Ficus Leaf damages
Prepared by Maher Jabado Feb 2010

The genus, Ficus, consists of over 800 species, several of which are desirable interior foliage plants. Although most ornamental figs are trees, a few are shrubs or vines.

Ficus benjamina, the weeping fig, was first introduced to industry during the late 1950's and has since become the most popular interior tree. Some cultivars of the species are listed along with their unique characteristics below:

Ficus elastica, the India rubber tree, was grown extensively as an indoor tree during the early 1950's and earlier. Today it is difficult to find commercial sources of the plant because it has been replaced with several cultivars listed below:

`Decora' was a significant new cultivar at the time of its introduction, about 1950. With its broad elliptical leaves and more attractive growth habit, it soon replaced the species.

`Doescheri' has the narrow leaf shape of the species and a striking variegated pattern of green, grayish green, yellow, white and a pink midrib and petiole.

`Robusta' is a compact form which resembles `Decora', but is more compact and free branching.

`Rubra' has dark, wine red leaves when grown in full sun. Much of the red color is lost as the plant grows under reduced light intensity. `Rubra' is also listed under the names `Burgundy' and `Abidjan'.

`Sophia' is a new green cultivar with leaves which are smaller and more rounded than `Robusta'.

Ficus lyrata, the fiddleleaf fig, has the largest leaves of those figs being produced for indoors. The cultivar `Compacta', which is widely propagated from tissue culture, has large closely spaced leaves with short petioles.

Ficus maclellandi `Alii', sometimes called the Alii fig, is a relatively new plant, with long, narrow, willow-like leaves, which is particularly well suited for medium and large tree production.

Ficus retusa `Green Gem' is a patented cultivar (Plant Patent No. 5900) which looks much like `Nitida', except it is more vigorous, has coarser leaves, and grows much more symmetrically.

Ficus retusa `Nitida', the Cuban laurel fig, has a long history of use as and interior tree. Although it has leaves which are similar in size to the weeping fig, its branches are much stiffer and lack the weeping habit.

Ficus retusa `Hawaii' has leaves that are highly variegated with green, grayish green and ivory.

Table 1. Suggested light intensity ranges and fertilizer application rates for production of selected acclimatized Ficus

    Species and             Light intensity   Fabric Shade  Actual nitrogen
    cultivars               (foot candles)      (percent)   rate (lb N/1000 
                                                            ft2/month)z
----------------------------------------------------------------------------
F. benjamina (cultivars)        4000-6000         60-40         4

F. benjamina `Florida Spire'    1000-2500         80            4

F. elastica (cultivars)         4000-8000         60-30         4

F. lyrata (and cultivars)       2000-6000         72-40         4

F. maclellandii `Alii'          4000-6000         60-40         4

F. retusa (cultivars)           4000-6000         60-40         4

 z Use a complete fertilizer with an approximate ratio of 3:1:2.

The potting medium used will vary depending upon plant size and type. All mixes should have good moisture holding capacity and aeration. Potted trees are frequently grown in a medium with 10 to 20% coarse sand by volume added to reduce frequency of plants tipping in the wind. Measures should be taken to avoid excessive root development into soil beneath containers, otherwise plants will be shocked severely at the time they are moved.

Cold Plant injury usually occurs below 2C , depending upon plant species, physiological condition of the plant and specific conditions of the cold period - rate of change, duration, wind and humidity.

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PHYSIOLOGICAL PROBLEMS

1) Excessive light intensity during final stage of production

Symptoms -

Leaves, medium to light green with sides of leaf blade folded upward and margin wavy. Branch angle of some species tends to be narrow and branches stiff. Such plants are not light acclimatized and usually defoliate excessively when moved to interior conditions.

Control -

Plants should be exposed to shade levels of 70% or more (3000 or less ft-c) for a minimum of 2 to 6 months depending on plant size (2 months for up to 8", 3 to 4 months for 20 to 17", and 4 to 6 months for larger container sizes).

2) Excessive moisture stress

Symptoms -

Small reddish spots, 1-3mm across, on the undersides of leaves of F. lyrata. The symptom is usually observed on stock plants in full sun which have been air layered, and most frequently during the driest months of December through June. This condition is rare on plants grown in shade. Leaves on wilted layers or cuttings of F. elastica, and possibly some other species, remain in relaxed orientation after normal moisture content is restored. This is a permanent condition. Branches of trees in an active state of growth may bend under moisture stress, then partially recover, leaving a permanent kink or "dogleg" in the stem.

Control -

Severe moisture stress can usually be avoided through good nursery practices. Leaf spotting can be prevented by timely irrigation of stock and use of the vertical slit technique of air layering versus the girdling procedure. Permanent petiole wilt and stem kinking can be avoided with adequate soil moisture and high humidity during propagation.

Prevention of excessive root development outside the container eliminates most of the shock that occurs when large segments of root are severed from plants because roots extend into soil below the pot. Use of plastic ground covers, drip irrigation and root pruning during production usually eliminates root pruning shock when plants are removed.

3) Excessive soluble salts

Symptoms -

Plant damage from high salinity can be placed in two categories based on stage of development. Plants in production with excessive salinity in the root zone become stunted and, in severe cases, defoliate, starting with the oldest leaves, and eventually die if the condition is not corrected. Foliage in early stages of stress from excessive fertilizer in the soil appears dark green, but later new growth appears wilted and chlorotic if soil conditions are not corrected. Root tips of plants exposed to excessive salinity shrivel and eventually die. Plants placed indoors under less than 200 ft-c, with fertility levels above that recommended for production, usually defoliate excessively and, in some cases, die.

Control -

Avoid over-application of fertilizer and do not use soil mix components with high salinity. Irrigate with water that is low in salts. Salts accumulation can be corrected in most cases by leaching soil thoroughly. Reduce soil fertility at the end of the production cycle as part of the acclimatization process.

4) Essential element deficiencies

A. General deficiency of primary nutrients due to under-application of complete fertilizer.

Symptoms -

Plants are generally light green with older leaves exhibiting the greatest chlorosis. Plant growth is slow.

Control -

Adjust fertilizer program to elevate fertility of soil mix, using a 2-1-2 or 3-1-2 ratio fertilizer.

B. Potassium (K) deficiency.

Symptoms -

Lower leaves exhibit marginal chlorosis and necrosis. This problem is seen occasionally on F. elastica stock. Leaf tissue analysis is the best way to confirm suspicions of a nutritional disorder.

Control -

Supply potassium to the soil at rate based on soil and tissue tests. Potassium chloride and potassium nitrate are good potassium sources.

C. Magnesium (Mg) deficiency.

Symptoms -

Lower leaves, primarily on F. nitida, become chlorotic at the most distant margins first.

Control -

Plants grown with adequate soil-incorporated dolomite should not develop Mg deficiency. Foliar or soil surface applications of magnesium sulfate at the rate of 1 pound per 100 gallons will correct the deficiency.

D. Manganese (Mn) deficiency

Symptoms -

Terminal leaves of primarily F. nitida exhibit an interveinal chlorosis.

Control -

Prevention is accomplished through incorporation of a microelement blend such as MicromaxTM or PerkR, at the rate of 1 to 2 pounds per cubic yard of potting mix. Manganese-deficient plants can be sprayed with manganese sulfate at the rate of 0.5 pounds per 100 gallons.

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BACTERIAL PROBLEMS

1) Crown gall - (Agrobacterium tumefaciens)

Symptoms -

Slightly swollen areas on the stems, leaf veins and even roots are initially apparent. These swollen areas enlarge and become corky. In cases of severe infection they may enlarge and merge to create a very distorted stem or root mass. Galls may also form on the ends of cuttings or stems where cuttings have been removed.

Control -

Remove and destroy all plants found infected with the bacterium, then sterilize any cutting tools used on them. Since a fungus is also known to cause galls on Ficus, and accurate disease diagnosis must be made.

2) Xanthomonas leaf spot - (Xanthomonas campestris pv. fici)

Symptoms -

Foliar infections on ficus start as tiny pinpoint water-soaked areas which can rapidly enlarge. They tend to remain confined to the areas between leaf veins. Sometimes lesions have a bright yellow border. In severe infections leaf abscission is common. All ficus species tested have been found susceptible to the pathogen, although the most commonly affected plants are Ficus benjamina.

Control -

Eliminate all stock plants which have Xanthomonas leaf spot. The disease can be difficult to control if plants are produced with overhead watering or exposure to rainfall. Bactericides such as copper containing compounds may be somewhat effective if used on a preventative and regular basis. In addition, use of elevated rates of fertilizer have been shown to reduce severity of Xanthomonas leaf spot on Ficus benjamina.

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FUNGAL PROBLEMS

1) Anthracnose - (Glomerella cingulata, Colletotrichum spp.)

Symptoms -

Anthracnose is characterized by yellow and later dark brown spots anywhere on the leaf. Yellowish masses of spores form in zones along leaf veins or in concentric rings in the spot. Eventually leaves may abscise. Ficus elastica cultivars are commonly infected with this pathogen during the summer months and appear especially susceptible when they are being rooted under mist conditions.

Control -

Keep plant stresses from water and heat to a minimum. Do not use any cuttings which have spots when taken from the stock plants. On rooted plants minimize overhead irrigation and exposure to rainfall if possible.

2) Botrytis blight - (Botrytis cinerea)

Symptoms -

Large, tan to brown leaf spots with concentric rings, usually found between the leaf and sheath or on leaf tips. Botrytis blight occurs primarily on Ficus elastica during cool periods of the year especially on cuttings.

3) Cercospora leaf spot - (Cercospora sp.)

Symptoms -

Tiny and slightly raised, red or dark green spots on lower surface of Ficus elastica leaves.

Control -

4) Corynespora leaf spot - (Corynespora cassiicola)

Symptoms -

Small to large, reddish leaf spots on the youngest mature leaves, with leaf abscission common in severe infections when leaf spots expand interveinally.

Control -

This disease occurs on both green and variegated forms of Ficus benjamina and Ficus nitida but is more severe on the variegated cultivars. Keep fertilizer applications at recommended levels, and eliminate overhead water if possible.

5) Southern blight (Sclerotium rolfsii)

Symptoms -

Plants with southern blight may initially appear similar to those infected with many stem or root infecting fungi. As the disease advances, however, the white cottony masses of mycelia and brown seed-like sclerotia set this disease apart. The sclerotia usually form on the basal portion of stems of infected plants but may also be found on infected leaves. Eventually the entire cutting or plant may be covered with the fungus.

Control -

Southern blight must be controlled through preventions. Use pathogen-free potting medium, pots and planting materials.

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NEMATODE PROBLEMS

1) Foliar nematode - (Aphelenchoides besseyi)

Symptoms -

Leaf spots begin near the midvein on lower leaves and extend to the margin. They are usually rectangular in shape. The primary species of Ficus which is a host for this nematode is F. elastica.

Control -

Infection of Ficus elastica occurs through movement of nematodes from weeds to lower leaves. Mow weeds in field plantings to stop this movement.

2) Lesion nematode - (Pratylenchus sp.)

Symptoms -

Root systems are greatly reduced in vigor and appear rotted in many cases. Since the symptoms caused by fungal root pathogens are so similar, accurate diagnosis of the problem is critical to disease control.

Control -

Use sterile soil and grow plants off the ground if possible.

3) Root knot nematode - (Meloidogyne spp.)

Symptoms -

Galls occur on roots and the root system may be drastically reduced; plant stunting and wilting occur when severe infestations are present.

Control -

Use sterile soil and grow plants off the ground if possible.

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INSECT AND RELATED PROBLEMS

The major insect pests of this plant group include mealybugs, scales and thrips. However, there are a number of minor arthropod pests such as mites, fungus gnats and aphids which will attack Ficus spp. occasionally, but will not be discussed here. 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) Mealybugs

Symptoms -

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

Control -

Systemic materials are preferred.

2 Scales

Symptoms -

Infested plants become weakened or stunted and die. Scales can be found feeding on leaves, petioles or stems. Their shapes, sizes and colors are variable and many are hard to distinguish from the plant material on which they are feeding.

Control -

See mealybugs.

3) Thrips

Symptoms -

Infested leaves become curled or distorted, with silver-gray scars where feeding has occurred. Thrips damage is most severe on F. nitida.

Control -

Many materials are registered and effective in controlling thrips.