Report No. 70-1-44 February 1970

5230

STATUS OF THE BALSAM WOOLLY APHID IN THE SOUTHERN APPALACHIANS-1969

By

John L. Rauschenberger and H.L. Lambert

U.S. Fore st Service Asheville, North Carolina

ABSTRACT

During 1969, established infestations of the balsam woolly aphid on State, Private and Federal lands continued to thrive and new ones were detected. Only the fir type of in continues through 1969 to be free of aphid infestation.

Emphasis was placed, during 1969, on establish­ ment of protection boundaries around accessible, high value stands of fir. Protective spraying has been discontinued and the policy has become one of spraying only actively infested trees. Intensive trapping procedures carried out in the respective protection areas revealed two areas of infestations on Roan Mountain, one on and also infestations on fir seed trees in the Linville River Forestry Facility at Crossnore, North Carolina. The aerial and ground phase of the 1969 balsam woolly aphid evaluation covered 60,000 acres of host type. INTRODUCTION

The balsam woolly aphid, Adel r;es pl ce ae Ratz. was accidentally introduced into North America in the early 1900' s and detected in North Garolina in 195 7 ( Speers, 19 5 8). Since that time the aphid has become established in every major area of host fir type in the three state area of North Garolina, Virginia and Tennessee with the single exception of a 500-acre fir stand on Mount Rogers in Virginia ( Fig. 1). The two native species of fir which serve as host in the Southern Appalachians are Fraser, Ables fras e rt ( Pursh. ) Poir. and bracted balsam fir, A. balsamea Var. pi a ne role p ts Fern. For a detailed history of the aphid in the Southern Appalachians, the reader is referred to the selected references cited at the end of this report.

METHODS

The host fir type of the Southern Appalachians can be separated into two major catagories-accessible and inaccessible. For purposes of control, this consideration is of prime importance since suppression measures involve spraying of individual trees using heavy hydraulic ground equipment. Therefore, the 1969 survey and evaluation tech­ niques were modified from previous years to take into account the accessibility or inaccessibility of given areas.

Evaluation surveys were conducted in two ways; first, the general trend and status of the aphid was determined through one hundred percent aerial surveys of all host type acreage wi1h the exception of Mount Mitchell. All areas of dead or dying fir which had not been observed or ground checked previously were plotted on topographic maps. Ground checking was carried out on as many spots as possible on a priority basis dependent upon proximity to known infestations, size of spot and aesthetic and commercial value of the stand.

The second method of evaluation was designed for and restricted to use on accessible high value stands of fir where applied control, if needed, could be carried out. The objective was to detect the aphid's presence prior to any tree mortality, arr impossible task using standard sketch map aerial survey techniques. The evaluation consisted of an intensive aphid trapping program which was restricted to those high value, accessi­ ble host fir stands designated as "protection areas". By intensively trapping within the boundaries of the protection area for motile nymphs of the balsam woolly aphid during the time of their dispersal, aphid activity was detected prior to any tree mortality.

- 2 - MARION RED SPRUCE - FRASER FIR TYPE

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Fig. 1 Location of Fraser-fir type in the Southern . The traps consisted of standard microscope slides coated with a thin layer of tanglefoot.l/ At each trap location, three such coated microscope slides were attached with spring clips to a specially de­ signed holder and attached to a host tree ( Fig. 2 ) . The traps were oriented in a horizontal position to the tree to entrap any motile nymphs which fell from that tree or blew in from surrounding host trees ( Fig. 3 ) . Traps were left exposed in the field approximately two weeks. They were then returned to the laboratory and examined microscopically with a !OX binocular scope for motile nymphs of the balsam woolly aphid.

The balsam woolly aphid has two complete generations per year with evidence of a partial third. Motile nymphs are present in June and again in September. Due to the intensity of trapping, only the September motile nymph generation was trapped.

A total of six host fir stands were designated as protection areas during 1969. Nine-hundred and fifty-four microscope slide traps were prepared, set and examined.

The restriction of trapping to within protection areas facilitated a much more effective evaluation due to the limited land areas involved. More­ over, it permitted a more realistic approach to the aphid problem in that the most effort was placed on that portion of the resource that could be saved. Restrictive trapping within the protection areas in 19 69 was also important because preventative type spraying for control of the balsam woolly aphid on high value areas has been permanently discontinued. Chemical control measures are now carried out only on stands verified as being actively infested. This policy renders detection of aphid activity prior to any host tree mortality imperative.

RESULTS

Great S..!!!Qky Mountains National Pa.rk. - The aerial survey of the 22,280 acres of host fir type on the National Park was carried out on May 29, 1969. Results of that survey revealed that established infestations in inaccessible areas continue to thrive causing increased mortality of host fir on the Park. On Mount Sterling, the aerial survey revealed hundreds of red fading fir trees that have succumbed to the aphid during 19 69 ( See cover ) . Although this area has been recognized as infested since 1963, this year's mortality sur­ passes that which has occurred in any single year on Mount Sterling since its detection .

.l/ Mention of trade name does not imply endorsement by the U. S.D.A.

- 4 - Fig. 2 Microscope slide traps and holder in place on host tree.

Fig. 3 Motile nymph of the balsam woolly aphid. On Spruce Mountain, approximately fifty additional dying host fir were detected in the 200 acre infestation discovered in 1968. Fifty dying fir were also detected in 1969 south of Luftee Knob.

Two roadside stretches of host fir stands were designated as protection areas on the Park during 1969. These areas were selected and cited by Park personnel as being worthy of control considerations at their dis­ cretion should aphid infestations be detected within them. The two areas designated were the fir stands located between Newfound Gap and Clingman' s Dome and those located between Paul's Gap and Heintooga Overlook (Fig. 4). The protection boundaries ran parallel to existing roads three hundred feet on each side of them.

A total of 2 76 microscope slide traps were placed in the two protection areas during September, 1969. Three slides were attached to host fir trees at 500-foot interval trapping sites parallel to the road. Collection of the traps was made two weeks later by Park personnel who then returned the exposed traps to Division of Forest Pest Control entomologists for examination.

Microscopic examination of the slide traps failed to reveal any aphid activity. Likewise, ground examinations conducted by Park personnel at the time of trap placement and collection revealed no aphid activity.

Mount Mitchell State Park - Aerial surveys have not been conducted on Mount Mitchell since 1963 because infestations are known to occur over the entire 7,000 acres of host type.

A protection area was established on Mount Mitchell State Park in 19 62. Between 1962 and 1968, preventative type spraying was carried out on a three-year rotation basis. In 1968 a trapping procedure using micro­ scope slides was initiated to detect the aphid's presence in high value roadside stands of host fir. ( Rauschenberger and Lambert, 1968) . The present trapping methods have stemmed from this initial trial on Mount Mitchell State Park.

The protection area on Mount Mitchell State Park consists of approxi­ mately 300 acres along a 2. 5 mile access road between the Blue Ridge Parkway and the crest of the mountain ( Fig. 5). Protection area status is also applied to a walking trail near the summit.

A total of 300 microscope slide traps were placed in the protection area during September, 19 69. Three slide traps were attached to each of 100 host fir trees scattered throughout the designated area. The slide traps were collected two weeks later and examined microscopically for evidence of aphid activity.

- 6 - GREAT SMOKY MOUNTAINS NATIONAL PARK

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Fig. 4 Location of balsam woolly aphid infestations and protection areas on the Great Smoky Mountains National Park - 1969. I I MOUNT MITCHELL STATE PARK), I

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Fig. 5 Balsam woolly aphid protection area and infestation within and on Mount Mitchell State Park, North Carolina - 1969. A total of six traps revealed motile nymphs of the balsam woolly aphid. Four of these positive traps were ones which had been set consecutively in the same vicinity. An intensive ground check of the suspect area, which was located along the walking trail south­ east of the Mount Mitchell tower, revealed a very light infestation on the boundary of the protection area. Mature aphid adults were observed in the crown portion of several trees. Due to the extreme lightness of the infestation, no mortality is likely to occur during 1970 within the protection boundary.

Two other trap locations revealed a single motile nymph each. Inten­ sive ground checks within the protection area failed to reveal any established infestations. It is believed that these traps captured wind borne nymphs from nearby known infestations outside the boundary.

Balsam Mountains - The aerial survey of the Balsam Mountains was carried out in May 1969 ( Fig. 6). The survey indicated that the three­ spot infestations on Jones Knob detected in 1968 have converged. Ground checks revealed that there is presently one large spot encompassing approximately 25 acres.

Ground checking of two dying trees detected from the air on Lickstone Ridge in the Balsam Mountains revealed a 25-tree aphid infestation, Close to this spot, on the same ridge, another 25 tree spot containing green infested trees was detected as a result of a report by a biological technician of the Southeastern Forest Experiment Station working in the area.

A total of 186 microscope slide traps were placed in fir stands designated as protection areas along the Blue Ridge Parkway between John Rock Overlook and Cranberry Ridge Overlook. The trapping interval through this protection area varied due to the scattered nature of the fir stands. Traps were placed in the field during September 19 69 by personnel of the Blue Ridge Parkway and collected 14 days later. Microscopic exami­ nation of the slides by entomologists of the Division of Forest Pest Control failed to reveal any aphid activity.

Roan Mountain - An aerial survey conducted during May 1969, over Roan Mountain did not reveal any new areas of aphid-caused mortality. Established infestations, however, continue to thrive with additional mortality evident (Fig. 7 ) .

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Fig. 6 Location of balsam woolly aphid infestations and protection area in the Balsam Mountains - 1969. •

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Fig. 7 Location of balsam woolly aphid infestations and protection areas on Roan Mountain, North Carolina and Tennessee - 1969. One-hundred and ninety-two microscope slide traps were set in 64 locations within the protection area on Roan Mountain during September, 19 69. Collection of the slide traps two weeks later and subsequent microscopic examination revealed a single motile nymph on each of two slides from separate areas.

Intensive ground checking failed to reveal any aphid infestation within the protection areas.

Based on the proximity of known established infestations to the protection area, additional ground checks were performed over certain areas. As a result, two active infestations were detected within the protection boundary. The first infestation, approximately one acre in size, is located along the near the Roan Mountain Garden road. The second infestation encompasses approximately six acres and is located along the Roan Mountain Garden road three-quarters of a mile from the junction of Tennessee 143 and North Carolina 261.

Neither of these infestations were detected as a result of trapping. It is believed that the slide traps failed because they were not centered in the fir stands but placed too close to the access roads. Both infestations are located on the back side of the protection boundary away from the access roads.

The areas of infestation had been sprayed three years ago for prevention of the aphid. It is believed however that the spraying operation did not reach the back boundaries of the protection areas. As a check for aphid fecundity on trees which may or may not have been sprayed, a sample of infested bolts were collected and returned to the laboratory for rearing ( Fig. 8 ) . Results indicated that healthy populations existed on all bolts collected with eggs and motile nymphs successfully reared from them (Fig. 9 ).

Grandfather Mountain - An aerial survey during May 19 69 revealed no new areas of infestation other than those previously established. These infestations continue to grow in size ( Fig. 10 ) .

Mount Rogers National Recreational Area - An aerial survey over the 500 acres of host fir on Mount Rogers National Recreational Area in Virginia during September 19 69 ,. revealed a spot of four dying fir. Ground checks conducted on October 1, 1969 failed to reveal any aphid activity and cause of mortality remains unknown. Mount Rogers continues to remain the sole host fir area free of aphid infestation.

- 12 - Fig. 8 Laboratory rearing technique for the balsam woolly aphid. Water gravity fed into bolts provided optimum moisture essential to prolonged aphid survival.

Fig . 9 Bal sam woolly aphid adults on bark of sample bolt. NORTH CAROLINA

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Fig. 10 Location of balsam woolly aphid infestations on Grandfather Mountain, North Carolina - 1969. The central portion of the in Virginia which contains only scattered host fir was aerially surveyed on the same date as Mount Rogers. The only detectable sign of aphid visible from the air were old dead snags on and around .

The fir species present on the Shenandoah National Park differs from that of North Carolina and Tennessee. Although some dis­ agreements have been expressed, the species is generally re­ garded as A. balsamea Var. Jjl,anerolepts Fem. ( Little, 1953 ). This species has exhibited an overall capability to withstand aphid attack longer than the A .fraser i,,. It also exhibits symptoms of branch gouting much more readily than Fraser fir.

Ground checking of the Shenandoah National Park on September 30, 1969 revealed the same chronic type damage that has been occurring since the aphids discovery in 195 6 ( Mccambridge and Kowal, 195 7 ) . On Hawksbill Mountain and at Skyland Recreation area, host fir in all stages of dying and deterioration were evident.

It is estimated that since 1956, well over 40 percent of the fir in these two areas has either been lost or is presently infested to the point of imminent mortality. Living infested trees examined were all fourrl to exhibit some degree of gouting. In the more lightly infested trees, the gouting was generally less obvious and restricted to the crown portion.

In addition to the host fir occurring at Skyland and Hawksbill, widely scattered fir occurs elsewhere among the predominately oak type cover of the Park. A stand of planted fir at Big Meadows was found to be free of aphid attack. Elsewhere in the scattered fir between Big Meadows and StonyMan Overlook , the aphid follows a hit and miss pattern. Single trees as well as groups seem to be equally susceptible to attack.

Linyille River Forestry Facility. Crossnore. North Carolina - Approxi­ mately 300 Fraser fir were planted at the Linville River Forestry Facility during 1968 and early 1969 to serve as future seed trees. The trees ranged from two to seven feet in height and were five to twelve years of age. At the request of State personnel, entomologists of Forest Pest Control carried out a detection survey during 19 69 to detect any aphid activity in this high value area.

- 16 - Two microscope slide traps were placed at the base of every third tree ( 100 tree total ) in the orchard during September 1969. The two microscope slide traps were attached to each side of a "T" stake driven in the grourrl next to each sample tree. The trap on one side was positioned next to the tree bole and the other trap on the opposite side of the "T" was positioned under the outer periphery of the bottom branches.

At the time of trap placement, sample trees were given a cursory exam­ ination for aphid activity. As a result of these examinations, four trees were found to be lightly infested. One of the trees exhibited symptoms of gouting indicating that the attack had been initiated prior to trans­ planting.

Four additional trees became suspect as a result of trapping. Although trash and debris on the low traps rendered reading difficult, four suspected motile crawlers were detected on four separate traps.

Based on the results of this evaluation, the fir seed trees at Crossnore are considered light to moderately infested by the balsam woolly aphid.

DISCUSSION

In the 1969 evaluation of the balsam woolly aphid, primary emphasis was placed on the establishment of protection areas, i.e •. , that portion of the resource which in addition to being threatened, was also accessible and could be saved. The 1969 aerial sketch map portion of the survey accompanied by limited ground checking was, as in years past, used only to determine the general status and trend of the aphid. Although an accurate tally of all actively infested fir in inaccessible areas might be desirable, the time and economics of such an endeavor would be imprac­ tical due to the fact that no satisfactory methods of control is presently available for such areas. Rather than a survey to determine actively infested trees, the Division of Forest Pest Control proposes to conduct a damage appraisal survey in 19 70 to determine overall losses to date. The survey, which is proposed to take place on a three to five year interval hereafter will utilize aerial photographic procedures combined with ground sampling.

The development of improved survey techniques and equipment now renders an appraisal survey of losses a practical and useful tool. The loss figure acquired will permit an ov srall look at the aphids cumulative damage and indirectly provides a basis to predict the future potential for damage by the balsam woolly aphid.

- 17 - SUMMARY

1. Emphasis was placed during 1969 on establishment of protection areas where control, if deemed necessary, could be carried out. Three infestations worthy of control considerations were detected. Two are located on the Roan Mountain of the Toecane Ranger District, Nantahala National Forest and the third in fir seed trees at the Linville River Forestry Facility at Crossnore, North Carolina. Damage in the form of branch flagging, decreased tree vigor and possible mortality can be expected in these areas if control actions are not taken in 1970.

2. A very light infestation of balsam woolly aphid was detected on the boundary of the protection area on Mount Mitchell State Park in North Carolina. No mortality or heavy damage is expected to result in 1970 due to the lightness of infestation. Control actions to save the presently infested trees can be delayed until at least 1971.

3. The balsam woolly aphid in remote, inaccessible areas continues to cause widespread damage. New infestations were detected during 19 69 in the Balsam Mountains and the Great Smoky Mountains National Park. Established infestations elsewhere continue to grow in size.

4. Mount Rogers National Recreational Area in Virginia continues to remain free of aphid infestations. It is the last major host fir area in Virginia, Tennessee and North Carolina to remain so.

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- 18 - Revised 3/20/70

5. On those infested areas where damage and/or mortality is imminent and where land managers deem the resource worthy of control measures, the following procedures are recommended: All trees known to be infested and any in the immediate surrounding area suspected of being infested should be sprayed with a one-eighth percent Lindane emulsion in a water carrier. The finished spray is prepared by mixing five pints of 20 percent emulsifiable concentrate Lindane in 100 gallons of water. The entire trees must be completely covered with the spray for adequate control.

- CAUTION -

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 -- and 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.

-18a- 6. The Division of Forest Pest Control will conduct another evaluation of the balsam woolly aphid in 1970. Depending upon financing and manpower, it will include an appraisal of aphid caused losses throughout the Southern Appalachians.

LITERATURE CITED

Little, E. L. , 1953, Check list of native and naturalized trees of the ( Including Alaska ) . U.S. Forest Service, Agr. Handbook 41. 472 pp.

McCambridge, W,F. andR.J. Kowal, 1957. Forest insect conditions in the southeast during 1956. U.S. Forest Service, Southeastern Forest Experiment Station Paper 76, 7 pp.

Rauschenberger, J.L. andH.L. Lambert, 1968. Status of the balsam woolly aphid in the Southern Appalachians- 1967. USDA, USFS, SA, S &PF, Div. FPC, Asheville, N. C. Report No. 68-1-17.

Speers, C. F. 1958. The balsam woolly aphid in the Southeast. J. Forestry 56 ( 7 ) : 515.

ADDITIONAL SELECTED REFERENCES

Amman, Gene D. 1963. Seasonal biology of the balsam woolly aphid on Mt. Mitchell, N.C. J.E. on Entomol. 55 (1) : 96-98.

Balch, R. E. , 1952. Studies of the balsam woolly aphid, Adelges piceae Ratz. ( Homoptera: phyloxeridae) and its effects on balsam fir, Abies balsamea ( L.) Mill. , Canadian Department of Agriculture. Ottawa. 76 pp,

Ciesla, W. M. and W. D. Buchanan. 1962. Biological evaluation of balsam woolly aphid, Roan Mountain Gardens, Toecane Ranger District, Pisgah National Forest- North Carolina. USDA, USFS, Div. S&PF, Atlanta, Georgia. Report No. 62-93.

Ciesla, W.M., H.L. LambertandR.T. Franklin. 1963. The status of the balsam woolly aphid in North Carolina and Tennessee. USDA, USFS, SA, S&.PF, Div. FPC, Asheville, N.C. Report No. 1-11-63.

- 19 - Ciesla, W. M., H. L. Lambert and R. T. Franklin. 1965. Status of the balsam woolly aphid in North Carolina and Tennessee - 19 64. USDA, USFS, SA, S&PF, Div. FPC, Asheville, N.C. Report 65-1-1.

Lambert, H.L. and W.M. Ciesla, 1967. Status of the balsam woolly aphid in North Carolina and Tennessee- 1965. USDA, USFS, SA, S&PF, Div. FPC, Asheville, N.C. Report 66-1-1.

Lambert, H. L. and W. M. Ciesla. 1967. Status of the balsam woolly aphid in the Southern Appalachians- 1966. USDA, USFS, SA, S&PF, Div. FPC, Asheville, N. C. Report No. 67-1-3.

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