Report No. 73-1-35 April 1973 5230
STATUS OF THE BALSJl.MWOOLLY APHID Adelges piceae (RATZ.) IN THE SOUTHERN APPALACHIANS-1972
By J. D. Ward , E.T. Wilson, and W. M. McDowell
ABSTRACT
Aerial and ground surveys to evaluate the status of balsam woolly aphid Adelges piceae (Ratz.) , on the 60,000 acres of Fraser fir Abies fraseri type were con tinued in the southern Appalachians during 1972. Results of the survey showed a continuation of tree killing by the aphid outside the established protection zones and an increase in the populations inside some of the protection zones. The most significant findings of the surveys we r e a new infestation in the Shining Rock area of the Pisgah National Forest and a possible but not ve rified infestation in the previously unin fested Clingman' s Dome area of the Great Smoky Mountains National Park. Mount Rogers in Virginia con tinues as the only maj o r stand o f Fraser fir that r emains uninfested.
INTRODUCTION
The balsam woolly aphid Adelges piceae (Ratz.), which is native to Europe, was discovered in the southern Appalachians during 1956 (Mccambri dge and Kowal, 1957) on the Shenandoah National Park. It was found on Mt. Mitchell in 1957 (Speers, 1958), on Roan Mountain in 1962 (Ciesla and Buchanan, 1962), in the Great Smoky Mountains National Park in 1963 (Ciesla et al., 1963), and in the Balsam ~ountains of the Blue Ridge Parkway in 1968 (Rauschenberger and Lambert, 1969). The activity of the aphid is a very serious problem in the South because of the high value of the fir stands and the difficulty of con trolling infestations . Like many other introduced species it has an advantage because of the absence of its natural enemies. In addition, Fraser fir is extremely sensitive to its attack and climatic factors in the southern Appalachians rarely reach extremes necessary to control the aphid population . Systematic aerial and ground surveys have been conducted annually since the early 1960s to detect new infestations and to determine the status of previously detected infestations. The current report is based on aerial surveys and ground observa tions beginning in June 1972 and ending in January 1973. Participants in these surveys include personnel from the Blue Ridge Parkway and Great Smoky Mountains National Park of the National Park Service, the North Carolina Division of Forestry, the Toecane District of the Pisgah National Forest, and the Pest Management Group of the U. S. Forest Service. We gratefully appreciate the assistance of all who partici pated in these surveys.
SURVEY METHODS
In June 1972 the 60,000 acres of spruce-fir type were aerially sur veyed to detect infestations of balsam woolly aphid in the southern Appalachians. The survey included fir type on the Great Smoky Mountains National Park, Blue Ridge Parkway, Roan Mountain, Grand father Mountain, Mount Mitchell State Park, and Mount Rogers National Recreational Area (Figure 1). The objective of the survey was to detect any new infestations of the balsam woolly aphid and to determine the status of known infestations. Follow-up ground checks were made of the infestations during the following summer, fall, and winter. The trapping program was continued during September and October 1972 in the established protection zones. Sl ide traps coated with a sticky substance were placed at permanent trap l ocations and left for two to three weeks (Figure 2) . The traps were collected and examined in the lab for presence of the motile stage (crawler) or eggs of the balsam woolly aphid (Figure 3) . Trap locations suspected of being i nfested were ground checked.
RESULTS
Blue Ridge Parkway - Balsam Mountains The aerial survey of the Balsam Mountains found no new infestations along the Parkway; however, a large infestation was observed in the Shining Rock Wilderness Area which is administered by the Pisgah National Forest. This infestation contained approximately 500 red and fading trees. (Figure 4).
-2- ,, MAR IO N RED SPRUCE - FRASER FIR TYPE
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Figure 1. Location of Fraser fir type i n the So uthern Appalachi an Mountains. Fig. 2 Microscope slide traps and holder in place on host tree.
Fig. 3 Motile nymph of the balsam woolly aphid. Barnett Knob a CANTON
Q CHEROKEE WAYNESVILLE Water rock 0
Mount Pisgah
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BALSAM MOUNTAINS Shining Wagon Rood Gap 0 miles Balsam
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l!l BWA infestations - 1971
@ New infestations
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Figure 4. Location of balsam woolly aphid infestations in the Balsam Mountains - Slide traps set out by personnel of the Blue Ridge Parkway picked up aphids onl y in areas that were known to be infested. Ground checks revealed about 200 infested trees in the spot located near the Shining Rock Road. This spot, discovered in 1970, has now extended to both sides of the Parkway and has killed 81 trees. Th e infestation on Lickstone Ridge which was discovered in 1969 now contains approximately 1,000 infested trees. Considerable mortality is expected to occur here in 1973. This infestation is outside the protection zone and is along the boundary of the Park way and Pisgah National Forest .
Great Smoky Mountain National Park Severe tree mortality resulted in balsam woolly aphid infestations during 1972. Aerial surveys revealed hundreds of red-topped trees between Tricorner Knob and Cataloochee Mountain (Figure 5). A considerable number of trees were also killed in the Spruce Mountain and Cataloochee Balsam areas, especially along the old protection zone near Heintooga Overlook. The aerial survey detected a 50-tree spot of dying trees near the edge of the host type in the Clingman's Dome area. This spot could not be located on the ground check or on a second aerial survey. If it was caused by the aphid, it will be the first infestation in the Clingman's Dome area. Sticky traps set out in the protection zone from Newfound Gap to Clingman's Dome -picked up one suspect aphid crawler at Newfound Gap. Ground checking did no t reveal any balsam woolly aphid infestations in the area.
Roan Mountain-Toecane District, Pisgah National Forest The aerial survey of Roan Mountain found two new spots of red and fading trees. Ground check revealed 10 dead fir and spruce. Cause of the mortality was unknown, but the trees were not killed by the balsam woolly aphid. The trapping survey picked up one new aphid infestation in the pro tection zone. This infestation is along the road above Carver's Gap and is an extension of the infestation outside the protection zone (Figure 6). For additional details on the status of balsam woolly aphid on Roan Mountain, see Report No. 73 -1-34 .
-6- GREAT SMOKY MOUNTA INS NATIONAL PARK
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CHEROKEE c=::::::> Spruce - Fir Type ffllJ Bolsom Woolly Aphid lnfestotion 19 71 □ - G.S.M.N.P. Boundary • New infestations
Location of balsam wooll aphid infestations on the Great Smoky Mountains National Park - 1972. I
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ROAN MOUNTAIN
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,,nn•u Ap,P.t:D:icimate locat::ton of protecti on zones
figure 6. location of balsam woolly aphid infestation on RDon Mouhtain. Mount Rogers National Recreation Area Th e aerial survey detected two new spots of tree mortality near the edge of the spruce-fir type (Figure 7). During the ground check only the 5-tree spot cou ld be located . This spot was red spruce and cause of death was unknown. There are currently no known balsam woolly aphid infestations on Mount Rogers.
Grandfather Mountain The aerial survey of this privately owned mountain revealed three new areas of fir mortality (Figure 8). No ground checks were made of these spots.
Mount Mitchell The North Carolina Division of Forestry placed slide traps at 75 locations during September 1972. Forty-eight percent of the slide traps picked up balsam woolly aphid infestations (Figure 9). A summary of trapping results compiled by the North Carolina Division of Forestry for the past three years on Mt. Mitchell is as follows:
Number of Infested Stations* 1970 1971 1972 Inside Protection Zone 10 14 28
Outside Protection Zone 13 14 15
Total 23 28 43 * Results are from 75 permanent trappi ng locations. These data indicated a substantial increase in the number of infesta tions in the protection zone . Th e State conducted a suppression program in 1972 to prevent fir mortality in the protection zone. This was the first spray application since 1967.
DISCUSSION
Si nce the balsam woolly aphid was detected in the southern Appalachian Mountains nearly 18 years ago, it has killed mill i ons of Fraser fir. Its impact in the six areas has ranged from negligible to very severe,
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PARK BOUNDARY
PARK ROADS
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BWA infesta ~ tions in 1971
I Additional in I • festation in / " 1972.
118 1/4 318 '"
SCAL( !N MILES
Figure 9. Location of balsam woolly aphid infestation in the protection area on Mount Mitchell State Park - 1972.
-12- depending on how long the infestations have been established, pro portion of spruce and fir, value of the fir stands, accessibility of the stands, and other factors. Most of the locations with susceptible host type are heavily visited park and recreation areas that are noted for the alpine setting which is created by the spruce-fir type. Although the aphid has been found throughout most of the range of Fraser fir, there are still some stands that are not infested. Aphid infestation may take 2 to 6 years to kill trees once they become infested so it is quite possible that some of these apparently un infested stands are infested. Spraying individual stems which is currently the only effective means of killing the aphid is becoming less popular due to the high cost of application and the possible effects on the environment. Thus far, no adverse environmental effects of the chemical spray have been found . The only areas where spraying is applied is in protection zones. These zones were established in 1969 by the individual land managers and include narrow strips of host type along scenic roadways and high-value recreation sites. So far little tree mortality has occurred in most of the protection zones; however, infestations are beginning to cause some mortality along the Blue Ridge Parkway and on Roan Mountain. Unless these infestations are controlled, the rate r- of tree mortality will increase in 1973 . The tree mortality detected in the Clingman's Dome area of the Great Smoky Mountains National Park is significant since this large tract of spruce-fir type has had no infestations previously. Another attempt will be made in 1973 to locate the spot and determine the cause of mortality.
CON CL US IONS
The decision for or against suppression action is up to the individual land manager. His decision should be based on a thorough evaluation of resource values, cost-benefit ratio for treatment, and environmental impact with or without treatment. The alternatives available to the land manager are as follows: l. Let the infestation alone. This will result in the eventual destruction of the fir in the infested area. 2. Remove the most heavily infested trees during the dormant season . This will reduce the rate of fir mortality but will probably result in the removal of the fir from the stand. This measure may be most desirable in stands containing red spruce and could result in pure spruce stands which are not attacked by the aphid.
-13- 3. Al/8th percent emulsion of lindane in water is the most effective means for killing the balsam woolly aphid. The spray is formulated by mixing 5 pints of 20-percent lindane emulsi fiable concentrate with enough water to make 100 gallons of finished spray. The spray should be applied to the point of runoff to the entire bole and branches of infested trees. Spraying should be done from May to October with high pressure spray equipment. One treatment is generally sufficient for several years protection (see Precautionary Statement).
REFERENCES
Ciesla, W. M. and W. D. Buchanan. 1962. Biological evaluation of balsam woolly aphid, Roan Mountain Gardens, Toecane District, Pisgah National Forest, North Carolina. USDA, USFS, Div. FPM, S&PF, Atlanta, Ga. Report 62-93. Mccambridge, W. F. and R. J. Kowal. 1957. Forest insect conditions in the Southeast during 1956. USFS, Southeastern Forest Experiment Station Paper 76, 5 pp., illus. Speers, C. F. 1958. The balsam woolly aphid in the Southeast. Jour. Forestry 56: 515-6 . Ciesla, W. M., H. L. Lambert, and R. T. Franklin, 1963. The status of balsam woolly aphid in North Carolina and Tennessee. USDA, USFS, Div. FPM, S&PF, Zone 1, FI&DC Office, Asheville, N.C. Report 1-11 -63. Rauschenberger, J . L. and H. L. Lambert. 1969. Status of balsam woolly aphid in the southern Appalachians. USDA, USFS, Div. FPM, S&PF , Zone l, Asheville, N. C. Report 69-1-29.
-1 4- PRECAUTIONARY PESTICIDE USE STATEMENT
Pesticides used improperly can be injurious to man, animals, and plants. Follow the directions and heed all precautions on the labels.
Store pesticides in original containers under lock and key -- out of the reach of children and animals -- away from food and feed.
Apply pesticides so that they do not endanger humans, livestock, crops, beneficial insects, fish, and wildlife. Do not apply pesticides when there is danger of drift, when honey bees or other pollinating insects are visiting plants, or in ways that may contaminate water or leave illegal residues.
Avoid prolonged inhalation of pesticide sprays or dusts; wear protective clothing and equipment if specified on the container.
If your hands become contaminated with a pesticide, do not eat or drink until you have washed. In case a pesticide is swallowed or gets in the eyes, follow the first aid treatment given on the label, and get prompt medical attention. If a pesticide is spilled on your skin or clothing, remove clothing immediately and wash skin thoroughly.
Do not clean spray equipment or dump excess spray material near ponds, streams, or wells. Because it is difficult to remove all traces of herbicides from equipment, do not use the same equipment for insecticides or fungicides that you use for herbicides.
Dispose of empty pesticide containers promptly. Have them buried at a sanitary land-fill dump, or crush and bury them in a level, isolated place.
NOTE: Some States have restrictions on the use of certain pesticides. Check your State and local regulations. Also, because registrations of pesticides are under constant review by the U.S. Department of Agriculture, consult your county agricultural agent or State Extension specialist to be sure the intended use is still registered.
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