1-3). 8 p. A seedling root-dip treatment in a 5-percent active ingredient benomyl-kaolin mixture prior to packing at the nursery or at the reforestation site is very effective in reducing brown spot in the field. Scirrhia acicola), is common on longleaf pine seedlings within the natural range of longleaf pine, that is, within the Coastal Plain from North Carolina to Texas. Forest Service. The fungus causes two kinds of needle spots. Pruning of longleaf pine seedlings in nurseries promotes brown spot needle blight. They are hyaline, oblong - cuneate, unequally two-celled, and 15-19 x 3.5-4.5 microns, with two prominent oil drops in each cell (fig. The fungus also … CE. Brown Spot Needle Blight BSNB040515 IMPORTANCE: Longleaf pine is the only species in the South damaged by brown spot needle blight (Scirrhia acicola.) Brown spot needle blight symptoms are nearly identical to those of Dothistroma blight. Brown spot needle blight. 1-3). ; Affeltranger. Brown spot needle blight, caused by the fungus Mycosphaerella dearnessii (syn. Scotch pine is the major host, and we generally make the distinction based on the presence of spores and the host species. Brown spot needle blight of pines. AG. Avoid pruning when it is raining or at any time when the seedlings are wet.Root prune seedlings to a depth of 7 inches from 6 to 12 weeks before lifting.Spray with a fungicide the day before pruning and again immediately after pruning. It has also been reported on pines in plantations in nine additional States (fig.1-1).Infected seedlings are seldom killed, but severe defoliation reduces vigor, which, in turn, may result in poor survival and growth following outplanting.Although lesions may develop on secondary needles at any time, they most commonly appear from May to October.
In contrast to Lophodermium needle cast, which becomes evident in spring, lesions caused by brown spot needle blight do not usually appear until mid-late summer. Look for small, grayish-green spots, which become a straw-yellow color and then light brown with chestnut-brown margins (fig. Infected needles have three distinct zones: a green basal portion, a mottled middle portion, and a dead apical portion (fig. Brown spot needle blight (Mycosphaerella dearnessii, syn. The symptoms of brown spot needle blight infection are now beginning to show up in Scots pine Christmas trees.
32: 506-511.Phelps. Ascospores are disseminated by the wind and initiate light, scattered infections, sometimes at great distances from the source.
Conidia are produced in acervuli, which appear on lesions as small black dots visible to the naked eye (fig. Swab cutting blades with denatured alcohol or a 10-percent solution of sodium hypochlorite. Spots coalesce, and the needle tissue dies beyond and between groups of spots. Nursery grown longleaf pine seedlings are particularly susceptible. 1-6). The fungus can also infect the cut ends of pruned longleaf pine seedlings. Needles with multiple lesions appear mottIed. This treatment is very economical and significantly improves both growth and survival of outplanted seedlings.Kais, AG. Ascospores are produced in pseudothecia embedded in dead leaf tissue. : Cordell.
Spray with a fungicide the day before pruning and again immediately after pruning.
Hosts—Most pines are hosts, but the diseases are common on ponderosa, lodgepole, and Austrian pine in the Region.
Brown Spot Needle Blight Scott A. Enebak and Tom Starkey Conifer Diseases Hosts Brown spot needle blight, caused by the fungus Mycosphaerella dearnessii (syn. The fungus also infects seedlings of slash, loblolly, and white pines in nurseries within or slightly beyond this area. 1-7). Brown spot needle blight, caused by the fungus Mycosphaerella dearnessii (syn. Needle blights can occur throughout the range of - Typical lesions caused by the brown spot fungus.Figure 1-4.
Needle spots can appear on needles at any time of the year, but most commonly occur during August and September when trees suddenly turn brown just before growers are ready to harvest. Brown spot needle blight, caused by the fungus Mycosphaerella dearnessii (syn. Jr., Toko H.V., 1989. CE.1986. The sexual form is Mycosphaerella acicola. Avoid pruning when it is raining or at any time when the seedlings are wet. 1.eall. 1-7).Figure 1-2. Scirrhia acicola), is common on longleaf pine seedlings within the natural range of longleaf pine, that is, within the Coastal Plain from North Carolina to Texas.