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Forest Health Conditions in the South

Summer, 2002

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Conditions in Brief

Status of Forest Insect pests

• Gypsy Moth
• Southern Pine Beetle
• Pine Engraver Beetles
• Black turpentine Beetle
• Hemlock Woolly Adelgid
• Balsam Woolly Adelgid
• Forest Tent Caterpillar
• Pink Hibiscus Mealybug
• Locust Leafminer
• Red Oak Borer
• Juniper Budworm
• Grasshoppers
• Fall webworm

Status of Forest Disease Pests

• Annosum root disease
• Fusiform Rust
• Dogwood Anthracnose
• Hypoxylon Canker of Oak
• Oak Decline
• Oak Wilt
• White Pine Blister Rust

Status of Forest Tree Nursery and Seed Orchard Pests

Status of Other Problems

• Beavers
• Air Pollution

Acknowledgements and Links to State Forestry Agency Web Sites

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Conditions in Brief

Another year of severe drought throughout much of the region has set the stage for compounded losses to a variety of forest and tree stressors. The most recent data from the National Oceanic and Atmospheric Administration show the drought in the South is concentrated in the east, with the piedmont of Georgia, South Carolina, North Carolina, and the coastal plain of Virginia most severely affected: (http://www.cpc.noaa.gov/products/analysis_monitoring/regional_monitoring/palmer.gif)

(NOTE: The linked map above is updated weekly. Depending on weather changes, it might not be consistent with the above narrative) 

While this area includes several forest types, it is perhaps best known for its large concentration of loblolly pine, the main distribution of which coincides remarkably with areas of severe and extreme drought conditions. Foresters are therefore especially on guard for secondary pests of yellow pine (such as pine engraver beetles and turpentine beetles) that exploit trees weakened by these extended dry conditions. Other tree species and pests are also of concern. For example, Hypoxylon canker of oak, caused by a facultative fungus, is typically most destructive during and immediately following such dry periods.

Nevertheless, the drought helps to retard development and spread of some conditions (such as anthracnose diseases and damping off of forest trees in nurseries) that thrive during prolonged cool and moist conditions.

By September, tropical storms Hanna and Isidore had settled over the eastern South for several days, soaking the area with rain. While this weather system helped to recharge some reservoirs, it occurred at the end of the growing season and did little to replenish badly depleted ground water supplies. At this writing, the NOAA Climate Prediction Center forecasts possible major drought relief through November for much of the eastern South. http://www.cpc.ncep.noaa.gov/products/expert_assessment/seasonal_drought.html

Though limited in its outbreak range, southern pine beetle (SPB) is very active in the piedmont, with South Carolina suffering its worst outbreak on record. The epidemic in the mountains has sharply subsided and has collapsed in Kentucky.  Activity in the western South is minimal to non-existent.

Gypsy moth activity was down dramatically from 2001, and surveys predict a mild defoliation season for next year.

 

Status of Forest Insect Pests

Gypsy Moth

Gypsy moth (Lymantria dispar) defoliation in Virginia in 2002 declined roughly 88% from last year (approximately 55,000 acres versus more than 440,000 in 2001).  (http://state.vipnet.org/dof/resinfo/ri-gypsy-moth-02-index.htm). The defoliation reduction resulted from a combination of factors including adverse weather during egg hatch, larval disease, and effective cooperative suppression efforts.  Central mountain counties were most significantly impacted, both in acres and severity. Egg mass surveys suggest the possibility of heavy defoliation in 2003 in some of these areas. Elsewhere in Virginia, activity was little changed from 2001. Local infestations occurred throughout the piedmont into the coastal plain. Surveys indicate that defoliation in these areas is possible in 2003, but that extensive defoliation is unlikely. http://fhpr8.srs.fs.fed.us/idotis/insects/gm.html

Southern Pine Beetle

Southern pine beetle (Dendroctonus frontalis) populations are concentrated in the eastern South, with activity diminishing toward the western Gulf States. Texas, Louisiana, Arkansas and Oklahoma reported no activity. To date, 156 counties are in outbreak status. An estimated $346 million dollars in timber has been lost in over 46,000 infestations.

In South Carolina, the long-term impacts of the severe multi-year infestations are being felt in earnest. In the worst SPB outbreak in the state’s history, the South Carolina Forestry Commission estimates that over the last five years, 27 million trees have been killed, at a value of $350 million. Over half of all spots reported in the South for the summer of 2002 occurred in South Carolina. There is no sign of the Palmetto State outbreak diminishing, with some of the heaviest losses developing along the North Carolina border.

In Eastern Kentucky, so extensive is the loss of yellow pine that the forest ecosystem is significantly changed for several decades to come. Happily, the outbreak in Kentucky collapsed this summer, but unfortunately this was due in large part to host depletion. Kentucky federal land managers are further alarmed by two hazards posed by large areas of dead trees – wildfire fuel and hazardous tree proliferation.  In years past, such trees would have been removed through salvage projects, but objections by individuals and groups, compounded by poor markets for wood, have precluded such operations in this latest outbreak. Like other parts of the country, the southern Appalachians are being affected by the ever-expanding wildland-urban interface that further complicates land management activities adjacent to population centers.

In North Carolina, the southern pine beetle situation is mixed. Dramatic losses witnessed in recent years in the higher mountain elevations have tapered off sharply, but damage has increased proportionately in the piedmont, especially along the South Carolina border.

In Virginia and Tennessee, SPB populations are down sharply, but because of the drought there is an exceptionally high incidence of Ips beetles, especially in the mountains of Virginia (see “Pine Engraver Beetles” below).

At this writing, several southern state forestry agencies are conducting formal, end-of-summer SPB surveys. This table shows preliminary data. Finalized statistics and an outbreak map will be available in the Annual 2002 Pest Conditions Report available on the web around February 1, 2003.

http://fhpr8.srs.fs.fed.us/idotis/insects/spb.html

 

Pine Engraver Beetles

All three common species of Ips pine engraver beetles (Ips avulsus, Ips grandicollis, and Ips calligraphus) are very active in dry areas of the South. While normally secondary pests preferring to attack weakened trees, these insects are capable of reaching more aggressive primary pest status when large areas of hosts are stressed (as with the current drought). In some cases, the engravers are found in association with southern pine beetle. The Commonwealth of Virginia reports a very high incidence of Ips beetles, especially in the mountains and on the drier, south-facing slopes.

(http://fhpr8.srs.fs.fed.us/idotis/insects/ipsengrv.html)

Black Turpentine Beetle

Much like pine engraver beetles, the black turpentine beetle (Dendroctonus terebrans) prefers to attack stressed, weakened trees. In combination with the drought, stands stressed by logging injury, soil compaction, and wildfire are especially vulnerable. When populations of turpentine beetles often increase significantly in damaged stands, they are sometime capable of achieving primary pest status (i.e., successfully attacking trees with no overt damage or evident susceptibility). Because of the drought, there is an inordinately high incidence of turpentine beetles, especially in the extreme eastern South.

(http://fhpr8.srs.fs.fed.us/idotis/insects/blkturpb.html)

Hemlock Woolly Adelgid

Mortality in the Southeast caused by the hemlock woolly adelgid has been aggravated by the extended drought that further stresses infested trees. To date, adelgid infestations are confirmed in 45 Virginia counties, 23 in North Carolina, 3 in Tennessee, one in Georgia and one in South Carolina. (see map).

http://fhpr8.srs.fs.fed.us/pubs/pestalrt/hwa/hwa.htm

Balsam Woolly Adelgid

The summer of 2002 was another bad one for the balsam woolly adelgid, with populations high in all infested areas. Nevertheless, there is an abundance of uninfested or lightly infested regeneration. Many observers falsely believe this portends well for the future. In fact, these trees will almost certainly become heavily infested as they mature.

http://fhpr8.srs.fs.fed.us/idotis/insects/bwa.html

Forest Tent Caterpillar

The South Carolina Forestry Commission reports significant forest tent caterpillar (Malacosoma disstria) defoliation of bottomland hardwoods in the upper coastal plain. Pure stands of gum suffered the worst defoliation, with up to 100% of foliage lost. Other bottomland hardwood species were also affected with some showing 50% or more of leaves eaten by the caterpillars. Affected river basins included the Congaree, Pee Dee, Little Pee Dee, and the Santee.

(http://fhpr8.srs.fs.fed.us/idotis/insects/fortent.html)

Pink Hibiscus Mealybug

The pink hibiscus mealybug (Maconellicoccus hirsutus) is a serious pest of over 200 plant species. In recent years, the insect has spread throughout much of the Caribbean and into northern South America. Most alarming was the discovery of the pest in South Florida in June. In response, the Florida Department of Agriculture has initiated an aggressive survey and biological control program. Entomologists are releasing two predator insect species of the pink hibiscus mealybug -- Anagyrus kamali and Gyranusoidea indica – two gnat-sized wasps reared in a USDA laboratory in Puerto Rico.

(http://www.aphis.usda.gov/oa/pubs/phmpaler.pdf)

Locust Leafminer

The locust leafminer (Odontata dorsalis) has been especially active this summer, with damage becoming evident earlier than usual. Discoloration is most obvious along the Appalachian chain, with the Blue Ridge Parkway being especially hard hit. This has prompted many public inquiries to the Park Service, Forest Service, state forestry agencies and even elected representatives. While damage is normally of little consequence other than aesthetic, very heavy infestations during drought periods can contribute to vigor reduction.

( http://fhpr8.srs.fs.fed.us/idotis/insects/loclfmnr.html )

Red Oak Borer

A massive red oak borer (Enaphalodes rufulus) outbreak in the Arkansas-Missouri Ozark Mountains has caused an estimated $1 billion in lost timber.  The outbreak began in 1999, and the borer population has since achieved a remarkably high density. Ordinarily, the trees are able to mound a defense against the typical invasion of 3-4 attacks, but with infestations rates up to ten times normal, defensive mechanisms are overwhelmed.  Most entomologists investigating the phenomenon credit a combination of factors for weakening the trees, thereby increasing vulnerability to attack. These include advanced age, high tree densities, and the extended drought.

( http://www.newswise.com/articles/2002/6/BORER.UAR.html )

Juniper Budworm

During the spring and early summer of 2002, an unusual outbreak of the juniper budworm (Cudonigera houstonana) occurred in central Texas on ashe juniper. While this tree species is of little commercial importance, it nonetheless fills an important ecological niche. It serves as an important source of nesting material for the endangered golden-cheeked warbler.

( http://txforestservice.tamu.edu/forestry_education/insects_and_diseases/insects/juniper_budworm.html )

 Grasshoppers

In central Oklahoma, a large area of the "Crosstimbers" (post oak-blackjack Woodlands) was defoliated this year by grasshoppers. While no formal survey was conducted, this area comprises roughly eight-  to  ten-thousand acres.

Fall webworm

In Oklahoma, fall webworm populations are building this year with the cooler, relatively humid summer. In the eastern South, the dry, hot weather has generated the opposite condition, with webworm populations decidedly lower than normal.

( http://fhpr8.srs.fs.fed.us/idotis/insects/fallweb.html )

 

Status of Forest Disease Pests

Annosum Root Disease

A South Carolina Forestry Commission survey showed that annosum root disease has been increasing in severity and occurrence for several years. Losses average 2 cords per acre of recorded damage. A total of 31 counties had some level of apparent annosum-caused loss. Total acreage affected was 53,850, and direct loss was placed at $1.94 million.

( http://fhpr8.srs.fs.fed.us/idotis/diseases/annosus.html )

Fusiform Rust

Fusiform rust doubtless continues to be the most significant disease of loblolly and slash pine in the South, although there are no known survey reports generated this summer. Anecdotal reports suggest that the incidence of main stem infection is decreasing, and that the disease is more and more confined to branches where the impact is minimized. The Resistance Screening Center in Asheville has been very busy screening seed lots for fusiform rust resistance.

( http://fhpr8.srs.fs.fed.us/pubs/rsc/rsc_brochure.html )

Dogwood Anthracnose

Dogwood anthracnose is now found generally throughout the range of the host in the South (see map 50K). The very dry conditions in the eastern part of the region have served to inhibit spread during the summer of 2002. Nevertheless, the disease continues to intensify within the generally infested area. North Carolina reports a notable decline in mountain county mortality attributable to dogwood anthracnose because of the extended drought that inhibits development of the disease. As of October 1, 2002, the confirmed infection state/county statistics for dogwood anthracnose in the South were as follows:

 

( http://fhpr8.srs.fs.fed.us/pubs/dogwood/r8%2Dpr26/dwr8pr26%5Fpdf1.htm )

Hypoxylon Canker on Oak

This summer has seen a large number of reports of hypoxylon canker (caused by Hypoxylon spp.) on oak species and other species in the eastern South, especially in the Appalachians. Damage seems most severe on south-facing slopes and on shallow, rocky sites stressed by drought. Hypoxylon canker often proliferates under conditions that stress its hosts. The North Carolina State Forest Service reports not only a much higher incidence of the disease on forest trees, but on shade trees as well.

( http://fhpr8.srs.fs.fed.us/idotis/diseases/hypox.html )

Oak Decline

The oak resource in the southern United States is significant. Approximately two-thirds of the hardwood forest is classified as upland hardwood, where a malady known as “oak decline” is prevalent.

Oak decline has been reported in the United States for over 130 years. It is a syndrome that involves the interaction of predisposing factors such as climate, site quality, and tree age. Drought and insect defoliation escalate the condition. The severe drought of the past four years has seriously aggravated the condition both in the eastern South and the Arkansas Ozarks. In the Appalachians, tress on couth-facing slopes and rocky, shallow soils are most affected. Pests such as armillaria root disease and the two-lined chestnut borer, which are ordinarily non-aggressive pests on vigorous trees, successfully attack trees stressed by oak decline. Decline is characterized by a gradual. but progressive, dieback of the crown. Mortality typically results after several years, with mature overstory trees the most heavily afflicted.

( http://fhpr8.srs.fs.fed.us/pubs/oakpests/p49.html )

Oak Wilt

In Tennessee, oak wilt aerial survey flights over Lincoln, Franklin, Moore, and Marion Counties were negative this summer. At this writing, the State of North Carolina is finishing its 2002 oak wilt survey in the western part of the state. That information will be available on the Annual Conditions Report available here around February 1, 2003.

( http://fhpr8.srs.fs.fed.us/idotis/diseases/oakwilt%5Fpdf.html )

White Pine Blister Rust

White pine blister rust continues to be a disease of concern for North Carolina landowners and the North Carolina Forest Service. Areas of particular hazard are the northwestern mountains or a five county area ranging from Ashe to Yancey County. The disease can be particularly devastating to Christmas tree and ornamental growers, many of which are centered in the aforementioned area. The North Carolina Forest Service continues to review seedling applications for white pine seedlings and to screen or examine areas prior to planting. In 2002, 78 applications for over 300,000 white pines were reviewed. A total of 678 planted acres (and the area surrounding them) were examined to prevent the occurrence of this disease.

http://www.na.fs.fed.us/spfo/pubs/howtos/ht_white/white.htm

 

Status of Forest Tree Nursery and Seed Orchard Pests

Nurseries

A new nematode in the genus Longidorus (needle nematodes) was discoveredcausing a stunting of loblolly pine seedlings in a Georgia nursery. Laboratory tests have shown that slash and longleaf pines can also host the pest.

Despite the drought, damping-off continued to be one of the most significant problems of nurseries in the South.  Other diseases included Rhizoctonia root rot of Fraser fir, Phomopsis blight of cedar, etc. Feeding damage by Lygus bugs, mole crickets, cutworms, and grubs also caused sporadic problems in tree nurseries. An invasive sedge (Cyperus spp.) was one of the most significant nursery problems reported in the summer of 2002.

Seed orchards

Besides the normal incidents of seed and cone insect pests, southern seed orchard managers in the summer of 2002 had to deal with a high incidence of drought-caused mortality, especially in eastern seed orchards. Seed orchard trees are among the most valuable individual trees propagated. Thus, these losses are especially severe.

 

 Status of Other Problems

Beavers

The South Carolina Forestry Commission reports significant beaver damage to forest trees throughout much of the State. Forty-five counties reported at least some losses. Most damage was to hardwoods, and the Commission estimates 4,475 acres are affected, representing 80,550 cords valued at nearly $1.5 million. Nevertheless, the mortality due to beaver activity was less than half of 2001 levels, apparently due to the drought and a lack of water for the animals to impound.

Air Pollution

The impact of air pollution on southern forests is difficult to measure and subject to some controversy. Nevertheless, its affect on long distance visibility in the Southern Appalachians is well documented. The National Park Service reports that in the Shenandoah National Park, average visibility declined 60 percent between 1948 and 1983, with an 80 percent decrease in summer months and a 40 percent decrease in winter months. The summer of 2002 has certainly been another season of sharply decreased visibility in the Appalachians owing to man-caused haze. Additional adverse impacts have been demonstrated on aquatic ecosystems, soils, and via direct impact on sensitive plants. Park Service researchers write that there is no indication that the severity of air pollution is likely to lessen in the foreseeable future.

(http://www.shenandoah.national-park.com/nat.htm#air)

Acknowledgements and Links to
State Forestry Agency Web Sites

The Southern Region, Digital Arborist, Forest Health Protection Unit appreciates the assistance of our state forestry agency partners in preparing this report. Please click on states below for more detailed, state-specific information about forest and shade tree pests and programs:

[ AL | AR | FL | GA | KY | LA | MS | NC | OK | TN | TX | VA ]