Schefflera Production Guide

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CFREC-A Foliage Plant Research Note RH-91-31

R.T. Poole, A.R. Chase and L.S. Osborne

University of Florida, IFAS
Central Florida Research and Education Center - Apopka
2807 Binion Rd., Apopka, FL 32703-8504


SCHEFFLERA

The popular Brassaia actinophylla (schefflera or umbrella tree) has been widely grown for many years in Florida as an indoor foliage plant, while Schefflera arboricola (dwarf schefflera) has been of major importance since the mid 1970s. Other cultivars and varieties have become available during the past ten years with improved disease and pest resistance such as B. actinophylla `Amate'. Additionally, variegated cultivars of dwarf schefflera are constantly being introduced. The 1991 Florida Foliage Locator lists the following cultivars of S. arboricola; `Covette', `Gold Capella', `Jacqueline', `Renate', `Trinette', and `Variegata'. Although these scheffleras are available in virtually any size from 3 to 38 inch pots they are primarily available in 6 to 14 inch pots.

Schefflera arboricola can be from cuttings about 1 inch long below the leaf and taken from below the two uppermost fully developed leaves and above the lower oldest leaves. Seed of S. arboricola stored for 3 weeks at 65, 75, 85 or 95°F had germination percentages of 69, 75, 73 and 35, respectively, 3 weeks after planting compared to 93% germination of seeds planted immediately. Brassaia actinophylla are not generally propagated from cuttings although seeds and tissue cultured plantlets are commonly employed. Seed of B. actinophylla were reported to have a 67% germination when planted immediately.

Both schefflera and dwarf schefflera can be grown in full sun, but most plants are produced in 47 to 55% shade (approximately 5,000 to 7,000 foot-candles). High quality plants can be grown at this light level with a 3-1-2 ratio fertilizer, such as 9-3-6 or 18-6-12 at a rate of 1800 to 2400 lbs N/acre/year (equivalent to 41 to 55 lbs N/1000 square ft-year or 6 grams 19-6-12/6" pot and 10 grams/8" pot-3 months) plus micronutrients. Higher fertilizer levels will be necessary to produce plants of good quality if higher light levels are provided, but plants will not be acclimatized for interior conditions. Both slow-release and liquid fertilizer sources have been successfully used. Brassaia actinophylla growth or quality was not affected by the ammonium:nitrate ratio, plants grew equally with 100% ammonium as with 100% nitrate, but less Xanthomonas leaf spot was observed when plants were grown with a 50:50 ratio of ammonium:nitrate. In addition, high levels of fertilizer, 8 grams Osmocote 19-6-12 per 4 inch pot greatly reduced Alternaria, Pseudomonas and Xanthomonas leaf spots and produced excellent quality plants.

Good quality S. arboricola have been found to contain 2.8-3.7% dry weight N, 0.26-0.35% P, 2.5-3.5% K, 1.5-2.0% Ca and 0.4-1.0% Mg and good quality B. actinophylla contained 2.0-4.5% N, 0.15-0.50% P, 2.0-3.5% K, 0.5-1.8% Ca and 0.3-0.7% Mg. Good quality B. actinophylla was grown in a range of 2.5 to 10.2 mhos/cm when under 70 ft-c and 100-150 mhos x 10-5 when grown under 1200 ft-c.

Potting media used for schefflera must have good aeration, especially if plants are grown where they are subjected to rainfall, since root loss may be extensive during rainy periods when soil oxygen levels are low. Schefflera will tolerate 35 to 105°F without chilling or heat damage, but best growth and quality occur between 65 and 90°F. Schefflera `Gold Capello' was reported to bring greatest returns when grown at a minimum temperature of 60°F as opposed to 64 or 68 in Belgium during the winter. Brassaia actinophylla had less symptoms of Alternaria leaf spot when grown at a minimum night temperature of 75°F than at 60 and almost no symptoms when grown continuously at 80°F. S. arboricola grew taller and had better color when produced in 85% relative humidity compared to 60% relative humidity. B. actinophylla is very susceptible to ethylene. Both species can be shipped at 50-55°F for 4 weeks with slight loss of quality. Growth of S. arboricola was equal when grown indoors under fluorescent or incandescent light at equal intensities.


PHYSIOLOGICAL PROBLEMS

1) Low root oxygen levels

Symptoms -
Foliage can appear wilted or droopy following rainy periods with subsequent root loss. This condition can occur on plants grown outdoors, in shadehouses or in greenhouses when they are watered excessively and grown in potting media with poor aeration.

Control -
Corrective measures are similar to treatment for root rots, since pathogens frequently invade these damaged roots. The problem can be prevented by utilizing potting media with at least 10% noncapillary pore space and avoiding excessive water application.

2) Cold weather yellowing of plants

Symptoms -
Plants develop an overall light green to yellowish appearance when soil temperature drops below 60°F during cold winter periods.

Control -
Keep the soil at 65°F or above, or spray plants with a micro element mixture containing iron, manganese, copper and zinc. About 2 weeks after soil temperatures rise above 65°F, plants will return to the normal green color without treatment since they can begin absorption of the minor elements which were previously not available due to low soil temperatures.

3) Excessive soluble salts

Symptoms -
Newer foliage develops brownish edges and partial root death can occur, especially beneath large amounts of slow-release fertilizer which may have been placed on one side of a pot.

Control -
Check fertilizer rates to be sure they are not excessive and water sources to be sure they are below 1000 ppm soluble salts. Leach containers with 2 to 4 inches of water to rapidly reduce salts levels and always apply slow-release fertilizers evenly on the soil surface.

4) Fertilizer imbalances

Symptoms -
Tall, thin and light green plants are often lacking in fertilizer while plants with dark green, soft, floppy leaves are probably receiving excessive amounts.

Control -
Recheck fertilizer rates by comparing to those recommended for scheffleras and apply proper amounts.


BACTERIAL PROBLEMS

Reference Pest Control Guides Here

1) Pseudomonas leaf blight (Pseudomonas cichorii)

Symptoms -
Leaf spots are found primarily on margins of dwarf schefflera and are initially small, water-soaked areas, rapidly enlarging and turning black. Severe leaf drop is common and the overall appearance of plants is quite similar to those infected with Alternaria leaf spot. Schefflera is also slightly susceptible to this bacterial disease.

Control -
Bactericides can be used, but are not very successful. Control must be based on maintenance of dry foliage and removal of infected leaves or plants from the growing area to reduce spread to healthy plants.

2) Xanthomonas leaf spot (Xanthomonas campestris pv. hederae)

Symptoms -
Symptoms on scheffleras and dwarf scheffleras are generally confined to pinpoint yellow to tan lesions scattered across the leaf surface, although they can become large and confined between leaf veins. Lesions are mostly 1 mm wide with irregularly raised edges giving the lower leaf surface a corky appearance. Severe infections of lower leaves often result in complete chlorosis and finally leaf abscission.

Control -
Nutritional studies with schefflera, dwarf schefflera and English ivy have shown that applications of higher than recommended rates of fertilizer produce plants with higher resistance to this disease. Use of streptomycin sulfate (Agri-mycin) on scheffleras is not advisable due to development of severe chlorosis of new growth on many cultivars.


FUNGAL PROBLEMS

Reference Pest Control Guides Here

1) Alternaria leaf spot (Alternaria panax)

Symptoms -
Large, dark brown to black leaf spots appear anywhere on the leaf and sometimes on petioles and stems. Severe infections commonly result in leaf drop and give the plant a sparse appearance which can be confused with similar leaf loss associated with root rot. Leaf spots appear wet and can spread in a few days to encompass the entire leaf. This disease occurs on both schefflera and dwarf schefflera as well as Tupidanthus, Dizygotheca, Fatsia and Fatshedera spp.

Control -
Many chemicals control Alternaria leaf spot on schefflera but can cause some phytotoxicity. Keeping the foliage dry will completely control this disease without any need for fungicides.

2) Damping-off (Pythium splendens is the most common pathogen)

Symptoms -
Poor germination and emergence or seedling loss after emergence are common symptoms of damping-off. Many organisms including Alternaria, Fusarium, Phytophthora, Pythium and Rhizoctonia can be responsible for this disease although Pythium splendens is by far the most common pathogen of schefflera seeds and seedlings.

Control -
Diagnosis of the causal organism is the most important step toward control of damping-off diseases.

3) Phytophthora leaf spot (Phytophthora parasitica)

Symptoms -
Phytophthora leaf spot appears essentially the same as Alternaria leaf spot except that the spots generally appear on lower leaves close to the ground first. The disease occurs on both forms of schefflera.

Control -
Again, many fungicides cause phytotoxicity on schefflera. Treatments must include drenching potting media and the soil around the pots if the plants are grown on the ground.


INSECT AND MITE PROBLEMS

Reference Pest Control Guides Here

There are a number of serious mite and insect pests which attack schefflera. Most of these are easily controlled on other host plants, but B. actinophylla present problems as it is one of the most susceptible foliage plants to pesticide damage. In the 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.

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 antennas 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. 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 (Twospotted 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 under surfaces of leaves; nymphs and adults have two dark patches on either side of their bodies.

Control -
Mites can be controlled with specific miticides. 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. Biological control programs have worked in small scale studies but remain unproven in commercial greenhouses.

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) Shore flies

Symptoms -
Shore flies are small black flies (1/8 inch long) and are frequently observed sitting on the tips of leaves or on the soil surface feeding on algae. The adults have very short antennas. These insects are very strong fliers and exhibit directed flight (straight between 2 points). The larvae inhabit the soil and are small legless "worms" with clear bodies and no obvious heads. No known damage is caused by larvae. This insect is believed to feed only on algae. Adults do not cause any direct damage, but may be responsible for spreading plant pathogens, reducing value by defecating on the leaves (small black to green spots) and for many consumer complaints to growers. Adults emerge and fly around in retail shops, homes, or offices and are therefore a nuisance.

Control -
Reduce the amount of water applied to each pot where possible. Avoid algae growth on walkways, benches, and cooling pads. Chemicals are not believed to be very effective in the control of this pest.

9) Thrips

Symptoms -
Thrips are small (less than 1/20), thin insects. Adult thrips can be identified by a long fringe of hairs 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. Beel, E. and A Schelstraete. 1986. Influence of energy savings on the quality and salability of hothouse plants. Verbondsnieuws voor de Belgische Sierteelt 30(11):575-581.

2. Blake, J.H. and A.R. Chase. 1988. Effect of ammonium-nitrate ratio on growth and quality of Brassaia actinophylla and susceptibility to Xanthomonas campestris pv. hederae. Proc. Fla. State Hort. Soc. 101:337-339.

3. Chase, A.R. 1983. Phytotoxicity of some fungicides used on tropical foliage plants. ARC-Apopka Research Report, RH-83-2.

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

5. Chase, A.R. and R.T. Poole. 1987. Effects of fertilizer rates on severity of Xanthomonas leaf spot of Schefflera and Dwarf Schefflera. Plant Disease 71:527-529.

6. Chase, A.R. and R.T. Poole. 1987. Temperature affects severity of three foliar diseases of foliage plants. CFREC-Apopka Research Report RH-87-9.

7. Conover, C.A. and R.T. Poole. 1986. Factors influencing shipping of acclimatized foliage plants. CFREC-Apopka Research Report RH-86-11.

8. Conover, C.A. and R.T. Poole. 1990. Light and fertilizer recommendations for production of acclimatized potted foliage plants. CFREC-Apopka Research Report RH-90-1.

9. Frank, D.F. and A. Donnan. 1975. Influence of A-rest on tropical foliage plants. Proc. Fla. State Hort. Soc. 88:531-534.

10. Gislerod, R.H., L.M. Mortensen and I. Bratberg. 1989. Decorative houseplants are fed too little. Gartneryket 79(3):16-17.

11. Hansen, J. and E.E. Anderson. 1987. Propagating Schefflera arboricola from single-node cuttings. The significance of stem length. Gartner Tidende 103(25):709-711.

12. Hansen, J. and P. Mose. 1987. Propagation of Schefflera arboricola by single-node cuttings. Position of cuttings on the mother plant. Gartner Tidende 103(17):491-493.

13. Henley, R.W. and R.T. Poole. 1974. Influence of growth regulators on tropical foliage plants. Proc. Fla. State Hort. Soc. 87:435-438.

14. Nolan, S.L., T.H. Ashe, R.S. Lindstrom and D.C. Martens. 1982. Effect of sodium chloride levels on four foliage plants grown at two light levels. HortScience 17(5):815-817.

15. Perry, L.P. and J.W. Boodley. 1980. Germination of foliage plant seeds in response to pre- sowing ultrasonic exposures, water soaks and fungicides. HortScience 15(2):192-194.

16. Poole, R.T. and A.R. Chase. 1987. Response of foliage plants to fertilizer application rates and associated leachate conductivity. Proc. Fla. State Hort. Soc. 22(2):317-318.

17. Poole, R.T., A.R. Chase and C.A. Conover. 1988. Chemical composition of good quality tropical plants. Revision. CFREC-Apopka Research Report RH-88-6.

18. Poole, R.T. and C.A. Conover. 1983. Influence of simulated shipping environments on foliage plant quality. HortScience 18(2):191-193.

19. Poole, R.T. and C.A. Conover. 1988. Seed germination of several indoor ornamental foliage plants. CFREC-Apopka Research Report RH-88-8.

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

1. 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.

22. 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.

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

24. Turner, M.A., D.L. Morgan and D.W. Reed. 1987. The effect of light quality and fertility on long term interior maintenance of selected foliage plants. J. Environ. Hort. 5(2):76-79.

25. Wang, Y.T. and T.M. Blessington. 1990. Growth of four tropical foliage species treated with paclobutrazol or uniconazole. HortScience 25(2):202-204.