Cotton Disease Management: The Key To Higher Yields And Bigger Profits

Cotton (Gossypium sp) is one of the most important fibre and cash crop in India. It is vulnerable to infections by pathogens like fungi, bacteria and viruses. All parts of the plants are infected and crop losses are common in the crop. Cotton diseases can significantly reduce crop yield and cotton quality leading to reduced profits for farmers.  

The severity of yield loss depends on the type of disease, the timing of infection, and the environmental conditions. The estimated average yield loss due to cotton diseases in India ranges from 10% to 15%. However, in severe outbreaks, yield losses can be as high as 50% or more. Effective disease management can help minimize crop losses and improve yield. 

The Major Diseases of Cotton having significant impact on cotton yield are as follows;

1. Fusarium wilt:

Scientific name of causal agent: Fusarium oxysporum f.sp. vasinfectum 

Stage of occurrence: Affects at all stages of the crop 

Symptoms of Fusarium wilt in cotton:

• Initially the symptoms appear as yellowing and browning of cotyledons and the base of petiole shows brown ring
• It is followed by wilting and drying of the affected seedlings
• Affected plant’s leaves loses turgidity, gradually turns brown, droops and finally drops off
• Tap roots are usually stunted with a smaller number of lateral roots.

• Vascular tissues show browning or blackening symptom and black streaks or stripes may extend upwards to the branches and downwards to the roots
• Affected plants become stunted with fewer bolls which are very small and opens before attaining maturity

Favourable conditions for Fusarium wilt infection in cotton:

Soil temperature of about 20 – 30°C, warm and dry weather followed by rain, high dosage of nitrogen and phosphatic fertilizers, black soils with high alkaline reactions, and wounds caused by nematode and grubs of ash weevil are favourable conditions for fusarium wilt infestation in cotton. 

2. Verticillium wilt

Scientific name of causal agent: Verticillium dahliae 

Stage of occurrence: Square and boll formation stage 

Symptoms of Verticillium wilt in cotton:

• Early infection leads to stunted growth of the plant
• ‘Bronzing of veins’ followed by yellowing of leaves and interveinal chlorosis

• It is followed by yellowing of leaves and interveinal chlorosis
• Affected leaves dry up giving scorched appearance
• Drying of leaf margins and areas between the leaves gives “Tiger stripe” or “Tiger claw” appearance
• Branches remain barren due to falling of affected leaves
• When infected stems and roots are split open, pinkish appearance of woody tissue can be seen

• Affected plants may produce smaller bolls with immature lint

Favourable conditions for Verticillium wilt infection in cotton:

High nitrogen fertilization, heavy soil with alkaline reaction, low soil temperature (15-20°C), excessive soil moisture or poor drainage in soils, lack of crop rotation and presence of host crops like tomato, brinjal, chilli, bhendi can create favourable conditions for verticillium wilt infection. 

Management of Fusarium wilt and Verticillium wilt disease in cotton:

Product name	Technical content	Dosage (per acre or per lit water)
Biological Management
Nanobee 7 Star Bio Fertilizer	Beneficial Lyophilized Microbes Consortia: 1.5 %	Mix 25-50 gm/lit of water and keep it in shade for 3-5 hr. Then mix it in 200 lit of water
Amruth Almonas Bio Fungicide	Pseudomonas sp	2ml/lit water
Terra Fungikill	Herbal formulation	2 ml/lit water
Ecoderma Bio Fungicide	Trichoderma viride	Seed treatment: 10 gm/lit water Soil application: 2 – 3 kg Ecoderma +150 – 200 kg FYM
Chemical management
Benmain Fungicide	Carbendazim 50% DF	Soil drenching: 2 gm/lit water
Amistar Fungicide	Azoxystrobin 23% SC	Drenching/Spraying: 0.5 – 1 ml/lit water
Ridomil Gold Fungicide	Metalaxyl 4% + Manconzeb 64%	Soil application: 1 – 1.5 gm/lit water
Taqat Fungicide	Hexaconazole 5% + Captan 70% WP	Drenching: 2 gm/lit water
Roko fungicide	Thiophanate Methyl 70% w/w	Foliar spray: 1 gm/lit water Drenching: 2 – 4 gm/lit water
Dithane M45 fungicide	Mancozeb 75% WP	Spraying: 2 – 2.5 gm/lit water

 

3. Root rot:

Scientific name of causal agent: Rhizoctonia bataticola 

Stage of occurrence: Seedling to vegetative stage 

Symptoms of root rot in cotton:

3 types of symptoms caused by the pathogen – Seedling disease, sore shin and root rot   

Seedling stage:  

• Germinated seedling affected by the fungus shows black lesions on hypocotyl
• Causes girdling of stem and death of affected seedling

Sore shin stage: 

• Dark reddish-brown canker appears on stem near soil surface, later turning black
• Drying of leaves and entire plant due to plant breakage at the collar region

Root rot: 

• Bark of affected plant shreds and may extend above ground level
• Dark brown sclerotia appears on the wood or on the shredded bark
• Entire root system becomes rotted, plants dry and can be easily pulled out

Favourable conditions for root rot infection in cotton:

Heavy rainfall followed by dry weather, high soil temperature of about 35 – 39°C, presence of host crop like vegetables, growing cotton after cultivation of oilseeds and legumes, wound caused by nematodes and ash weevil grubs increases root rot disease incidence. 

Management of root rot disease in cotton:

Product name	Technical content	Dosage (per acre or per lit water)
Biological Management
Nanobee 7 Star Bio Fertilizer	Beneficial Lyophilized Microbes Consortia: 1.5 %	Mix 25-50gm/lit of water and kept it in shade for 3-5 hr. Then mix it in 200 lit of water
Multiplex Nisarga	Trichoderma viride 1.5% WP	1 – 2 kg Multiplex Nisarga + 100 kg FYM
Ecomonas Bio Pesticide	Pseudomonas fluorescens	Drenching:10 gm/lit water Soil application: 10 – 15 gm/lit
Anand Dr Bacto’s Herz	Spores and conidia of Mycoparasitic Fungi	10 ml/lit water
Chemical Management
Vitavax powder 75% Fungicide	Carboxin 37.5% + Thiram 37.5% DS	Seed treatment: 3 gm/kg seed
Dhanustin Fungicide	Carbendazim 50% WP	Drenching: 0.5 – 0.75 gm/lit water
Sprint Fungicide	Mancozeb 50% + Carbendazim 25% WS	Drenching: 2.5 to 3 gm/lit water
Katyayani Samartha	Carbendazim 12% + Mancozeb 63% WP	Spraying: 1.5 – 2 gm/lit water

 

4. Grey / Areolate mildew:

Scientific name of causal agent: Ramularia areola  

Stage of occurrence: Seedling to Reproductive stage  

Symptoms of Grey or Areolate mildew in cotton:

• Irregular to angular pale translucent lesions appear on the lower surface of affected leaf
• Light green or yellow green specks appear on the upper leaf surface
• Whitish grey powdery growth appears on the lower surface, later coalesce and cover the entire leaf surface
• Under severe infection, white/grey powdery growth may occur on the upper leaf surface
• Affected chilli leaves dry up from margin, curl inward, turn yellow and fall off prematurely.

Favourable conditions for Grey / Areolate mildew infection in cotton:

Wet humid conditions, Low temperature (20 – 30°C), close planting, very early or very late sowing of cotton, intermittent rains and excessive application of nitrogenous fertilizers may increase grey mildew infection in cotton field. 

Management of Grey mildew in cotton:

Product name	Technical content	Dosage (per lit water)
Biological Management
Amruth Abacil Liquid	Bacillus subtilis 2% A.S	1 ml/lit water
Chemical Fungicide
Amistar Top Fungicide	Azoxystrobin 18.2% + Difenoconazole 11.4% SC	Foliar: 1 ml/lit water
Taqat Fungicide	Hexaconazole 5% + Captan 70% WP	Foliar: 2 gm/lit water
CM 75 Fungicide	Carbendazim 13%+Mancozeb 63%	Foliar: 1.5 gm/lit water
Bavistin Fungicide	Carbendazim 50% WP	Foliar: 0.5 ml/lit water
Ergon Fungicide	Ergon 44.3% SC	Foliar: 0.6 ml/lit water

 

5. Anthracnose:

Scientific name of causal agent: Colletotrichum gossypii 

Stage of occurrence: All growth stages 

Symptoms of Anthracnose in cotton:

• This disease affects all parts of the cotton plant
• Small reddish circular spots appear on the cotyledon and primary leaves of seedlings
• Causes seedlings to wilt and dry
• In affected mature plants, stem splitting and shredding of bark can be seen
• “Boll spotting” is the most cotton symptom
• Sunken, circular, reddish-brown spots appear on the bolls and the infected boll stops to grow, burst and dry up.

Favourable conditions for Anthracnose infection in cotton:

Prolonged rainfall during the boll formation stage, presence of crop debris, weed hosts and close planting may be favourable for anthracnose infection in cotton. 

Management of Anthracnose in cotton:

Product name	Technical content	Dosage (per lit water)
Biological Management
Terra Fungikill	Herbal formulation	2 ml/lit water
Sonkul Sun Bio Monus	Pseudomonas fluorescens	5 ml/lit water
Chemical Management
Borogold Fungicide	Combination of Nano Silver Particles & Peroxy Acid	Spraying; 1.5 gm/lit water
Turf fungicide	Carbendazim 12 % + Mancozeb 63 % WP	Drenching/Spraying: 1.8 – 2.5 gm/lit water
Taqat Fungicide	Hexaconazole 5% + Captan 70% WP	Drenching: 2 gm/lit water
Splash Fungicide	Chlorothalonil 75% WP	Spray: 2 ml/lit water
Dhanustin Fungicide	Carbendazim 50% WP	Drenching/Spraying: 0.5 – 0.8 gm/lit water

 

6. Alternaria leaf blight:

Scientific name of causal agent: Alternaria macrospora 

Stage of occurrence: Vegetative and Reproductive stage 

Symptoms of Alternaria leaf blight in cotton:

• Small, brown, irregular or round spots appear on the leaves
• Central lesion of each spot may be surrounded by concentric rings
• These spots coalesce together, and form blighted areas
• Affected cotton leaves become brittle and fall
• In case of severe infection, spots may appear on bracts and bolls.

Favourable conditions for Alternaria leaf blight infection in cotton:

High humidity, temperature of about 25 – 28°C, intermittent rainfall, wet foliage, dense planting and presence of crop residues due to lack of field sanitation create favourable conditions for Alternaria leaf blight infection in cotton. 

Management of Alternaria leaf blight in cotton:

Method of Application of Chemicals – Spraying 

Product name	Technical content	Dosage (per lit water)
Biological Management
Sanjeevni Bio fungicide	Trichoderma Viride	Seed treatment: 8 – 10 gm/50 ml (per kg seed) Soil drenching: 5 – 10 kg/lit
Ecomonas Bio Pesticide	Pseudomonas fluorescens	Foliar: 8 – 10 ml/lit water
Chemical Management
Tilt fungicide	Propiconazole 25 % EC	1 ml/lit water
Bavistin Fungicide	Carbendazim 50% WP	0.5 ml/lit water
Avtar fungicide	Zineb 68% + Hexaconazole 4%	1 gm/lit water
Amristar Top Fungicide	Azoxystrobin 18.2% + Difenoconazole 11.4% SC	1 ml/lit water
Dithane M45 fungicide	Mancozeb 75% WP	2 – 2.5 gm/lit water
Tata Ishaan Fungicide	Chlorothalonil 75% WP	2.5 gm/lit water
Priaxor Fungicide	Pyraclostrobin 333gm/ltr + Fluxapyroxad 167 gm/ltr SC	0.6 ml/lit water
Nativo Fungicide	Tebuconazole + Trifloxystrobin 75 WG (50% +25% w/w)	0.2 – 0.5 gm/lit water

 

7. Bacterial blight:

Scientific name of causal agent: Xanthomonas campestris pv.malvacearum 

Stage of occurrence: Seedling to harvest 

Symptoms of Bacterial blight in cotton: 5 common phases of symptoms are noticed.

• Seedling blight: Water soaked, irregular or circular lesions appear on the cotyledons, which may spread to petiole and stem causing withering and death of seedlings
• Angular leaf spot: Small, dark green, water-soaked lesions develop on the under surface of leaves and become angular when restricted by veinlets and veins. Later, the lesions turn to reddish brown colour and becomes visible on both sides of the leaf
• Vein blight/Vein necrosis/Black vein: Blackening of veins and veinlets gives ‘blighting appearance’. The presence of bacterial oozes on the lower side of the leaf. Affected leaves show crinkling appearance, withering and are twisted inward.
• Black arm: Black lesions are developed on stem and branches, causing premature drooping of leaves, cracking of stem and gummosis, leading to die back
• Boll rot: Dark black, sunken and irregular spots appear on the bolls. It leads to premature bursting of bolls. The spread of bacterium inside the bolls causes yellow staining of lint.

Favourable conditions for Bacterial blight infection in cotton:

Optimum soil temperature of 28°C, relative humidity of 85%, early sowing, high atmospheric temperature of 30 – 40°C, delayed thinning, late irrigation, poor tillage, K-deficiency in soil and rains followed by bright sunshine are highly favourable parameters for bacterial blight infection. 

Management of Bacterial blight in cotton:

Product name	Technical content	Dosage (per lit water)
Biological Management
Spot Bio Fungicide	Pseudomonas fluorescens	10 ml/lit water
Biofix Kito Star	Fatty acids and stabilizers	1 – 2 ml/lit water
V-Kure	Eugenol, Thymol, potassium salts, cationic surface agent, sodium salts & preservatives	1.5 – 2 gm/lit water
Chemical Management
Turf fungicide	Carbendazim 12 % + Mancozeb 63 % WP	Foliar: 1.8 – 2.5 gm/lit water
Vitavax powder 75% Fungicide	Carboxin 37.5% + Thiram 37.5% DS	Seed treatment: 3 gm/kg seed
Dithane M45 fungicide	Mancozeb 75% WP	Spraying: 2 – 2.5 gm/lit water
Avtar Fungicide	Zineb 68% + Hexaconazole 4% WP	Foliar: 1 gm/lit water

 

8. Para wilt or Sudden wilt:

• Exact cause of this physiological disorder is still unknown

Stage of occurrence: Flowering and fruit filling stage 

Symptoms of Para wilt or Sudden wilt disease in cotton:

• Premature death of top leaves, followed by collapse of the plant
• Within few hours of heavy rainfall or soil saturation, wilting of leaves can be seen
• If sunshine is brighter and hot, leaves may immediately dry
• Wilted plants shed all the leaves and are left only with small immature fruits
• Under cloudy weather, leaves turn yellow and die with no or little wilting

Favourable conditions for Para wilt infection in cotton:

Excessive water or sudden rainfall, poor soil drainage, bright sunshine or hot air temperature may create conditions favourable for para wilt incidence 

Management of Para wilt or Sudden wilt in cotton:

The exact cause of this disorder is still unknown. Preventive measures can be taken to minimize the para wilt incidence to some extent. Some of the measures include growing wilt tolerant varieties, accurate management of irrigation, reducing waterlogging conditions by providing adequate drainage and maintaining optimum vegetative growth by avoid using excessive of FYM and fertilizers. 

9. Leaf curl disease

Scientific name of causal agent: Cotton leaf curl virus 

Stage of occurrence: All stages 

Vector: Whitefly 

Symptoms of leaf curl disease in cotton:

• ‘Upward and downward curling’ of leaves and thickening of veins
• Enation can be noticed on the underside of the leaves
• In severe cases, all the leaves curl and the plant growth is retarded
• Leads to reduced boll bearing capacity

Favourable conditions for Leaf curl virus infection in cotton:

Primary source of spread is Whitefly (Bemisia tabaci). Presence of alternate hosts like chilli, bhendi, tomato, warm temperature, late planting can be favourable for leaf curl virus infection.  

Management of Leaf curl virus in cotton:

Spread of leaf curl virus disease can be managed by controlling the vector whitefly, which spreads the virus. The following chemicals can be used to control whitefly in cotton. 

Product Name	Technical Content	Dosage (per lit water)
Mechanical Management
Tapas Yellow Sticky Trap	11 cm x 28 cm	4 – 6/acre
Biological Management
Amruth Alestra Liquid	Verticillium lecanii	2 ml/lit water
T.Stanes Nimbecidine	Azardiractin 300 PPM (EC formulation)	5 ml/lit water
Chemical Management
Lancer Gold Insecticide	Acephate 50 % + Imidacloprid 1.8 % SP	0.4 ml/lit water
Pager Insecticide	Diafenthi uron 50% WP	1.2 gm/lit water
Ulala Insecticide	Flonicamid 50 WG	0.3 gm/lit water
Actara Insecticide	Thiamethoxam 25 % WG	0.5 gm/lit water
Kaitaku Insecticide	Acetamiprid 20 % SP	0.1 – 0.2 ml/lit

 

10. Tobacco streak virus

Scientific name of causal agent: Tobacco streak virus 

Stage of occurrence: All stages 

Vector: Thrips (Thrips tabaci) 

Symptoms of Tobacco streak virus in cotton:

• Ring like purplish necrotic spots appear on the leaves
• Chlorotic streaks develop on the leaves
• Stunted growth

Favourable conditions for Tobacco streak virus infection in cotton:

Presence of weed hosts, high temperature (25 – 30°C), infected plant debris may create favourable conditions for tobacco streak virus disease spread in cotton crop. 

Management of Tobacco streak virus in cotton:

Spread of Tobacco streak virus disease can be managed by controlling thrips, which spread the virus. The following chemicals can be used to control thrips in cotton. 

Product name	Technical content	Dosage (per lit water)
Mechanical Management
Tapas Yellow Sticky Trap	22 cm x 28 cm	6 – 8/acre
Biological Management
Pesto Raze Bio-insecticide	Botanical Extracts	2 ml/lit water
Control TRM Bio-pesticide	Organic blend of botanical extracts	2 ml/lit water
Econeem Plus	Azadiractin 10000 ppm	2 ml/lit water
Chemical Management
Summit Insecticide	Spinetoram 11.7 % SC	0.5- 1ml/lit water
Admire Insecticide	Imidacloprid 70% WG	0.3 gm/lit water
Karate Insecticide	Lambdacyhalothrin 5% EC	1.5 ml/lit water
Nurelle D Insecticide	Chlorpyriphos 50% + Cypermethrin 5% EC	2 ml/lit water
Katyayani Thioxam	Thiamethoxam 25% WG	0.4 gm/lit water
Shinzen Plus Insecticide	Fipronil 5 % SC	3 gm/lit water
Osheen Insecticide	Dinotefuran 20 % SG	0.6 – 0.8 gm/lit water
Marshal Insecticide	Carbosulfan 25% EC	2.5 ml/lit water

 

(Note: Refer to the product label to find the right time of Application and more details of the product)