Gall on Virginia Pine

Wednesday afternoon, this sample of Virgina Pine came into the Master Gardener Info line. The gall on this branch is caused by a disease known as Pine-Oak Gall Rust. This fungal disease, caused by Cronartium quercuum, requires two different hosts to complete its life cycle. It lives part of its life-cycle on pines and part of its life-cycle on oaks.

Symptoms on pine include swollen areas on the branches, lumps or galls measuring up to 4 inches across, and slowed growth. Trunk galls on young trees may result in death or breakage of the trunk or branches at gall location. Galls on branches may girdle and kill tissue beyond the infection. Symptoms on oak leaves include small dark brown spots with yellow borders on the upper leaf surfaces, and reproductive structures develop on the underside of infected leaves.

In the spring, mature galls on the pine host release windblown spores, which infect expanding oak leaves. About one week after infection, orange spores are released from the underside of infected oak leaves, causing additional oak leaf infections.

The above photograph shows the orange spores produced by the pathogen and being released on the surface of the gall.

Control measures include removal of infected branches on pines to remove the source of inoculum (spores) available for infecting oak trees. No control measures are feasible on oak trees.

Be on the lookout for bagworms now!

Bagworms hatched a couple weeks ago and are still quite small. Therefore they can be difficult to find although they have constructed tiny bags that can be seen on leaves and needles of infested plants. It is easier to look for the large bags left from last year’s bagworm adults. These will be empty, but are a good indication that small bagworms are likely roaming a plant. This is because female bagworms are flightless and overwinter and lay eggs in their bags on trees and shrubs. Thus, baby bagworms hatch and grow up on the same plant as their mother was on the previous year.

Early in the year the best strategy is to hand pick the bags before eggs hatch to prevent infestations. Although it is too late for that now, at this point the small caterpillars have not eaten much or caused much damage. This increases dramatically as they will grow until they easily defoliate branches, causing unsightly ornamental plants. Small caterpillars are also much easier to kill than large ones. This is because they have less body mass to dilute toxins and their protective bags are not as thick. Therefore less toxic chemicals such as Bt formulations can be very effective when targeting small caterpillars. Other chemical options that are considered compatible with natural enemies are Acelepryn, TriStar, and spinosad. More information can be found in Ornamentals and Turf Insect Information Note No. 81.

Steve Bambara, NCSU Extension Entomologist

Question: How Do Make a Plant Pathologist's Day?

Answer: Bring in a sample of the spore horns (or telial horns) of the Cedar Apple Rust pathogen. This sample was brought in today from a Henderson County homeowner.

The fungus that causes the disease, Gymnosporangium juniperi-virginianae, is unusual because it must spend a phase of its life cycle as a parasite on Juniperus species, such as red cedar or ornamental junipers and a part of its life cycle on apple or crabapple trees.

Cedar-apple rust can be severe on apple, therefore Henderson County apple growers are more aware of this disease than most homeowners. Infections of apple fruit result in lower fruit quality and early fruit drop. Leaf spots may cause early defoliation, especially during dry summers. If trees are defoliated several years in a row, they become weakened and stressed. Fruit bud formation may be reduced after one year. The disease is not as harmful to juniper, causing galls but not severely affecting plant vigor.

Click on the link for more information on Cedar Apple Rust.

Let it Snow, let it snow, let it snow......

As I write this post, there is 14" of snow in my front yard and the snow is still falling. I just love the snow but my plants can be damaged by severe winter weather. The large Southern Magnolia in my front yard has already had three limbs broken and the heavy, wet snow could do more damage before its all over. The boxwoods just in front of my house also look awful.
While it's true that heavy, wet snows and ice often cause broken branches, snow itself will not hurt landscape plants. In fact, the opposite is true. Snow is a very good insulator against chilling temperatures that may injure plants.
If you are concerned about injury to your favorite plants from the settling snow, protect them by scooping the snow away from the plant. Then, with gloved hands, carefully remove the snow from the branches. Natural snowfall or windblown snow seldom result in plant injury. It's usually the devices we use to remove snow that cause the most damage.
If snow is dumped on plants, it may be better to leave it than to try to remove it to prevent further breakage of the branches. If you do have branches break out of trees and shrubs, be sure to prune the broken limbs as soon as possible after the storm has passed.
For more information, call your local extension agent.

Advantages of Real Christmas Trees

This morning I walked into the Extension office to the aroma of a freshly cut Christmas tree, selected from a local grower. This year our commercial agent selected a Concolor Fir, Abies concolor. This hard to find attractive tree has needles that are longer and spaced further apart than those on the Fraser Fir. Michael Dirr calls this tree the most handsome of all firs. Which ever tree you choose this Holiday Season, just remember this list of reasons to buy local and living trees.

- Real Christmas trees are plantation grown on American family farms, making an important economic contribution to many rural communities in the United States.
- Real Christmas trees absorb carbon dioxide and other harmful “greenhouse” gases and release fresh oxygen into the air.
- A Real Christmas tree has a fragrance beyond compare.
- One acre of Christmas trees provides the daily oxygen requirement for 18 people.
- Real Christmas trees are an all-American renewable, recyclable resource. After the holidays, Real trees are chipped into biodegradable mulch, which replenishes soil in landscapes, parks, and schools.
- Real Christmas trees can be used as a feeding station and winter shelter for songbirds in your yard.
- The safest Christmas tree is a fresh, well-watered tree. A Real tree has never started a fire. Faulty Christmas lights, candles, and fireplaces can start tree fires.

The Value of a Leaf

Leaves are truly a valuable natural resource! They contain 50 to 80 percent of the nutrients a plant extracts from the soil and air during the season. There are four basic ways in which leaves can be managed and used in the landscape.

Leaf Management - Mowing
A light covering of leaves can be mowed, simply leaving the shredded leaves in place on the lawn. This technique is most effective when a mulching mower is used.

Leaf Management - Mulching
Mulching is a simple and effective way to recycle leaves and improve your landscape. Mulches reduce evaporation from the soil surface, inhibit weed growth, moderates soil temperatures, keep soils from eroding and crusting, and prevent soil compaction. As organic mulches decompose, they release valuable nutrients for use by your landscape plants.

Leaf Management - Soil Improvement
Leaves may be collected and worked directly into garden and flower bed soils. A 6 to 8 inch layer of leaves tilled into a heavy, clay soil will improve aeration and drainage. The same amount tilled into a light, sandy soil, will improve water and nutrient holding capacity.

Leaf Management - Composting
Compost is a dark, crumbly and earth-smelling form of organic matter that has gone through a natural decomposition process.Compost can be used to enrich the soil by adding a natural source of nutrients, loosen tight, heavy soils, help sandy soils retain moisture and nutrients, add to potting soils for container grown plants, and mulch around landscape plants. If you have a garden, lawn, trees, shrubs, or even planter boxes or house plants, you have a use for compost.

Taken from Don't Bag It: Leaf Management Plan, Texas A&M University publication.

Dogwood Defoliators

I have seen at least five samples of red twig dogwoods here in the Extension office with completely defoliated twigs. The culprit is known as the Dogwood Sawfly. Dogwood Sawfly, Macremphytus tarsatus, is a significant pest to dogwood (Cornus) species. Because the Dogwood Sawfly takes on several forms while in the larval stage, it may not be easy to identify. The larvae strips plants at the end of season, normally just before late August.

The wasp-like adult sawfly lays eggs that hatch into larvae, the first instar of which is an almost translucent yellow. Look for groups of these larvae on the undersides of leaves that are being skeletonized. The second instar appears to be covered with a chalky powder, and the last instar is a one inch long creamy-yellow larva that has a shiny black head and black spots (see photo).

Normally damage is short lived, therefore control is not warranted.

What is up with the locust trees?

I have had many calls the past few weeks regarding the bronzing of the locust leaves throughout Henderson County. The locust leafminer is primarily a pest of black locust. Adults skeletonize and eat holes in the leaves; whereas, larvae mine the tissue between the upper and lower-leaf surface (mining damage is the most destructive). Under outbreak conditions, whole hillsides turn gray or brown, often suggesting fall color change. Outbreaks of the locust leafminer are generally more spectacular than destructive. Control of the locust leafminer is generally not necessary.

Recycle Your Christmas Tree

The Environmental and Conservation Organization (ECO) is coordinating their annual tree recycling event in conjunction with Henderson County Parks and Recreation. Residents are encouraged to drop off their trees at a designated site in Jackson Park near the covered picnic area. Hendersonville city residents may leave their trees at curbside, where they will be gathered and included in the recycling project.

Be sure to remove all lights and decorations before dropping your trees at the park. No wreaths, balled trees or greenery with wire will be accepted. Christmas trees will be chipped to make mulch on Jan. 10 at Jackson Park. Mulch created from the chipping will be given away free of charge, so bring a bag if you’re interested in taking some home.

Call the ECO office at 692-0385 for more information.

Choosing a Christmas Tree

With Thanksgiving just a couple of weeks away many people are already beginning to think about purchasing their Christmas tree. I thought this excerpt from of one of our extension publications may be helpful as you consider this years tree.

Selecting the Right Tree
Selection of the "perfect" Christmas tree can be an enjoyable and rewarding experience. By following a few simple procedures, buyers can select trees which will meet their needs throughout the holiday season.
Before setting out to purchase a tree, determine where in the home the tree will be located, the size required, and whether all sides will be displayed. Other characteristics such as tree density, color, and fragrance should also be considered. Next, determine whether a cut tree or one "balled and burlapped" is to be purchased, or if a visit to a "choose and cut " farm is preferred. A large number of growers, civic and charitable organizations and retail stores provide trees that only need to be purchased and taken home. "Ball and burlap" trees are sold with roots intact so that replanting is possible after the holiday season. At "choose and cut" farms, trees are chosen where they are growing in the field and then cut for use.

Caring for a Tree After Purchase
Once a tree is purchased, keeping it fresh requires watering on a regular basis and avoiding high temperatures. If the tree is bought several days before it is to be decorated, it should be stored outside in a cool, shaded area. The base should be sawed on a diagonal about one inch above the original cut, and the base placed in a container of water. Sprinkling or misting the tree with water will also help retain freshness, but the tree should not be soaked.
Whether stored or not, before bringing the tree in the house, a square cut should be sawed on the base. The base of the tree should be kept in water throughout entire period that the tree is in use. The water level in the stand should be checked daily. Research has indicated that water additives are not needed and may even result in excessive drying.
The tree should be well supported and placed away from sources of heat. Tree lights should not be left on unless someone is at home, and should be turned off when the family goes to bed. Electrical cords should also be checked for any signs of damage or wear. Trees do not cause fires but will support combustion when dry. Dry trees should be removed before they create a fire hazard.

For more info go to:
http://www.ces.ncsu.edu/fletcher/programs/xmas/ctnotes/ctn027.html

Fall Color is Just Beginning, What is the Cause?

All during spring and summer the leaves have served as factories where most of the foods necessary for the trees' growth are manufactured. This food-making process takes place in the leaf in numerous cells containing the pigment chlorophyll, which gives the leaf its green color. Along with the green pigment leaves also contain yellow or orange carotenoids which, for example, give the carrot its familiar color. Most of the year these yellowish colors are masked by the greater amount of green coloring. But in the fall, partly because of changes in the period of daylight and changes in temperature, the leaves stop their food-making process. The chlorophyll breaks down,. the green color disappears, and the yellowish colors become visible and give the leaves part of their fall splendor.

At the same time other chemical changes may occur and cause the formation of additional pigments that vary from yellow to red to blue. Some of them give rise to the reddish and purplish fall colors of leaves of trees such as dogwoods and sumacs. Others give the sugar maple its brilliant orange or fiery red and yellow. The autumn foliage of some trees, such as quaking aspen, birch, and hickory, shows only yellow colors. Many oaks and others are mostly brownish, while beech turns golden bronze. These colors are due to the mixing of varying amounts of the chlorophyll and other pigments in the leaf during the fall season.

Fall weather conditions favoring formation of brilliant red autumn color are warm sunny days followed by cool, nights with temperatures below 45o F. Much sugar is made in the leaves during the daytime, but cool nights prevent movement of, sugar from the leaves. From the sugars trapped in the leaves the red pigment called anthocyanin is formed. The degree of color may vary from tree to tree. For example, leaves directly exposed to the sun may turn red, while those on the shady side of the same tree or on other trees in the shade may be yellow. The foliage of some tree species just turns dull brown from death and decay and never shows bright colors.

Through fallen leaves, Nature has provided for a fertile forest floor. Fallen leaves contain relatively large amounts of valuable elements, particularly calcium and potassium, which were originally a part of the soil. Decomposition of the leaves enriches the top layers of the soil by returning part of the elements borrowed by the tree and at the same time provides for more water-absorbing humus.

North Carolina leads the parade for leaf lookers, and depending upon the season, the species of trees involved, and the relative proportion of the three pigments, just about every imaginable color combination may be seen.

Prepared by Dr. Robert Bardon Extension Specialist

Fun Online Tree Pruning Guide

One of my fellow extension agents sent me a link to this website about pruning. I thought it was great and I think you will enjoy it. The virtual pruning lesson is especially fun.

http://www.arborday.org/trees/pruning/animation/launch.cfm

For additional information about pruning trees and shrubs, contact your local extension agent.

Christmas Tree Recycling

The Environmental and Conservation Organization (ECO) is coordinating their annual tree recycling event in conjunction with Henderson County Parks and Recreation. Residents are encouraged to drop off their trees at a designated site in Jackson Park near the covered picnic area. Hendersonville city residents may leave their trees at curbside, where they will be gathered and included in the recycling project.

Be sure to remove all lights and decorations before dropping your trees at the park. No wreaths, balled trees or greenery with wire will be accepted. Christmas trees will be chipped to make mulch from 9 a.m.-2 p.m. on Jan. 5 at Jackson Park. Mulch created from the chipping will be given away free of charge, so bring a bag if you’re interested in taking some home.

Call the ECO office at 692-0385 for more information.

Advantages of Real Trees

Did you ever think that by using a live Christmas tree in your house that you were actually helping the environment? Real trees help the environment from the time they are planted until after the holiday season when they can be recycled.

While they are growing, Christmas trees support life by absorbing carbon dioxide and other gases while giving off fresh oxygen. Every acre of Christmas trees planted gives off enough oxygen to meet the needs of 18 people. Today in America there are enough Christmas trees planted that 18 million people a day are supplied with oxygen. Also, the farms that grow Christmas trees stabilize soil, protect water supplies, and provide a refuge for wildlife while creating a nice scenic view. Often, Christmas trees are grown on soil that will not support any other crops. And when one Christmas tree is cut down, one or two are replanted in its place.
Artificial trees are made from oil-based products that use up our natural resources. They are also not recyclable and will remain in land-fills for centuries after disposal.
Real Christmas trees, on the other hand, are recyclable. The branches and trunk are biodegradable and can be made into mulch for the garden. A Christmas tree placed in the back yard will make a nice bird feeder and the birds can also use the trees branches for shelter during the winter winds. Large quantities of trees make effective barriers on beaches to prevent soil erosion. Sunk into ponds, the trees will also make an excellent refuge and feeding area for fish.

Keeping Your Christmas Tree Fresh

Before setting out to purchase your perfect Christmas tree, determine where in the home the tree will be located, the size required, and whether all sides will be displayed. Other characteristics such as tree density, color, and fragrance should also be considered. Next, determine whether a cut tree or one "balled and burlapped" is to be purchased, or if a visit to a "choose and cut " farm is preferred.

Once a tree is purchased, keeping it fresh requires watering on a regular basis and avoiding high temperatures. If the tree is bought several days before it is to be decorated, it should be stored outside in a cool, shaded area. The base should be sawed on a diagonal about one inch above the original cut, and the base placed in a container of water. Sprinkling or misting the tree with water will also help retain freshness, but the tree should not be soaked.

Whether stored or not, before bringing the tree in the house, a square cut should be sawed on the base. The base of the tree should be kept in water throughout entire period that the tree is in use. The water level in the stand should be checked daily. Research has indicated that water additives are not needed and may even result in excessive drying.

The tree should be well supported and placed away from sources of heat. Tree lights should not be left on unless someone is at home, and should be turned off when the family goes to bed. Electrical cords should also be checked for any signs of damage or wear. Trees do not cause fires but will support combustion when dry. Dry trees should be removed before they create a fire hazard.

Why Leaves Change Color

You may have noticed that leaf color varies every year. Leaf color is most spectacular when the right combination of factors are present. Scientists don't fully understand all of the complicated interactions that cause the best display of leaf color, but they do know that leaf pigments, length of night, the type of tree, genetic variation, and the weather all play a role.

Where Do Leaves Get Their Autumn Colors?
Tree and plant leaves contain pigments that give them their color. Three pigments are involved in fall color:
· Chlorophyll — gives leaves their green color.
· Carotenoids — provide the yellow, orange, and brown colors
· Anthocyanins — give the red and purple colors.
In contrast to the other two pigments, anthocyanins are produced in the autumn, in response to bright light and excess plant sugars in the leaf cells.
During the growing season, most tree leaves are green because they are full of chlorophyll. Plants use chlorophyll to capture sunlight for photosynthesis, the process that enables them to manufacture their own food. The amount of chlorophyll is so high during the summer that the green color masks all other pigments present in the leaf. As the days grow shorter in the fall, chlorophyll production slows down and eventually stops. The carotenoids and anthocyanins that are present in the leaf then become visible.

Do Different Kinds of Trees Turn Different Colors?
Certain colors of leaves are characteristic of particular species of trees.
· Oaks turn red, brown, or russet;
· Hickories turn golden bronze;
· Dogwood turns purplish red;
· Beech turns light tan;
· Red maple turns brilliant scarlet;
· Sugar maple turns orange-red;
· Black maple turns glowing yellow;
· Sourwood and black tupelo turn crimson;
· Aspen, birch, and yellow-poplar turn golden yellow.

Leaves of some species such as the elms simply shrivel up and fall off, exhibiting little color other than brown. The timing of the color change also varies by species. Sourwood in southern forests can become vividly colorful in late summer while all other species are still green. Oaks put on their colors long after other species have already shed their leaves. These differences in timing among species seem to be genetically inherited. The timing of color change for certain species appears to be consistent regardless of local weather patterns or changes in latitude.

Why Are Some Autumns More Colorful?
Temperature and moisture greatly influence autumn color. Since each of these vary greatly, no two autumns are ever alike. A succession of warm, sunny days and cool, but not freezing nights seems to bring about the most spectacular color displays. Since carotenoids are always present in leaves, yellow and gold colors are fairly constant from year to year. In order for the brilliant scarlet, purple and crimson colors to develop, bright sunlight in the early fall is needed. Bright sunny days increases food production in trees and plants. These sugars are trapped in the leaves spurring the production of anthocyanin pigments, providing the red tints to fall foliage.

The amount of moisture in the soil also affects autumn color. A late spring, or a severe summer drought, can delay the onset of fall color by a few weeks. A warm period during fall lowers the intensity of autumn color. Trees defoliated by insects during the growing season may also show less fall color.

Taken from United States Department of Agriculture Forest Service;
Northeastern Area Fact Sheet SP-01-01

Canker Diseases Follow Drought

Sharpen your pruners to remove dead branches on woody ornamentals due to a two punch combination of drought and fungal pathogens such as Botryosphaeria and Seiridium. The long term effects of this summer’s drought are becoming visible in landscapes throughout the Southeast. Much of this dieback has appeared in the last month. Drought stress has predisposed many of our woody plants to infection by fungal pathogens and in some cases wood boring insects. Rhododendron and Leyland cypress are two common hosts for these diseases, but you may see similar dieback on laurel, viburnum, holly and some juniper species.

Chemical treatments are not effective for the control of most fungal canker diseases. The best preventive strategy is drip irrigation during dry periods. Once dieback has occurred, diseased branches should be pruned out below the canker; below discolored wood in the stems.

Taken from article written by Alan Windham, Ornamental Pest and Disease Update, 9/07
Photo of Seiridium canker on Leyland Cypress, credit to J. Williams-Woodward, UGA

Construction and Tree Protection

As western North Carolina continues with our rapid growth, we hear of many concerns of how to protect our mature trees during construction. North Carolina Cooperative Extension has developed a new publication to help the homeowner and builder develop a tree protection plan. For more information and to view the publication online, click the link below.
Construction Publication

Top Tree Topping Myths

Myth: Topping a tree will reduce storm damage and make the tree easier to care for.
Topped trees can regain their original height in as little as two years. The fast growing, extremely long and loosely attached shoots caused by topping will be more susceptible to breakage and storm damage. Ultimately, a topped tree requires more attention in the future than a properly pruned tree.
Myth: Topping invigorates a tree.
Topping immediately injures a tree and starts it on a downward spiral. Topping wounds expose the tree to decay and invasion from insects and disease. Also, the loss of foliage starves the tree, which weakens the roots, reducing the tree's structural strength. While a tree may survive topping, its life will be significantly reduced.
Myth: Topped trees will add value to your home and property.
Topped trees are ugly and may reduce your property values. Also a topped tree can become hazardous and cause property damage, making it a liability.
Myth: Topping is the best way to keep a tree from getting too big.
A tree's genetics and environment determine how tall it will grow. Topping just shortens the life of the tree and creates long term maintenance problems.

Shade Trees Oozing Slime .... Yuck

Over the past several growing seasons, there have been more inquiries about the foul-smelling and unsightly seepage of sap from the trunk of shade trees that is commonly called slime flux or wet wood. It occurs in apple, birch, elm, hemlock, maple, mulberry, oak, poplar and willow. In North Carolina slime flux is very common in large, mature, landscape oaks, tulip poplar and elms. This disease is not normally a serious problem if the tree is otherwise healthy.

Slime flux is caused when bacteria infects the wood causing it to become discolored or appear water soaked (wet wood). Gas (carbon dioxide) is produced by fermentation by bacteria. The gas produces pressure in the wood. This pressure forces sap from the trunk through cracks in branch crotch unions, pruning wounds, lawn mower wounds, other injuries and occasionally unwounded bark. This oozing of sap is termed fluxing. The flux is colorless to tan at first but darkens up exposure to the air. As fluxing continues, large areas of the bark become soaked. Many different microorganisms grow in the flux producing a foul or alcoholic smell. Various types of insects are attracted to the slime flux.

There is no curative or preventive measures for slime flux except to maintain trees in a general good state of vigor and minimize wounds and injuries. More damage can be done to the tree in attempting to cure slime flux than the flux will do alone.