Grape Ivy Production Guide

CFREC-A Foliage Plant Research Note, RH-91-19

R.W. Henley, A.R. Chase and L.S. Osborne University of Florida, IFAS Central Florida Research and Education Center - Apopka 2807 Binion Road, Apopka, FL 32703-8504

GRAPE IVY

Grape Ivy, Cissus rhombifolia, has an appropriate common name because it is a member of the grape family, Vitaceae, and also resembles some of the other ornamental vines which bear the name ivy. The genus Cissus consists of approximately 350 species of tropical and subtropical vines and shrubs. Cissus antarctica, Kangaroo Vine and C. discolor, Trailing Begonia, are other representatives of the genus which are grown commercially for interior use, but are less durable indoors than C. rhombifolia.

Grape Ivy has evergreen leaves which are divided into three leaflets (trifoliage) with coarsely-toothed margins (serrate). The leaves range in length from 2 to 9 inches, depending upon cultivar and plant vigor. The leaf color is a medium to dark green; darker color is achieved with heavy shade and adequate nutrition.

PRODUCTION

Grape Ivy is grown commercially in 3 to 10 inch pots and 6 to 22 inch hanging baskets. The plant is used very effectively where a trailing vine is required. It will tolerate light levels as low as 75 foot-candles indoors which makes it a good choice for many interiors.

Grape Ivy is best grown in greenhouses where light intensity, temperature, and soil moisture can be properly regulated. Stock can be grown in either benches or hanging pots. Some producers cut back their hanging plants one or more times to obtain cuttings before selling them.

Grape ivy stock and finishing plants should be grown at light intensities of 1200-2000 foot-candles and fertilized at the rate of 3.4 pounds of nitrogen per 1000 square feet per month using a complete fertilizer with a 3-1-2 or similar N-P205-K20 ratio.

Propagation and potting medium selection is important because the roots of Grape Ivy need good aeration. A mixture of fibrous peat and other particles (bark, perlite, styrofoam and/or calcined clay) are frequently used by commercial growers. The medium should be water retentive but well drained. When acidic peats are used, about 6 to 8 pounds of dolomitic limestone (dolomite) should be added per cubic yard to adjust the pH of the blended medium to 5.5 to 6.2. If microelements are desired in the initial medium, one pound of a granular micronutrient blend such as MicromaxR can be used per cubic yard. Microelements can also be added later in a liquid fertilizer program.

Good growth of Grape Ivy is observed between temperatures of 68 and 82°F. As temperatures rise into the upper 80's and the 90's, growth is suppressed and propagation is difficult.

Grape Ivy is propagated primarily by single node cuttings. Cuttings are generally trimmed 1/4 inch above the node (point of leaf attachment), and 3/4 to 1 1/4 inches below. Most growers feel there is benefit from use of a rooting hormone. A noticeable callus layer forms at the base of most cuttings and roots develop in the calloused area.

CULTIVARS

Cissus rhombifolia - leaf size moderate, 3 to 6 inches long, with coarsely toothed leaflets. The leaf shape is somewhat like that of poison ivy.

Cissus rhombifolia `Ellen Danica' - large leaves with leaflets lobed deeply, in some cases forming secondary leaflets. The loosely arranged leaflets and leaflet lobing give this cultivar a finer texture than the others.

Cissus rhombifolia `Fionia' - large, broad leaflets, some with deep cut lobes. The lateral leaflets have noticeably shorter stalks than other cultivars, giving the leaf a full compact appearance.

Cissus rhombifolia `Mandiana' - leaves coarser and stems thicker and more upright than the other cultivars.

Cissus rhombifolia `Mandiana Compacta' - a very compact form of `Mandiana' with very short internodes, and tightly organized, broad, coarsely-toothed leaflets.

Reference Pest Control Guides Here

FUNGAL PROBLEMS

1) Anthracnose (Colletotrichum sp.)

Symptoms - Anthracnose of both Grape Ivy and Kangaroo Vine often occurs during the rooting process. Many leaves can be affected and often cuttings are lost due to leaf abscission. Single lesions can appear anywhere on the leaf and are water-soaked, roughly round, and sometimes contain the fruiting bodies (acervuli) of the pathogen in concentric rings. The acervuli are usually black and appear to be the size of pepper grains. If the lesions dry out they often turn tan to gray and can be papery. Many lesions coalesce on plants under high moisture conditions. Large, well established plants are also susceptible to Colletotrichum sp. Under conditions of high moisture and high disease pressure many lesions may form. These lesions are frequently small (1/8") and are angular (bordered by leaf veins). In these cases, the youngest leaves are most severely affected.

Control - Use only disease-free stock plants for cuttings since infected plants rarely give rise to healthy new plants. Minimizing the amount of water applied to leaves can reduce disease as can wide spacing of plants which enhances rapid drying of the foliage.

2) Botrytis blight (Botrytis cinerea)

Symptoms - Botrytis infections are typified by large grayish areas on leaf margins and sometimes in leaf centers. Tissue in the center of the plant is commonly infected since moisture levels in these areas are highest. The dusty-gray to tan spores of the pathogen form all over the tissue and can easily be seen with a 10X hand lens. Affected leaves collapse and turn mushy or dry. This disease is primarily a problem during the relatively cool and darker winter months in Florida.

Control - Many plants other than Cissus spp. can be infected with Botrytis blight and control measures should be extended to all susceptible crops. Examples of these crops include Lipstick Vine, Hoya, African Violet, and English Ivy. Reducing moisture levels around foliage by limiting water applications and increasing air movement are recommended cultural controls for this and many other foliar diseases of foliage plants.

3) Pestalotiopsis dieback (Pestalotiopsis menezesiana)

Symptoms - Wilting of cuttings in propagation beds is the first symptom of this dieback disease. Leaflets and roots dieback with infected stems tissue discolored.

Control - This disease has been reported to cause severe losses in rooting of cuttings in Canada, but has not been reported in Florida to date. Control of this dieback disease should be possible with use of pathogen-free plants, rooting medium and minimizing water applications.

4) Powdery mildew (Oidium sp.)

Symptoms - A white powdery coating covers the top and sometimes the bottom leaves of the affected plants. The covering sometimes forms in circular lesions and sometimes covers the entire surface of the leaf.

Control - This disease is rarely a problem in Florida but occurs regularly in the interiorscape where the low humidity conditions favor development.

5) Rhizoctonia aerial blight (Rhizoctonia solani)

Symptoms - Rhizoctonia aerial blight occurs primarily during the summer months. Disease development can occur in less than 1 week, so plants should be monitored carefully and frequently for initial symptoms. Brown, irregularly-shaped spots form anywhere on the foliage, but are most commonly in plant centers or near the soil where the inoculum originates. Sometimes the first lesions appear near the top of the plant confusing the source of the disease. Lesions spread rapidly over the plants and cover them with the reddish-brown, weblike mycelium of the pathogen.

Control - Cultural control of this disease is the same as that discussed for the other diseases. In addition, since the source of the pathogen can be the potting medium, the plants should be grown in new or clean pots and potting medium and on raised benches in an enclosed structure. Temperatures above 85°F promote disease development, so cooling the greenhouse during certain times of year can aid disease control.

Reference Pest Control Guides Here

INSECT AND RELATED PROBLEMS

The major arthropod pests of this plant species include aphids, moths (worms), fungus gnats, mealybugs, mites, scales, and thrips. Mealybug, mite, and scale infestations are typically the result of bringing infested plant material into the greenhouse. Aphids, moths, fungus gnats and thrips have the ability to fly and thus invade the greenhouse from weeds and other infested plants outside. In the control section for each pest, a few of the many registered and effective pesticides will be listed. For a complete listing please consult the references at the end of this report.

1) Aphids

Symptoms - Aphids are pear-shaped, soft-bodied insects which vary in color from light green to dark brown. Infestations may go undetected until honeydew or sooty mold is observed. Aphids can cause distortion of new growth or, in extreme cases, infested plants can be stunted.

Control - Aphids are relatively easy to control with many registered materials. Phytotoxicity to this plant has been caused by many different chemicals. Please conduct your own tests to see what is safe under your conditions. Root aphids have been controlled with soil drenches.

2) Caterpillars (worms)

Symptoms - Infestations are easy to detect because worms, their excrement and the damage they cause, are usually quite visible to the unaided eye. Damage appears as holes in the center or along the edges of leaves. Damage by worms is often confused with slug or snail damage. The only way to determine which pest is involved is to find a specimen. Old damage can be distinguished from new by the calloused appearance of the older damaged areas (worms are usually gone by this time).

Control -

3) Fungus gnats

Symptoms - Fungus gnats are small black flies (1/8 inch long) and are frequently observed running around the soil surface or on leaves and are often confused for Shore flies (see later section). The adults have long bead-like antennae and their legs hang down as they fly. These insects are very weak fliers and appear to "flit" around randomly. The larvae are small legless "worms" with black heads and clear bodies that inhabit the soil. The larvae spin webs on the soil surface which resemble spider webs. Damage is caused by larvae feeding on roots, root hairs, leaves in contact with the soil and lower stem tissues. Feeding damage may predispose plants to disease and they are often found in close association with diseased plants or cuttings. Adults do not cause any direct damage, but are responsible for many consumer complaints to growers. Adults emerge and fly around in retail shops, homes, or offices and are therefore a nuisance. For further information please consult Extension Entomology Report #74 (Management of fungus gnats in greenhouse ornamentals).

Control - Reduce the amount of water applied to each pot where possible. Avoid algae growth where possible. Soil drenches or soil-surface sprays are effective at controlling the larvae. Nematodes that seek out insects in the soil are sold commercially and have been shown to control these pests without causing any negative effects to the host plants. Adults are very sensitive to most chemicals.

4) Mealybugs

Symptoms - Mealybugs appear as white, cottony masses in leaf axils, on the lower surfaces of leaves and on the roots. Honeydew and sooty mold are often present and infested plants become stunted, and with severe infestations, plant parts begin to die.

Control - Systemic materials are preferred. Control of root mealybugs is accomplished with soil drenches with an insecticide. When pesticides are applied to the soil, care must be taken to assure that the pots have good drainage and that no saucers are attached, or phytotoxicity may result.

5) Mites (Broad mite)

Symptoms - Mites are very small and go unnoticed until plants become severely damaged. Broad mites cause foliar necrosis of the vegetative shoot apex. Initial symptoms of injury show new leaves cupped downward, puckered, stunted and have serrated margins. Broad mite eggs are covered with many tubercles which give them the appearance of being jeweled.

Control - The critical point in any control program is thorough coverage with the pesticide. The best control program is to minimize the possibility of introducing mites into the growing area on infested plant material.

6) Mites (Two-spotted spider mite)

Symptoms - Two-spotted spider mites are very small and go unnoticed until plants become severely damaged. Damaged foliage begins to turn yellow or become speckled due to the feeding of mites. Webbing, loss of leaves and plant death can occur when mite populations reach high levels. Often the presence of this pest is overlooked because the cast skins and webbing produced by this mite are confused for dust on undersides of leaves. Mites have round pale yellow to reddish eggs deposited on the undersurfaces of leaves; nymphs and adults have two dark patches on either side of there bodies.

Control - The best control program is to minimize the possibility of introducing mites into the growing area on infested plant material. Biological control programs have worked in small scale studies but remain unproven in commercial greenhouses.

Symptoms - Two-spotted spider mites are the major mite pest of ivy, but this plant is often also attacked by broad mites.

7) Scales

Symptoms - Infested plants become weakened or stunted and begin to die. Scales can be found feeding on leaves, petioles, or stems. They are usually distinct from the plant material on which they are feeding. Their shape (round to oval), size (pinpoint to 2 mm long), and color (light to dark brown) are quite variable and many scales are hard to distinguish from the plant material on which they are feeding.

Control - See Mealybugs

8) Slugs

Symptoms - Slug and caterpillar damage are similar and determining which pest is present can be difficult. Snails and slugs are voracious feeders, with small stages feeding on surface tissue and larger ones eating irregular holes in foliage. Generally, the culprit can be found on close examination of the plant. Slugs often live under benches or in dark, moist protected places close to the damage. These pests are nocturnal and can be found feeding at night.

Control - Sprays or baits applied to moistened soil around plants are effective. Repetitive applications are necessary. Good sanitation with removal of extraneous plant material and debris which might shelter these pests aids in control.

9) Thrips

Symptoms - Thrips are small (less than 1/20), thin insects. Adult thrips can be identified by a long fringe of hair around the margins of both pairs of wings. Color varies between species with western and other flower thrips being yellow to light brown and banded greenhouse thrips and a few other thrips that feed mainly on leaves being dark brown to black. Feeding takes place with rasping type mouth parts. Infested leaves become curled or distorted, with silver-gray scars or calloused areas where feeding has occurred. Thrips can transmit the tomato spotted wilt virus to many different ornamentals. Any unusual symptoms should be investigated.

Control - Many materials are registered and effective at controlling thrips.

Pesticides should be applied according to label directions.

Regardless of the pesticide or mixture of pesticides used, it is
strongly recommended that the effects be evaluated on a few
plants, under your particular conditions before treating all plants.

Mention of a commercial or proprietary product in this paper
does not constitute a recommendation by the authors,
nor does it imply registration under FIFRA as amended.

Reference Pest Control Guides Here

REFERENCES

1. Chase, A.R. 1990. Phytotoxicity of bactericides and fungicides on some ornamentals. Nursery Digest 24(5):11.

2. Price, J., D.E. Short and L.S. Osborne. 1989. Management of fungus gnats in greenhouse ornamentals. Extension Entomology Report #74.

3. Short, D.E., L.S. Osborne and R.W. Henley. 1984. Phytotoxicity of insecticides and miticides to foliage and woody ornamental plants. Extension Entomology Report #57.

4. Short, D.E., L.S. Osborne and R.W. Henley. 1991. 1991-1992 Insect and related arthropod management guide for commercial foliage plants in Florida. Extension Entomology Report #52. 13 pp.

5. Simone, G.W. and A.R. Chase. 1989. Disease control pesticides for foliage production (Revision #4). Plant Protection Pointer. Extension Plant Pathology Report #30. [also in Foliage Digest 12(9):1-8].