe infections will cause an entire tree to appear scorched, with only small, green shoots appearing at the end of branches. As the disease progresses, infected needles generally drop from the tree, leaving only the healthy, new growth.
By late summer, fruiting bodies are mature and can be found on cast needles under the tree, lodged in branches, and on the few browned needles remaining on the branches (Figure 3). When moisture is present, the fruiting bodies split longitudinally to release minute spores. This often occurs during cool rain events in late summer and fall. Since most of the infection comes from needles already on the ground, poor air circulation under the tree is a major contributor to the spread of the disease. The infection from needles already cast from the tree is unique to Lophodermium. Most other fungal diseases are spread from structures remaining on the tree.
Figure 1. Lophodermium fruiting bodies. Courtesy of Tracey Olson, PDA
Figure 2. Infected needles from the previous year turn reddish brown and drop in the spring. Courtesy of USDA Forest Service Northeastern Archive, Bugwood.org (#1398006)
Figure 3. Characteristic football-shaped Lophodermium fruiting body. Courtesy of Tracey Olson, PDA
Disease Cycle Calendar (Single Year's Growth of Needles)
Monitoring and Management Strategies
- Choose a site that will promote drying of trees (southern slope, good drainage, nonshaded).
- Do not plant near windbreaks of other susceptible conifers.
- Remove infected trees around the block; rake and remove disease-bearing needles under infected trees.
- Adequately space trees when planting to encourage drying and minimize disease transmission.
- Avoid planting short-needled “Spanish” Scotch pine and “French Green” varieties since they are very susceptible to infection.
- Examine all seedlings before planting and cull any suspected of being infected. Buy from a reputable producer.
- Control weeds around and under trees to allow for good air circulation and drying of foliage.
- In very early spring, scout for yellowing of needles. Needles often have small, brown spots with yellow margins that increase with time. Tag any suspect trees to examine later for reddening of needles.
- Examine dead needles under suspect trees for evidence of fruiting bodies from previous year.
- Scout for symptoms of Lophodermium in May and June by examining the lower branches of at least 50 trees of varying ages scattered throughout the block. Tag several suspect trees to watch for fruiting body production.
- Threshold level: If at least 10 percent of the examined trees show injury, consider treating the entire plantation.
- At the end of the season, evaluate results and update records.
- No recommendations are available at this time.
- In spring, remove and destroy severely infected trees. Rake and remove any fallen needles and branches.
- After harvest, examine needles around fresh stumps. If fruiting bodies are found, remove and destroy debris.
- Avoid tip-ups (live branches on stumps) that may contain infected needles.
- No recommendations are available at this time.
- Apply an appropriate fungicide three to four times beginning in July and continuing at three-week intervals. If early summer is warm and/or wet weather is prolonged, adjust the timing and number of the sprays accordingly.
- Apply the fungicide during periods of low air movement and when material will have adequate time to dry on needles.
- Inspect plants/nursery stock and buy from a reputable company.
- Collect seeds from trees showing resistance for a seed-collection program.