Month: September 2013

Source(s): Jacob G Price

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Bahiagrass is an aggressive mat-forming perennial in many southern lawns. It is a warm season grass that spreads by seeds and shallow underground rhizomes. It is native to South America and is common in the Gulf States.

Description

Bahiagrass is best know for it’s seedhead which normally has two branches that form a “Y” shape. The rhizomes are usually thick and have a purplish or reddish color. Leaves are somewhat folded and smooth on both surfaces.

Pre-emergence Control

For Centipedegrass, St. Augustinegrass, dormant Bermudagrass, and Zoysiagrass. Apply Atrazine as labeled for fair, (70-79), supression. Do not apply Atrazine near the root zones of ornamentals or during spring green-up.

Postemergence Control

For St. Augustinegrass, Centipedegrass, Zoysiagrass, and Bermudagrass, Manor (metsulfuron) may be used for good control. For Centipedegrass only, apply sethoxydim, (Vantage), for fair suppression. Apply Vantage no sooner than three weeks after greenup. May be applied at low rate to newly planted centipedegrass after stolons have grown three inches. Do not mow 7 days prior to or 7 days after application. Repeat treatment 10-14 days after the first application. Two applications per season may be used in established centipedegrass. After spring green-up for Bermudagrass and Zoysiagrass apply MSMA 2 or 3 times at the recommended rate 5-7 days apart. Image also suppresses bahiagrass and may be used in all of the above turf grasses.

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Center Publication Number: 66

Source(s):

• M.F. Potter, Extension Entomologist, The University of Kentucky College of Agriculture.
• L.H. Townsend, Extension Entomologist, The University of Kentucky College of Agriculture.

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Bagworms are caterpillars that make distinctive spindle-shaped bags on a variety of trees and shrubs in Georgia. They attack both deciduous trees and evergreens, but are especially damaging to juniper, arborvitae, spruce, pine and cedar. Large populations of bagworms can strip plants of their foliage and eventually cause them to die. Infestations often go unnoticed because people mistake the protective bags for pine cones or other plant parts.

Description and Habits

Bagworms are the larval (caterpillar) stage of a moth that is rarely seen. Only the males develop into typical moths capable of flight. The adult female is grub-like and remains inside the bag until just before she dies. Bagworms pass the winter as eggs inside the bag that contained the previous year’s female. In mid to late May the eggs hatch, and the tiny larvae crawl out from the end of the bag in search of food. By using silk and bits of plant material, they soon construct a small bag around their hind part that looks like a tiny, upright ice cream cone. As the larvae continue to feed and grow, they enlarge the bag enabling them to withdraw into it when disturbed. Older larvae strip evergreens of their needles and consume whole leaves of susceptible deciduous species, leaving only the larger veins. The bag is ornamented with bits of whatever type of vegetation they are feeding upon. By early fall, the bags reach their maximum size of 1-1/2 to 2 inches. At this time the larvae permanently suspend their bags (pointing downward) from twigs, and transform into the pupa or resting stage before becoming an adult.

Adults emerge from the pupal stage in early fall. Males are black, furry, clear-winged moths with about a 1-inch wing span. They are active fliers and fly in search of females which remain inside their bags. The females produce a powerful scent, or pheromone, that attracts the males. The creamy white females lack wings and legs and appear to be no more than grubs. The male flies to the female bag, inserts his abdomen in the hole in the bottom of the bag and mates with the female. After the fertilized female has laid several hundred eggs inside her old pupal case within the bag, she drops from the bag and dies. The eggs remain in the bag until the following May when the cycle begins again. There is one generation per year. Bagworms have two means of dispersing from plant to plant. Very young larvae may spin strands of silk and be carried fairly long distances by wind. Larger larvae may move short distances by crawling.

Bagworm Control

If only a few small trees or shrubs are infested, picking the bags off by hand and disposing of them may afford satisfactory control. This approach is most effective during fall, winter or early spring before the eggs have hatched. When many small bagworms are infesting evergreens, an insecticide may be needed to prevent serious damage. The best time to apply an insecticide is while the larvae are still small (less than 1/2-inch long). In Georgia, this is usually in June. Small larvae are more vulnerable to insecticides, and inflict less damage. Carefully inspect susceptible landscape plants, especially evergreens, for last year’s bags. Young bagworms are harder to see; look closely for the small, upright bags which have the appearance of tiny ice cream cones constructed of bits of plant material. Preventive treatment is often justified on plants that were heavily infested with bagworms the previous year.

Several products are available for homeowner and professional use. For homeowners, conventional insecticides such as Sevin, malathion, various pyrethroids or the microbial insecticide Bacillus thuringiensis (Bt) provide satisfactory results. For commercial operators, acephate (Orthene TTO, Pro 75), tebufenozide (Confirm 2E), Bt (Dipel 3.2WP) and various pyrethroids work well. The BT products have very low mammalian toxicities, but are only effective against younger larvae. If large bagworms are present (more than about 3/4-inch long), a conventional insecticide probably will provide better results. The foliage should be throughly wetted with the insecticide spray in order to achieve thorough coverage. Trade names are used as examples. No endorsement is intended, nor criticism implied of similar products not named. Always read and follow directions on the label.

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Resource(s): Insect Pests of Ornamental Plants

Center Publication Number: 203

Source(s): Willie O Chance

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As we head toward the end of the year, gardeners want their landscapes to look their best. But sometimes, in spite of our best efforts, the leaves on certain evergreen plants turn yellow and unsightly! This is especially true of azaleas, gardenias and hollies.

Why Are My Azaleas’ Leaves Turning Yellow?

One of the main questions at this time of the year is – “Why are so many of the leaves on my azalea plants turning yellow?” This year, it appears many azalea plants have more yellow leaves than green leaves! Usually we see a few older leaves yellowing with the younger leaves remaining green. However, in some cases, many leaves are turning yellow. Why is this condition so bad this year?

Remember, a plant losing some of its leaves is a normal process. The older leaves die and younger ones replace them. You would only be concerned if most of the leaves are yellow.

The traditional reply is that the plants have run out of fertilizer – particularly nitrogen. Nitrogen-deficient azaleas will shed older leaves. This is certainly a possible cause. And why did this happen? Azaleas may have missed their last fertilization in July or August or just never took up the fertilizer available.

Don’t worry about these plants. They should bloom normally in the spring. Fertilize them after the danger of frost is past – about April 1. Do not fertilize them now. This may cause the plant to start growing again. And this new growth, in turn, will be cold-tender and may be burned back by our winter weather.

Our unusual weather may be causing a problem with azaleas. Azaleas are a Southern favorite, but they are somewhat temperamental. Their fine fibrous roots like well-drained but moist soils. This year’s summer drought, followed by a wet autumn, may have damaged these roots. This is especially a problem in areas not suited for growing azaleas. Azaleas do not like wet or very dry soils or full sun locations.

There is not much we can do about this now. Fertilizing now will not fix this problem, and in fact, could further complicate the situation. Proper planting and maintenance will help prevent this problem in the future.

Plant azaleas in well-drained soils in partially shaded locations. The shade provided by planting them next to a building is not always enough shade. If they must be planted in the sun, they prefer the morning sun. Plant azaleas in slightly raised beds, if possible. Plant them no deeper than they originally grew.

The roots may be pot-bound when you buy them. This is when the roots are tightly matted together. Pot-bound roots form a tough ball that the roots may never grow out of. Cut the root ball or break the roots down four sides of the root ball if the plant is pot bound. Spread the roots out as you add soil.

Also, plant azaleas in beds, if possible, and not individual holes dug in the ground. Till the area well. You do not need to add compost to the soil. Put a three-inch mulch over the entire bed after planting. Water the soil well to settle the roots. Plant in fall and winter for best results.

Proper planting and watering are critical steps in assuring success in growing azaleas. Azaleas and other shrubs must be watered for best results. This is especially true during the first year. Water the soil so as it keeps it moist but not wet for the first six months. After that, water when soil dries out, wetting the soil to a depth of twelve inches. Water three-quarter to one inch a week during drought conditions. After plants are established, do not water every day or every other day! Frequent watering can kill plants.

Two other leaf problems with azaleas are: 1)iron deficiency and 2) lace bugs. An iron deficient azalea will have yellow or white younger leaves. The leaf will be yellow with green veins. Use a soil applied iron fertilizer at the labeled rate. If the iron deficiency returns quickly or repeatedly, the azalea may have root injury or the soil pH may be too high.

Lace bugs make the leaves look speckled or silvery. The underside of the leaves will be brown speckled. Wait until March and treat the plants with Orthene or other recommended insecticides. Read and follow all label directions.

Enter the New Year with healthy azaleas. Azaleas may look sad and unsightly now, but they can return to healthy plants with proper care.

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Center Publication Number: 230

Look at this too from our friends in Cobb County: Azalea Leaves Turning Yellow, Dropping?

Source(s): Laurene Hall

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Azalea leaf gall is a very common and widespread fungus disease that occurs in early spring on new azalea foliage. The leaves become thickened, curled, fleshy and pale green to white in color. Fortunately, this disease is more alarming than damaging.

Description

Caused by a fungus, Exobasidium vaccinii, which is dormant in the developing buds from one year to the next. When bud growth begins in the spring, the pathogen renews activity also, and one or more of the leaves on the shoot may develop symptoms. A spore-bearing hymenium is eventually produced which completes its development on exposed leaf surfaces. Spores are blown about by air currents, some of them lodge on the plant and finally invade leaf buds. The actual damage to plants is not nearly so important as it appears to be. However, if disease is severe, the vigor of the plant can be affected due to the loss of young leaves.

Detection

First noticed soon after leaf buds open in the spring. All or only part of the individual leaf may be affected. Part of the leaf becomes distorted with a pale green to whitish, bladder-like thickening. When young, the thickened, fleshy-like leaf is covered with a white growth. As the galls age they turn brown, dry up and fall to the ground. Occasionally, a black coating may develop on the surface of the gall, particularly during rainy weather, which results from secondary invasion of the galls by the fungus Pestalotia.

Control

1. Handpick or prune out and destroy (burn) galls.
2. Spray with recommended fungicides, such as Daconil 2787 or Mancozeb.
3. Serious outbreak in large plantings: spray in early spring when leaf buds just begin to open and at two-week intervals (if spring is relatively dry) through early summer (mid-June) with Bordeaux mixture which may reduce incidence of disease in the following season. Timing of sprays is critical because the spores over-winter in the bark and bud scales.

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Resource(s): Common Landscape Diseases In Georgia

Center Publication Number: 44

Source(s): Jacob G Price

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The azalea lace bug attacks azaleas and a few other ornamentals. They damage plants by feeding on sap from leaves through sucking mouth parts. Lace bugs often go undetected on the undersides of leaves until their numbers are high. Prolonged attacks can severely weaken azaleas and may be the primary cause of death.

Description

Adult lace bugs are about 1/8 of an inch long, flattened and rectangular shaped. The wings are almost transparent. Nymphs are flat, oval, and have spines projecting from their bodies in all directions. Both nymphs and adults cause damage which is seen as many chlorotic spots on the leaf. Brown and black excrement and old skins are often seen under the leaves.

Biology

Eggs are transparent to cream colored and football shaped. The eggs overwinter on the undersides of leaves and hatch in March to early April. Development from egg through five nymphal instars, to adult takes a month. There are at least four generations per year.

Cultural Control

If only a few lace bugs are present, they may be washed off with a strong stream of water. Also natural predators such as Mirid plant bugs and the mymarid wasp help control the azalea lace bug. Azaleas in full sun appear to have heavier infestations.

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Resource(s): Insect Pests of Ornamental Plants

Source(s): Stephen D Pettis

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The azalea lacebug is a pest that gardeners in the South face nearly every year. As azaleas begin to bloom, the insect begins its lifecycle. By the end of the summer, gardeners find their azalea leaves covered with yellow speckles and the plants are stressed. This leads to reduced vigor and flowering the subsequent year is diminished.

This nuisance pest infests most Rhododendron species although less serious infestations may go unnoticed. Damage appears as stippling or yellow spotting caused by the insect’s feeding on leaves with its sucking mouthparts. Feeding mars the appearance of foliage on both deciduous and evergreen azaleas. The feeding occurs on the underside of the leaves and is apparent on the upper leaf surface in the form of bleached, chlorotic spots that persist through leaf drop. Severe infestations can cause leaves to turn brown and impact overall plant health and vigor.

The adults are between 3 mm long and 1.5 mm wide and dark in color. The insects have a hood-like covering on the head and net-like, lacy, off-white wings with mottled brownish-black markings that may be seen with a hand lens. The insect resembles a fly that has lacy wings thus the name lacebug. Eggs may be visible with the use of a hand lens and appear as smooth, white football shaped objects that are deposited on the underside of leaves. These deposits are usually found along the central leaf vein and are covered with blackish, varnish-like fecal spots that are a diagnostic sign.

Nymphs, the tiny immature insects that follow the eggs in the lacebug lifecycle, are colorless when newly hatched, but quickly become dark and develop spines. The insect passes through five nymphal stages and sheds its skin each time. The cast skins often remain attached to the underside of leaves.

Azalea lacebugs over-winter primarily as eggs on the underside of leaves thus favoring evergreen azaleas. Eggs mature in response to temperature and in Georgia typically begin to hatch in March to early April. There are usually 3 to 4 generations per year and during the growing season the insect progresses from egg to adult in about 30 days.

Controlling this insect is simple. Growers should begin scouting for the eggs and cast skins in Mid March. Usually, a single well-timed spray is sufficient to prevent serious aesthetic injury. Applications should be timed to coincide with the first signs of the nymphal hatch stage that normally occurs in March to mid April. Chemical controls include acephate Orthene (acephate), Bayer Advanced Insect Spray (imidacloprid), oils, and soaps. Remember to read the label carefully and follow all instructions when using pesticides. If you have any questions about azalea culture or about azalea lacebug control, please contact your local County Extension Agent.

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Resource(s): Insect Pests of Ornamental Plants

Center Publication Number: 65

Source(s): Jacob G Price

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Azalea caterpillars feed almost exclusively on azaleas. They usually feed in groups and emerge mostly in August or September. These caterpillars raise their head and posterior in unison when disturbed. Can defoliate plants if left untreated.

Azalea Caterpillar Description

The immature caterpillar is approximately 1/2 inch long and reddish to brownish-black with white and yellow stripes. The mature caterpillar is about 2 inches long, black, and has 8 yellow to white longitudinal broken stripes. The head and legs are crimson or reddish in color.

Life Cycle

Little is known about this insect. There seems to be only one generation per year. Eggs are deposited by the in masses of 80-100 on the underside of the leaf. The first-instar caterpillars feed in a cluster side by side unless disturbed. The adult form is a light brown moth with a wingspan of approximately two inches.

Control

Bacillus thuringiensis (Dipel) may be used when the larvae are small. Sevin, malathion, horticultural oils and cyfluthrin are products recommended. Follow label recommendations for chemicals. If the numbers are small enough they can be removed by hand. Larger caterpillars must be sprayed directly to control because of decreased eating when nearing pupae stage.

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Resource: Azalea Caterpillar

 

Source(s): Randy Drinkard

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Birds can be an important aspect of our backyard environment. In many cases, the quality of our environment is perceived to be directly related to the population of birds. The bird population in your yard or neighborhood park can be increased with the proper selection and arrangement of ornamental trees and shrubs. The selection of food-producing plants can ensure the presence of birds year-round.

To attract and maintain a bird population, a habitat should provide (1) food, (2) cover, (3) nesting areas, and (4) water. Ornamental trees and shrubs can supply the necessary cover (shelter) and nesting areas. Many ornamental plants can satisfy more than one habitat requirement. For instance, multi-stem plants that form a dense canopy will satisfy the needs for nesting and also provide cover.

The food source for birds should be supplied, as much as possible, by the trees and shrubs in the yard. To maximize the natural food source, select plants to ensure an available food source year-round. The use of trees and shrubs native to your locale will help ensure that appropriate fruits and berries are available for the local bird population. If the landscape does not supply food during certain periods, you can supplement with commercial mixes of bird seed. This will help keep birds in the vicinity of your yard. Some birds eat a wide variety of seeds while others prefer one or two types. The seeds that appeal to the majority of birds are sunflower, proso millet, and peanut kernels.

Birds require a place of cover or shelter if they are to become long-term residents. They require protection from inclement weather (sun, heat, wind, and rain) and natural predators. This is why the multi-stem plants that form a dense canopy are preferred by birds. The dense canopy also provides an ideal environment for nesting. Since birds require shelter year-round, the yard should have a mix of deciduous and evergreen plants. Evergreen plants include broadleaf evergreens, such as holly, and conifers, such as red cedar. Several references suggest that at least 25% of the trees and shrubs should be evergreen.

A source of fresh water is also necessary to maintain your bird population. The water source should be shallow (no more than 2″-3″ deep) and replaced on a regular basis. Running water, such as a shallow fountain, is the ideal water source. The water source should be elevated or in the middle of an open area to minimize predation by cats and other animals. An elevated bird bath or fountain is ideal.

A recommended list of trees and shrubs to enhance the bird population follows. Attributes that must be considered before selecting the trees/shrubs for your yard include, (1) the habitat element provided, (2) fruiting season, (3) deciduous (loses leaves in winter) or evergreen, and (4) size of mature tree (to fit with available space).

Trees and Shrubs for Attracting Birds
Southeastern Trees & Shrubs	Provides:		Fruiting Season	Deciduous or Evergreen	Size (sm, med, lg)
	Cover	Food
Beech		X	Fall, winter	D	M
Black cherry	X	X	Summer	D	M
Black gum	X	X	Summer	D	L
Blueberry	X	X	Summer	D	S
Dogwood	X	X	Fall, winter	D	M
Elderberry		X	Summer	D	S
Hawthorn	X	X	Spring	D	M
Holly	X	X	Winter, spring	E	M
Japanese yew	X	X	Summer, fall	E	M
Magnolia	X	X	Summer	E	L
Mulberry		X	Spring, Summer	D	L
Nandina	X	X	Fall, winter	E	S
Oaks	X	X	Fall	D	L
Pines		X	Spring, summer, fall	E	L
Pyracantha	X	X	Fall, winter	E	S
Red cedar	X	X	Fall, winter	E	M
Red maple	X		Spring	D	L
River birch	X		Summer, fall	D	M
Sumac		X	Fall, winter	D	M
Sweet gum		X	Summer, fall	D	L
Vibernum	X	X	Winter	E	S
Wax myrtle	X	X	Summer, fall	E	M

To make your yard more suitable for birds, conduct an inventory of trees/shrubs in your landscape and develop a table similar to that in this article. From this list, a) determine the mix of evergreen and deciduous trees, b) look at the time of fruiting and identify season(s) without food supply, and c) ensure that adequate cover and nesting habitat is provided. The following are two examples of possible situations in your yard and how to use the chart:

• You have very few evergreen trees/shrubs (hence minimal shelter in the winter) but also have only small areas for additional plants. Select plants that are classified as evergreen (E) and are small sized at maturity. These plants (red cedar, nandina, viburnum, pyracantha, Japanese yew, holly, and wax myrtle) are relatively small trees.
• You need a food source for the spring but have limited yard area available. An excellent solution is to plant hawthorn, especially mayhaws. They are a small multi-stem shrub that bear fruit in the spring and attract a wide variety of birds.

In most instances, you will find that the addition of a few carefully selected plants can increase the bird population in your yard.

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Resource(s): Landscape Plants for Georgia

Center Publication Number: 163

Source(s): Faith Peppers, CAES- Office of Communications, The University of Georgia.

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It is often said that gardening is good for the soul. Gardeners in Bobby Wilson’s Atlanta Urban Gardening Program find it’s not only good for the soul, but the mind and the wallet as well.

“The Atlanta Urban Gardening Program is more than just planting a seed and watching it grow,” Wilson said. “It’s about growing communities, training new leaders, feeding the hungry and homeless, establishing farmers markets and working with youths and adults through gardening.”

Wilson, an area Cooperative Extension agent for Fulton and DeKalb counties, is the coordinator of the Atlanta Urban Gardening Program. He came to UGA’s College of Agricultural and Environmental Sciences 16 years ago from St. Paul, Minnesota to get closer to his Mississippi roots.

“I really wanted to get back to the South,” Wilson said.

Since Wilson took over the urban gardening program, more than 200 garden sites have been established, and he has helped form community partnerships with the Atlanta Community Food Bank, the Federation of Southern Coops, the Buddy Valentino Foundation, the Sullivan Center and others. The vital partnerships have helped the program reach deeper into the community.

“This year alone we started 12 new gardens at local daycare facilities, public housing complexes and facilities for the physically challenged,” Wilson said.

In 1995, Wilson added the Atlanta Urban Gardening Leadership Program to the gardening program.

“The leadership program is designed to give community gardeners a leadership lesson, a gardening lesson and a chance to meet other gardeners from across Atlanta,” Wilson said. “From this program we also started an outreach program. We feed more than 300 homeless people once a month in an Atlanta shelter. We adopted a school in Costa Rica where we sent school supplies for two years, and we give coats and blankets to the homeless.”

The gardeners also are learning about business.

“Participants have learned business skills through our value-added products developed from our community gardens,” Wilson said. “We have our own labeled brands of pepper sauce, chow-chow, pepper jelly and scrub-a-dubs made from loofa sponges from our gardens.”

These products produced by the gardeners and packaged under their label, Atlanta’s Own Hot Urban Success, are available for sale by the community gardens and can be found in some restaurants in the metro area.

“The money from the products goes back into their local community garden program,” Wilson said, “It helps the gardeners learn that they can feed their families and make a little money from gardening.”

If you are thinking Wilson works with new city dwellers in expensive new lofts and high-rise condos, think again.

“Our community gardeners, who themselves are from underserved communities, feel they have been blessed and because of these blessings they know they can be a blessing to someone else,” he said.

“It wasn’t so much agriculture or horticulture as it was working with people. I enjoy working with people, and this is the ideal job for me: Working in communities throughout Atlanta. I get to interact with people from all walks of life,” he said.

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Resource(s): Vegetable Gardening in Georgia

Center Publication Number: 236

Source(s): Jacob G Price

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Description

Adults are glossy black with up to 20 irregular distinct white spots. Their bodies are from 1-1 1/2 inches long and their antennae are the same length or longer.

Biology

In China there is one or two generations per year. In June/July or September/October, females chew a small cavity in the bark and deposit an egg which becomes a larvae that burrows deep into the tree, feeding first on the phloem, then the xylem. The larvae overwinter deep within the tree and upon maturation, the mature beetle chews its way out leaving a 3/8’s of an inch diameter hole. Beetles emerge from May to August, peaking in early July. Females live 14-66 days and males live 3-50 days. After mating the female usually only moves a short distance before laying 30-70 eggs individually on a host tree.

Control

There are no approved pesticides in use in the United States which control the ALB. Once a tree becomes infested the only option is to cut, chip and burn, the infested tree.

Host Trees

Prefers maples and horsechesnut. Readily attaches poplars, willow, elms, mulberry, black locust, and several commercial fruit trees. Since the ALB is new to North America, new species of hardwoods are continually being added to the list of host species.

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Resource(s): Insect Pests of Ornamental Plants

Center Publication Number: 79