Chemical control is effective but extremely costly and thus limited to very high-value areas along scenic road-ways. Other control measures include removal and destruction of infested material.
Fraser fir infested by balsam woolly aphid.
DISEASES
NEEDLE CAST
Needle cast is a very common disease of conifers throughout eastern and southern United States. Eastern white, loblolly, longleaf, pitch, pond, shortleaf, table mountain, and Virginia pines are all susceptible. Hypoderma lethale is probably the most common cause of needle cast on the above hosts, with the exception of longleaf pine. Lophodermium pinastri is also associated with needle cast.
Hypoderma needle cast on loblolly pine.
Current pine needles are infected in the early summer, and by winter or early spring begin to turn brown at the tips. At this time the tree usually has a scorched appearance. Later, the browning progresses down the needle and the fungal fruiting bodies are produced. These are small, black, elongated structures known as hysterothecia, which open along a slit during moist weather to release their spores. The infected needles are often “cast,” leaving only the new growth, and causing the tree to have a tufted appearance.
Controls are seldom needed for this disease in forest stands. Infected trees usually recover and put out new foliage the year following heavy attacks. Nurseries or plantations should not be established in areas where needle cast is prevalent.