MAY 1999


Goodbye April, Hello May, Ready or Not! In visiting a few nurseries and in my own mini-world, life seems like the classic I LOVE LUCY sitcom where Lucy is making chocolate candy and is positioned along the conveyor belt rolling the candy balls in chocolate. The conveyor belt continues to get faster until Lucy has lost control and is frantically eating the candy, stuffing it in her pockets and anywhere else she can find to keep it from running off the end of the conveyor and on to the floor. Does that resemble your world at this time of year? I think by June, most nurseries are able to take a little breath and assess the damage. I hope you are doing well, keeping up, and nothing is falling on the floor. Please call if we can help. (I do not want a position on the conveyor line but I will try to help with the chocolate recipe.)

The Nursery Industry is being highlighted by the Alabama Agribusiness Council this year. On Wednesday, May 5, the officers of the Alabama Nursery and Turfgrass Associations along with other Green Industry representatives will be in Montgomery. We will have the floor and will be touting the value of the Green Industry to Alabama. We will try to educate the legislators as well as other ag industries on the services and products we provide and how they benefit our State. Below is the script we wrote to narrate a video tape that will be shown at the meeting. This tape will be available through your local county Extension office should you need to use it for a high school career day or to educate local city officials about our business.

Send your pictures of what's blooming to feed our new offering. I am excited about this section but, like you, it is hard to get it all done. Bernice does a great job of posting the new flowers if I would get them labeled and to her. Feel free send in you favorite plants if you would like to see them posted.

Have a great May! The Horticulture Department and Auburn University were created to serve all the people of Alabama and we enjoy helping when we can. Send us your questions, comments, suggestions, and ideas.

Ken Tilt


DISCLAIMER: Please remember that all information presented is a summary of research and not an endorsement of any product or a recommendation of chemicals. The official labels from the manufacturing companies offer the legal and proper use and handling information for all products.

THE FOLLOWING ARTICLES ARE FEATURED IN THIS MONTH'S SOMETHING TO GROW ON:

1. ALABAMA'S GREEN INDUSTRY
2. WORLD ECONOMIC PLANTS: A STANDARD REFERENCE
3. TWO TROUBLESOME PLANTS BANNED
4. 'HALIFAX' MAIDENCANE
5. AMERICAN STANDARD FOR NURSERY STOCK - NEWLY REVISED
6. MAGNOLIAS AT MONROVIA
7. MAINTAINING THE GREENHOUSE COOLING SYSTEM
8. ARE YOUR GERANIUMS HAPPY?
9. A TIMELY WARNING
10. BOOK REVIEW: SOUTHERN LIVING GARDEN PROBLEM SOLVER
11. JACKIE MULLEN'S PLANT PATHOLOGY REPORT
12. UPCOMING EVENTS

Alabama's Green Industry:
One of Alabama's Leading Agricultural Enterprises

The green industry of Alabama is composed of nursery, greenhouse, turf, and landscape businesses. There are wholesale, retail, and service components to the Green Industry that provide over 15,000 jobs with a variety of skill and management levels. These kinds of businesses provide large economic benefits as well as valuable aesthetic and psychological contributions to the people of Alabama and the country.

The Green Industry is in every county in Alabama and touches the lives of almost everyone in our state every day. It contributes close to 300 million dollars each year to our economy at the farm gate. When their products are taken through to the consumer, they represent over 1.5 billion dollars to our state's economy. It is an industry that has been on a continuous, steady rise. Since 1980, sales have increased over 200% and the future looks bright. Alabama ranks 16th among the states in gross sales of nursery crops.

There are the obvious aesthetic benefits that come from our industry but there are also the corresponding psychological as well as strong economic benefits of having a pleasing landscape. Apartment landlords and restaurant owners have found higher occupancy ratings and increased business when a good landscape is added to their properties. Research shows that hospital patients go home faster when they recover in a pleasant environment. Realtors have shown increased value of property and homes when a pleasing arrangement of turf, trees, shrubs and other hardscaping features such as decks, arbors, patios or walks are added. Environmentally, our landscape provides a filter for pollutants, a screen for excessive winds, a deterrent for runoff and loss of valuable topsoil, and also offers flood control as well as habitat for wildlife. City officials and architects of urban areas have discovered that it is imperative to have green belts for the survival of cities. When urban revitalization projects are initiated, one of the first priorities is to reestablish trees and green areas within the city to make it both habitable by people and wildlife.

The Green Industry is involved in the production, distribution, sales, establishment and maintenance of plants in the landscape. Our nursery farmers are involved in the container and field production of landscape plants. Container production has increased since the 1950's to become the predominant method of producing nursery crops. It can be found throughout Alabama with heavy concentrations in Mobile, Baldwin, Montgomery, Limestone and Morgan counties. Limestone and Morgan counties are traditional field production areas but are growing in container production. The soils are good for field production in north Alabama and balled and burlapped plants are still relied on for large landscape materials.

The greenhouse segment of the industry provides herbaceous bedding and perennial plants, interior plants, holiday crops, and cut flowers to florist's shops, garden centers and mass market outlets. Of all the greenhouse crops, bedding plants account for the largest proportion of gross sales. The most important production and marketing season, therefore, is spring. However, fall has developed into an important market dominated by pansies, garden chrysanthemums and poinsettias. With approximately 250 growers statewide, the industry can be found throughout Alabama with heavy concentrations in Mobile, Baldwin, Montgomery, and Calhoun counties.

The turfgrass industry produces the grass needed for home lawns, athletic fields, golf courses and all other areas that enjoy the benefits of turfgrass. Most people would be surprised at the size of Alabama's Turfgrass industry and how much turfgrass is worth. There are no solid surveys available for this industry but let's start with golf. There are approximately 270 public and private golf courses in Alabama. More than 10 million 18 hole rounds of golf are played on those courses each year. With an average cost of $25 per round over $300,000,000 is generated by greens fees alone. Turfgrass is the heart of a billion dollar Alabama golfing industry, and no matter how nice the shoes and clubs are, 'ya gotta have grass. A quality golf course is only obtained from quality turfgrass production and maintenance. There are over 16,000 acres of sod production in Alabama. This intensively managed crop supplies a growing market that no longer is willing to wait for seeded lawns. The trend in landscaping is instant effect and instant beauty.

Unlike many traditional agricultural crops, each nursery, greenhouse and turf business is family owned and operated and entirely responsible for marketing and distributing their own products and services. Each plant that goes out of any of these businesses has the name and reputation of that individual or family farm on the plant. There are no large cooperatives that purchase all the plants for redistribution. It is one of the last vestiges of true free enterprise agriculture. Plants are marketed through person–to-person meetings that begin and end with a smile and a handshake, the "old fashioned way". Relationships are built on trust, proven reliability and quality products.

Plants are sold through ads in trade magazines, through nursery catalogs, and availability lists. Mail order and Internet sales are alternative marketing channels and are an increasing niche for some of our growers. Most nurseries market their plants through large trade shows. Each business displays their products in trade show booths in their market areas in Alabama as well as at trade shows around the world. These are large, extravagant events and combine business, pleasure and education for the families of the various enterprises. It brings the whole Green Industry together.

The Green Industry distributes their products through retail garden centers to the public or through landscape designers or architects through the contractors and out to the landscape. It is the landscape architects and designers that use their knowledge, experience, and artistic talents to bring together the thousands of different plants as well as hardscape materials in a functional, pleasing blend that creates a living, dynamic portrait on your properties. Landscape contractors install and maintain the landscapes. This has become a major part of our industry and continues to grow both in quantity of business and quality of the final product. With the thriving economy and the increasing demands for higher quality landscape designs and maintenance, Alabama's Green Industry is positioned well to continue to be a leader in this segment of agriculture for many years to come.


WORLD ECONOMIC PLANTS: A STANDARD REFERENCE

"USDA released a new 784-page book, "World Economic Plants: A Standard Reference," which catalogs more than 10,000 economically important plants. The book replaces "A Checklist of Names for 3,000 Vascular Plants of Economic Importance," last updated in 1986. The book costs $125 and includes crop plants, weeds, poisonous plants and plants with medicinal and industrial potential. (http://www.ars-grin.gov/npgs).

(from David Morgan's Weekly NMPRO e-mail, dated April 27, 1999)


TWO TROUBLESOME PLANTS BANNED

The Tennessee Department of Agriculture has banned two plants, purple loosestrife (Lythrum salicaria and related cultivars) and tropical soda apple (Solanum viarum), which have been designated as "pest" plants. It is now illegal to propagate or sell these plants in Tennessee. Tennessee Department of Agriculture plant certification administator Gray Haun, said the ban was the result of combined efforts between several agencies and groups concerned with the protection of Tennessee's water, wildlife, and native plants.

(from David Morgan's Weekly NMPRO e-mail dated April 27, 1999

'HALIFAX' MAIDENCANE

We have used 'Halifax' maidencane grass with success in our research and demonstration work on filter strips to reduce nitrates and pesticides from entering our ground water. Filter strips are a recommended best management practice outlined in our manual, Best Management Practices for Container Nurseries. Maidencane grass is a native warm-season perennial aquatic or semi-aquatic grass that grows 2-3 feet tall. It spreads from numerous, creeping rhizomes which form a dense vegetative mat. The plant is recommended for shoreline erosion control on small lakes, ponds, irrigation reservoirs, channels and stream banks, and constructed wetlands. 'Halifax' maidencane was released by the USDA Soil Conservation Service, presently the Natural Resources Conservation Service, in 1974. Known for its cold tolerance, rapid spread and vigorous growth, it can grow on mineral clays to floating organic soils. The grass is established from rhizomes planted in May or June.

For more information contact local USDA, NRCS office which can be found in telephone directories under U.S. Government Department of Agriculture, Natural Resources Conservation Service.

(from July 1998 brochure printed by the Mississippi Agricultural and Forestry Experiment Station)

AMERICAN STANDARD FOR NURSERY STOCK - NEWLY REVISED

The Horticultural Standards Committee has recently revised the American Standard for Nursery Stock. The publication is used by landscape architects, specifiers, growers and landscapers. Changes have to do with the reclassification of container sizes by volume in cubic inches rather than dimensions; the addition of 5 new small plant containers to facilitate specification of bedding plants and perennials; addition of 3 new larger containers. Many revisions have been made. The ANSI Z60.1 can be ordered from NCAN, P.O. Box 400, Knightdale, NC 27545-0400 or fax to 919-266-2137. The cost is $15 (plus 6% NC sales tax and $2.50 shipping).

(from Nursery Notes, January/February 1999).

MAGNOLIAS AT MONROVIA

Of the 200,000 magnolias grown and sold at Monrovia (18 varieties), only one, Magnolia grandiflora, is propagated from seed. Seeds are collected or purchased and will serve as understock for grafting named varieties. The red flesh from gathered seeds must be removed. Seeds are soaked for 24 hours, then scrubbed with Ajax cleanser on a course metal screen over a sink. Seed is then mixed with medium grade perlite, moistened lightly, sealed in a plastic bag, and placed in a cooler for 30-60 days at 40 degrees F. until germination (when the seed coat begins to open). Seed is sown in a medium of firbark, peat moss and perlite in 17" x 17" x 2 1/2" flats and placed in a greenhouse with bottom heat until the first set of leaves has partially developed. Flats are moved outside to a shaded area for 2 - 4 weeks to be hardened off and then seedlings are potted into a bottomless pot and set outside.

Nine of the fourteen deciduous varieties that are produced are done so from cutting propagation. When stems are slightly hardened, softwood cutting material is collected in April and May. Cuttings are approximately 6 inches long (with 2 or 3 leaves). One inch of bark on one side of the base is sliced off to improve hormone absorption and the formation of roots. Cuttings are placed in a perforated bucket which, when full, is dipped in a 10 ppm chlorine solution to kill any harmful pathogens. Then cuttings are taken to the greenhouse where they are dipped in Dip N' Gro, a liquid rooting hormone, diluted with methanol at ratios of 1:1, 1:3 and 1:9, and Hormex 16 rooting powder to promote rapid, abundant, and consistent rooting. In about three months the cuttings will root (success rate is 45%-75%). They are then placed outside in full sun.

Evergreen and deciduous varieties are grafted and kept in special grafting tents (made of wood or metal frames covered with clear polyethylene plastic). The grafting is done by covering a bench surface with waxed paper, then with peat moss and then sprayed with Cleary's 3336 fungicide and kept moist so the grafts don't dry out. The evergreen varieties are grafted in December through February onto M. grandiflora produced from seed. To prepare understock, healthy plants in all container sizes are selected, pruned to 3' and all but three leaves at the top are removed. They are then drenched with Cleary's 3336 fungicide and placed on prepared benches in the greenhouses. Scion wood is collected from plants in the ground. All leaves are removed and scions are cut to a length of 8". Scions are then rinsed with water, dipped in Cleary's 3336 fungicide, wrapped in newspaper, placed in a platic bag and stored in a cooler for up to one week.

Grafting on greenhouse benches is begun with the grafter making a two inch downward cut into the understock. A scion is selected and the grafter makes an equal tapered slice on each side of the base of the scion. The graft is wrapped with a grafting rubber. The plant is placed on the bench with the graft facing south towards the sun to promote a more vigorous scion. Five inch pots are placed at a 30% angle with the graft facing up so that as many pots as possible can receive the required amount of sunlight. Gallon containers are left standing straight up. When the bench is full, the tent is sealed and the beginning date, completion date and name of the varieties are written on both ends of the tent. After two weeks, the tent is opened and the grafts are sprayed with Cleary's 33336. They are moved to a shade area outside once callus has formed at the graft and the scion has at least three leaves. About two weeks after this the understock above the graft is removed.

(from "Propagation of Magnolias at Monrovia" by Brian Jacob - published in Magnolia, Journal of the Magnolia Society, Issue 64)


MAINTAINING THE GREENHOUSE COOLING SYSTEM

Maintaining the greenhouse cooling system is vital to a successful commercial operation. There are many things one needs to consider. Upon installing a new system or an existing system, the top covers must be removed so the water can be tested. The pH must be between 6.0 and 9.0 and the salt concentrates should be below 40,000 ppm. Water that tests out of those ranges can be very corrosive. Continue with the following steps:

General maintenance for cooling system:

Pad maintenance:

End of season maintenance:

(from an article by Linda Barnett, published in Greenhouse Product News, April 1999)


ARE YOUR GERANIUMS HAPPY?

Last month we had an article on the serious problem of bacterial blight in the greenhouse which can result in loss of entire blocks of infected plants. Another common problem with a much better prognosis is dealing with micronutrient toxicities in zonal geraniums caused by too low of a root substrate pH.

Micronutrient toxicities (Fe and Mn) manifest themselves as lower leaf yellowing followed by necrotic spots or margins on the lower to mid-level leaves. It is important to monitor the pH of geraniums by in-house testing or sending samples to a commercal or university lab. 6.0 to 6.5 is the optimal pH range for zonal geraniums. Methods of control are as follows:

Continual Control: Monitor pH weekly or bi-weekly. Adjust with an acidic fertilizer (20-10-20 or 20-9-20) to lower the pH. Use basic fertilizer (calcium nitrate plus potassium nitrate). Corrective Measures: To lower pH - use an acid-based fertilizer (20-10-20, 20-20-20, or 21-7-7). Use these with caution as ammonium toxicity or acid injection could occur. To increase pH - use a basic fertilizer, dolomitic limestone, or hydrated lime.

Rapid Corrective Measures: Iron sulfate, aluminum sulfate and hydrated lime will burn most plant tissue so these must only be applied to the root substrate. If solution contacts plant, rinse immediately. Test a few plants before applying to a large number. The method will adjust pH rapidly but only for a short time. Recheck in a week and reapply if necessary. To lower pH - dissolve 1 to 2.5 pounds of iron sulfate or aluminum sulfate in 100 gallons of water. Apply to root substrate and rinse the foliage after application. Both iron sulfate and aluminum sulfate will increase the root substrate EC level and may release toxic levels of minor elements from the root substrate's exchange sites. To increase pH - Mix 1 pound of hydrated lime with 3 to 5 gallons of warm water in a plastic bucket. Allow mixture to settle; pour off clear solution into another plastic bucket. Apply the clear solution with a fertilizer injector set at 1:100 or 1:128. Since hydrated lime is corrosive, avoid contact with skin and metal. The hydrated lime may displace ammonium from the root exchange sites of the root substrate into the soil solution causing root injury. Avoid using hydrated lime if high levels of ammonium fertilizer are present in the root substrate.

(From an article by Brian E. Whipker and Tom C. Creswell, from the North Carolina Commercial Flower Growers' Association newsletter, February 1999)


A TIMELY WARNING

Some Ohio nurserymen and farmers have been called by high pressure telemarketers. They are selling pesticide products that they claim provide effective weed control. The problem is that the product is for "total vegetation control" and can actually kill the growers' crops. The Ohio Department of Agriculture's Pesticide Regulation Section is helping grower's contact the Ohio Attorney General's office to make complaints regarding the telemarketer's misrepresentation of the herbicide.

(from David Morgan's weekly NMPRO e-mail, dated April 20, 1999)


BOOK REVIEW: SOUTHERN LIVING GARDEN PROBLEM SOLVER

For those of you, nursery owners and gardeners alike, who can't pass up a luscious new book, filled with photos of all things pertaining to the southern landscape, Southern Living's Garden Problem Solver is for you. It is a lovely book filled with information about plants and pests. It's about getting things in your garden right - a rather large task but certainly one that is possible with correct information.

You will be able to find answers quickly to daunting garden problems. There are also lots of interesting facts, tips and observations. You will be able to diagnose many plant diseases from very clear photographs in the book. Solutions to problems cross the whole spectrum from chemical, organic, cultural and biological. You can then choose which solutions are best for your situation. It is the kind of book that will spend more time off of the bookshelf than on it.


JACKIE MULLEN'S PLANT PATHOLOGY REPORT

March seemed to come in and go out like a lamb! And, dogwoods, azaleas, red buds and flowering cherries have been and are looking good!

Cold damage (in late February) will be less of a problem this year as temperatures did not drop to damaging levels except in some parts of North Alabama.

Most of our 76 March plant samples continued to be predominantly landscape ornamentals. Typically at this time of year, if cold damage has not been a problem, dieback and decline result from winter-related environmental stress. Cold or water-availability problems are often involved with problems at this time of year. More than 20 of our March samples were 'suspect root (or trunk) problem'. The cold events of late February may have resulted in some cold damage (dieback) in northern sections of the state.

Diseases seen in March are the following: algal leaf spot and Colletotrichum leaf spot on camellia; Pythium stem and root rot of geranium; Phytophthora and Pythium root rot of holly; Botryosphaeria (and Phomopsis) crown decay of Helleri holly; Cercospora needle blight, probable Seiridium or Botryosphaeria canker, secondary types of fungal needle blights on Leyland cypress; Phomopsis leaf spot on southern magnolia; pine needle rust and sooty mold on pine; Pythium root rot on dwarf red maple; Armillaria root rot of photinia; Coniothyrium canker on rose.

In March we saw an increase in the number of dieback samples on landscape trees and shrubs. Foliage disease was not present on these samples. Since cold incidents this early spring were not severe, we assume that much of the dieback at this time of year relates to a root stress problem from a stress situation that affected the whole state. We suspect drought stresses last fall are responsible for some of these dieback problems this early spring. Samples of landscape dieback were received on eleagnus, azalea, boxwood, Leyland cypress, Burford holly, pachysandra, holly, juniper, cedar, Helleri holly, quince, photinia from all sections of the state. Some of the above problems from northern most areas of Alabama may relate to incidence of cold damage to trunks.

Algal leaf spot often occurs on camellia and southern magnolia when temperatures have been cool-moderate and wet. This leaf spot is usually not severe enough to cause significant damage to the over-all health of the plant, but the spotting is aesthetically damaging. Spots are usually reddish-brown in color and slightly raised, especially around the spot wavy edges. As spots age they may become colonized secondarily by a lichen (called Strigulla) which causes the spots to become white in color. See the Alabama Pest Management Handbook for control recommendations. Also, sanitation of fallen spotted leaves is helpful.

We have received several samples of Leyland cypress lately. The problems have been foliage blight, canker disease, and/or suspect root stress. The predominant problem appears to be suspect root stress which may relate to dry weather last fall, especially if plants are small and/or recently planted (within last 1-2 years). Cercospora blight has been diagnosed on Leyland cypress. This fungal blight causes a browning of needles. Usually the infection/blight begins on lower and inner needles where conditions tend to be more humid. Once established, the fungus may spread to upper and outer branch sections. Sanitation and protective treatments of Cleary's 3336 will help control this disease. Canker disease on Leyland is typically the result of infections from Seiridium or Botryosphaeria fungi. Stem/branch lesions are typically brown and sunken and sticky droplets of resin may be present. Tiny black dots (use hand lens) (fruiting bodies) may be present in and around the edges of lesions. Identification of the pathogen usually requires microscopic study of spore structures. Control requires pruning. Post pruning protective sprays of Cleary's 3336 may help. In addition to the above cases of fungal disease, we have noted the occurrences of secondary fungal needle blights and fungal canker associations. Needle blights have been seen in association with Pestalotia and Macrophoma. We suspect that these fungi are stress-related, causing damage on plants previously weakened or stressed--probably by drought last fall. Also, we have observed Phomopsis and Macrophoma in association with some canker lesions. Again, we believe the activity of these fungi is dependent on plants being in a stressed condition. In addition to the above fungal situations, some samples showed a dieback with no fungi associated. Root stress is again suspect.

Armillaria trunk and root rot of photinia was observed. The diagnosis was based upon the characteristic appearance of the thin white mycelial layer just under the bark of the dying/dead section of trunk. Armillaria will usually cause a sudden wilt/dieback of infected shrubs/trees. Infection takes place in the roots and will spread to the trunk of the plant. When root/truck damage is severe, the top of the plant will typically develop severe symptoms and dieback quickly. In addition to the diagnostic appearance of the mycelium, Armillaria will also produce characteristic black thread-like structures and/or honey-colored mushrooms around the infected roots and base of the trunk. Tree removal is required so as to help prevent movement of the fungus to other trees through root grafts and root infections. See ANR-907 for more information.

Pine needle rust is caused by five species of Coleosporium, and rust pustules on needles are diagnostic for the fungus genus. The pustules appear as cream-colored or orange 2-4 mm swellings on needles. The outer covering of the pustule is cream-colored; the inner rust spores are orange. The orange spores will be carried by wind and will infect plants in the aster or goldenrod groups. Once these plants become infected, new spores are produced which will infect only pine needles. Elimination of the aster-goldenrod species in the area will prevent continuation of this fungus disease, but the complete removal of these weeds is usually impractical. This disease does not typically cause significant damage to the pine and control measures are usually not needed.

Common and Brand canker of rose are caused by two different species of the fungus Coniothyrium. Symptoms of these two canker diseases can be similar. Cankers are generally differentiated on the basis of spore structures. Cankers seen on hybrid tea and miniature rose samples were light brown lesions with reddish-brown or brown margins. The early canker stage of reddish cane blotches was also present. The hybrid tea cankers contained immature black spherical bodies (observable with hand lens) typical of brand or common canker. The miniature rose cankers contained mature bodies with spores typical of common canker (Coniothyrium fuckelii). Control of rose canker diseases requires pruning, making cuts 3-4 inches beyond the edge of the damage. Post-pruning protective fungicides labelled to control black spot will give protective control of fungal canker diseases of rose. J. Olive (Mobile) reports seeing a Puccinia rust on Lantana. He also noted a dieback disease of six foot tall yaupon holly (Ilex vomitoria). Fusarium spores and spore structures were associated with the stem and a vascular discoloration.

Table 1.
1999 MARCH DISEASES SEEN IN THE PLANT DIAGNOSTIC LAB

PlantDiseaseCounty
CamelliaAlgal Leaf SpotButler
CamelliaColletotrichum SpotJackson
GeraniumPythium Stem & Root Rot*
HollyPhytophthora & Pythium Root RotMarshall
Holly, HelleriBotryosphaeria (& Phomopsis) Crown DecayJefferson
Leyland CypressCanker Disease (Suspect Seiridium or Botryosphaeria)Marshall
Leyland CypressCercospora Needle BlightJefferson
Leyland CypressSuspect Root Problem; Secondary Macrophoma and Pestalotia Needle BlightJefferson
Leyland CypressSuspect Root Stress With Secondary Macrophoma and Phomopsis CankersTusaloosa
Magnolia, SouthernPhomopsis Leaf SpotBaldwin
Maple, Dwarf RedPythium Root RotMontgomery
PachysandraPythium Root RotJefferson
PhotiniaArmillaria Root RotMorgan
PinePine Needle Rust (Coleosporium)Covington
PineSooty MoldCoosa
RoseConiothyrium Canker Probably 'Common Canker'Madison
*County locations for nursery/greenhouse problems are not reported. Disease Possibilities For April

April diseases are abundant, and I have included a long list of possibilities for reference purposes.

Cold damage will be much less of a problem this year than some previous years. But, the very early warm temperatures in February followed by a few freezing-temperature nights in late February may have resulted in some cases of trunk/branch cambial injury and bark cracking. This damage will not be obvious to the casual observer until foliage dieback develops later on in the spring, usually developing in March-May. If you see dieback at this time of year, usually occurring after the trees have leafed out normally, check for bark cracks on trunks and lower branches of woody plants.

Rust diseases often become noticeable in March and April. With fusiforme rust on loblolly and slash pine, the rusty spores will cover the fusiforme swellings that develop on branches and trunks. These spores are wind-carried to oaks where infections occur on the leaves. Tiny black leaf spots on the oak will produce orange spores on lower leaf surfaces March-May. These spores are wind-carried and will cause infection of the loblolly and slash pine. Once infection occurs on the pine needles/twigs, 2-3 years may pass before galls develop. Disease control is difficult. In a nursery situation, fungicides are recommended for protective control. (See the Alabama Pest Management Handbook.) In a landscape, usually sanitation is the only practical recommendation. Watch for other rust diseases in April. Cedar-apple rust (also, cedar-quince or cedar-hawthorn rusts) will probably appear in April this year.

Dogwood anthracnose is present in Alabama and has been identified in wooded (mostly state park) areas at elevations of 600 ft. and higher in the northern and northeastern sections of the state. The disease first appears as a leaf spot (brown irregular spots with purple margins) problem, usually in the lower foliage canopy. If conditions are favorable for disease development (60-70(F and wet), leaf spots will spread to involve a leaf blight and eventually a dieback problem. Blighted leaves will typically remain attached to the branches throughout the winter months. Progress of this disease is somewhat restricted in Alabama due to high summer temperatures which are not conducive to disease development and spread. To control this disease in the landscape, sanitation and application of protective fungicide drenches are recommended. See ANR-551 for a list of fungicides.

Dogwood spot anthracnose is a disease that usually is significant only in that it diminishes the beauty of the foliage and blossoms. Tiny red or brown spots may cover the bracts and leaves when weather is wet and warm. When desired, fungicides may be applied for protective disease control. See the Alabama Pest Management Handbook.

Powdery mildews are a problem on a wide variety of plants in the spring when moderate temperatures and high humidity situations exist. The fungus grows in the upper-most epidermal cells of leaves (on upper leaf surfaces) and stems. The white powdery coating on leaves and stems is characteristic of the disease. Infected leaves eventually become yellowed, withered and browned. Control involves sanitation and protective fungicide sprays. See ANR-407 for recommended fungicides. Some of the powdery mildews are also a problem in the summer.

Oedema, another spring problem on a wide variety of plants, develops when plants are subjected to cool, cloudy days and prolonged wet soil conditions. Under these conditions, water uptake by plants may greatly exceed water loss in transpiration. As a consequence, some excessively turgid cells in the leaves burst. These burst cells occur in groups on lower leaf surfaces and they appear as small corky spots. Upper leaf surface areas corresponding to the lower leaf surface corky spots become yellow spotted. The only remedy for oedema is a reduced irrigation schedule and improved soil drainage. Some woody plants damaged by edema are camellia, Eucalyptus, ivy species, jasmine, ligustrum, schefflera, and Fatsia x Fatshedera.

Botrytis blight is a common foliage disease when conditions are wet, humid and temperatures are relatively cool (61-73(F). Leaves and stems may become covered with brown spots and blotches. When conditions are humid and cool, spore production on the spots causes lesions to appear gray with a fine, delicate, superficial, gray fuzzy layer. Disease control can be achieved by sanitation, raising temperatures, increasing air circulation (reducing humidity) and protective fungicide treatments.

The list below includes some common disease problems received in the lab during April of the past few years. Comments on control practices are brief. Refer to fact sheets, timely information sheets, and the Alabama Pest Management Handbook for details.

Table 2.
BRIEF DISEASE DESCRIPTIONS AND CONTROL RECOMMENDATIONS
FOR DISEASES OFTEN SEEN IN APRIL
PlantDiseaseDescriptionControl
Many OrnamentalsPowdery MildewWhite-buff colored, raised dots or pads of mycelium.Fungicides; See Cir. ANR-407.
AmaryllisStagnospora Leaf SpotDark red blotches on leaves (5-15 mm long.)Sanitation; Cleary's 3336 or Domain.
AzaleaBotrytis Petal BlightLarge irregular areas of blossoms turn brown; brown areas are covered with a gray delicate webbing during humid weather.See Ala. Pest Management Handbook.
AzaleaExobasidium GallSwollen blossom, leaf, and shoot galls. From mid-April to mid-May, galls change from a green to a white or pink-white color.Sanitation; removal of galls while they are still green; see the Ala. Pest Management Handbook.
AzaleaOvulinia Petal BlightSmall white-brown spots enlarge to become large browned areas on the blossoms.See Ala. Pest Management Handbook.
AzaleaPhytophthora Crown & Root RotCrowns & roots become brown and water-soaked.Sanitation; See Ala. Pest Management Handbook.
AzaleaRhizoctonia Aerial BlightLower leaves become spotted and eventually whole leaves become dark brown and fall.See Ala. Pest Management Handbook.
BegoniaBacterial Leaf SpotDark, black, water-soaked spots and blotches.Strict sanitation. Do not water overhead.
BoxwoodMacrophoma Blight (Stress)Individual branches become yellowed and brown. Tiny black pin-point dots (fruiting bodies of the fungus) appear scattered on yellowed leaf surfaces; sometimes sunken cankers develop on twigs and branches. Prune out damaged areas. Cleary's 3336 or Domain protective treatments may be applied. Identify and correct other stress problems.
CamelliaArmillaria Root RotSudden dieback; roots show thin white mycelial layer and sometimes black thread-like structures (Rhizomorphs); honey-colored mushrooms are also a diagnostic sign.Remove the plant with associated roots.
CamelliaBotryosphaeria CankerSunken, cracked stem lesions.Sanitation.
CamelliaCercospora Leaf SpotBrown circular or irregular spots of variable size.Sanitation. Cleary's 3336 or Domain protective sprays.
CamelliaExobasidium GallSee Azalea..
CamelliaVirus RingspotsYellow spots and ring spots; may be a reduction in plant growth.Sanitation.
CherrySeptoria Leaf SpotMedium brown, angular spots (about 1 cm or 1/4-1/2 inch long) on leaf surfaces; when severe, defoliation results.Sanitation.
CleyeraAnthracnose (Colletotrichum)Reddish, black spots, blotches. Orange pustules develop in spring and summer.Sanitation; Cleary's 3336 may help.
CrabappleCedar Apple Rust (Gymnosporanium)Light yellow spots (1 cm or 0.5 inch diam.) on leaves; leaf fall when spots are numerous.See the Ala. Pest Management Handbook.
DaylilyKabatiella Leaf SpotNumerous small (5 mm or 1/4 inch long) brown spots; leaf yellowing around spotted areas. The disease is often associated with stress.Sanitation.
DianthusFusarium Crown RotBrown, dried rotted tissues on lower stems. Top dieback.Sanitation. Crop rotation.
DogwoodSpot Anthracnose (Elsinoe) Small (1-2 mm) red-brown spots with reddish borders occur on bracts, leaves, and young twigs. Spotting may be severe and new leaves may appear reduced in size; foliage death may result.Sanitation; See Ala. Pest Management Handbook.
DogwoodAnthracnose (Discula)This disease is characterized by leaf necrosis, twig and branch cankers and stem dieback which all begin in the lower branches and progress to the upper canopy. The disease generally begins as purple-rimmed brown spots on leaves. Spots soon develop into a general blight of infected leaves. Leaf death is followed byprogressive infection and death of associated twigs and then branches.See ANR-551 or the Ala. Pest Management Handbook.
EuonomyusPowdery Mildew (Microsphaera)A white powdery dusting appears on upper leaf surfaces; when disease is severe some leaf distortion occurs.See the Ala. Pest Management Handbook.
ExacumImpatiens Necrotic Spot VirusNew growth was stunted. Brown spots and blotches were present on the newly matured foliage.Sanitation. Control thrips.
Fern, BostonColletotrichum Leaf SpotBrown spots/blotches on fronds.Sanitation. Protective sprays of Cleary's 3336.
ForsythiaCrown GallWoody Galls on lower stem/trunk near the soil line.Sanitation; crop rotation to boxwood, holly, redbud or other nonsusceptible plants. See ANR-944.
GeraniumBotrytis BlightGray blotches occur on the foliage. Whole leaves may become involved and die. When weather is cool and moist with a high relative humidity, a delicate webbing of spores and hyphae can be seen.See the Ala. Pest Management Handbook. Sanitation.
GeraniumBacterial Leaf Spot/Stem Rot (Xanthomonas)Black spots on leaves and stems; total collapse of stem may occur; bacteria may develop in vascular system and become systemic.Strict sanitation. Bordeaux mixture protective sprays.
Holly, HelleriPhytophthora Root RotRoots become brown and decayed. Outer tissues easily pull away from the root central core.See the Ala. Pest Management Handbook.
HollyColletotrichum Leaf SpotBlack circular spots (about 5mm diam.) sometimes with cream-colored spores covering centers of spots.Sanitation; protective sprays of Cleary's 3336 or Domain may be used.
HollyPhyllosticta Leaf SpotSmall (1-2mm diam.) black spots sometimes with a whitish center.Sanitation; protective sprays of Cleary's 3336 or Domain may be used.
HydrangeaBotrytis Blossom BlightBlossoms are brown-gray spotted/blotched.Sanitation. See ANR-912 for fungicide recommendations.
ImpatiensAlternaria Leaf SpotDark brown-black, angular leaf spots.Sanitation; Kocide 101.
IrisHeterosporium Leaf SpotSmall-large (1/4-1/2 inch long), elliptical or oval shaped medium brown leaf spots.Sanitation. See Ala. Pest Management Handbook.
IrisBorers/Soft Rot (Erwinia)Leaves and rhizomes become decayed with a wet, foul-smelling rot; wounds are often evident in the rhizome rotted areas. Wounds are often caused by the iris borer, but other insects may be involved.Sanitation. Especially in the fall, all diseased rhizomes should be destroyed. To further prevent & control borers, an insecticide dust may be applied weekly in the spring from new growth initiation to the beginning of June.
IvyAnthracnose (Colletotrichum)Brown irregular spots (3 mm diam. & larger) that sometimes occur along veins.Sanitation. See the Ala. Pesticide Handbook. Use Cleary's 3336 or Domain.
Japanese Pagoda TreeNectria CankerSunken canker with tiny orange raised specks scattered over lesion.Sanitation.
JuniperPhomopsis Tip BlightDieback.Pruning; Fungicide application. See the Ala. Pesticide Handbook.
JuniperCedar-Apple Rust (Gymnosporangium)Large woody spherical galls (2-5 cm diam.) become covered with orange, jelly-like finger-like projections. See ANR-468.
JuniperCedar-Quince or Hawthorn Rust (Gymnosporangium)Orange powdery sunken cankers.See ANR-468.
Leyland CypressCercospora Needle BlightBeginning with lower branches and inner needles, blight develops and spreads upward & outward.Sanitation; protective sprays of Cleary's 3336.
LigustrumMacrophoma Leaf SpotBrown circular or oval leaf spots.Sanitation; Cleary's 3336 or Domain protective sprays.
LilacBacterial Leaf SpotDark angular spots.Sanitation. Do not water overhead.
LiriopeAnthracnose (Colletotrichum)Brown lesions on leaves, some on leaf tips.Sanitation. Protective sprays with Cleary's 3336.
LupinRhizoctonia Lower Stem DecayDark brown, black lower stem dry rot.---
Magnolia, SouthernAlgal Leaf Spot (Cephaleuros)Green or red-brown, slightly raised, circular spots (1 cm diam.) with slightly wavy margins.Usually none. Sanitation.
Magnolia, SouthernPhyllosticta Leaf SpotBrown irregular spots (3 mm diam. and larger) which often become brown bordered with lighter centers as spots age. Sanitation. Protective sprays of Cleary's 3336 or Domain.
MagnoliaStressMany older leaves become yellow and then brown; excessive leaf drop. (Some leaf senescence is normal during April-June.)Water when conditions are droughty.
Maple, JapaneseAnthracnose (Kabatiella)Brown, irregularly-circular spots which often follow along leaf veins. Spots begin small, but may develop to involve larger portions of leaves.See Ala. Pest Management Handbook.
Maple, JapanesePhomopsis CankerBrown-gray elliptical sunken lesions on smaller branches, twigs.Sanitation.
Maple, RedPhyllosticta Leaf SpotCircular pale brown spots with darker brown borders (about 1/4 inch diam.).--
Maple, RedPythium Root Rot (Seedlings)Roots brown, water-soaked, rotted.Sanitation. Reduce watering schedules.
MarigoldAlternaria Leaf SpotBlack circular or irregular leaf spots (1-3 mm diam.).See Ala. Pest Management Handbook.
Mayhaw (Hawthorn)Cedar-Quince Rust (Gymnosporangium)Yellow irregular spots with tiny white-orange aecial cups (spore masses) developing on lower leaf surfaces opposite upper leaf yellow spots.Removal of cedar cankers. See ANR-468.
OakAnthracnose (Apiognomonia)Brown-black spots and irregular blotches which often develop along leaf edges and/or leaf veins.Sanitation. See Ala. Pest Management Handbook.
OakAlgal Leaf Spot (Cephaleuros)Gray-green or brown-red spots with irregular margins (1 cm or 1/4 inch diam.) on leaves; spots may coalesce.See Ala. Pest Management Handbook.
OakHypoxylon CankerEnvironmental stressed oak may develop a dieback where Hypoxylon acts to hasten the dieback problems. The fungus causes decay of inner bark and sapwood and silver gray or coal black stroma develops in the decay area, causing the bark to crack and fall away.Pruning and tree removal.
OakOak Leaf Blister (Taphrina)Concave-convex spots (10-15 mm or 1/4-1/2 inch diam.) on leaves. As spots age, they change from a light green-brown color to a medium-dark brown.See Ala. Pest Management Handbook.
OakPowdery MildewWhite powdery dusting on leaves; infected new growth may be deformed.Sanitation of leaves in the fall.
PansyColletotrichum Leaf SpotCircular gray spots with dark borders.See the Ala. Pest Management Handbook.
PansyThielaviopsis Black Root RotBlack lesions on roots. Plants are stunted.Sanitation. See the Ala. Pest Management Handbook.
PeriwinkleBotrytis BlightBrown gray spot/blight.Sanitation. Increase air circulation. Increase temperature. See the Ala. Pest Management Handbook.
PeriwinklePhyllosticta Leaf SpotMedium-brown, circular-oval spots (5 mm diam.).Sanitation; Protective sprays of Cleary's 3336 or Domain.
PeriwinklePhytophthora BlightBrown lesions on leaves and stems.Sanitation. See Ala. Pest Management Handbook.
PeriwinkleThielaviopsis Root RotPlants grow poorly. Roots have black lesions, sections, and tips.Sanitation. Cleary's 3336 protective drenches.
PetuniaThielaviopsis Root RotPlants grow poorly. Roots have black lesions, sections, and tips.Sanitation; Cleary's 3336 protective drenches.
PhotiniaAnthracnose (Colletotrichum)Light-brown, zonate spots (10-15 mm or 1/3 - 2/3 inch long) sometimes associated with leaf margins.Sanitation; See Ala. Pest Management Handbook under Entomosporium Leaf Spot.
Pine, LoblollyFusiforme Rust (Cronartium quercuum f. sp. fusiforme) Spindle-shaped (fusiform) swellings (galls) develop on branches and trunks. In March-April the orange spore masses (aecia) of the fungus develop on the bark surface. The powdery spores cover the whole gall area. (Oaks are the alternate host for this fungus.)Sanitation; removal of galled branches and/or trees when galls occur on trunks. See the Ala. Pest Management Handbook.
Pine, LoblollyLophodermium (Ploioderma) Needle CastLast year's needles become spotted, blighted, and fall off. Tiny, black football-shaped fungal fruiting bodies can be seen on needles with hand lens.Fungicide applied in spring and fall. See Ala. Pest Management Handbook.
Pine, LoblollyRhizosphaeria Needle Blight, Twig BlightNeedles and small twigs turn brown, die.Sanitation. See spray recommendations for needle cast; may need to continue in summer.
Pine, SlashRhizosphaeria Needle BlightSee Pine, Loblolly..
Pine, VirginiaLophodermium Needle CastSee Loblolly Pine..
PineNeedle Rust (Coleosporium)Needles covered with numerous cream-color pustules (2-3 mm).Remove asters and other composite plants/weeds in the area.
Red CedarArmillaria Root RotDieback and total death of tree. Mushrooms or black thread-like structures may develop at base of tree and just under the bark, respectively.Sanitation.
RoseBotrytis BlightGray-brown irregular areas on flowers and leaves; gray mycelium and spores give spots/blotches a gray, cloudy appearance.Lower humidity levels; increase temperatures; prune out diseased plant parts; fungicides.
RoseBlack Spot (Diplocarpon)Black spots (1/8-1/4 inch diam. or 4-8 mm) with feathery margins.Follow a regular spray schedule; sanitation.
RoseDowny Mildew (Pernospora)Irregular pale yellow spots on upper leaf surfaces; grayish-sometimes with thread-like growth-spots on lower leaf surfaces. Leaves eventually become brown, withered and drop.Sanitation. See Ala. Pest Management Handbook. Decrease humidity.
RosePowdery Mildew (Sphaerotheca)Whitish powdery growth on leaf surfaces; new growth may be distorted; leaves dry & turn yellow then brown; leaf drop. See Ala. Pest Management Handbook.
Shasta DaisyAlternaria Leaf SpotGray-brown, roughly circular spots.Sanitation. Cleary's 3336 or a benomyl fungicide should give some protective control.
SnapdragonPythium Root RotFoliage wilt; roots brown and water-soaked.Sanitation. See Ala. Pest Management Handbook.
Tulip PoplarAlternaria Leaf SpotMedium-brown, circular-irregular spots (1-2 cm or 1/3-2/3 inch long).Sanitation.

(from Jackie Mullen's Monthly Plant Problem Report from the Plant Diagnostic Lab-March, dated April 12, 1999)

UPCOMING EVENTS:

July 22-27, 1999:
American Nursery & Landscape Association Annual Convention.
Philadelphia, PA. Contact ANLA at 202-789-2900; http://www.anla.org

July 28-31, 1999:
96th American Society for Horticultural Science.
Minneapolis Convention Center, Minneapolis, MN. Contact ASHA: 703-836-4606, Fax: 703-836-2024; e-mail: ashs@ashs.org

July 30-August 1, 1999:
SNA 99 - Southern Nurserymen's Association Researcher's Conference and Trade Show.
Georgia World Congress Center, Atlanta, GA. Contact SNA at 770-973-9026; SNA Infoline at 770-973-4636;
http://www.sna.org

August 1-4, 1999:
International Society for Arboriculture Annual Conference. Stamford, CT. Contact ISA at 217-355-9411; http://www.ag.uiuc.edu/~isa

September 10-11, 1999:
TNA's "Tennessee America's Nursery" Trade Show and Conference.
Opryland Hotel Convention Center, Nashville, TN. Contact TNA at 931-473-3971; fax 931-473-5883; e-mail nurseryassn@blomand.net

September 23-25, 1999:
6th Biennial Southern Plant Conference.
Richmond, VA. Contact SNA at 770-973-9026; SNA Infoline at 770-973-4636; http://www.sna.org

October 3-6, 1999:
Southern Region International Plant Propagators' Society.
Mobile, AL. Contact David Morgan: 817-882-4148, SR IPPS, P.O. Box 1868, Ft. Worth, TX 76101; e-mail dmorgan@bsipublishing.com

October 8 and 9, 1999:
Middle Tennessee Nursery Association Horticulture Trade Show.
Civic Center, McMinnville, Tennessee. For more information call 931-668-7322, fax 931-668-9601; e-mail: MTNA@blomand.net
www.growit.com/MTNA

November 4-6, 1999:
Gulf Coast Native Plant Conference
Camp Beckwith, Fairhope, Alabama
Featuring four habitats with guided field trips. For more information contact Thayer Dodd, Conference Coordinator, at 1-888-808-3633

January 11-13, 2000:
Kentucky Landscape Industries Winter Educational Conference and Trade Show.
The Lexington Center, Lexington, KY. Contact Debbie Cain, KNLA Exec. Dir. at 502-899-3622; fax 502-899-7922

January 19-21, 2000:
Mid-AM Trade Show.
Navy Pier, Chicago, IL. Contact Don W. Sanford at 847-526-2010, fax 847-526-3993; e-mail midam@mc.net

January 29-February 2, 2000:
Southern Region American Society for Horticultural Science Annual Convention.
Lexington, KY. Contact Paul Smeal at 1107 Kentwood Drive, Blacksburg, VA 24060-5656, 540-552-4085; fax 540-953-0805; e-mail psmeal@vt.edu

February 3-6, 2000:
The Management Clinic.
Galt House, Louisville, KT. Contact ANLA at 202-789-2900; http://www.anla.org

June 1-3, 1999:
Mid-South Greenhouse Growers Conference.
Ramada Inn - Southwest Conference Center in Jackson, MS. More information will be available soon or you can contact Allen Owings, Extension Horticulturist at LSU.

July 8-12, 2000:
Ohio Florists' Association Short Course and Trade Show.
Greater Columbus Convention Center. Contact OFA at 614-487-1117; e-mail ofa@ofa.org; web: http://www.ofa.org

July 11-16, 2000:
American Nursery & Landscape Association Annual Convention.
Location TBA; contact ANLA at 202-789-2900; http://www.anla.org

July 14-18, 2000:
Ohio Florists' Association Short Course and Trade Show.
Greater Columbus Convention Center. Contact OFA at 614-487-1117; e-mail ofa@ofa.org; web: http://www.ofa.org

July 16-19, 2000:
American Society for Horticultural Science 97th International Conference.
Disney Coronado Springs Resort, Orlando, FL. Contact ASHS at 703-836-4606; fax 703-836-2024; e-mail ashs@ashs.org

August 3-6, 2000:
SNA 2000 - Southern Nurserymen's Association Researcher's Conference and Trade Show.
Georgia World Congress Center, Atlanta, GA. Contact SNA at 770-973-9026; SNA Infoline at 770-973-4636; http://www.sna.org

August 11-18, 2000:
International Society for Arboriculture Annual Conference.
Baltimore, MD. Contact ISA at 217-355-9411; http://www.ag.uiuc.edu/~isa

September 15-16, 2000:
TNA's "Tennessee America's Nursery" Trade Show and Conference.
Opryland Hotel Convention Center, Nashville, TN. Contact TNA at931-473-3971; fax 931-473-5883; e-mail tnurseryassn@blomand.net

October 8-11, 2000:
Southern Region International Plant Propagators' Society.
Norfolk, VA. Contact David Morgan at 817-882-4148; fax 817-882-4121, SR IPPS, P.O. Box 1868, Ft. Worth, TX 76101; e-mail dmorgan@bsipublishing.com

January 27-31, 2001:
Southern Region American Society for Horticultural Science Annual Convention.
Fort Worth, TX. Contact Paul Smeal at 1107 Kentwood Drive, Blacksburg, VA 24060-5656, 540-552-4085; fax 540-953-0805, e-mail psmeal@vt.edu

August 2-5, 2001:
SNA 2001 - Southern Nurserymen's Association Researcher's Conference and Trade Show.
Georgia World Congress Center, Atlanta, GA. Contact SNA at 770-973-9026; SNA Infoline at 770-973-4636; http://www.sna.org

October 18-21, 2001:
Southern Region International Plant Propagators' Society.
Houston, TX. Contact David Morgan at 817-882-4148; fax: 817-882-4121; SR IPPS, P.O. Box 1868, Ft. Worth, TX 76101; e-mail: dmorgan@bsipublishing.com

Send questions and comments to bfischma@acesag.auburn.edu.

Letters to Bernice Fischman - 101 Funchess Hall - Auburn University, AL 36849.