This document provides information on diseases that affect cotton plants. It discusses several major diseases including seedling diseases caused by fungi like Rhizoctonia solani and Pythium spp. It also discusses root rot caused by Rhizoctonia bataticola and R. solani, Fusarium wilt caused by Fusarium moniliforme and F. vasinfectum, Verticillium wilt caused by Verticillium albo-atrum, and boll rot caused by various fungi and bacteria. It provides the symptoms and control methods for each disease. The objectives of the document are to familiarize readers with cotton diseases, their signs and symptoms, and management and control strategies.

1. WEL-COME

2. An Assignment on
Disease of
Cotton
Plants
Submitted by:
Santosh pathak
IAAS, Lamjung Campus (B.sc AG )

3. Introduction :
 Cotton is a soft, fluffy staple
fiber that grows in a boll, or
protective capsule, around the
seeds of cotton plants of the
genus Gossypium.
 Cotton is the king of fibres,
usually referred as white gold .
 Current estimates for world
production are about 25 million
tones annually, accounting for
2.5% of the worldˋs arable land.
China is the worldˋs largest
producer of cotton, but most of
this is used domestically

4.  The United States has been the largest
exporter for many years.
 Cotton is grown mainly for its fibre used in
manufacture of cloth for the mankind. It is
also used for several other purposes like
making threads, for mixing in other fibres and
extraction of oil from the cotton seed.
 Cotton seed after extraction of oil is a good
manure and contains about 6% nitrogen, 3%
phosphorous and 2% potash.
 Cotton seed, cotton linter and pulp obtained
during oil extraction and cotton meal are
good concentrated feed for cattle.
Contd….

5.  cultivated cottons are annuals. Cultivated cotton is a
herbaceous plant which attains a height of 60 to 200cm.
The plant has a tap root with secondary roots that branch
laterally from primary root.
 The main stem is erect and much branched; the branches
develop from buds located at the nodes of the main stem.
The leaves are spirally arranged on the main stem.
 Cotton belongs to the malvaceae family and the genus
Gossypium. The genus Gossypium has been one of the
most difficult to classify. Genus Gossypium includes 50
species in which 46 are wild and 4 are cultivated.
 According to classification by Hutchison (1947) the
following four cultivated species contain almost all the
varieties of cotton in case of India.
 Gossypium arboreum
 Gossypium herbaceum
 Gossypium hirsutum
 Gossypium barbadense


6. Objectives:
 To be familiar with the diseases found in the
cotton.
 To be able to know the sign and symptoms of
disease.
 To get maximum ideas regarding the control
measures and management of disease found in
cotton.
 To be familiar about the pesticides like fungicides,
insecticides and their use in the crop at different
times applying different methods

7. Review of literature
 Cotton crop is attacked by a number of diseases. Symptoms of
important diseases and their suitable control measures are
given below.
 Seedling diseases:
 Seedling diseases are presently causing great losses to cotton
producers in Tennessee. They comprise the number one
disease problem. The estimated loss is an average of 9.72
percent annually based on a range of 5 to 18 percent since
1989.
 Loss estimates do not include cost of replanting or losses due
to lateness of replanted cotton.
 CAUSE
 . The organisms include both seed and soil-borne fungi and
bacteria. The soil-borne fungi, Rhizoctonia solani and Pythium
spp., are the most important causes of seedling diseases in
Tennessee.
 Rhizoctonia solani is the fungus most commonly associated
with seedling diseases; however, during cool, wet seasons
Pythium spp. may become more prevalent.

8.  SYMPTOMS
 The various phases of seedling diseases
include seed-rot, root-rot, pre emergence
damping-off, and post emergence damping-off.
Root-rot (or black-root) may occur anytime.
 Pre emergence damping-off refers to the
disease condition in which the seedling is killed
between germination and emergence from the
soil.
 The death of seedlings resulting shortly after
their emergence from the soil is termed post
emergence damping-off. The latter is referred
to as "sore shin" when only stem girdling
occurs. Rhizoctonia is usually the cause of sore
shin.
 CONTROL
 Fungicides seed treatment helps control seed
rot and some pre emergence damping off.
 Some of the practices include use of correct
planting equipments and date of planting, good
Contd…..

10.  Root rot
 This disease is caused by soil-borne fungi
Rhizoctonia bataticola and Rhizoctonia solani
.
 The diseased plants occur in more or less
circular areas and this is very characteristics
of the disease.
 The affected plants can be easily pulled out of
the ground. The roots of the affected plants
decay and a yellowish brown discoloration
sets in. In badly affected plants the wood
becomes brown or thick.
Due to this disease perfectly healthy plants
may wilt within 24 hrs with leaves dropping
without showing any discolouration.
 Control measures:
 Irrigate frequently to keep down soil
temperature.
 Follow a wheat-jowar-paddy-cotton rotation.
 Treat the seed with Brassicol(75w.p.) 200g/50
kg of seed of acid delinted seed and 300g/ 50
kg of machine delinted seed.

12. Fusarium wilt
 This disease is caused by a soil-borne
fungus Fusarium moniliform, Fusarium
vasifectum.
 Plants can be affected this disease in
any stage. Disease incidence in
seedlings can be high in cold soils, but
mean temperatures about 230c favors
the disease
 . In young as well as old plants the initial
symptoms are stunting followed by
yellowing, wilting and dropping of most
of the leaves.
 The cut stems of wilted plants shows
brown or black vascular tissues inside.
 In old plants, lower leaves towards the
base are affected first followed by
younger ones towards tips.
 Leaf discoloration appears around the
edges and progresses towards the
midrib and leaves gradually drop.

13.  Control measures:
 .Grow tolerant varieties like
LD-694.
 Application of potash and
organic matter in sufficient
amount is helpful in reducing
disease.
 Soak 4 kg seed(non-delinted)
in 8 litres of water containing
8 g of Bavistin/Derosal for 6-8
hrs and 2-3 hrs in case of
delinted.
 Avoiding over irrigation and
over application of nitrogen..
 Crop rotation
 Field inspection for early
detection and containment of
isolated outbreaks.
 Farm hygiene.

14.  Verticillium wilt:
 . Verticillium wilt is caused by the soil-borne
fungus, Verticillium albo-atrum.
 This fungus can survive in the soil for many
years even in the absence of cotton.
 Cotton seedlings infected with Verticillium
usually turn yellow, dry out, and die.
 Plants which become infected later in the
season are stunted and exhibit a yellow
condition along the leaf margins and between
the major veins.
 This yellow imparts a mottled appearance to
the plant. Severely affected plants will shed
their leaves.
 Sprouts or new shoots may develop near the
base of infected plants.
 The discoloration associated with Verticillium
wilt is usually more evenly distributed across
the stem than that associated with Fusarium
wilt.
 The browning of the stem tissues are also
usually less intense where the wilt is caused by
Verticillium.
 Control by using Deltpine and crop rotation.

16. Boll rot:
 Boll rots have caused heavy losses to cotton producers during wet
growing seasons.
 Rain and high humidity during late summer and fall are optimum
conditions for boll-rot development and increase the incidence of the
disease.
 A number of fungi and bacteria have been associated with boll rots.
Some of these organisms invade the cotton bolls directly, whereas
others enter through insect wounds or as secondary invaders.
 Infected seed will result in seedling blights the following season. Boll
rots usually first appear as water-soaked spots.
 Later, as the infection spreads, the bolls turn black and may be covered
with a moldy fungus growth. Badly infected bolls may drop from the
plant.
 Control measures:
 To prevent boll rots, cotton growers should avoid excessive
applications of nitrogen which promotes rank growth of cotton.
 It has been found that skip-row cotton provides better air drainage,
resulting in less boll rot. Defoliation will also help reduce boll rots.

18.  Angular leaf Spot (Xantomonas malvacearum):
 It is also known as Bacterial blight. This disease is usually least
severe in or absent in hot dry condition, but it can be severe during
warm wet weather.
 It is quite sever in the irrigation cotton growing area of the country.
• Symptoms will be most severe on leaves when the humidity is high
with air temperature average 86-95 degrees F and when rain, heavy
dew, fog or sprinkle irrigation are frequent.
 Small round spot occur in the cotyledon during the early
seedling stage of growth and angular lesions on the older plants.
 The disease on the leaves appears first as water soaked spot that
enlarge to angular brown to black lesion.
 The spot occurs on the leaves from the seedling to the mature plants
stage during of high temperature.
 The spot are light-green spots that are visible on the upper and lower
surface of the leaves. These spots quickly turn dark brown to black
 . The margin of this spots has sharp angles. The round, light green
lesions on bolls may develop into boll rot. Black elongation lesion
occurs on the young stem.

19.  Control measure:
 The acid delinted seed should be treated with 0.1%
Streptocycline solution, by keeping it emmersed for 2hrs (Two
grams of streptocycline dissolved in 20 liters of water is enough
to treat seed required for one acre).It should be dried on the shade
and the seed should be treated with Ceresin wet or Agrosan.
G.N@25- 10 kg of the seed .If seed is not acid delinted it should
be treated with Streptocycline as described and after coating it
with slurry of ash and dung it should be treated with Ceresan or
Agrosan G.N.
 The crop should be sprayed from the time of the first appreance
of the disease with Blitox 50, flytolan, Blue copper 50 or
Cupramer in a concentration of 0.3 to 0.5 % considering the
severity of the disease.
 Resistance variety should be used.
 Rotating cotton with soybean or corn planting for once or more
years will help reduce the severity of bacterial blight on next
cotton crop.
 Plant only acid-delinted seed produced in fields free from this
disease.
Contd……

21.  Anthracnose (Colletorichum indicum):
 . This disease is caused by two species of colletotrichum which
are seed born in nature. The disease is chiefly attacks seedling,
bract and bolls.
 Affected seedling have reddish or dark brown lesion on the
stems below the soil surface and on roots.
 Symptoms on bracts appear on the form of circular water soaked
spot which enlarge and may spread to the bolls. When the
disease area extend to the base of the bolls, the bolls shed away.

 Control measures:
 Seed treated with 5 g of ceresan wet and 8 g of
agrimycin-100 in 5 liters of water per 6-8 kg seed for 6-
8hrs is effective in eliminating seed-born infection.
 Spray seedling copper fungicides such as Bliotx or
Fytolan at the rate of 2 kg per hectare in 1000 liters of
the water once or twice checks seedling blight. Spraying
during boll formation reduces damage from boll rot.
 Spray the seedling with Bordeaux mixture help in
checking the disease in seedling stage.
 One year rotation and ploughing under the disease debris
after harvesting the crop are quite effective in
eliminating the source of primary inoculum.
 Defoliation of the crop by dusting with calcium
cyanmide @15 ks/acre reduces humidity round the boll
and results in rapid drying of the bolls and lint after the
rain, thereby reducing the boll rot phase of the disease

23.  Alternaria leaf spot (Altenaria termis, Alternaria
macrospore; A. gossypium and A. gossypina)
 The disease is common of occurance in the cotton
growing area of our country. It makes it appearance in the
form of pale to brown round or irregular spot on the
affected leaves of the plants.
 Sometimes the leaf veins may also get infected.
Ultimately the affected leaves become dry and fall of. In
the rare case the disease may cause canker on the
stems.
 The infection spread to the bolls only when the attack is
very severe and they may finally fell off.

 Control measures:
 Destruction of disease plant debris along with all other
practices included under clean the cultivation are
essential for reducing disease appearance.
 Spray the cop with Zineb or Ziram in the concentration of
0.2 to 0.25 and 0.15 to 0.2% respectively keeping an
interval of 7 to 10 days can effectively control the disease

25.  Root-knot nematode:
 Missouri scientist recently surveyed for cotton parasitic
nematodes in Dunklin, New Madrid, and Pemiscot counties,. Root-knot nematodes
are so named because the galls they produce on roots look like knots in a rope. The
most common species are Meloidogyne incognita, Meloidogyne arenaria etc.
 Root-knot nematodes will be a greater problem when cotton is planted year after
year and when planted in sandy soil. Root-knot nematodes are best adapted to
coarse-textured, sandy soils rather than fine-texture silty or clay based soils.
Symptoms:
 Root-knot nematodes are not uniformly distributed in soil; they occur in
irregular patches. These patches may be small and limited in number, or they may be
large and widely distributed.
 Depending on the nematodes population, plants in these patches may be damaged
and show symptoms ranging from mild severe stunting. Leaves on infected plants
may wilt at mild day more readily than healthy plants.
 In addition, root-knot nematodes cause visible galls or knots on roots. Swellings of
the infected root tissues can be found on the cotton taproots and the lateral roots
from about six weeks after emergence until harvest.
 The galls are easier to detect if cotton plants are carefully dug from the soil. For a
positive diagnosis, send root and plant testing laboratory. The soil and roots should
be kept cool from the time they are collected until shipment. Store the material in a
plastic bag in a cooler bag in a cooler and ship it by overnight express it to the lab.

 Management:
 Rotate cotton with resistant soybean varieties.
 Use a nematicide.


27.  Bronze wilt:
 During the late summer of 1995, cotton plants in several southeast Missouri fields
began to discolor.
 The leaves turned from green to bronze, and the leaves wilted at mid day. This
malady was refered to as bronze wilt.

 Symptoms:
 The first visible symptom of bronze wilt is the red and bronze discoloration
of leaves.
 The discolored leaves will feel warmer to the touch than leaves of normal
plants.
 The stems and petioles of affected plants turn red soon after the leaf color
changes. The leaves of affected plants will drop during the hottest part of
the day and may recover partially or completely by early morning.
 These plants may occur next to plants that appear normal. The leaf
discoloration may disappear soon after a rain or irrigation but will develop
soon after the soil dries.
 All squares and small bolls will shed from affected plants within a week of
when symptoms begin to develop. However , squares that develop on
these plants after soil moisture becomes abundant may remain attached
and mature bolls may develop.
 Management:
 Plant varieties that have exhibited few if any symptom

29.  Summary of general cotton disease control measures:
 Plant high- quality seed.
 Plant on a high bed and enhance drainage of field.
 Plant when the soil temperature 4 inches deep at 8:00 am is 60
degree F and when five days of warm weather are predicted.
 Plant only in fertile soil.
 Use an in furrow fungicide when planting cotton early in the
season(mid April in Missouri), in clay soils and in poorly
drained fields.
 Rotate cotton with wheat, soybean or corn crops. Plant
varieties that have high yield potential and resistance to
disease.

30. Pesticides used in cotton:

31. Contd……

33. Conclusion:
 Cotton is a cash or commercial crops which has its high values in the market.
Cotton has not only importance in making cloth but also used in different
purposes. In case of Nepal, there is not enough research in the field of cotton.
Cotton development board which was established in 1986 and could not
completed its task due to various reasons. It was established at Khajura,
Nepalgunj which is the western part of Nepal. The western part of Nepal like
Banke, Bardiya, kailali, kanchanpur etc is the famous for cotton production
before some decade ago. Nowadays, there is not any research program but
only cultivation practices are done. There are not so good facilities of
laboratory and the storage houses.
 Disease is also important aspect that reduces the yield which causes lots of
loses, so farmers are not interested to cultivate this crop. Diseases like
Verticillium wilt, Fusarium wilt, Root rot, Bacterial disease are common in
case of Nepal. We have different ideas about the diseases symptoms and
control measures by the assignment given by our respected sir. We are able to
know the disease symptoms found in cotton plants. We have deal a lot of
farmers and scientist related to this crop. We had got a lot of experience in the
field and the laboratory. Disease is very fatal to crops. We had learnt controls
methods of diseases which is very useful. We had collected different problems
of farmers like disease, insect pest management etc.


34. References:
 Thakur. C, Scientific Crop Production, New Delhi,
Metropolitant Book Co. Pvt. Ltd.
 Martin, John.H et.al, Principles of Field Crop Production,
3rd Edition, New York, Macmillan Publishing Co. Inc.
 Singh et.al, Modern Techniques Of Raising Field Crops,
2nd edition, New Delhi, Oxford & IBH Publishing
Co.Pvt.Ltd,2009.
 IPM, Cotton Pests Scouting and Management, Boyd M.L
et al, retrieved from
http://www.ipm.missouri.edu/ipm_cotton.pdf
 http://www.daff.qld.gov.au/26_3766.html

35. Thank you