May 2001

It is May and without talking to anyone in the nursery business, I know you are behind. I have never talked to anyone in the business that needed some help in finding something to do. The definition of Horticulture is aptly described as intense management or garden cultivation. The operative word is "intense". I know a number of people who are fanatics about having everything done before they leave work. They would have a short life in the nursery business.

Please take a look at our plant identification page, if you have not seen it. It is a work in progress designed for our certified nursery program and to help our students in their plant identification courses. I noticed Mike Dirr and PlantAmerica had a new addition of his plants on CD along with the herbaceous plants library from Allan Armitage. If you need to have all the cultivars of woody and herbaceous plants on hand, these CDs would be good to invest in.

Water is the life’s blood of our business and last year we found out what can happen when shortages occur. The problems were not at the nursery but on the landscape end where Birmingham imposed restrictions on watering of turf and landscapes. So, landscaping came to a halt and plants jackknifed at the nursery gate. The Alabama Nurserymen’s Association (ANA) and some good, rabid nursery producers worked hard to educate the city officials. ANA along with ALFA are trying to take some proactive steps to influence legislation and irrigation practices to avoid this problem as much as possible this year and in the future. They voted to provide educational materials and seminars to offer alternative plans for city officials this year.

Water is continually in the news. Last month, I read about the imposition of water restrictions for the nurseries in Florida. Another article this month discussed Wichita Falls, Texas where the Water Resource Commission is currently working on a proposal to submit to their City Council a permanent water use ordinance. Without nursery leader intervention there, the ordinance would have created a similar hardship to the lawn and landscape industry as Birmingham nurseries experienced last year. The commission settled on a draft document including a permanent ban on outdoor irrigating from 11 a.m. to 6 p.m. any day of the week. It also saved a provision that requires hand-held hoses to have a shut off nozzle.

In the paper today, news from the “Water Wars” with Alabama, Georgia and Florida announced another extension to find a peaceful settlement to who gets what and how much for how long. Much of the research today is trying to address the shortages and regulations that are surely coming. A summary of one of those efforts is included below. Research takes time. Hopefully the answers will be ready before they turn off the pump.

I hope you will be able to remain a respectable distance behind this month. Give us a call if we can help. Of course, we are fighting that same battle and probably not doing as well as you. Have a nice May.


The following articles are featured in this month's Something to Grow On:








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.


From Wheeler Foshee, Pesticide Information Specialist, ACES, Auburn University

Syngenta, the major manufacturer of diazinon, has agreed with EPA to phase out production of this widely used insecticide. All indoor uses will end by March 2001. In the fall, its use inside and around the home was cancelled. Diazinon will still be available for purchase at retail and home-garden centers until 2004. However, the amount of diazinon manufactured will be decreased by 25% in 2002 and by 50% in 2003. Also, sales to retailers will stop by August 2003. It is important to note that existing stocks of diazinon can and should be used according to the label. It is unknown if other companies will pick up the existing agricultural uses for diazinon. However, Sygenta will not continue to sell or market in the agricultural crops area after 2004.

The fate of malathion now appears to be clearer. EPA has released its preliminary risk assessment of malathion and the news is mixed. Dietary, drinking water, carcinogenicity, and most home and garden risks are not a concern for EPA. A few residential applications are troubling: adult applicator and toddler post-application exposure to turf. Some risks to applicators could increase the restricted entry interval (REI) for some agricultural applications. For instance, it is proposed that the REI for peaches will be 3 days for hand thinning and 5 days for thinning.

It appears that most homeowner applications will be re-approved. Turf applications have some "sticky points" yet to be decided. The following uses are being proposed to be DELETED for malathion:

All other current labels appear to be headed for approval - but it isn't final yet.

It's not too late for you to make your opinions known on these issues. You can write to the EPA. Before writing, though, you may want to read some of the prelimiary health risk and other data, which is posted on the web. The address is:

You can send comments electronically to the EPA to Be sure to add the correct docket number for malathion (OPP-34223B) in the subject line of your message or hard-copy letter which should be addressed to:
Public Information and Records Integrity Branch
Information Resources and Services Division (7502C)
Office of Pesticide Programs
Environmental Protection Agency
401 M St., SW
Washington, DC 20460

Be aware that the agreement with EPA concerning chlorypyrifos (Lorsban and Dursban) mandated that ll Lorsban 4EC formulations are not restricted used pesticides (RUPs). The granular formulation of Lorsban is still in general use.


Consumer and Professional Chefs have been surveyed on their reactions to the taste of three edible-flower species, Viola tricolor 'Helen Mount' (viola), Borago officinalis (borage), and Tropaeolum majus 'Jewel Mix' (nasturtium). Authors of the study wanted to determine opinions and preferences for taste, fragrance and visual appeal of these flowers. The attributes were rated as:
VISUAL - "appealing","desirable," and "very interested in tasting"
FRAGRANCE - "appealing" and "pleasant"
TASTE - "tasty" and "desirable".

Seventy-six percent of consumers rated the three species on visual appeal and desire as acceptable. Similar results were found with consumers on taste and participants indicated they would likely purchase and serve the flowers. Sixty-six percent of the participating chefs from the members of the Michigan Chefs de Cuisine Association found "acceptable" the visual and fragrance qualities of viola and nasturtium. Chefs' ratings of the fragrance of borage as "appealing" and "pleasant" were higher than those of consumers but still low for this flower. While the consumers liked the taste of viola, only 29% of the chefs found the taste of viola appealing and desirable.

(from an article, "Consumer and Professional Chef Perceptions of Three Edible-flower Species" by Kathleen M. Kelley, Bridget K. Behe, John A. Biernbaum, and Kenneth L. Poff, published in HortScience, Vol. 36, No. 1)


Ornamental grasses are becoming a popular addition to landscapes. They require little maintenance, are drought tolerant, survive in difficult sites and are relatively pest free. They provide movement, varying textures, form, and a natural look to the landscape. They are usually propagated from seed and crown division. It is necessary to use vegetative propagation to maintain specific cultivars. This study found good success in rooting culm cuttings of tender purple fountaingrass with the nodes at the base showing the highest rooting potential.

The grass used in this study, Pennisetum setaceum 'Rubrum' is an attractive bunch grass with narrow, dark purple-red foliage approximately 3.2 feet in height with an upright-arching growth habit and pink-red flower spikes 12 inches or longer. It can be used as a specimen plant, in combination with other perennials, in containers, or in mass plantings.

Availability of this grass has been limited. It is killed by frost, so stock plants must be over-wintered for successful propagation. This popular, attractive grass has not been widely available due to limited method of propagation. This study investigated the feasibility of using culm cuttings as a method of propagation. The culm is the flowering stem of a grass plant. Culms are generally hollow except at the nodes where there are transverse partitions. Roots form readily at the nodes of the shoots. This study investigated the formation of P. setaceum 'Rubrum' shoots and roots from culm cuttings taken from three node positions, in different rooting media (sand, coarse perlite, sphagnum peat, vermiculite, and sphagnum peat:part coarse perlite), and with or without the use of indole-3-butyric acid (IBA).

Results showed that the older nodes were the most successful in forming roots. Pennisetum setaceum 'Rubrum' can be successfully propagated from culm cuttings. All nodes showed potential for successful propagation; nodes closest to the crown had a significantly higher percentage of rooted cuttings and adventitious roots.

(from a research report, Propagation of Pennisetum setaceum 'Rubrum' from Cuttings, published in the Journal of Environmental Horticulture 19(1):1-3. March 2001 by Bruce A. Cunliffe, Mary Hockenberry Meyer, and Peter D. Ascher from the University of Minnesota).


The perennial problem of having enough water for horticulture crops is particularly acute in Florida. Declining water resources and water quality problems have resulted in an increased need for water conserving irrigation techniques as well as improved water management methods. A growing population and increased industrial development severely constrains water needed for irrigation purposes. Future water regulations affecting Florida's nursery industry (85% of the value of Florida landscape and foliage crops is from container-produced materials) may require an application efficiency of 75% for overhead sprinkler irrigation systems.

An efficient water management system would use rainfall in such a way that would eliminate or minimize runoff. A new plant production system, Multi-Pot Box System (MPBS), addresses this concern. It increases irrigation efficiency and utilizes rainfall harvesting techniques for container-grown crops. The system captures rain and excess overhead irrigation water, usually lost between the containers in conventional production systems. The captured water is later supplied to plants by sub-irrigation as needed. Since the MPBS is a semi-closed system, the evaporation losses from the water surface in the reservoir are minimal and most of the rain and irrigation water collected in the reservoir was available for use by the plants.

The results of this study (on Viburnum odorattissimum) indicate that plants grown in a MPBS with a water reservoir had substantially reduced needs for supplemental irrigation. The quantity of irrigation water applied to the MPBS was approximately 84% less than that applied using conventional irrigation practices (overhead sprinklers). These savings can be further increased when the MPBS is equipped with a rain shut-off device. Irrigation water use efficiency (IWUE) was carefully monitored.

The research results also indicated that the final growth indices of plants grown in the MPBS were significantly greater than those of control plants grown during the two years of the study. The system allows more plants to be irrigated with limited water resources. Irrigations for the MPBS can easily be automated and MPBSs are easy to transport to other locations.

(from an article, "Seasonal Irrigation Water Use Efficiency of Multi-Pot Box System" published in the Journal of Environmental Horticulture 19(1):4-10, March 2001; written by Suat Irmak, Dorota Z. Haman, Thomas H. Yeager, and Claudia Larsen, University of Florida, Gainesville)


The benefits from root colonization by mycorrhizal fungi are thought to be maximized when colonization occurs as early as possible during plant growth. This study examined whether the addition of VA mycorrhizal fungi (VAMF) inoculum into rooting medium during cutting propagation would increase the quantity of rooting and the quality of rooted cuttings for five different cultivars of miniature roses (Rosa spp.). Cultivars respond differently to the addition of VAMF inoculum into the rooting medium so it is important to test crops before using this on a large scale.

Four weeks after cuttings were stuck, the number of cuttings with roots for two cultivars that normally take longer to root, increased with addition of VAMF inoculum into the rooting medium. The combination of hormone treatment (IBA and NAA) and VAMF inoculum in the rooting medium increased the number of rooted cuttings and the number of roots per cutting for three cultivars when compared to cuttings that only received hormone treatment.

Increases in root initiation and root growth of cuttings rooted in medium containing VAMF inoculum were not always associated with increased levels of root colonization by VAM fungi. Results indicated that although adding VAMF inocolum into the rooting medium does not always increase root initiation, in some cultivars the combination of VAMF inoculum and rooting hormones can increase root initiation and potentially increase the quality of rooted cutting produced. The cuttings that did benefit usually resulted in a higher quality cutting that is better able to withstand the stress of transplanting and increase growth during later stages of plant development.

(from "Cultivar Specific Effects of Mycorrhizal Fungi on the Rooting of Miniature Rose Cuttings" by C.F. Scagel, Oregon, published in the Journal of Environmental Horticulture 19(1):15-20, March 2001)



Jackie Mullen, Extension Plant Pathology Specialist-Auburn
Jim Jacobi, Extension Plant Pathology Specialist-Birmingham

(J. Mullen)

We can definitely tell that spring is here in the lab with our increased sample numbers! Botrytis, brown patch on centipede, tomato spotted wilt virus, and the usual spring leaf spot problems were seen last month.

Brown patch on centipede seems to be well established in the southern sections of the state. Samples seen in the lab have had abundant microscopic mycelial growth on the lower leaves and stolons with accompanying leaf-stolon blight. Several fungicides are labeled for control of brown patch on turf. It is also important to keep nitrogen fertilization at a low-normal levels, collect clippings and irrigate early in the day. See ANR-492.

Botrytis blight has been seen as a problem on greenhouse rosemary, lavender, and geranium. Also, we recently saw it causing a blossom blight on dogwood. In a greenhouse, Botrytis is controlled by reducing humidity levels, sanitation, and protective fungicide sprays. Several fungicides will control Botrytis. See the 2001 APMH. Tomato spotted wilt virus was confirmed on Gomphrena globosa. New growth showed unusual patterns of yellow spots. Thrips were also present. This can be a difficult disease to control. Sanitation and thrips control is important.

Pestalotia leaf spots were seen on azalea, gardenia, holly, and rhododendron. Pestalotia usually causes damage on plants in the early spring following cold damage or other stress situations. This fungus is not often a problem later in the spring, summer, or fall.

Other fungal leaf spot diseases seen included Botryosphaeria and Colletotrichum on holly and Colletotrichum on pepper.

Botryosphaeria canker was noted on oak; Botryosphaeria often causes cankers on stressed or previously damaged trees and shrubs. It is a fairly common occurrence in the spring after cold damage.

Pythium blight was noted as an unusual occurrence on annual periwinkle and Torenia. We believe this fungal damage followed after injury from excess fertilizer salts.

2001 March Diseases Seen In The Auburn Plant Diagnostic Lab.
AzaleaPestalotia Leaf SpotMarion
BegoniaPythium Blight *
DaffodilFusarium Basal Bulb RotCalhoun
DaylilyPythium Crown & Root RotPike
GardeniaPestalotia Leaf SpotLee
GeraniumBotrytis BlightLee
GomphrenaTomato Spotted Wilt Virus *
HollyBotrytosphaeria Leaf SpotCovington
HollyColletotrichum Leaf SpotCovington
HollyPestalotia Leaf SpotMarion
LavenderBotrytis Blight *
Million BellesPythium Root Rot *
Myrica CuttingsFusarium Cutting End Rot *
OakBotryosphaeria CankerLee
Periwinkle, AnnualPythium Blight *
RhododendronPestalotia Leaf SpotMarion
RosemaryBotrytis Blight *
RosemaryPythium Root Rot *
SnapdragonColletotrichum Leaf SpotLee
SnapdragonPythium irregulare Crown & Root RotOut-of-State
ToreniaPythium Blight *
Counties are not reported for greenhouse and nursery samples.

(J. Jacobi)

The first days of spring were cooler and wetter than normal, providing good conditions for certain diseases and an increase in samples received at the lab. We continued to see damage from cold and drought on a wide range of plants including azalea, juniper, rose, and turfgrass. The effects of last summer's severe drought are and will continue to produce dieback and other related problems. Cold damage to Orchid (Phalaenopsis spp.) was seen last month. Symptoms are yellow depressed streaks on the leaves that eventually turn tan and then black and become pitted. The streaking is most prominent along the margins of the leaves. Exposure to cold temperatures (as little as 45oF for two hours on young leaves) or cold water that condenses and falls on newly developing leaves causes the problem. Symptoms show up about six weeks after the cold temperatures. This was a new problem for the lab and was identified with the help of another plant pathologist. Other unique samples seen during March included crown gall on apple and Armillaria root rot on peach. See ANR-944 and ANR-907 for more information on crown gall and Armillaria root rot, respectively.

Mulches and composts have many beneficial side effects including improving soils, conserving moisture, and controlling weeds. However, uncomposted or fresh materials comprised primarily of wood with little bark can result in the development of detrimental and nuisance fungi including different types of mushrooms and slime molds. Last month, a columned stinkhorn (Linderia columnata) was brought into the lab– and immediately taken back outside. This and other stinkhorns have a foul odor similar to rotting meat. In this case, the fungus colonized a landscape bed mulched with one of the colored mulches (largely uncomposted wood product with little bark). In addition, some of the mushroom (fungi) that colonize mulch are toxic and should be destroyed when small children have access to the area. Once these fungi have colonized the mulch there may be little that can be done. Removal or spading the affected mulch into the soil and wetting the area may provide some level of control. The best strategy is to purchase composted products low in wood content and prevent a potential problem. Additional information on nuisance and detrimental molds in mulches and composts can be obtained at the following site

2001 March Diseases Seen In The Birmingham Plant Diagnostic Lab
AzaleaLace BugsJefferson
BoxwoodBoxwood LeafminerJefferson
BoxwoodMacrophoma Leaf SpotJefferson
BoxwoodMacrophoma Leaf Spot and Pythium Root RotJefferson
Evergreen ClematisPythium Root RotSt. Clair
OrchidCold InjuryJefferson
PhotiniaEntomosporium Leaf SpotJefferson
*Counties are not reported for greenhouse and nursery samples.


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

Rust diseases were not very noticeable in March, but we will see them in 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 mature, spore-producing galls are present. Disease control is difficult. In a nursery situation, fungicides are recommended for protective control. (See the APMH.) 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.

Peach leaf curl, caused by the fungus Taphrina, is easily recognized by the curling, distortion, and swelling it causes on infected leaves. Spores produced in the spring are carried by wind and rain to near-by peach trees where they fall onto the bark areas of twigs and branches. These spores will over-winter in protective niches in the bark. In the spring the spores may be moved by wind and rain so that they infect new leaves as they emerge and develop. For control, a dormant fungicide treatment is applied once (see the APMH) in the fall after leaf drop or in the spring before budswell.

Phomopsis canker has been a problem on peach the last few years. It usually develops in April. Typical cankers develop on twigs and small branches as elliptical gray sunken lesions. Lesions will enlarge, and foliage wilt and dieback will result. Check with Ed Sikora for more information.

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 (60-70oF 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. Spread 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 sprays 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 APMH.

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 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. Geranium and related plants are also prone to edema when wet, cloudy conditions exist.

Botrytis blight is a common foliage disease when conditions are wet, humid and temperatures are relatively cool (61-73oF). Flowers, 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.

While temperatures are still cool in the spring, Thielaviopsis black root rot may be a problem on cotton. Infected roots display black spots, lesions. Often root tips are affected. Infected root systems are poorly developed and top growth is consequently reduced. Control involves crop rotation away from cotton or a Batan seed treatment (1 oz./100 seed wgt). Black root rot may also occasionally be a problem on Helleri holly and pansy.

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 APMH for details.

MANY ORNAMENTALSPowdery MildewWhite-buff colored, raised dots or pads of mycelium.Fungicides; See Cir. ANR-407.
AGLAONEMA Bacterial Leaf SpotCircular-angular, dark, water-soaked leaf spots. Sanitation. Water at pot level.
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 APMH
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 APMH.
AZALEAOvulinia Petal BlightSmall white-brown spots enlarge to be-come large browned areas on the blossoms.See APMH.
AZALEAPhytophthora Crown & Root RotCrowns & roots become brown and water-soaked.Sanitation; See APMH.
AZALEARhizoctonia Aerial BlightLower leaves become spotted and eventually whole leaves become dark brown and fall.See APMH.
BEE BALMPowdery MildewLeaf distortions; powdery white dusty patches on foliage leaves (upper leaf surfaces) and stems.Sanitation.
BEGONIABacterial Leaf SpotDark, black, water-soaked spots and blotches.Strict sanitation. Do not water overhead.
BENTGRASSBrown Patch (Rhizoctonia)Circular-irregular patches in lawn become brown. Brown lesions present on individual grass blades.Reduce nitrogen fertilization. Protective fungicide treatments.
BENTGRASSPythium BlightFoliage becomes pale brown and water-soaked.See APMH, spray guide.
BERMUDADrechslera Leaf Spot See Helminthosporium Leaf Spot. --
BERMUDA Helminthosporium-type Leaf Spot/Blight (Exserohilum)Small brown elongated spots (2-3 mm) which may merge and cause leaf blight.See APMH.
BERMUDARhizoctonia Brown PatchSee bentgrass.See bentgrass comments.
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.
CAMELLIA Algal Leaf Spot (Cephaleuros)Red-green-brown raised circular leaf spots with wavy edges.Sanitation. See APMH.
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.
CHRYSANTHEMUM Rhizoctonia Root RotRoots become brown, decayed and dried.Sanitation. See the APMH.
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 APMH.
DAYLILYKabatiella Leaf SpotNumerous small (5 mm or ¼ 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 APMH.
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 by progressive infection and death of associated twigs and then branches. See ANR-551 or the APMH
EUONYMUSPowdery Mildew (Microsphaera)A white powdery dusting appears on upper leaf surfaces; when disease is severe some leaf distortion occurs.See the APMH.
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 APMH. 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.
HAWTHORN, IndianPhytophthora Root RotRoots become brown and decayed. Outer tissues easily pull away from the root central core. Foliage wilts and dieback occurs.See the APMH.
HOLLY, HelleriPhytophthora Root RotRoots become brown and decayed. Outer tissues easily pull away from the root central core.See the APMH.
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.
HYDRANGEA, Oak LeafBacterial Leaf SpotSmall (2-5mm), dark, angular spots on leaves.Sanitation; irrigate at soil level.
IMPATIENSAlternaria Leaf SpotDark brown-black, angular leaf spots.Sanitation; Kocide 101.
IMPATIENSPythium Root RotRoots become pale brown and decayed. Outer tissues easily pull away (separate) from the inner central core. Foliage is stunted, wilted. --
IRISHeterosporium Leaf SpotSmall-large (¼-½ inch long), elliptical or oval shaped medium brown leaf spots.Sanitation. See APMH.
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.
IVY, EnglishBotryosphaeria CankerElongated, sunken, cracked stem lesions.Pruning. Protective sprays of Cleary's 3336.
IVY, EnglishAnthracnose (Colletotrichum)Brown irregular spots (3 mm diam. & larger) that sometimes occur along veins.Sanitation. See the APMH. Use Cleary's 3336 or Domain.
IVY, EnglishBacterial Leaf SpotSmall (2-4mm diam.), angular, dark leaf spots with wet looking edges on leaves.Sanitation. See the APMH.
IVY, EnglishEdemaSmall, brown, corky spots on lower leaf surfaces.Reduce irrigation.
IVY, EnglishFusarium/Pythium Root DecayRoots become brown decayed, dried and also wet rotted.Sanitation. Banrot protective treatments.
JAPANESE PAGODA TREENectria CankerSunken canker with tiny orange raised specks scattered over lesion.Sanitation.
JUNIPERPhomopsis Tip BlightDieback.Pruning; Fungicide application. See the APMH.
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 Blight Beginning with lower branches and inner needles, blight develops and spreads upward & outward.Sanitation; protective sprays of Cleary's 3336.
LEYLAND CYPRESSSeiridium CankerElongated sunken lesions on trunk usually with sap oozing around lesion edge.Pruning. See APMH.
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.
MAGOLIAStressMany 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 APMH.
MAPLE, JapanesePhomopsis CankerBrown-gray elliptical sunken lesions on smaller branches, twigs.Sanitation.
MAPLE, RedPhyllosticta Leaf SpotCircular pale brown spots with darker brown borders (about ¼ 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 APMH.
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.
MONDOGRASSRoot Knot Nematode (Meloidogyne)Poor growth; root galls.Sanitation. See ANR-689 and ANR-856.
MONKEY GRASS (Liriope)Anthracnose (Colletotrichum)Pale brown blotches and spots on foliage. Blotch margins are sometimes dark brown or red-brown. Spots may involve large sections of leaves. Often leaf tips are involved.Sanitation; Protective sprays of Cleary's 3336 or Domain may be used.
OAKAnthracnose (Apiognomonia)Brown-black spots and irregular blotches which often develop along leaf edges and/or leaf veins.Sanitation. See APMH.
OAKAlgal Leaf Spot (Cephaleuros)Gray-green or brown-red spots with irregular margins (1 cm or ¼ inch diam.) on leaves; spots may coalesce.See APMH.
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 ¼-½ inch diam.) on leaves. As spots age, they change from a light green-brown color to a medium-dark brown.See APMH.
OAKPowdery MildewWhite powdery dusting on leaves; infected new growth may be deformed.Sanitation of leaves in the fall.
PANSYCercospora Leaf SpotBlack superficial, slightly raised spots with ropey appearance and irregular feathery spot edges.Sanitation. See APMH.
PANSYColletotrichum Leaf SpotCircular gray spots with dark borders.See the APMH.
PANSYThielaviopsis Black Root RotBlack lesions on roots. Plants are stunted.Sanitation. See the APMH.
PERIWINKLEBotrytis BlightBrown gray spot/ blight.Sanitation. Increase air circulation. In-crease temperature. See the APMH.
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 APMH.
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 _-_ inch long) sometimes associated with leaf margins.Sanitation; See APMH under Entomosporium Leaf Spot.
PHOTINIAEntomosporium Leaf SpotRed-black spots (5-10 mm diam.) on upper & lower leaf surfaces. Spots generally have dark red-black borders. Spots may coalesce.Pruning; Fungicide treatment; See Cir. ANR-392.
PHOTINIAArmillaria Trunk RotSudden wilt and dieback; thin white mycelial layer beneath bark; sometimes black thread-like rhizo-morphs and/or honey-colored mushroom present.Sanitation--removal of plants.
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 APMH.
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 APMH.
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.
RAPHIOLEPSISColletotrichum Leaf SpotBrown, circular-irregular shaped leaf spots.Sanitation. Protective sprays of Cleary's 3336.
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 APMH. 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 APMH.
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 APMH.
TULIP POPLARAlternaria Leaf SpotMedium-brown, circular-irregular spots (1-2 cm or 1/3 - 2/3 inch long).Sanitation.
AllSlime MoldWet-looking thin sheets of fungus material which may be green, reddish or brown in color. When the spore stage is present, plant material may be covered with a powdery coating of black, brown, red or yellow spores.Fungal sheets or masses may be physically removed; spore masses may be washed off with a strong stream of water; when conditions become dry, slime molds will disappear. These fungi do not cause damage to plants except for a shading effect.


June 20 - 23, 2001:
2001 Southeast Greenhouse Conference and Trade Show.
Greenville, SC.
For more information call 877-927-2775;

July 24 - 28, 2001:
Cullowhee Conference: Native Plants in the Landscape.
Western Carolina University in Cullowhee, North Carolina
For more information call 770-922-7292.

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;

September 30 - October 3, 2001:
Eastern Region International Plant Propagators' Society Annual Meeting.
Lexington, KY. Contact Margot Bridgen, 26 Woodland Road, Storrs, CT 06268; phone 860-429-6818; e-mail

October 12-13, 2001:
Middle Tennessee Nursery Association Horticultural Trade Show.
McMinnville Civic Center, McMinnville, TN
phone: 931-668-7322; fax: 931-668-9601; e-mail:, or

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:

November 30 - December 1, 2001:
The Great Southern Tree Conference.
Contact Heather Nedley at; 1-800-375-3642.

October 11-12, 2002:
Middle Tennessee Nursery Association Horticultural Trade Show.
McMinnville Civic Center, McMinnville, TN
phone: 931-668-7322; fax: 931-668-9601; e-mail:, or

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

Send horticultural questions and comments to

Send questions and comments to

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