Around 1936 many of the shortleaf pine stands that had seeded-in on abandoned farm lands in the Piedmont regions of Georgia were characterized by trees having yellow-green foliage and unusually short needles (Figure 52). These trees were best described as having littleleaf symptoms; hence, the name littleaf disease. Many of the stands were 20- to 30-years-old. Further investigations associated the syndrome with soil series such as Wilkes, Mecklenburg, Tatum, Orange, and Vance. The sites were severely eroded due to previous agricultural activities and subsequent abandonment. The topsoil was almost completely eroded away. On such sites tree roots were weakened by heavy clay subsoils with poor internal drainage.

Research then and more recently has identified at least two soil-borne fungi associated with littleleaf; Phytophthora cinnamomi, and species of Pythium. These fungi kill the root tips of stressed trees. As more and more feeder roots are killed, essential element uptake by the tree is reduced even though adequate elements may be present. As trees weaken, the symptoms become more pronounced. Trees eventually die from litteleaf.

The disease is most prevalent in stands 30-to 50-years-old. The fungi associated with littleaf are widely distributed in the soils of the southeastern United States.

There are no quick cures for littleleaf disease but there are several recommendations that foresters can follow to minimize losses. Trees under 20 years of age or 3-4 inches in diameter rarely show littleleaf symptoms. Infected trees can live as long as 5 to 6 years after initial symptoms appear but some trees may die in as little as one year. This is particularly true during extended droughts or when trees have been attacked by bark beetles.

The amount of littleleaf in a stand dictates the management of that stand. The following guidelines should help foresters and landowners better manage their littleleaf stands:

• lf up to 10 percent of the trees in the stand have symptoms, diseased trees should be removed by 10 year intervals.
• lf 10-25% of the trees in the stand have symptoms, remove all diseased trees at six year intervals.
• lf 25-50% of the trees in the stand have symptoms, clearcut and regenerate with Virginia pine or hardwoods. This is particularly true for stands being managed for pulpwood. Loblolly pine is about one-third as susceptible as shortleaf and may be considered as an option on littleleaf sites. It does, however, sustain severe damage on many sites within the range of littleleaf disease. Rotations for loblolly on high hazard sites should be shortened to 30 or 40 years.

Pitch Canker

The pitch canker fungus, Fusarium moniliforme var. subglutinans , can infect most of the southern pines but more damage is done to slash and Virginia pines. It gains entrance into trees through wounds. After the fungus gains entrance into the tree, the tips of terminal and lateral branches are often girdled and killed (Figure 53). Upon close examination of the dead shoots, the wood will be pitch soaked beneath the bark. Trunk cankers are also caused by the fungus (Figure 54).

The disease has not been a serious problem to pine plantations in Georgia. However, since the disease has the potential to outbreak (sporadically), the land manager should be aware of its presence.

Several management options are available for managing the disease in slash pine plantations:

• Infected trees should he removed during thinnings.
• When regenerating stands, consider using the seed tree method because native seed sources may be more disease resistant than nursery seedlings from a particular seed source.
• When establishing new plantations, avoid regenerating near existing diseased stands. Regulate stocking densities to avoid over crowding and individual tree stress.