Bombax ceiba grows to an average of 20 meters, with old trees up to 60 meters in wet tropical regions. The trunk and limb bear numerous conical spines particularly when young, but get eroded when older. The leaves are palmate with about 6 leaflets radiating from a central point (tip of petiole), an average of 7–10 centimetres (2+5⁄6–4 in) wide, 13–15 centimetres (5+1⁄6–5+5⁄6 in) in length. The leaf's long flexible petiole is up to 20 centimetres (8 in) long. Huge Red Cotton Tree at Kodungallur, India Cup-shaped flowers solitary or clustered, axillary or sub-terminal, fascicles at or near the ends of the branches, when the tree is bare of leaves, an average of 7–11 centimetres (2+5⁄6–4+1⁄3 in) wide, 14 centimetres (5+1⁄2 in) in width, petals up to 12 centimetres (4+2⁄3 in) in length, calyx is cup-shaped usually 3 lobed, an average of 3–5 centimetres (1+1⁄6–2 in) in diameter. Staminal tube is short, more than 60 in 5 bundles. The stigma is light red, up to 9 centimetres (3+1⁄2 in) in length, ovary is pink, 1.5–2 centimetres (2⁄3–5⁄6 in) in length, with the skin of the ovary covered in white silky hair at 1mm long. Seeds are numerous, long, ovoid, black or gray in colour and packed in white cotton. Huge trunk of Red Cotton Tree Immature fruits of Bombax ceiba in Hong Kong. The fruit, which reaches an average of 13 centimetres (5 in) in length, is light-green in color in immature fruits, brown in mature fruits.

1. Veer Chandra Singh Garhwali Uttarakhand University
Of Horticulture & Forestry
College of Forestry (CoF)
Ranichauri (T.G)
Session 2023
Presentation topic on : Diseases of SEMUL/SEMAL (Bombax ceiba)
Presented By :
Sagar Chaudhary
ID No.- 22342
M.Sc. Forestry (Silviculture)
Submitted To : Dr. Laxmi Rawat

2. CONTENT
• Semul/semal tree : taxonomical classification
• Semul/Semal tree : key facts
• Semul/Semal tree : physical description
• Semul/Semal tree : disease and protection
• References

3. TAXONOMICAL CLASSIFICATION:
• Kingdom: Plantae
• Division: Magnioliophyta
• Class: Magniolipsida
• Order: Malvales
• Family: Malvaceae (Bombacaceae)
• Genus: Bombax
• Species: ceiba
• Binomial name: Bombax ceiba L.

4. SEMAL: KEY FACTS
Botanical name: Bombax ceiba
Type: Deciduous tree
Leaf type: Large, glossy leaves that are lanceolate in shape, meaning that they are narrow and pointed at the ends
Flower: Showy, red flowers about 2 inches in diameter and have a pleasant, sweet fragrance
Varieties available: 4
Also known as: Silk cotton tree, red silk cotton tree, semal
Height: Height up to 30 m
Sun exposure: A location that receives total sun exposure, meaning that it gets at least six hours of direct sunlight per day
Ideal temperature: Ranges 28 – 42o C
Soil type: Well-draining, Sandy loam soil
Soil pH: pH between 6.0 & 6.5
Basic requirements: Most soil with regular fertilization and total sun exposure
Ideal location for
placement:
The best location for Semal tree is one that provides the tree with plenty of sunlight, well-draining soil, and enough
space to grow
Ideal season to grow: A distinct dry season
Maintenance: Low maintenance

5. PHYSICAL DESCRIPTION
The silk cotton tree, or the semal tree, is a large, quick-growing tree with a broad,
spreading canopy. It has a straight, sturdy trunk and a rough, dark-coloured bark. The tree
leaves are large and glossy, and it bears clusters of showy, red flowers that bloom in the
summer.
After the flowers bloom, the tree produces long, fluffy seed pods containing a cotton-like
substance. The seed pods are green at first and turn brown as they mature. The tree is
known for its distinctive, spiky red flowers and fluffy seed pods, giving it a unique and
striking appearance.
In addition to its ornamental value, the silk cotton tree is also prized for its medicinal
properties. The tree’s bark, leaves, and seeds are utilized in traditional medicine to cure
various ailments, including fever, diarrhoea and skin conditions. The tree is also used as a
natural remedy for wounds and cuts.

6. SEMUL/SEMAL TREE: DISEASE &
PROTECTION
PATHOGENIC DISEASES
ROOT ROTS
• Ganoderma lucidum (Leyss.) Karst. Causes root rot
and finally death of the affected plants.
• The species is fairly resistant to the disease.
• Vigorous trees are rarely attacked, while suppressed
trees are liable to attack by the fungus.
• Other root rots are recorded on semul/semal are
Fomes lignosus (klotzsch) Bress. From Malaysia and
Fomes lamoensis (Murr.) Sacc. & Trott. From Ceylon
(Spaulding 1961, Browne 1968.)
Basidiocarps (fruiting
bodies) of Ganoderma
root rot on Semul
Occurrence of
carpophores Fomes
lignosus at the neck of
the Semul

7. SYMPTOMS AND DIAGNOSIS
• If you are concerned that your tree is infected, there are a few Ganoderma
symptoms you can look for:
• Yellowing leaves
• Wilting leaves
• Undersized leaves
• Dead branches
• But the most telling sign of infection is often the formation of fruiting bodies
that look like small shelves or mushrooms on the lower portion of the trunk.
These are called conks (a conk is a mushroom without a stalk).
Honey-colored armillaria mushrooms
and the fruiting body of Ganoderma
root rot growing from the base of
Semul.

8. Life Cycle
New spores released from the conks are
dispersed throughout the summer during humid
periods, and infect open wounds on root flares
and lower trunk areas of susceptible trees. The
spores germinate, and the infection advances to
attack the sapwood of major roots and the lower
tree trunk. The amount of decayed wood
increases year after year, resulting in
dangerously soft, spongy wood in the part of the
tree that serves as its anchor. The conks are
annual; new conks may be produced each
summer and fall, after which they die and
deteriorate.

9. Integrated Pest Management
Strategies
1. Proper planning. Appropriate species and cultivar selection to match the
right tree for the right site will make it easier to keep trees healthy for their
entire life.
2. Proper tree maintenance. Subsequent good cultural practices (planting,
fertilizing, watering, pruning, etc.) will help to maintain the health and vigour
of any tree.
3. Avoid damage to tree trunks and roots. Even small wounds from mowers
and trimmers can allow infection by decay fungi. Avoid damaging all
deciduous trees, both young and old.
4. As soon as possible, remove trees that exhibit conks on the lower trunk
and exposed root areas. Large trees with severe internal rot may fall with little
warning, injuring people and causing extensive property damage. Consult a
certified arborist for removal of large trees.
Organic Strategies
All of the recommended IPM strategies are strictly organic approaches.
NOTE:- The best way for Ganoderma
management is to prevent it. Proper
watering (not too much), using mulch and
applying soil care products can keep your
tree healthy. Also, avoid damage to tree
trunks and roots that can open the tree up
to Ganoderma infection.

10. PHOMOPSIS DIE-BACK
• Phomopsis salmalica attacks young succulents shoots of semul, upto 4 years old plant.
• The affected bark becomes brown and pulpy and gives out an odour of fermentation.
• Affected plants exhibit die-back and eventually die (Browne 1968).

11. Symptoms and Signs
Fruit symptoms of Phomopsis fruit rot
include extensive grayish brown discolored and
shriveled hulls that often have clear gum secretions
and shriveled kernels. Affected fruit frequently
abscise. Second-year symptoms include twig and
branch dieback (see LOWER LIMB DIEBACK).
Phomopsis Dieback: A semal Trunk Disease
Caused by Phomopsis salmalica in California

12. Life Cycle
Infection occurs in the spring from conidia that
overwintered on shoots or stems killed the previous year.
Late season infections may occur if cultural practices
(improper watering and maintaining high fertility)
encourage prolonged plant growth. Prolong wet and warm
conditions increase the severity of infection and symptoms
on the susceptible hosts. The central part of the plant is
often more affected than the outer portion, with the new
growth showing almost continuous infection. Under certain
conditions favorable for fungal development, entire young
shrubs and trees may be affected, and all the evergreens
needles and stems will die and turn brown. Severe
infection for several years in a row, may result in the death
of larger or older plants.

13. Management
• Plant only resistant species, varieties and cultivars.
• Avoid planting in poorly drained areas.
• Avoid wounding or injuring when planting or cultivating.
• Do not use infected branches or needles as a mulch
• Sterilize pruning tools between cuts and especially between plants, using rubbing alcohol or use a twenty-five percent
solution of a chlorine bleach.
• Keep in mind that aggressive, maintenance pruning will promote the growth of new and susceptible tissue, so wait for
the dry conditions of mid June to mid July for this activity.
• If overhead sprinkling or in ground sprinklers must be used, water early in the day to allow for fast drying of plant
tissue.

14. PINK DISEASE
Corticium salmonicolor Berk.& Br., the cause of pink disease
possesses a wide host range including semul (Browne 1968).
The cause of pink disease is widely distributed in the tropics
and subtemperate regions of Asia, Africa, West Indies, New
South Wales and New Zealand and is probably indigenous in
the region where it occurs.

15. Symptoms
• In young plants, infection results in
girdling branches and the main stem
towards the latter part of the rainy season.
• The affected plants are killed outright in
Bombax ceiba. Infection on the stem or
branches causes girdling and death of
parts above the girdled region.
Pink disease of Bombax ceiba

16. Pathogen
Corticium salmonicolor occurs on the host in four growth forms as :
1. Pustules : pustules appear on branch and stem within a few weeks after infection at the beginning
of the monsoon as pink to salmon coloured sterile cellular bodies upto 1 mm in diameter.
2. Cobweb : the infected parts produce on the bark thin white, arachnoid mycelia originated from
pustule or form the edges of the pink incrustation.
3. Nectar : the fruit bodies are orange red, about 2 mm in diameter and develop on the upper side of
the attacked branch exposed to sun. conidia develop after the rains.
4. Pink incrustation : this comprises the perfect stage of the fungus develops as thin, light pink
incrustation on the bark. It develops during autumn on stems and branches originating at the fork
usually on the under surface of the stem.

17. Control
• Effective control of pink disease of
Bombax ceiba has not yet been obtained.
• In high rainfall areas in Kerala and
Karnataka where the pink disease has
limited the success of B. ceiba it may be
necessary to replace them with other
species of semal.
• Pink disease is effectively controlled by
application of Bordeaux paste to infected
trees.

18. LEAF BLIGHT
• Dicellomyces bombacis Bakshi, the leaf blight fungus, causes gelatinous rusty-brown
patches on lower surface of leaves.
• Areas of the leaf on the upper surface corresponding to infection spots are bleached and
later turn yellow to dark-brown.
• In advanced stages of attack, the infection spots become necrotic, leaves get wrinkled,
curled and are shed permanently.
• The disease may become serious on young plants.

19. Symptoms
Leaf blight symptoms are characterized by the presence of
long, elliptical, and necrotic lesions on the leaf lamina. The
center of the lesion is straw in color and the margin is usually
dark brown. The dark color of the margin is, however, not
conspicuous in nonpigmented (tan type) cultivar.

20. LEAF RUSTS
• Chrysomyxa bombacis Petch attacks semul/semal leaves in Ceylon. The
rust is believed to be autoecious (Brown 1968).
• Uredo bombacis petch is recorded on semul leaves in Balehonnur,
Karnataka. The rust is also reported from Ceylon (Spaulding 1961,
Sarbhoy, Girdhari Lal and Varshney 1975).

21. Symptoms
• Pale leaf spots eventually develop into spore
producing structures called pustules.
• The pustules are found most commonly on the lower
leaf surface and produce huge numbers of microscopic
spores.
• Pustules can be orange, yellow, brown, black or white.
• In some cases there may be dozens of pustules on a
single leaf.

22. REFERENCES
• http://en.wikipedia.org/wiki/Bombax_ceiba
• Troup R.S., Forest Research Institute and College, Dehradun, India (1981 reprint)
Silviculture of Indian Trees, Vol III.
• Bakshi B.K., Forest Pathology Principles and Practice in Forestry.