May 2002

Happy May!

Instead of Tilt Ramblings this month we offer up the Fischman apology. I have a new computer and had that classic delete moment (so well illustrated in a cartoon I've seen many times featuring someone sitting at a computer, hitting the delete button by mistake and seeing all of their files disappear in a puff of smoke). I did something that deleted everything from the zip disk where I store all of my current newsletter files. It didn't seem practical to redo everything (since it is already May 8th) that I had lost so we are just including the Plant Pathology report and Upcoming Events and next month we will publish photos of 30 of the 600 azaleas planted at the Piedmont Substation as well as summaries of articles on consumer poinsettia preferences and fungicides for leaf spot diseases of ornamentals. Ken will tell you more about his recent trip to China and we will find other things of interest.

Much more in June,
Bernice Fischman

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:





Jackie Mullen
Extension Plant Pathology Specialist

Most of our 74 samples were ornamentals and turf grasses. Brown patch (Rhizoctonia) was noted on bermuda, centipede, and St. Augustine grass from areas in the southern half of the state. Colletotrichum leaf spot disease was noted on azalea and Carolina Jessamine. Macrophoma and Volutella blights were observed on boxwoods. The Colletotrichum fungus is known to exist as a primary or secondary disease agent. Macrophoma and Volutella are both considered to be stress-related pathogens. These leaf spots and blights often occur on azalea and boxwood in early spring, and I suspect these pathogens may be dependent on stress (in this case winter time stresses) in order for plants to be weakened and thereby more susceptible to infection.

Entomosporium leaf spot was a common disease on photinia and Indian hawthorn. Spots are red with dark black pustules (tiny, cup-shaped bodies containing spores) scattered across the surface of the leaf spots. Spore bodies do not often form on the cleyera, but the red spot symptom is similar to that seen on Indian hawthorn. Cleyera spots may be smaller than spots seen on Indian hawthorn or photinia. Entomosporium leaf spot is a difficult disease to control, even when regular fungicide treatments are applied.

A crown rot was noted on some cyclamen plants being sold for Valentine=s Day in the Auburn area. Culture isolations consistently produced the fungus Fusarium which is reported to cause crown rot of cyclamen.

Daylily rust (Puccinia hemerocallidis) was observed on a sample from Butler County and reports indicate it was present in other scattered areas of the state in landscapes and greenhouses. Sanitation and protective fungicide sprays are recommended. See the Timely Information PP-506 by A. Hagan.

Cercosporella blight (formerly called Cercospora) of Leyland cypress was observed in a sample from Choctaw County. This disease can cause a serious needle/leaf blight. See the AL Pest Management Handbook for information on controlling this disease with protective fungicide treatments.

A sample of oats from Coffee County was diagnosed as suspect barley yellow dwarf virus. Older leaves were showing a yellow-red discoloration which seemed to have begun at the leaf tips and generally moved downward. Plants were stunted and tillering was reduced.

A rose canker disease from Lawrence County was diagnosed as brown canker caused by the fungus Diaporthe umbrina. Spores of the fungus were present on the old cankers which appeared as small whitish lesions on the canes. Sanitation (pruning) and protective fungicide treatments (See fungicides labelled for control of black spot.) are usually recommended for control of rose canker diseases.

A severe bacterial leaf spot disease on strawberry was sent to us from Escambia County. Leaf spots were black and angular. Microscopic study showed the presence of active bacterial streaming. See the AL Pest Management Handbook for control recommendations.

A greenhouse tomato sample arrived in the lab looking like a foliage burn. Leaves of the 3 inch tall plants showed bleached, dried lesions and blotches. After a couple of days, the lower stems developed a glassy water-soaked appearance and some plants developed a crown decay. Moist chamber incubations produced the diagnostic spore structures of Phytophthora infestans. This sample was unusual because the typical dark brown, wet, necrotic, foliage lesions did not develop. See the AL Pest Management Handbook for information on control of late blight.

March 2002 Plant Diseases Seen In The Plant Diagnostic Lab at Auburn

AzaleaColletotrichum Leaf SpotCovington
BermudaBrown Patch (Rhizoctonia)Florida
BlackberryAnthracnose (Colletotrichum)Baldwin, Houston
BoxwoodMacrophoma BlightGeorgia
BoxwoodVolutella BlightGeorgia
Carolina JessamineColletotrichum Leaf SpotLimestone
CentipedeBrown Patch (Rhizoctonia)Montgomery
CleyeraEntomosporium Leaf SpotHouston
CyclamenFusarium Crown RotLee
DaylilyDaylily Rust (Puccinia hemerocallidis)Butler
HollyToo Wet and Pythium Root Rot *
Indian HawthornEntomosporium Leaf SpotHouston
Leyland CypressCercosporella BlightChoctaw
PinePloioderma Needle CastCoffee
PineRhizosphaeria Needle CastCoffee
PlumBlack Knot (Plowrightia morbosum)Russell
RoseBrown Canker (Diaporthe umbrina)Lawrence
St. AugustineBrown Patch (Rhizoctonia)Montgomery
St. AugustineTake-All Patch (Gaeumannomyces graminis pv graminisMontgomery
ZinniaBotrytis CankerJackson
*Counties are not reported for greenhouse and nursery samples.

J. Jacobi
Extension Plant Pathology Specialist

The lab received 54 samples for the month. Cold injury was a common problem seen on roses and other woody ornamentals after hard freezes in late February and early March. Some of the problems received last month included spruce spider mite damage to arborvitae and juniper, Phytophthora root rot on azalea and boxwood, leaf miner on boxwood, Cercospora leaf spot on leucothoe, herbicide injury to southern magnolia, rose rust, and daylily leaf streak. Leaf streak is caused by the fungus Aureobasidium microstictum. Symptoms include circular to elongate tan to brown spots and yellowing along the central vein. Research by Holcomb (1976) indicated that cultivars vary considerably in their susceptibility to fungus that causes leaf streak. Both of the daylily samples were brought to the lab to check for daylily rust, but it was not observed on these samples. In the early stages of disease development, leaf streak might be confused with the early symptoms of daylily rust (Puccinia hemerocallidis). The main difference is that rust produces raised spots or pustules on infected leaves. These pustules will produce yellow-orange powdery spores that can easily be rubbed off. Leaf streak is not considered a serious disease and can be controlled by removing infected leaves, avoiding overhead irrigation and cultivar selection.

Cercospora leaf spot was seen on leucothoe. This disease causes small tan leaf spots that may enlarge to cover large areas of the leaf. In severe cases, defoliation may occur. Control can be achieved by raking fallen leaves and application of fungicides to protect new growth in spring. Multiple applications may be needed during periods of extended wet weather.

Leaf miner was a frequent problem seen on common boxwood last month. Infested leaves are often off-color (yellow-orange or brown) and may drop earlier than healthy leaves. The leaf miner overwinters within the leaf as larvae. Adults emerge the following spring just as growth starts on the boxwoods. These small, orangish flies (less than 1/8 inch) can be seen swarming around boxwoods, especially in the morning. The adults have emerged in the Birmingham area and are active at this time. Leafminer can be controlled when damage becomes excessive by the application of insecticides. Insecticides are most effective immediately after the adult emerge and before the eggs are laid. The application of insecticides that contain the active ingredient acephate, or imidocloprid when adults are active is an effective control measure. Follow label instructions carefully.

2002 March Diseases Seen In The Birmingham Plant Diagnostic Lab

ArborvitaeSpruce Spider MiteJefferson
AppleWoolly Apple AphidJefferson
AucubaVole damageJefferson
AzaleaChemical InjuryJefferson
AzaleaCold InjuryJefferson
AzaleaPhytophthora root rotJefferson
Boxwood, CommonLeaf minerJefferson (2)
Boxwood, CommonPhytophthora Root Rot*
CherrylaurelCercospora Leaf SpotJefferson
ClematisCold Injury/AphidsJefferson
Cypress, LeylandSeridium CankerJefferson
DaylilyLeaf streak (Aurobasidium)* (2)
LeucothoeCercospora Leaf SpotJefferson
JuniperSpruce Spider MiteJefferson
Magnolia, SouthernHerbicide InjuryJefferson
PlumBlack knotJefferson
RoseCold InjuryJefferson
Yew, JapanesePoor Drainage/Pythium root rotJefferson
Disease Possibilities for April

Go to:
Disease Reports see a list of some common disease problems received in the lab during April of the past few years. Comments on control practices are brief. Refer to the fact sheets, timely informations, 2000 or 2001 spray guides, and the Alabama Pest Management Handbook for details.


April to October, 2002:
Floriade 2002.
See the AmeriGarden (5,400 square feet), part of the world horticulture exhibition in the Netherlands.
For more information call 808-961-6660 or visit or

May 31 - June 1, 2002:
A Center for Applied Nursery Research Topical Meeting
Hydrangeas - Beginning to End
Augusta Technical College and the Center for Applied Nursery Research
Thomson and Dearing, GA
Call 706-597-8309; Internet:

June 19 - 22, 2002:
Southeast Greenhouse Conference and Trade Show.
Greenville, South Carolina
Information for attendees call: 1-877-927-2775; for exhibitors call: 1-800-453-3070 URL:

July 12 - 15, 2002:
ANLA Convention & Executive Learning Retreat.
San Diego, CA. Contact ANLA at 202-789-2900; Fax, 202-789-1893

July 25 - 27, 2002:
Cullowhee Conference: Native Plants in the Landscape.
Western Carolina University, Cullowhee, North Carolina
For information call 770-922-7292.

August 1-4, 2002:
SNA 2002 - Southern Nursery Association Researcherís Conference and Trade Show
Georgia World Congress Center, Atlanta, GA.
Contact SNA at 770-953-3311; Fax 770-953-4411; SNA Infoline, 770-953-4636; e mail:

August 11-17, 2002:
American Society for Horticultural Science and XXVI International Horticultural Congress & Exhibition.
Metro Toronto Convention Centre, Toronto, Ontario, Canada.
Contact ASHS at 703-836-4606, Fax: 703-836-2024, E-mail:

September 26, 2002:
Fletcher Field Day.
Ornamentals field day at the Mountain Horticultural Crops Research Station in Fletcher, North Carolina.
Contact Dick Bir ( for more information.

September 29-October 2, 2002:
Eastern Region International Plant Propagators' Society NA and IPPS Southern Region NA Annual Meeting.
Hunt Valley (Baltimore), MD.
Contact Margot Bridgen at 26 Woodland Road, Storrs, CT 06268; 860-429-6818, E-mail: or Dr. David L. Morgan, 332 Warbler Drive, Bedford, TX 76021; ph. 817-577-9272; e-mail,

October 4-5, 2002:
Middle Tennessee Nursery Association Horticultural Trade Show.
McMinnville Civic Center, McMinnville, TN
phone: 931-668-7322; fax: 931-668-9601; e-mail:, or

January 15-17, 2003:
Mid-AM Trade Show.
Navy Pier, Chicago, IL. Contact: Rand Baldwin at 847-526-2010, Fax 847-526-3993, e-mail

January 30 - February 02, 2003:
ANLA Management Clinic.
Louisville, KY.
Contact ANLA at 202-789-2900; Fax, 202-789-1893

February 23-26, 2002:
Plasticulture 2002.
30th American Agricultural Plastics Congress
Contact ASP at 717-238-9762, Fax 717-239-9985, e-mail

July 15 - 20, 2003:
ANLA Convention & Executive Learning Retreat.
Location TBA. Contact: ANLA, 202-789-2900; Fax, 202-789-1893.

July 30-August 2, 2003:
SNA 2003- Southern Nursery Association Researcherís Conference and Trade Show.
Georgia World Congress Center, Atlanta, GA.
Contact SNA at 770-953-3311; Fax 770-953-4411; SNA Infoline, 770-953-4636.

September 30 - October 4, 2003:
American Society for Horticultural Science Annual Meeting and 100th Anniversary.
Providence, RI.
Contact ASHS at 703-836-4606, Fax: 703-836-2024, E-mail:

October 3-4, 2003:
Middle Tennessee Nursery Association Horticultural Trade Show.
McMinnville Civic Center, McMinnville, TN
phone: 931-668-7322; fax: 931-668-9601; e-mail:, or

October 5-8, 2003:
IPPS Southern Region NA.
San Antonio, TX.
Contact: Dr. David L. Morgan, 332 Warbler Drive, Bedford, TX 76021; phone 817-577-9272; e-mail,

July 29 - 31, 2004:
SNA 2004 - Southern Nursery Association Researcherís Conference and Trade Show.
Georgia World Congress Center, Atlanta, GA.
Contact: SNA 770-953-3311; Fax 770-953-4411; SNA Infoline, 770-953-4636

October 1-2, 2004:
Middle Tennessee Nursery Association Horticultural Trade Show.
McMinnville Civic Center, McMinnville, TN
phone: 931-668-7322; fax: 931-668-9601; e-mail:, or

October 3-6, 2004:
IPPS Southern Region NA
Greenville/Spartanburg, S.C.
Contact: Dr. David L. Morgan, 332 Warbler Drive, Bedford, TX 76021; phone 817-577-9272; e-mail,

Send horticultural questions and comments to

Send questions and comments to

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