ANR-1148

A L A B A M A A & M A N D A U B U R N U N I V E R S I T I E S

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Diseases ofEnglish Ivy

E nglish ivy is a woody ever-green vine that is popular inAlabama landscapes and in-

teriorscapes. It is typically usedas ground cover or as potted fo-liage. It grows best in full to par-tial shade and will tolerate theacidic soils common in manyparts of the state. There aremany cultivars, which aregrouped into classes based onleaf shape and color. The Ameri-can Ivy Society has developed aclassification system that includesnine English ivy classes.

Common infectious diseasesof English ivy include anthrac-nose, bacterial leaf spot, Phytoph-thora spp. root rot and leaf spot,and Rhizoctonia aerial blight androot rot. Edema, a noninfectiouscondition resulting from excessivemoisture, may also damageEnglish ivy.

AnthracnoseOn English ivy, anthracnose

may develop as a leaf spot, stemcanker, or blight disease and mayoccur in landscapes, nurseries, orinteriors. Although anthracnosecan badly damage nursery stock,landscape plantings of Englishivy can be devastated by the dis-ease. Symptoms of anthracnosemay be easily confused withthose of bacterial leaf spot; there-fore, a laboratory examination ofleaf specimens may be needed inorder to differentiate betweenthe two diseases.

The fungus Colletotrichumtrichellum is the most commonlyreported causal agent of ivyanthracnose, but C. gloeospori-odes is known to cause this dis-ease as well. Symptoms of an-thracnose begin as circular,necrotic areas that usually devel-op into irregular, dry, brown toreddish brown or black spotsabout 3⁄4 inch (2 cm) in diameter(Figure 1). Spots usually begin ator near the margins of the leaves.

In the nursery, anthracnosespreads easily when cuttings orliners are placed close to eachother and watered by overheadsprinklers. Fungal spores arespread by the splashing water.In the landscape, the spores maybe spread by splashing water, bywindblown rain, or by insects.The optimum temperature fordisease development and spreadis 68 to 77 degrees F.

Controlling anthracnose innurseries and landscapes re-quires the use of good sanitationpractices, good cultural practices,and protective fungicide treat-ments:• Remove dead leaves, stems,

and other plant debris fre-quently.

• Use tip cuttings for propaga-tion.

• Water early in the day so thatfoliage is dry before evening.Drip irrigation is recommended.

• Do not handle plants whenthey are wet.

• Control insects and mites.• Apply fungicide treatments in

accordance with label direc-tions.It is reported that chlorothal-

onil products may cause somefoliage distortions and brownleaf spots when applied toEnglish ivy. Fungicides labeledfor control of anthracnose onEnglish ivy are listed in Exten-sion publication ANR-500B,Alabama Pest ManagementHandbook, Volume 2.

Figure 1. Anthracnose leaf spots

Fruiting bodies of the fungus ap-pear as black specks scattered onthe surface of the leaf spot. At alow level of magnification, nu-merous black needle- or hairlikestructures (setae) may be seenon upper leaf surfaces. Girdlinglesions that develop on petiolesand stems may cause a shootdieback or defoliation.

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2 Alabama Cooperative Extension System

Studies conducted to checkthe relative susceptibilities ofEnglish ivy cultivars to anthrac-nose have not identified any re-sistant plants. Gold Dust andGreen Feather developed a lowlevel of disease after inoculationwith C. gloeosporioides. Perfec-tion and Han Variegated devel-oped moderate levels of disease;Manda Crested was heavily dam-aged. In another greenhousetrial, all five cultivars tested weresusceptible to anthracnose tovarying degrees. Crested wasmost severely damaged. Glacierand Needlepoint suffered moder-ate leaf spotting and dieback.Gold Dust and Shamrock devel-oped the least amount of dis-ease. In addition to English ivy,approximately 500 other speciesof ornamental plants are suscep-tible to C. gloeosporioides. Thedisease may spread among suchplants as aucuba, camellia,Codiaeum, Ficus, ligustrum, liri-ope, magnolia, and palms.

Bacterial Leaf SpotBacterial leaf spot, caused by

Xanthomonas campestris pv.hedera, is perhaps the most com-mon disease of English ivy.Nursery, landscape, and interiorivy plantings may be affected bythis disease, but it is most severein nurseries and landscapeswhere humidity is high. This dis-ease is distributed worldwide.Other members of the Araliaceaefamily, such as scheffleras andaralias, are also susceptible.Bacterial leaf spot can easily beconfused with anthracnose, andboth diseases can occur at thesame time on the same plant.

Initial bacterial leaf spot le-sions appear on the upper andlower surfaces of the leaves asgreen-brown, brown, or blackwater-soaked (oily) spots thatmay expand to 2 to 10 millime-ters in diameter (Figure 2).Lesion water-soaking is most no-ticeable on the undersides of theleaves early in the day or follow-ing rain or irrigation. Centers ofthe leaf spot are red-brown orbrown-black, and when condi-tions are moist, an orange-redooze is sometimes seen alongthe edges of the leaf spots.Lesions are vein-bound, angular,and may have a yellow halo 1 to2 millimeters wide. Leaf lesionsmay extend into the petioles andstems, causing leaf and shootdeath. The surfaces of older le-sions usually dry and crack.Symptoms often appear on theolder leaves first. Infections ofimmature leaves may cause leafspeckling and deformity. Onsome cultivars, red margins mayappear around spots on matureleaves. Small, dark browngirdling cankers may also beseen on mature stems.

The leaf spot bacteria arespread by splashing water andduring propagation when condi-tions are wet. Dense foliage andplants being packed closely to-gether facilitate spread of the dis-ease. The bacteria survive in in-fected plant debris and in thesoil, and infections occur mostoften where leaves are shadedand wet. Wet, poorly drained

areas are most conducive to dis-ease development. X. campestrispv. hedera has been reported onmany cultivars of English ivy. Itis also reported to occur onAlgerian ivy, Dizygotheca, Fatsiax Fatshedera, and Polyscias.

Controlling bacterial leaf spotrequires good sanitation, goodcultural practices, proper fertility,and sometimes protective chemi-cal sprays:• Maintain pathogen-free stock

plants.• Avoid overhead watering when

possible.• Keep workers out of produc-

tion ranges when the foliage iswet.

• Control insects and mites.• Remove all diseased plant ma-

terials, including infected stockplants and crop debris, fromproduction benches.

• Clean benches and tools, usinga surface disinfectant.

• Use proper levels of fertility.• Apply protective chemical

sprays.Although higher-than-recom-

mended rates of fertilizer may re-duce ivy’s susceptibility to bacte-rial leaf spot, overfertilizationmay increase its susceptibility toother diseases.

Chemical control of bacterialleaf spot has often proven diffi-cult. In trials, up to 90 percentcontrol of bacterial leaf spot hasbeen obtained using cupric hy-droxide (Kocide 101), fosetyl alu-minum (Aliette 80WDG), or a 1percent solution of white vine-gar. Streptomycin sulfate hasbeen reported to be phytotoxicto English ivy. Best control hasgenerally been achieved by usinga combination of chemical treat-ments, minimizing overhead irri-gation, using resistant cultivars,and adhering to a balanced fertil-izer application schedule.

Figure 2. Small water-soaked bacterialleaf spots

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Diseases of English Ivy 3

Cultivars of ivy with high lev-els of resistance to bacterial leafspot have not been found. In arecent study, leaf spotting devel-oped on all cultivars tested, butGold Dust, Perfection, SweetHeart, Eva, California, andManda Crested developed thefewest leaf spots. Hahn Varie-gated and Brokamp proved to bemost susceptible to bacterial leafspot. Telecurl, Green Feather,Ivalance, and Gold Heart wereintermediate in their susceptibili-ty to this disease.

E d e m aEdema (oedema) is a condi-

tion caused by excessive waterlevels in foliage. It is found pre-dominantly on greenhousecrops, but it may occur in land-scape plantings of English ivy.Symptoms of edema develop pri-marily on lower leaf surfaces butalso develop on the petioles andon immature stem tissue. Initialsymptoms are tiny water-soakedblisters on the undersides of theleaves. During extended periodsof wet, cloudy weather, extensiverupturing of the blisters may beseen. These blisters callus overinto noticeable light tan to rustybrown warts or pustules and donot disappear. Extensive edemacan cause chlorotic spots to ap-pear on the upper leaf surfaces.

Edema occurs primarily inmidwinter and in spring. Majorearly spring storm systems mayprovide the cool, wet weatherconditions that cause plant tis-sues to accumulate abnormallyhigh levels of water and, there-fore, to develop edema. Favor-able conditions for edema in-clude high soil moisture; a cool,moist air mass; poor air circula-tion or greenhouse ventilation;and reduced light intensity. Manyherbaceous foliage and floralcrop species develop edema inthe greenhouse. Among theother woody ornamentals affect-ed by edema are camellia,

Eucalyptus, Fatsia x Fatshedera,jasmine, ligustrum, schefflera,Taxus, and other ivy species.

To control edema in land-scape plantings of English ivy,monitor automated irrigation sys-tems to prevent overwatering,and space plants properly tohelp minimize problems. In thegreenhouse, use bottom heatcoupled with forced ventilation.There are no chemical treatmentsto control edema.

Phytophthora RootRot and Leaf Spot

Phytophthora species(palmivora, cinnamomi, nico-tiana var. parasitica and others)can cause root rot, stem blight,and leaf spot in landscape plant-ings and greenhouse crops ofEnglish ivy. Typical symptoms ofPhytophthora-incited diseases ofEnglish ivy are poor top growthand poor color. Often, the lowerleaves turn brown and curldownward (Figure 3). Although aroot rot sometimes is seen, leafspot and stem rot symptoms areusually more common. With P.palmivora, spots on the leavesare large, gray-black in color, andwater-soaked. A vascular necro-sis of stems and roots was re-ported to occur on H. helixCalifornia.

As with most Phytophthorainfections, the pathogen isspread by water, soil, and move-ment of infected plants or plantparts. Development of Phytoph-thora diseases is often triggeredby excessive moisture in the soilor potting media. English ivygrown in poorly drained soils oron sites prone to flooding is alikely target of Phytophthora dis-ease. Warm temperatures andfrequent rains or overwateringwill contribute to the develop-ment of the leaf spot and shootblight phases of this disease. P.palmivora has a host range thatincludes Dieffenbachia picta anda number of other tropical plantsincluding rubber, cacao, citris,breadfruit, papaya, and manyornamentals. Both P. nicotianaand P. cinnamomi will infectmany common herbaceous andwoody greenhouse and land-scape crops.

Controlling Phytophthoraroot rot and leaf spot requiresthe use of good cultural prac-tices, good sanitation practices,and good irrigation management:•Use pathogen-free potting

media and pathogen-freestock plants.

• Never reuse potting media.• Discard diseased plants.• Use protective fungicide treat-

ments to control this diseasein the greenhouse and nurs-ery.

• Clean greenhouse benches,using a surface disinfectant.

• Clean pots, using a surfacedisinfectant.

• Do not allow water to stand inplant areas or in pottingmedia.

• Mix soil or potting media withamendments to increase waterdrainage.

Figure 3. Foliar damage caused byPhytophthora root rot

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Jackie Mullen, Extension Plant Pathologist and Diagnostician, and AustinHagan, Extension Plant Pathologist, Professor, Plant Pathology, both at AuburnUniversity

Trade names are used only to give specific information. The Alabama Cooperative ExtensionSystem does not endorse or guarantee any product and does not recommend one product insteadof another that might be similar.

For more information, call your county Extension office. Look in your telephone directoryunder your county’s name to find the number.

Issued in furtherance of Cooperative Extension work in agriculture and home economics, Acts of May 8 and June30, 1914, and other related acts, in cooperation with the U.S. Department of Agriculture. The AlabamaCooperative Extension System (Alabama A&M University and Auburn University) offers educational programs,materials, and equal opportunity employment to all people without regard to race, color, national origin, religion,sex, age, veteran status, or disability. UPS, 4M31 New April 1999, ANR-1148ANR-1148

Composted pine bark orhardwood bark is recommendedin some situations as a pottingmix component because of itsgood drainage properties and itsdemonstrated protective natureagainst Phytophthora infections.Fungicide treatments are avail-able for protective control of thisdisease and are most effectivewhen combined with recom-mended cultural and sanitationpractices. A complete list of rec-ommended fungicides can befound in ANR-571, “Phytoph-thora Root Rot on WoodyOrnamentals,” and ANR-500B,Alabama Pest ManagementHandbook, Volume 2. SeeExtension publication ANR-571,“Phytophthora Root Rot onWoody Ornamentals,” for addi-tional information about manag-ing Phytophthora diseases ongreenhouse and landscape crops.

Rhizoctonia Root Rotand Aerial Blight

Rhizoctonia solani is a wide-spread aerial and root-rot patho-gen of many greenhouse andnursery crops including Englishivy. With the aerial blight phaseof this disease, brown, irregularlyshaped, water-soaked lesionsmay occur on all abovegroundplant parts. Symptoms usuallyappear first on lower leaves nearthe soil line.

Figure 4. Wilt caused by Rhizoctoniaroot rot

The red-brown mycelial mat ofthe causal fungus may be seen onblighted leaves. This disease alsomay involve the roots, which maydevelop brown, dried lesionssometimes involving the wholeroot system. Root rot will usuallyresult in foliage wilt, dieback, andpoor growth (Figure 4).

The causal fungus survives inplant debris and soil. Contami-nated soils or potting media aswell as infected cuttings are themost common means of diseasespread. Development of aerialblight is favored by warm, humidconditions. Root rot may developover a wide range of soil mois-ture levels.

Controlling Rhizoctonia rootrot requires the use of good cultur-al practices, good sanitation prac-tices, and chemical treatments:• Propagate English ivy in a soil-

less potting media.• Never reuse potting media.

• Do not reuse pots, flats, orother containers unless theyhave been carefully rinsed,sanitized with a surface disin-fectant, and dried.

• Clean water breakers, hoses,and tools, and keep them offthe greenhouse floor.

• Discard unsalable, dying, ordead plants.

• Wash down production bench-es after each crop, using a sur-face disinfectant.

• Schedule overhead irrigation atmidday—do not water late inthe afternoon or at night.

• Apply preventative fungicidedrenches throughout the pro-duction cycle if necessary.

• Remove damaged foliage fromthe planting area to controlthe aerial blight phase of thisdisease.

• Maintain dry foliage as muchas possible.

• Space plants so that air circula-tion allows for low relative hu-midity levels.

• Use protective fungicide treat-ments if necessary to controlRhizoctonia.Fungicides recommended for

the control of Rhizoctonia rootrot and aerial blight are listed inANR-500B, Alabama Pest Man-agement Handbook, Volume 2.

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