Major disease of oilseed crops

001: Major disease of oilseed crops.

 

   Major diseases of oilseed crops along with their symptoms, disease epidemiology, and control measures:

 

1.   Sclerotinia Rot (White Mold):

 

a) Symptoms: White mycelial growth on stems, leaves, and pods, leading to wilting and damping off.

 

b) Epidemiology: Favored by cool, moist conditions; spreads through airborne spores and infected crop debris.

 

c) Control Measures: Crop rotation, planting resistant varieties, timely fungicide application, and improving drainage.

 

2. Downy Mildew:

 

a) Symptoms: Yellow or pale green patches on leaves, often accompanied by a downy white or gray growth on the undersides.

 

b) Epidemiology: Thrives in cool, humid conditions; spreads through wind-dispersed spores.

 

c) Control Measures: Planting resistant varieties, practicing crop rotation, improving air circulation, and applying fungicides preventively.

 

3. Alternaria Blight:

 

a) Symptoms: Circular brown lesions with concentric rings on leaves, stems, and pods, leading to defoliation and reduced yield.

 

b) Epidemiology: Thrives in warm, moist conditions; spreads through rain splash and infected seed.

 

c) Control Measures: Crop rotation, sanitation (removing infected debris), planting disease-free seed, and applying fungicides preventively.

 

4. Phoma Blackleg:

 

a) Symptoms: Dark, sunken lesions on stems and pods, often with black specks (pycnidia), causing lodging and yield loss.

 

b) Epidemiology: Survives in crop debris and soil; spreads through infected seed and wind-blown spores.

c) Control Measures: Crop rotation, using certified disease-free seed, practicing deep tillage to bury infected residues, and applying fungicides during early stages.

 

5. Root Rot (Rhizoctonia Solani):

 

a) Symptoms: Rotting and discoloration of roots, leading to wilting, stunted growth, and poor nutrient uptake.

b) Epidemiology: Favored by warm, wet conditions; survives in soil and infected crop debris.

c) Control Measures: Improving soil drainage, practicing crop rotation with non-host crops, using disease-free seed, and applying fungicides at planting.

 

Implementing integrated pest management (IPM) practices, which combine cultural, biological, and chemical control methods, can effectively manage these diseases and minimize yield losses in oilseed crops.

 

 

002: Major diseases solanaceous crops(

potato,tomato,chilli and Brinjal).

 

 

Major diseases for each of the solanaceous crops along with their symptoms, disease epidemiology, and control measures:

 

1. Potato:

a. Late Blight (Phytophthora infestans):

 

I) Symptoms: Dark lesions on leaves, stem, and tubers, leading to rapid foliage death and rotting of tubers.

ii) Disease Epidemiology: Favored by cool, moist conditions. Spores spread through wind, water, and infected plant material.

III) Control Measures: Crop rotation, use of resistant cultivars, fungicide application, removal of infected plant debris.

b. Potato Early Blight (Alternaria solani):

 

I) Symptoms: Dark, concentric lesions with yellow halos on leaves, leading to defoliation and reduced yield.

ii) Disease Epidemiology: Thrives in warm, humid conditions. Spread through infected plant debris and splashing water.

III) Control Measures: Crop rotation, proper irrigation management, fungicide application, removal of infected plant material.

c. Potato Wart (Synchytrium endobioticum):

 

i) Symptoms: Warty outgrowths on tubers, reducing marketability and yield.

ii) Disease Epidemiology: Soilborne pathogen. Spread through infected tubers and soil movement.

III) Control Measures: Use of certified disease-free seed potatoes, crop rotation, soil sterilization, quarantine measures.

2. Tomato:

a. Tomato Yellow Leaf Curl Virus (TYLCV):

 

I) Symptoms: Yellowing and upward curling of leaves, stunted growth, reduced fruit yield.

ii) Disease Epidemiology: Transmitted by whiteflies. Warm temperatures favor disease spread.

III) Control Measures: Use of virus-resistant tomato cultivars, whitefly control through insecticides or biological control agents.

b. Tomato Late Blight (Phytophthora infestans):

 

I) Symptoms: Dark lesions on leaves, stem, and fruits, leading to rapid plant death.

ii) Disease Epidemiology: Similar to potato late blight. Favors cool, moist conditions.

III) Control Measures: Crop rotation, fungicide application, removal of infected plant material, resistant cultivars.

c. Tomato Powdery Mildew (Leveillula taurica):

 

I) Symptoms: White powdery growth on leaves, stems, and fruits, leading to reduced photosynthesis and fruit quality.

ii) Disease Epidemiology: Favors warm, dry conditions. Spread through windborne spores.

III) Control Measures: Proper spacing for air circulation, fungicide application, removal of infected plant parts.

3. Chilli:

a. Chilli Leaf Curl Virus (ChiLCV):

 

I) Symptoms: Leaf curling, yellowing, and vein clearing, stunted growth, reduced yield.

ii) Disease Epidemiology: Transmitted by whiteflies. Warm temperatures favor virus replication.

III) Control Measures: Use of resistant varieties, whitefly control measures, removal of infected plants.

b. Chilli Anthracnose (Colletotrichum spp.):

 

I) Symptoms: Circular, sunken lesions on fruits, with dark margins and pink spore masses.

ii) Disease Epidemiology: Favors warm, humid conditions. Spread through rain splashes and contaminated tools.

III) Control Measures: Fungicide application, crop rotation, removal of infected plant debris, proper drainage.

c. Chilli Wilt (Fusarium oxysporum f. sp. capsici):

 

I) Symptoms: Wilting of foliage, yellowing, and necrosis of leaves, vascular discoloration.

ii) Disease Epidemiology: Soilborne pathogen. Thrives in warm, moist conditions.

III) Control Measures: Use of resistant varieties, soil solarization, crop rotation, sanitation practices.

4. Brinjal (Eggplant):

a. Brinjal Fruit and Shoot Borer (Leucinodes orbonalis):

 

I) Symptoms: Entry holes on fruit and stem, with larval damage inside, leading to wilting and fruit rot.

ii) Disease Epidemiology: Moths lay eggs on leaves. Larvae bore into shoots and fruits.

III) Control Measures: Use of pheromone traps, insecticide application, regular scouting, early harvesting.

b. Brinjal Bacterial Wilt (Ralstonia solanacearum):

 

I) Symptoms: Wilting of foliage, yellowing, and necrosis of leaves, vascular discoloration.

ii) Disease Epidemiology: Soilborne bacterium. Thrives in warm, moist conditions.

III) Control Measures: Use of resistant varieties, soil solarization, crop rotation, sanitation practices.

c. Brinjal Leaf Spot (Alternaria solani):

 

I) Symptoms: Circular, dark lesions on leaves, which may coalesce, leading to defoliation and reduced yield.

ii) Disease Epidemiology: Favors warm, humid conditions. Spread through infected plant debris and rain splashes.

III) Control Measures: Fungicide application, proper spacing for air circulation, removal of infected plant material.

 

 

 

003: Major disease cucurbitaceous crops 

(Cucumber,sponge gourd,bitter gourd and pointed gourd)

 

       Major diseases for each of the given cucurbitaceous crops along with their symptoms, disease epidemiology, and control measures:

 

1. Cucumber:

 

a) Downy Mildew

       I) Symptoms: Yellowing of upper leaf surface, fuzzy grayish growth on the undersides, leaf curling, and eventual defoliation.

     ii) Epidemiology: Thrives in cool, humid conditions, spreads rapidly through water splash and windborne spores.

      III) Control Measures: Plant resistant varieties, provide good air circulation, practice crop rotation, and apply fungicides preventatively.

 

b. Powdery Mildew

 

I) Symptoms: White powdery spots on upper leaf surfaces, which later expand and cover the entire leaf, leading to reduced photosynthesis.

 

ii) Epidemiology: Favors warm days, cool nights, and high humidity; spreads through windborne spores.

 

III) Control Measures: Plant resistant varieties, provide proper spacing for air circulation, apply fungicides, and practice good sanitation.

 

c. Anthracnose

 

I) Symptoms: Circular, sunken lesions on leaves, stems, and fruit, which may ooze pinkish spores in humid conditions.

 

ii) Epidemiology: Thrives in warm, humid environments; spread through infected plant debris, seeds, and water splash.

III) Control Measures: Rotate crops, remove and destroy infected plant material, apply fungicides, and practice proper irrigation to avoid water splash.

2. Sponge Gourd:

 

a. Powdery Mildew

 

I) Symptoms: White powdery growth on leaves, stems, and fruits, leading to reduced plant vigor and yield.

ii) Epidemiology: Similar to cucumber powdery mildew, preferring warm days, cool nights, and high humidity.

III) Control Measures: Same as for cucumber powdery mildew.

 

b. Fusarium Wilt

 

I) Symptoms: Yellowing and wilting of lower leaves, vascular discoloration in stems, and eventual plant collapse.

ii) Epidemiology: Soilborne fungus, spreads through contaminated soil, seeds, and infected plant debris.

III) Control Measures: Rotate crops, use disease-free seeds, practice soil solarization, and apply fungicides preventatively.

 

c. Angular Leaf Spot

 

I) Symptoms: Angular, water-soaked lesions on leaves, which later turn brown and necrotic, leading to defoliation and reduced yield.

ii) Epidemiology: Bacterial disease spread through water splash, contaminated tools, and plant debris.

III) Control Measures: Plant disease-resistant varieties, avoid overhead irrigation, apply copper-based fungicides, and practice crop rotation.

 

3. Bitter Gourd:

 

a. Bacterial Wilt

 

I) Symptoms: Sudden wilting of leaves, yellowing of veins, and eventual plant collapse; vascular discoloration in stems.

II) Epidemiology: Soilborne bacterium, transmitted by cucumber beetles and infected tools.

III) Control Measures: Use disease-resistant varieties, control cucumber beetle populations, practice crop rotation, and maintain soil health.

 

b. Powdery Mildew

 

I) Symptoms: White powdery growth on leaves, stems, and fruit surfaces, leading to reduced photosynthesis and yield.

ii) Epidemiology: Similar to cucumber powdery mildew.

III) Control Measures: Same as for cucumber powdery mildew.

 

c. Leaf Spot

 

I) Symptoms: Circular, dark brown spots on leaves, which may have a yellow halo, leading to defoliation and reduced yield.

ii) Epidemiology: Fungal disease spread through water splash, wind, and contaminated tools.

III) Control Measures: Remove and destroy infected plant material, apply fungicides preventatively, maintain proper spacing for air circulation, and avoid overhead irrigation.

 

4. Pointed Gourd:

 

a. Downy Mildew

 

I) Symptoms: Yellowing of upper leaf surface, fuzzy grayish growth on the undersides, leaf curling, and eventual defoliation.

ii) Epidemiology: Similar to cucumber downy mildew.

III) Control Measures: Same as for cucumber downy mildew.

 

b) Anthracnose

 

I) Symptoms: Circular, sunken lesions on leaves, stems, and fruit, which may ooze pinkish spores in humid conditions.

ii) Epidemiology: Similar to cucumber anthracnose.

III) Control Measures: Same as for cucumber anthracnose.

 

c) Fruit Rot

 

I) Symptoms: Dark, sunken lesions on fruits, which expand rapidly, leading to fruit decay and reduced marketability.

ii) Epidemiology: Fungal disease spread through contaminated soil, water splash, and infected plant debris.

III) Control Measures: Remove and destroy infected fruits, apply fungicides preventatively, practice proper irrigation to avoid water splash, and improve air circulation around plants.

 

 

004: Major disease temperate fruits like 

Apple, grapes and strawberry 

 

      Major diseases each for apples, grapes, and strawberries, along with their symptoms, epidemiology, and control measures:

 

A. Apple:

 

1. Apple Scab

 

a) Symptoms: This fungal disease appears as olive-green to black lesions on leaves, fruit, and twigs. It causes leaf distortion, premature leaf drop, and fruit blemishes.

b) Epidemiology: Spores overwinter on fallen leaves and spread during wet weather in spring. It thrives in temperatures around 60-70°F (15-21°C) with high humidity.

c) Control Measures: Prune infected branches, remove fallen leaves, and apply fungicides preventatively during the growing season.

 

2. Fire Blight

 

a) Symptoms: Caused by the bacterium Erwinia amylovora, fire blight causes wilting, blackening, and "shepherd's crook" bending of shoots. Infected blossoms turn black and die.

b) Epidemiology: The bacterium overwinters in cankers on trees and is spread by rain, insects, and pruning tools. Warm, wet conditions favor its spread.

c) Control Measures: Prune infected branches at least 8-12 inches below visible symptoms, avoid excessive nitrogen fertilization, and apply copper sprays during bloom.

 

3. Powdery Mildew

 

a) Symptoms: Powdery white fungal growth appears on leaves, shoots, and fruit. Infected leaves may become distorted, and premature defoliation can occur.

b) Epidemiology: Warm, dry conditions with high humidity favor powdery mildew development. The disease spreads through airborne spores.

c) Control Measures: Plant resistant varieties, ensure good air circulation, remove and destroy infected plant parts, and apply fungicides preventatively.

 

B. Grapes:

 

1. Downy Mildew

 

a) Symptoms: Yellow to brown lesions appear on leaves, which later develop fuzzy, downy growth on the undersides. Infected fruit can develop dark spots and become deformed.

b) Epidemiology: This fungal disease thrives in warm, humid conditions and is spread by wind-dispersed spores.

c) Control Measures: Plant resistant varieties, prune for good air circulation, remove and destroy infected plant material, and apply fungicides preventatively.

 

2. Botrytis Bunch Rot

 

a) Symptoms: Grayish-brown fuzzy growth develops on grape clusters, causing them to rot. Infected berries become soft, brown, and shriveled.

b) Epidemiology: Botrytis cinerea fungus infects wounded or overripe berries, particularly in humid conditions or after rainfall.

c) Control Measures: Practice proper canopy management to improve air circulation, remove infected clusters promptly, and apply fungicides as needed.

 

3. Pierce's Disease

 

a) Symptoms: Leaves show yellowing between veins, progressing to scorched appearance and eventual defoliation. Infected vines may exhibit delayed or uneven ripening, and eventually, dieback occurs.

b) Epidemiology: Transmitted by the glassy-winged sharpshooter insect, Xylella fastidiosa bacteria block water movement in the plant, causing symptoms.

c) Control Measures: Control sharpshooter populations through insecticides or biological control methods, remove and destroy infected plants, and plant certified disease-free material.

 

C. Strawberries:

 

1. Anthracnose

 

a) Symptoms: Dark, sunken lesions develop on fruit, which may spread rapidly in wet conditions. Infected flowers can turn brown and die prematurely.

b) Epidemiology: Caused by the fungus Colletotrichum species, anthracnose spreads through splashing water, insects, and infected plant material.

c) Control Measures: Plant disease-free material, remove and destroy infected plant parts, practice proper spacing for good air circulation, and apply fungicides preventatively.

 

2. Verticillium Wilt

 

a) Symptoms: Wilting and yellowing of lower leaves progress upward in the plant. Vascular tissues show discoloration when stems are cut.

b) Epidemiology: Verticillium dahliae fungus survives in soil for years, infecting plants through roots. It spreads through contaminated soil, water, or plant material.

c) Control Measures: Rotate crops, choose resistant varieties, ensure proper soil drainage, and avoid planting in fields with a history of Verticillium wilt.

 

3. Botrytis Fruit Rot

 

a) Symptoms: Gray mold appears on ripe or overripe fruit, especially in wet conditions. Infected berries become soft and watery, with fuzzy gray growth.

b) Epidemiology: Botrytis cinerea fungus infects through wounds or damaged tissue, spreading rapidly in humid conditions.

c) Control Measures: Remove and destroy infected fruit promptly, maintain good air circulation, avoid overhead irrigation, and apply fungicides preventatively.

 

 

005: Major disease of each given cut flowers like 

Gladiolus, carnation,rose,gerbera and orchid

 

      Major diseases for each of the specified cut flowers, along with their symptoms, disease epidemiology, and control measures:

 

A. Gladiolus:

 

1. Fusarium wilt:

 

a) Symptoms: Yellowing and wilting of lower leaves, stunted growth, vascular discoloration, and eventual death of the plant.

b) Disease epidemiology: Caused by the soil-borne fungus Fusarium oxysporum, which infects plants through roots and spreads through contaminated soil, water, and tools.

c) Control measures: Practice crop rotation, use disease-free planting material, avoid overwatering, and treat seeds with fungicides before planting.

 

2. Botrytis blight (Gray mold):

 

a) Symptoms: Grayish-brown spots on petals and leaves, fuzzy gray mold growth, flower and bud rot.

b) Disease epidemiology: Caused by the fungus Botrytis cinerea, which thrives in cool, humid conditions and spreads through airborne spores and infected plant debris.

c) Control measures: Improve air circulation, avoid overhead watering, remove infected plant parts, and apply fungicides preventively.

 

3. Thrips infestation:

 

a) Symptoms: Silvery stippling on leaves, distorted growth, and flower damage (silvering or browning).

b) Disease epidemiology: Thrips are tiny, slender insects that feed on plant tissues by puncturing and sucking out cell contents, often transmitting viral diseases in the process.

c) Control measures: Use insecticidal soap or neem oil, employ sticky traps, maintain weed control, and introduce beneficial predators like predatory mites.

 

B. Carnation:

 

1. Powdery mildew:

 

a) Symptoms: White powdery growth on leaves, stems, and flowers, yellowing and distortion of leaves, premature leaf drop.

b) Disease epidemiology: Caused by various species of fungi in the genus Podosphaera, favored by high humidity and moderate temperatures.

c) Control measures: Provide good air circulation, space plants properly, avoid overhead watering, apply fungicides, and remove and destroy infected plant parts.

 

2. Fusarium wilt:

 

a) Symptoms: Yellowing and wilting of lower leaves, vascular discoloration, stunted growth, and eventual plant death.

b) Disease epidemiology: Caused by Fusarium oxysporum f. sp. dianthi, which infects plants through roots and spreads through contaminated soil, water, and tools.

c) Control measures: Practice crop rotation, use disease-free planting material, avoid overwatering, and treat seeds with fungicides.

 

3. Carnation rust:

 

a) Symptoms: Rust-colored pustules on leaves, yellowing, and premature defoliation, reduced plant vigor.

b) Disease epidemiology: Caused by the fungus Uromyces dianthi, which overwinters on infected plant debris and spreads through windborne spores.

c) Control measures: Remove and destroy infected plant parts, avoid overhead irrigation, apply fungicides preventively, and provide good air circulation.

 

C. Rose:

 

1. Black spot:

 

a) Symptoms: Circular black spots with fringed margins on leaves, yellowing, and premature defoliation, reduced plant vigor.

b) Disease epidemiology: Caused by the fungus Diplocarpon rosae, which thrives in warm, humid conditions and spreads through splashing water and infected plant debris.

c) Control measures: Remove and destroy infected leaves, provide good air circulation, avoid overhead watering, apply fungicides preventively.

 

2. Powdery mildew:

 

a) Symptoms: White powdery growth on leaves, stems, and buds, distorted growth, premature leaf drop.

b) Disease epidemiology: Caused by various species of fungi in the genera Podosphaera and Sphaerotheca, favored by high humidity and moderate temperatures.

c) Control measures: Provide good air circulation, space plants properly, avoid overhead watering, apply fungicides, and remove and destroy infected plant parts.

 

 3. Rose mosaic virus:

 

a) Symptoms: Yellow mottling, distortion, and discoloration of leaves, reduced vigor, and flower quality.

b) Disease epidemiology: Caused by various viruses including Rose mosaic virus (RMV), transmitted by infected plant material, and sap-feeding insects like aphids.

c) Control measures: Use virus-tested planting material, control aphid populations, and remove and destroy infected plants to prevent further spread.

 

D. . Gerbera:

 

1.  Botrytis Blight (Gray Mold):

 

a) Symptoms: Grayish mold on flowers, wilting, and decay of petals and stems.

b) Epidemiology: Favored by high humidity and cool temperatures. Spreads through spores in water or air.

c) Control Measures: Proper ventilation, spacing between plants, removal of infected plant parts, and fungicide application.

 

 

Author: Birendra Kumar Shah

Gauriganj Higher Secondary School

Gauriganj, Jhapa