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2000 Forest Insect and Disease
Conditions for the Southern Region


Note: bold hypertext links within the narratives (e.g., Dogwood Anthracnose) will take visitors to the on-line publication, The Health of Southern Forests that displays additional graphics and discusses the biology and southern history of the causal agent in more detail. Not all causal agents are linked. Non-bolded links provide for within-document navigation.

Most Significant Conditions in Brief

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In the year 2000, weather again profoundly influenced the course of events in southern forests. Some of the most severe extended dry periods in recent memory exacerbated a host of pest conditions ranging from pine bark beetles to annosum root disease to oak decline. The drought aggravated some of the heaviest infestations red oak borer infestations ever recorded in Arkansas Ozarks.The dry weather also inhibited development of the Entomophaga fungus which helped to hold gypsy moth populations in check last year. Consequently, there was a resurgence of gypsy moth defoliation in 2000.  Paradoxically, the drought helped retard certain fungus diseases such as dogwood anthracnose and damping off in nurseries.

Southern pine beetle activity increased dramatically across much of the region, with Alabama, South Carolina, Florida, Georgia, and Virginia all experiencing at least triple the losses recorded in 1999.

Status of Forest Insects

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Insects: Native

Black turpentine beetle,
Dendroctonus terebrans

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Regionwide

Host(s): Loblolly pine, longleaf pine, slash pine, shortleaf pine

Again in 2000, summer drought throughout the southern states resulted in higher-than-normal black turpentine beetle activity.  This insect is most evident in trees stressed by drought, logging injury, root compaction, and similar disturbance.  High activity was reported in Florida, Louisiana, North Carolina, South Carolina, Tennessee , and Texas.

Buck moth,
Hemileuca maia

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Louisiana and Virginia

Host(s): Live oak and other hardwoods

Buck moth defoliation of live oak has been a problem in New Orleans for a number of years.  It continues to be locally abundant in the city and of particular concern in the Federal Historic Districts.  Defoliation was widespread in 2000 and moth populations have been on the increase for the past 3 years.  Pheromone trapping of adult moths is being used to identify hot spots for further evaluation.  In Virginia, populations routinely fluctuate considerably, and were at locally high densities in 2000.

Fall cankerworm,
Alsophila pometeria

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North Carolina and Virginia

Host(s): Various oak species

In both Virginia and North Carolina, local outbreaks declined.  In recent years, the City of Charlotte, North Carolina sustained heavy defoliation requiring direct control, but this year, population levels were very low, and no control was deemed necessary.  Fall cankerworm populations declined to the lowest recorded levels in a decade in northeast Tennessee in 2000.

Forest tent caterpillar,
Malacosoma disstria

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Louisiana, North Carolina, South Carolina and Texas

Host(s): Tupelo gum, upland hardwoods

Defoliation occurred on 46,000 acres of forested wetlands in Ascension, Livingston, St. James and St. John Parishes in southeastern Louisiana. Defoliation was severe on 32,000 acres resulting in growth reduction of approximately 50% or radial growth.  In South Carolina, 257,610 acres were defoliated. Damage was worst in the Conagree, Santee, Pee Dee, and Wacamaw River Basins.  Sixty thousand acres were completely defoliated along the Roanoke River in North Carolina. In Texas, local infestations of the forest tent caterpillar occurred, but no serious outbreaks developed.

Nantucket pine tip moth,
Rhyacionia frustrana

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Regionwide

Host(s): Loblolly pine, shortleaf pine

Tip moth problems were most pronounced in Virginia and North Carolina.  North Carolina infestations were worsened by unusually dry weather. In Virginia, the tip moth seems to have evolved into a persistent problem in the coastal plain and piedmont. South Carolina populations declined slightly from 1999.  Tip moth populations increased in southwest Tennessee and on the Cumberland Plateau on planted loblolly pine in 2000.  Some plantations showed over 50% infestation.  In Texas, tip moth infestations remained static (about 75 percent tips infested).  Infestations increased markedly in July-September after the drought took hold.

Pine colaspis beetle,
Colaspis pini

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Regionwide

Hosts: Southern pines

Colaspis beetle damage was reported on 9,000 acres in Carroll and Hemphill Counties in Mississippi in 2000.  This beetle also caused significant, but localized defoliation to pine plantations in central Louisiana.  In Texas, an area of about 3,800 acres in Hardin and Jefferson counties was defoliated.

Pine engraver beetle,
Ips calligraphus, I. grandicollis, I. avulsus

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Regionwide

Host(s): Loblolly pine, shortleaf pine, slash pine

Drought conditions during the growing season across much of the South led to another year of higher-than-normal levels of Ips pine engraver beetle activity. Small groups of Ips-killed trees were scattered throughout the forest stands, consequently losses are difficult to quantify.  In the Gulf coastal states, activity increased into late summer and early fall. In Arkansas Ips mortality was heavy, and scattered as usual, except in CRP plantations in the Delta where fairly large groups of trees were killed. Many urban pines were also killed. Louisiana surveys in 2000 found 75 multiple-tree infestations. In addition, thousands of small spots and single trees were scattered statewide. Engraver damage was judged to be comparable to southern pine beetle damage in most years. Mississippi reported a great deal of damage in younger plantations, especially into the fall. Ips activity was high for a second straight year in Texas in 2000, particularly on the western edge of the piney woods region. A survey of 2 million acres in 4 counties estimated over $1.8 million in timber loss, mostly in sawtimber stands.  In the Carolinas and Florida, drought predisposed trees to unusually heavy pine engraver losses.  In South Carolina, Ips spots sometimes numbered 500 trees. Infestations were often located in overstocked, overmature trees.  Frequently, South Carolina Ips, black turpentine beetle, and southern pine beetle infestations were found together.  Florida Ips losses were exceptionally high compared to the norm.  Here too, damage was typically associated with tress being stressed by a variety of factors ranging from overstocking to overmaturity to root compaction.

Pine sawflies,
Neodiprion sp., Diprion sp.

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Arkansas, Florida, Louisiana, North Carolina, Texas, Virginia

Host(s): Southern pines

Several species of the pine sawfly were active across the South in 2000.  Defoliation by the loblolly pine sawfly (Neodiprion taedae linearis) occurred in 2 areas in Arkansas, although it was light. In Louisiana, the loblolly pine sawfly outbreak in the north-central part of the state dramatically subsided  Populations of the loblolly pine sawfly declined in west and middle Tennessee.  In Virginia, the loblolly pine sawfly was evident at various locations throughout the central coastal plain and piedmont.  Infestations of the blackheaded pine sawfly (N. excitans) declined to low levels in east Texas counties.  In Florida, the redheaded pine sawfly (N. lecontei) caused severe (>75%) defoliation in relatively small, but numerous scattered areas in 2000.  Overall, Florida activity was more evident than in any time over the past 10 years.  Damage was most pronounced in young (<15 years) longleaf and slash pine plantations.  Because of the drought that exacerbated sawfly defoliation impact, one industrial landowner aerially treated a large plantation. In North Carolina, this same pest species persisted in the western part of the state, but there was no noticeable population change over last year.  Populations of the red-headed pine sawfly increased on Virginia pine Christmas trees in north-central Tennessee and on loblolly pines in west Tennessee.

Red oak borer,
Enaphalodes rufulus

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Arkansas

Host(s): Northern red oak, black oak

Red oak borer attacks increased dramatically in 2000 in north central Arkansas in association with severe drought (for the third consecutive year). Populations are now at unprecedented levels. Damage was evident and contributed to drought-related mortality in red oaks. Degrade in lumber from attacked trees can lower product values.

Reproduction weevils,
Hylobius pales, Pachylobius picivorous

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North Carolina, Texas

Host(s): Southern pines

Weevil activity remained low in Texas during 2000. This is probably because most plantings in 2000 were actually replantings of trees killed during the 1998-1999 drought (the delay for replanting ameliorated the risk of weevil damage).  Reproduction weevil activity in North Carolina remained light to moderate throughout the state.

Southern pine beetle,
Dendroctonus frontalis

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Regionwide

Host(s): Loblolly pine, shortleaf pine, slash pine, longleaf pine, Virginia pine, eastern white pine [return]

In 2000, southern pine beetle (SPB) populations rapidly escalated in the Southern Region.  The mild winter and extended drought exacerbated the SPB situation by providing optimum habitat for this native forest pest.  The outbreak currently covered portions of Alabama, Florida, Georgia, Kentucky, Mississippi, North Carolina, South Carolina, Tennessee, and Virginia on federal, State and private ownerships (map showing southern pine beetle outbreak status by county -- text-only data). It will likely go down as one of the largest outbreaks in history (chart showing SPB infestations for 1999-2000. Also see table below). On the contrary there was not even a single SPB infestation in the entire states of Louisiana, Texas, Arkansas and Oklahoma.  Compared to 1999, the number of SPB infestations in 2000 increased by over three times (13,036 spots to 57,175 spots) and the number affected acres increased by almost 2 times (12,342,415 acres to 7,055,000 acres). 

The most heavily impacted area was the state of Alabama.  There were over 25,000 infestations statewide and 58 of Alabama's 67 counties experienced outbreak level populations.  Due to depressed timber markets, drought and increasing number of SPB spots, only 40 percent of of the spots were controlled.  Many of the spots were controlled using cut and leave.  The northwestern part of the state was most affected with 5 counties detecting more than 1,000 spots each.  The National Forests in Alabama (especially the Bankhead and Oakmulgee Ranger Districts) were heavily impacted.  Over 8,000 acres of pines were killed on the Sipsey Wilderness alone.

The southern Appalachian Mountain area in Georgia, Tennessee, North Carolina, Kentucky and Virginia was also devastated.  Periodically, SPB attacks hosts other than its favored southern yellow pines.  Such was the case in 2000 in the mountains where eastern white pine was commonly killed, and beetles actually attacked Norway spruce and eastern hemlock in western North Carolina.  The outbreak in southwestern and Virginia was the first in 25 years.  The losses were very very significant on the Daniel Boone National Forest in southern Kentucky.  The beetles killed between 75 to 90 percent of the habitat in the clusters of the red-cockaded woodpecker, a federally listed endangered species.  The beetle was in outbreak status in roughly the entire eastern half of Tennessee, as well as the counties bordering Mississippi.

In South Carolina, financial loses reached $40 million – the second worst year of financial loses on record.  The Piedmont area of the state experienced the highest losses.  In Georgia, 13 northern counties were in outbreak status. Infestations in the northern Atlanta metro area kept urban foresters and arborists busy. 

In Florida, SPB activity also reached record proportions. There were more infestations (1,172) in more counties (21), causing more dead trees (1.2 million) at a greater financial cost ($15.7 million) than ever previously recorded in the state.  Impact was exacerbated by severe drought that stressed the trees.  The urban-wildland interface outbreak in the Brooksville-Hernando County area was especially challenging to foresters and extension personnel.

Table 1. Southern Pine Beetle Infestations by State 1999 versus 2000

State

1999

2000

Percent
Difference

Alabama

4,743

26,407

456.76

Arkansas

-

-

0.00

Florida

220

1,172

432.73

Georgia

557

2,582

363.55

Louisiana

13

-

-100.00

Mississippi

380

809

112.89

N. Carolina

1,455

2,219

52.50

Oklahoma

-

-

0.00

S. Carolina

2,308

12,996

463.08

Tennessee

2,987

9,352

213.09

Texas

-

 -

0.00

Virginia

373

1,638

339.14

Totals

13,036

57,175

338.59


Texas leaf-cutting ant,
Atta texana

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Louisiana, Texas

Host(s): Southern pines and hardwoods

In 2000, localized defoliation of pine plantations occurred in east Texas and central Louisiana on sites with deep sandy soil. Populations of these ants remin fairly static from year-to-year. A new ant bait, Volcano, was given a special local need registration by the Texas Department of Agriculture last fall. A single application can eliminate an ant colony in as little as 4 weeks.

Variable oak leaf caterpillar,
Lochmaeus manteo

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Florida, Tennessee

Host(s):  Laurel oak

Thousands of acres across five counties were defoliated in Florida. While there was no evidence of mortality, the outbreak was a serious nuisance and generated many public inquiries to forestry and extension officials.  Variable oak leaf caterpillar defoliated over 900 acres of oak/hickory and oak/pine forests in southwest Tennessee in 2000.

 

Insects: Nonnative

Balsam woolly adelgid,
Adelges picea

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North Carolina, Tennessee, Virginia

Host(s):  Fraser fir

Fraser fir has a very limited range in the southern Appalachian Mountains and appears almost exclusively in pure stands on the highest mountain peaks or in combination with red spruce at somewhat lower elevations (map showing spruce/fir distribution).  Since the first introduction of the balsam woolly adelgid, approximately 64,700 acres of Fraser fir have been affected.  The insect attacks trees of all age classes, but prefers the older fir trees.  Adelgid populations were again high in 1999.

Gypsy moth (European),
Lymantria dispar

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Arkansas, Georgia, North Carolina, Tennessee, Virginia

Host(s): Hardwoods, especially oak species

In 2000, aerial surveys detected over 70,000 acres of defoliation by gypsy moth in Virginia (map showing gypsy moth defoliation area).  Due in part to drought, the effects of the an Entomoghaga maimaiga fungal outbreak subsided and gypsy moth populations rebounded throughout its eastern range.  Consequently, the potential for limited local area defoliation in Virginia is greater for next year than it was for 2000.

In 1998, North Carolina and Georgia, 23,000 acres in and around the town of Highlands, NC were treated as part of a gypsy moth eradication project.  Follow-up trapping showed very few moths and no treatment is planned there in 2001.

Tennessee lists three infested counties (Scott, Cumberland, and Sevier) all of which have ground eradication projects underway.  Two counties (Monroe and Campbell) showed noteworthy increases in trap catches, triggering heavier trapping grid densities in 2001.

In Arkansas, delimiting trapping was successful in eradicating gypsy moth from Carroll and Marion counties (no moths were caught in the 2000 trapping effort). In Newton County, 10 male moths were caught and another year of delimiting trapping is planned for 2001 in that county. In addition, an 80 square mile detection trapping block surrounding the delimiting trapping area to help define current infestation boundaries. No treatments are planned.

The Gypsy Moth Slow-the-Spread Pilot Project moved toward operational status in 1999.  Trapping and treatments were carried out in 8 states from North Carolina to Wisconsin.  Within the boundaries of the Southern Region, 9,090 acres were treated in eastern North Carolina and 24,640 acres in eastern and western Virginia.  Additional monitoring and treatment activities will be carried out in 2000.

Fiscal year 2000 was the first year that Congress provided full funding to the Forest Service for operational implementation of the strategy to slow the spread of the gypsy moth (STS).  The integration of STS into the USDA’s national policy for managing the gypsy moth will reduce spread rates of this non-native pest from a historical average of 13 miles per year to less than 5 miles per year.  The USDA (Forest Service and Animal Plant Health Inspection Service) and state partners located along the leading edge of gypsy moth populations cooperatively implement STS.

Currently the states of Michigan, Wisconsin, Illinois, Indiana, Ohio, West Virginia, Kentucky, Virginia and North Carolina are actively involved in STS and Minnesota and Iowa will join the program in the near future.  A band totaling approximately 56 million acres was brought under comprehensive management during 2000.  An additional 34 million acres behind the active management band were monitored less intensively to measure the programs effect on spread.

During 1999, STS state partners detected and delineated more than 100 distinct gypsy moth colonies within the STS area, which triggered treatment of 177,842 acres during the spring and summer of 2000.

STS state partners deployed 75,000 pheromone traps during 2000 to evaluate the effectiveness of the 2000 treatments, and to detect or delineate newly established colonies that may require treatment in 2001.

Hemlock woolly adelgid,
Adelges tsugae

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North Carolina and Virginia

Host(s):  Eastern and Carolina hemlock

This insect threatens the entire range of eastern hemlock, and is found throughout Virginia wherever hemlock is abundant with the exception of 6 counties in the southwestern portion of the state.  There are also six North Carolina counties infested.  Two new counties, Alamance and Alleghany, were added to the list in 2000 (map showing hemlock woolly adelgid occurrence by county -- text-only data).

Pink hibiscus mealybug,
Maconellicoccus hirsutus

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Puerto Rico, Virgin Islands

Host(s):  Hibiscus and many other species

The pink hibiscus mealybug (PHM) continued to spread in 2000, and has now reached over 25 Caribbean Islands.  It was detected in Puerto Rico in 1997, but has been confined to the eastern region.  Frequent monitoring surveys are conducted, assisted by the USDA Forest Service.  To date no infestations have been identified on the Caribbean National Forest.  It appears that parasitoids may have been introduced simultaneously with the mealybug, reducing the impacts in Puerto Rico.  With support from the USDA Forest Service and Animal and Plant Health Inspection Service, the Puerto Rico Department of Agriculture continues to rear and release parasitoids.  Surveys show that population reductions of 85-90 percent have been achieved at the parasite release sites.  An increase in populations of the predaceous ladybug, Cryptolaemus, has also served to reduce damage and limit the spread of the mealybug.  The PHM thus far has not been detected in Florida.


Status of Forest Diseases

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Diseases: Native

Annosus root disease,
Heterobasidion annosum

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Regionwide

Host(s): Southern pines

Localized mortality and growth loss occurred throughout the South in 2000 due to annosus root disease. (map showing annosus hazard ratings)  Alabama and Texas reported continuing localized losses, with the Texas infections occurring mostly in the northeast corner of the state.  In North Carolina, annosus root disease killed southern pine in scattered areas, and was also reported on coastal red cedar. Mountain sites in western North Carolina also saw pockets of mortality.  In South Carolina, annosus root disease was responsible for mortality across 5,000 acres of Conservation Reserve Program lands.  Impact was exacerbated by drought.

Fusiform rust,
Cronartium quercuum f. sp. fusiforme

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Regionwide

Host(s): Southern pines, especially loblolly and slash pines

Fusiform rust is the most damaging disease of loblolly and slash pine in the South. Other pine species may also be infected, but little damage or mortality occurs.  An estimated 13.8 million acres of loblolly and slash pine have at least 10 percent of the trees infected. Georgia is the most heavily impacted state, with 4.6 million acres (49 percent of host type) affected.  Texas surveys showed that the disease has declined during the past few years.  Exceptionally dry weather over much of the South over the last 2-3 years should have resulted in lower-than-normal levels of new infections in young pines.

Littleleaf disease,
Phytopthora cinnamomi

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Alabama, Georgia, Kentucky, North Carolina, South Carolina, Tennessee, and Virginia

Host(s): Loblolly and shortleaf pines

Littleleaf disease continues to cause growth loss and mortality across the Piedmont areas of the affected states.  Shortleaf pine is highly susceptible while loblolly pine is affected, but at a later age.  Many of the stands that were converted from shortleaf to loblolly to reduce the impact of this disease are now reaching their age of susceptibility.  These stands are often attacked by bark beetles once weakened by the root infection.

Oak wilt,
Ceratocystis fagacearum

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North Carolina, South Carolina, Tennessee, Texas

Host(s): Live and red oaks

Oak wilt continues to be a devastating tree killer in 60 counties in central Texas.  Urban, suburban and rural oaks are affected. Live oak is a premier shade tree species in the region and is highly valued for beauty, shade and wildlife benefits. The Texas Forest Service completed the 13th year of a cooperative suppression project. Since the project's inception, more than 2.4 million feet (>450 miles) of barrier trenches have been installed around 2,065 oak wilt infection centers in 34 counties.  Since its first confirmed appearance in South Carolina in 1998, oak wilt has now appeared in six additional counties (7 total).  In North Carolina, activity has also been increasing for the past two years. Surveys in 2000 showed that there are 33 active oak wilt infection centers involving 53 confirmed infected trees in five western North Carolina counties. This area has been documented as having active oak wilt since 1951.  In 2000, White and Putnam Counties in Tennessee were aerially surveyed to detect oak wilt activity;. no new infection centers were discovered.

Diseases: Nonnative

Beech bark disease,
Neonectria coccinea var. faginata

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North Carolina, Tennessee, Virginia

Host(s):  American beech

Beech bark disease was not found in any additional counties in 2000, but the disease continues to intensify within the currently affected areas (map showing beech bark disease occurence by county -- text-only data).  Beech bark disease was first reported in the Great Smoky Mountains National Park in 1994.  However, the first mortality in the South was reported as early as the mid-1980's in northern Virginia.  This is well outside the previous known distribution.  Tree mortality continues to intensify in Tennessee along the Appalachian Trail and in Blount, Cocke, and Sevier Counties within the Great Smoky Mountains National Park. The disease has intensified at a greater rate than predicted, and is spreading downslope toward the Cherokee National Forest.

Dutch elm disease,
Ophiostoma ulmi

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Regionwide

Host(s): American elm

Scattered, localized mortality continues to occur at low severity level in urban and wild populations of elm.

Diseases: Origin Unknown

Butternut canker,
Sirococcus clavigigenti-juglandacearum

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Regionwide

Host(s): Butternut

This disease has been in the South for at least 40 years (map showing butternut canker occurrence by county -- text-only data) and is believed to have killed 3 of every 4 butternuts in North Carolina and Virginia. The fungus kills trees of all ages. Butternut canker is expected to spread and kill most of the resource, including regeneration. The species will be replaced by other species on these sites (e.g., black walnut). It is too early to project the benefits of selection and breeding. However, trees exhibiting resistance have been found in Arkansas, North Carolina, Tennessee, Kentucky, and Virginia.

Dogwood anthracnose,
Discula destructiva

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Alabama, Georgia, Kentucky, North Carolina, South Carolina, Tennessee, Virginia

Host(s): Flowering dogwood

Dogwood anthracnose continues to intensify within its range, although the hot, dry summer weather in 2000 reduced its impact in some states.  The cool, wet fall and winter will likely increase the risk in 2001.  Three new counties with dogwood anthracnose infection in urban areas were reported in 2000:  They are:  Harrison County in Kentucky, Lincoln County in North Carolina, and Portsmouth County in Virginia. (map showing dogwood anthracnose occurrence by county -- text-only data)

Pitch canker,
Fusarium subglutinans f. sp. pini

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Regionwide

Host(s): Southern pines

Only scattered trees across the Region are infected, but impacts can be locally significant.  In Georgia, pitch canker continues to be associated with pine plantations near chicken houses.  The ammonia released from the brood houses creates conditions on the trees conducive to infection. The damage is usually confined to the area within the plantation nearest exhaust fans.  All species of pine (slash, longleaf, and loblolly) are affected.  Chicken houses are becoming a common sight throughout the coastal plain of Georgia.  Thus, problems with pitch canker are expected to increase there, especially during droughts.  Similar problems have been noted in North Carolina when chicken waste has been used as fertilizer in pine plantations.

Declines/Complexes

Oak decline, abiotic and biotic influences

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Regionwide

Host(s): Oaks, other hardwoods

The severe summer drought of 1998-1999 continued into 2000.  Oaks were particularly impacted in the Ozark and Ouachita Mountains of Arkansas where widespread red oak mortality occurred throughout the north-central part of the state.  Oak decline was also severe in the southern Appalachain Mountains, with North Carolina and Virginia incurring heavy losses on south-facing slopes.  Similarly, Tennessee noted increased loss of both red and white oak, with white oaks especially hard hit.  In Georgia, oak mortality was heaviest on rocky ridges and side slopes in the mountains.  Drought is just one component of oak decline, a syndrome resulting in dieback and mortality of dominant and co-dominant mature oaks.  Other causal factors are stressors, including frost, defoliation by insects (including the gypsy moth) and secondary pests such as Armillaria root disease and two-lined chestnut borer, and hypoxylon canker.  Oak decline and gypsy moth have been shown to interact: severe defoliation by gypsy moth can induce oak decline in previously unaffected areas; and, in areas of pre-existing oak decline, gypsy moth defoliation causes increased mortality.  Host, age and site conditions also play a role.  In the Ozark and Ouachita Mountain areas, an extremely high population of red oak borer is associated with oak decline and mortality (see Native Insects, Red oak borer).  Oak decline is on the rise in Tennessee, but at a lower rate of increase than in 1999. This syndrome is believed to have caused 2% mortality in some southwest Tennessee counties. Impact in 2000 was exacerbated by drought, which caused greatest impacts on dry, south-facing slopes. The syndrome is frequently associated with Hypoxylon canker, especially in western and middle Tennessee.


Seed Orchard Insects and Diseases

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Coneworms,
Dioryctria amatella, D. clarioralis, D. disclusa, D. merkeli

Regionwide

Host(s): Southern pines

Coneworms again caused approximately a 25 percent cone loss in untreated areas of a pine seed orchard in Texas in 2000.

Pitch canker,
Fusarium subglutinans f. sp. pini

Regionwide

Host(s): Southern pines

About 10 percent of the cone crop in the Texas state seed orchard was affected by pitch canker in 2000.

Seedbugs,
Leptoglossus corculus, Tetyra bipustata

Regionwide

Host(s): Southern pines

Seedbugs were abundant in untreated pine seed orchards in Texas in 2000, damaging about 24 percent of seed.

Southern cone gall midge,
Cecidomyia bisitosa

Florida

Host(s): Slash pine

An unusual outbreak of this extremely infrequent pest problem continued to cause losses in one industrial seed orchard in Nassau County for the second year in a row.  Among susceptible clones examined, average infestation rates of 1st year conelets ranged from 19-65%.  Individual ramets exhibited infestation rates of 0-100%.  Most infested conelets fail to reach maturity or yield any viable seed at harvest.  The estimated value of seed lost in 2000 was $4,600.

Southern cone rust,
Cronartium strobilinum

Florida

Host(s): Slash pine

Cone rust continued to cause problems in several industrially-owned slash pine seed orchards.  Infection levels ranged form 4-11%.


Nursery Insects and Diseases

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Rhizoctonia needle blight,
Rhizoctonia sp.

Regionwide

Host(s):  Longleaf pine seedlings

Losses were reported from North Carolina in 2000, but not at abnormal levels.  Over 85,000 seedlings were lost to this disease in 2000 in South Carolina’s Taylor State Tree Nursery.

Damping-off,
Fusarium sp. and Pythium sp.

Regionwide

Host(s): Southern pines

Damping off is the most common disease problem facing southern nurseries. Loss of seedlings to damping-off varies greatly from year to year owing to the interaction of pathogenic fungi (species of Fusarium, Pythium, Rhizoctonia, and Phytopthora) and environmental conditions. Seedling losses can be severe when germination is slow due to cold, wet weather. Losses in 2000 were lower than normal due to the very dry weather which inhibits fungus development.  Nevertheless, North Carolina reported scattered damping off in southern yellow pine and white pine seedbeds.


Abiotic Damage

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Drought

Regionwide

Host(s): All species

Drought conditions prevailed over much of the South again in 2000, for the third consecutive year.

In Texas, temperatures also reached record high levels with 105-110 degrees occurring over several days at a stretch. Seedling mortality was high on many tracts planted during the winter of 1999-2000.  Cone mortality of 50% of second-year cones in the state seed orchard near Jasper was attributed to the record drought and heat. Drought has led to higher than normal populations if Ips pine engraver beetles (see Native Insects, Pine engraver beetle) and increased oak decline and dieback (see Declines/Complexes, Oak decline).

Georgia suffered some of the worst drought on record. Georgia Forestry Commission officials estimate that loblolly and slash pine seedling mortality averaged 30%. Among longleaf pine seedlings, mortality sometimes reached 90%, but statewide, survival rates averaged 36 percent.  Nearly 149 million seedlings died in Georgia due to drought.  The estimated value of lost trees was nearly $4.5 million.  The drought, in combination with hypoxylon canker, also killed an estimated 154,000 oaks in Georgia.

Drought was less intense in Tennessee in 2000 than in the previous two summers, but the cumulative effect caused continued mortality in the oak/hickory forest type. In west Tennessee, the drought caused noticeable yellow poplar decline and mortality.

In Florida, a third successive year of drought occurred across virtually the entire year.  As a result, the Sunshine State saw a dramatic increase in stress related pest activity and associated tree death/damage.  Among the secondary insects and diseases proliferating in the weakened trees were Ips beetles, black turpentine beetle, redheaded pine sawfly, Kermes scale, two-lined chestnut borer, ambrosia beetles, and hypoxylon canker.

Fire

Florida, Oklahoma

Host(s):  All species

For the third year in a row, fire (both wildfire and prescribed burns) generated an inordinate incidence of tree mortality. This situation was aggravated by the drought. Besides outright fire-caused mortality, many trees succumbed to secondary insects and diseases that exploited the trees’ fire weakened condition.  Massive wildfires throughout Oklahoma from August through October, 2000 caused mortality, but also predisposed trees to a variety of opportunistic pathogens and insects. The long-term effects of the fires will be monitored throughout 2001.

Flooding

North Carolina

Host(s): All species

Although there was no noteworthy flooding in North Carolina in 2000, foresters continued to monitor stands damaged in 1999 for secondary insect and disease problems such as southern pine beetle and root rots.  These problems have yet to manifest themselves, but history has shown that in time, stressed forest stands will develop problems associated with insects and diseases that take advantage of the weakened state of the trees.

Hail

Texas

Host(s): All species

A March 25 thunderstorm near Marchall, Texas dropped several inches of marble-sized hail across 3,000 acres in Harrison County causing minor tree damage.

Ice

Arkansas, Oklahoma, Texas

Host(s): All species

The winter of 2000 may well go down in history as the year of ice for several western Gulf states. Two major ice storms hit portions of NE Texas, SE Oklahoma, and much of central and southern Arkansas. The storms occurred on December 14 and 24.  One to two inches of ice accumulation bowed, broke, and uprooted trees. Hundreds of thousands of acres of young pine plantations were completely destroyed and will have to be replanted.  Texas authorities estimated a loss of $46 million in timber values in 4 northeastern counties.  In Oklahoma, widespread damage to trees was reported across about 6 million acres in 39 counties.  The long-term impacts of this storm will be a significant factor in Oklahoma’s forests for the next 5-7 years.

Wind

Tennessee, Texas

Host(s): Southern pines and hardwoods

An April 23 (Easter Sunday) tornado touched down in Harrison County, Texas near Marshall causing a narrow, 5-mile-long strip of broken and twisted timber.  A tornado damaged 500 acres of red oak, white oak, and yellow pines in a north central state forest in Stewart County.


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