Tag: diseases

• Banana is a major tropical fruit crop with significant economic importance.
• Production is limited by physiological disorders, pests, and diseases.
• Effective management is essential for sustainable yield and fruit quality.

• Observed in cv. Poovan, mainly in Tamil Nadu.
• Fruits are conical, ill-filled, with a prominent central core and non-viable seeds.
• Spray 2,4-D at 20 ppm when last hand opens to prevent disorder.

Hard Lump

• Occurs in cv. Rasthali; pulp is pinkish-brown, firm, and tastes unripe.
• Spray 2,4-D at 1000 ppm or dip peduncle cut end for 5 minutes to reduce lumps.

Sunscald

• Caused by direct sun exposure on bunches and peduncle.
• Cover bunches and peduncle with banana or flag leaves to prevent damage.

• Short, narrow leaves clustered at pseudostem apex (‘bunchy’ appearance).
• Leaf margins wavy and rolled upward in advanced stages.

Management:

• Remove affected plants with rhizome.
• Plant virus-free suckers.
• Control aphids with insecticides (e.g., 0.3% Rogor, 0.05% Monocrotophos).

Banana Bract Mosaic Virus
Pathogen: Banana bract mosaic virus, transmitted by Aphis gossypii and Pentalonia nigronervosa.
Symptoms:

• Discoloration and necrotic streaks on male bud bracts.
• Spindle-shaped discoloration on pseudostem.

Management:

• Early detection and removal of infected plants.
• Control vectors as for other viral diseases.

Banana Streak Virus
Pathogen: Banana streak virus, transmitted by citrus mealybug (Planococcus citri).
Symptoms:

• Foliar mosaic and necrotic streaks on leaves.

• Yellowing and withering of leaves; petiole breaks and hangs.
• Longitudinal splitting of pseudostem; plant death.

Management:

• Remove infected plants; apply lime (2 kg/pit) and fallow for 6 months.
• Grow resistant varieties (Dwarf Cavendish, Poovan, Nendran).
• Crop rotation with paddy in wetland areas.
• Apply carbendazim (50–60 mg) in corm at 45° angle.

Sigatoka Leaf Spot
Pathogen: Mycosphaerella musicola.
Symptoms:

• Yellowish-green streaks along veins, enlarging into elongated spots.
• Coalescence of spots leads to leaf drying.

Management:

• Spray copper oxychloride or carbendazim (500 g/ha).
• Avoid close planting to reduce humidity.

• Yellowing starts from inner leaves, spreads upward; wilting of all leaves.

Management:

• Ensure good drainage.
• Biological control with Pseudomonas fluorescens.
• Crop rotation with non-hosts (e.g., sorghum).

Tip Over (Heart Rot)
Pathogen: Erwinia carotovora.
Symptoms:

• Rotting of central tender leaf; pseudostem detaches easily from corm.
• Bacterial ooze from corm and pseudostem edges.

Management:

• Use disease-free suckers.
• Grow resistant varieties (e.g., Poovan).

• Adopt integrated pest and disease management (IPDM) for sustainable production.
• Use resistant varieties and healthy planting material.
• Practice crop rotation and proper field sanitation.
• Apply recommended fungicides and insecticides judiciously.
• Bunches mature 100–150 days after flowering.
• Average yields (t/ha/year): Poovan 40–50, Monthan 30–40, Robusta 50–60, Dwarf Cavendish 50–60.

• Mango faces several physiological disorders, pests, and diseases affecting yield and quality.
• Major problems include alternate bearing, malformation, spongy tissue, and fruit drop.
• Effective integrated management is essential for sustainable production.

• Irregular fruiting pattern with heavy crop one year and little or none the next.

Occurrence:

• Common in north Indian varieties; south Indian varieties are mostly regular bearers.

Management:

• Soil drenching with paclobutrazol (5–10 g/tree) induces flowering and increases yield.
• Proper nutrition and irrigation management help reduce alternate bearing.

• Vegetative malformation (common in seedlings and young plants).
• Floral malformation (affects bearing trees, reduces productivity).

Symptoms:

• Bunchy top: compact leaves at shoot apex; arrested shoot growth.
• Malformed panicles in floral malformation.

Management:

• Deblossoming and spraying 200 ppm NAA reduce malformed panicles.
• Remove and destroy affected shoots and panicles.

• Distal end of fruit turns black, hardens, and ripens prematurely.
• Affected fruits become unmarketable.

Causes:

• Smoke from brick-kilns (CO, CO2, SO2, acetylene) within 600 m.

Management:

• Increase chimney height of brick-kilns.
• Spray borax (0.6%) at 10–14 day intervals from fruit set.

• Cluster of small, dark green fruitlets at panicle tip (bunch tip).
• Fruitlets grow to marble size, then growth ceases.

Causes:

• Adverse climate, especially low temperature during February–March.
• Poor embryo development.

Management:

• Protect trees from adverse weather; select tolerant varieties.

• Specific to Alphonso mango; affects export quality.

Symptoms:

• Normal external appearance; internal flesh patch is spongy, yellowish, and sour.

Causes:

• High temperature, convective heat, post-harvest sun exposure.

Management:

• Use sod culture and mulching to reduce incidence.
• Harvest at three-fourths maturity.
• Use resistant hybrids (e.g., Ratna, Arka Puneet).

• High fruit drop rate, especially in first four weeks after fruit set (up to 99%).

Management:

• Regular irrigation during fruit development.
• Timely pest and disease control.
• Apply NAA (50 ppm) or 2,4-D (20 ppm) six weeks after fruit set.

• Spray phosalone 0.05%, carbaryl 2 g/L, or phosphamidon 1 mL/L.

Nut Weevil (Cryptorrhynchus mangiferae):

• Maintain orchard cleanliness; destroy adults in bark crevices.
• Spray fenthion 0.1%.

Stem Borer (Batocera rufomaculata):

• Apply monocrotophos 36 WSC (10 mL/tree) via padding.
• Apply carbofuran 3G (5 g/bore hole) and plug with mud.

Fruit Fly (Bactrocera spp.):

• Plough interspaces to expose pupae.
• Use methyl eugenol traps; remove and bury fallen fruits.

• Apply sulphur dust (350 mesh) in early morning.
• Spray wettable sulphur 0.2% or tridemorph 0.05%.

Anthracnose and Stalk/End Rot (Colletotrichum gloeosporioides):

• Spray mancozeb 0.2% or carbendazim 0.1% preharvest, 3 times at 15-day intervals.

Sooty Mould (Capnodium spp.):

• Spray dimecron 0.03% + maida 5% (1 kg maida/starch boiled in 1 L water, diluted to 20 L).

• Adopt integrated pest and disease management (IPDM) for sustainable mango production.
• Combine cultural, chemical, and biological methods for effective control.
• Regular monitoring and timely interventions are crucial.
• Use resistant varieties and proper orchard sanitation.

• Definition of Integrated Pest Management (IPM)
• Importance of IPM in sustainable agriculture
• Focus on tomatoes as a key crop

• Fusarium wilt
• Blossom end rot
• Powdery mildew
• Tomato mosaic virus

• Yellowing leaves
• Wilting and stunted growth
• Dark spots on fruit
• Leaf curling

1. Crop rotation to prevent disease buildup
2. Use of resistant tomato varieties
3. Regular monitoring and scouting
4. Biological control agents

• Implementing IPM can enhance yield
• Regular education and training for farmers
• Collaboration with agricultural experts

• Bacterial canker
• Bacterial spot
• Bacterial wilt
• Bacterial speck
• Early and late blight

• Gram +Ve, non-motile bacteria
• First described in 1910
• Causes wilting and vascular discoloration

• Downward curling of lower leaves
• Light brown vascular discoloration
• Yellow bacterial ooze
• Birds eye appearance on fruits

• Infection through wounds or stomata
• Bacteria survive in soil for up to 5 years
• Spread via splashing water and contaminated tools

• Use disease-free seeds
• Hot water treatment for seeds
• Rotate crops every 3 years
• Sanitize tools and equipment

• Can cause unmarketable fruit
• Common in warm, wet climates
• Symptoms include water-soaked spots

• Small, circular water-soaked areas on leaves
• Brownish-red spots on mature fruit
• Spots may have yellow halos

• Survives in plant debris and seeds
• Spread by sprinkler irrigation
• Infection occurs through wounds

• Remove symptomatic plants
• Soak seeds in hot water
• Avoid overhead watering
• Use copper-based products cautiously

• Causes severe damage to over 200 plant species
• Symptoms include wilting during hot weather
• Visible dark streaks in infected stems

• Survives in soil and infested water
• High temperatures favor pathogen growth
• Spread through soil transfer and runoff

• No single control method is fully effective
• Use a combination of cultural practices
• Consider biological control methods

• Symptoms include dark spots on leaves
• Cool, rainy weather promotes disease
• Requires leaf wetness for infection

• Use resistant varieties
• Apply copper sprays
• Remove diseased debris promptly

• Symptoms start as small, dark lesions
• Lesions enlarge and cause defoliation
• Favorable conditions are warm and wet

• Use pathogen-free seeds
• Maintain plant vigor with proper care
• Rotate crops to reduce disease pressure

• Not a true fungus, but an Oomycete
• Causes rapid decay of fruits
• Severe in cool, moist conditions

• Select quick-maturing varieties
• Practice good crop sanitation
• Control weeds around tomato plants

• Overview of diseases affecting tomatoes.
• Importance of disease management in agriculture.
• Focus on early blight, late blight, and bacterial diseases.

• Early Blight: Alternaria solani
• Late Blight: Phytophthora infestans
• Bacterial Wilt: Ralstonia solanacearum
• Leaf Curl Virus: Tomato leaf curl virus

• Dark spots on older leaves, stems, and fruits.
• Yield losses can reach 79% in severe cases.
• Weakens plants, reducing fruit set.

• Temperatures between 15 to 27°C.
• High humidity (>90%) and rainy weather.
• Weak plants from June-July sowing are more susceptible.

• Use pathogen-free seeds and remove infected debris.
• Water in the morning to minimize leaf wetness.
• Implement crop rotation with non-Solanaceous crops.

• Caused by Phytophthora infestans.
• Can infect leaves, stems, and fruits rapidly.
• Historically linked to the Irish potato famine.

• Dark brown blotches on leaves with green-gray edges.
• Fruits develop dark, mushy spots.
• High humidity leads to white fungal growth.

• High humidity (>90%) and low temperatures (10-25°C).
• Cloudy weather with rainfall enhances spread.
• Soil-borne spread through oospores.

• Destroy infected potato piles before planting.
• Crop rotation with cereals to prevent recurrence.
• Use prophylactic sprays of copper fungicides.