This presentation provides an in-depth overview of the major insect pests affecting okra and other vegetable crops, focusing on their identification, life cycle, damage symptoms, and management strategies. Emphasis is placed on integrated pest management (IPM) approaches, highlighting the importance of biological, cultural, and chemical control methods for sustainable crop protection.
Okra Shoot and Fruit Borer (Earias spp.) – Identification and Biology
- Key species: Earias vitella and Earias insulana (Family: Noctuidae; Order: Lepidoptera).
- E. vitella adults have pale whitish forewings with a broad greenish band; E. insulana adults have uniformly green forewings.
- Larvae are brown with dorsal white streaks; pupae are brown and boat-shaped.
- Eggs are laid on tender shoots, flower buds, and young fruits; each female lays up to 250 eggs.
- Life cycle duration: 3 weeks in summer, 4 weeks in winter; up to 12 generations per year.
Economic Importance and Nature of Damage – Okra Shoot and Fruit Borer
- Serious pest of okra, cotton, ambadi, and other malvaceous plants.
- Larvae bore into tender shoots, flower buds, and fruits, causing withering and drying of shoots.
- Infested flower buds and fruits drop prematurely; remaining fruits show exit holes and become deformed.
- Significant yield losses due to direct feeding and secondary infections.
Management of Okra Shoot and Fruit Borer
- Install pheromone traps at 12 per hectare for monitoring and mass trapping.
- Collect and destroy affected fruits and plant parts to reduce larval population.
- Release egg parasitoid Trichogramma chilonis (100,000/ha) and predator Chrysoperla carnea larvae (10,000/ha).
- Apply Bacillus thuringiensis (2 g/l) or dust carbaryl 10% DP (25 kg/ha) as biopesticides.
- Recommended insecticides: Azadirachtin, emamectin benzoate, phosalone, pyridalyl, quinalphos (follow label rates and safety guidelines).
Leaf Hopper (Amrasca biguttula biguttula) – Identification and Damage
- Belongs to Family: Cicadellidae; Order: Hemiptera.
- Nymphs and adults suck sap from the underside of leaves, injecting toxic saliva.
- Damage symptoms: hopper burn, leaf crinkling, browning, stunted growth, and reduced fruit set.
- Severe infestations can cause significant yield reduction.
Management of Leaf Hopper
- Remove and destroy affected plant parts to reduce pest reservoirs.
- Encourage natural enemies such as spiders (Distina albina) and chrysopids (Chrysopa cymbela).
- Apply foliar sprays of dimethoate, methyl demeton, or fipronil at recommended concentrations.
Whitefly (Bemisia tabaci) – Identification and Damage
- Family: Aleurodidae; Order: Hemiptera.
- Nymphs and adults feed on leaf sap, causing loss of plant vigor and luster.
- Acts as a vector for yellow vein mosaic virus (YVMV), leading to yellowing of veins and stunted growth.
- Heavy infestations result in significant yield losses and virus spread.
Management of Whitefly
- Remove and destroy infested plants to prevent spread.
- Use yellow sticky traps for monitoring and mass trapping.
- Apply insecticides such as acetamiprid, thiamethoxam, or profenophos at recommended rates.
Aphids (Aphis gossypii, Myzus persicae) – Identification and Damage
- Family: Aphididae; Order: Hemiptera.
- Nymphs and adults suck sap from leaves, causing yellowing, deformation, and drying of plants.
- Secrete honeydew, promoting sooty mold growth and reducing photosynthesis.
- Can transmit plant viruses, compounding crop losses.
Management of Aphids
- Seed treatment with imidacloprid or thiamethoxam for early protection.
- Use yellow sticky traps to monitor and reduce aphid populations.
- Encourage natural predators and parasitoids for biological control.
Red Spider Mite (Tetranychus telarius/urticae) – Identification and Damage
- Family: Tetranychidae; Order: Acarina.
- Colonies found on the underside of leaves, protected by silk webbing.
- Polyphagous pest infesting brinjal, okra, beans, and other crops.
- Feeding causes blotches, leaf discoloration, and eventual drying and defoliation.
Management of Red Spider Mite
- Spray wettable sulphur (3–5 g/l) or dust sulphur (20–25 kg/ha) for effective control.
- Apply dicofol (2.7 ml/l), propargite (3 ml/l), or abamectin (150 ml/ha) as acaricides.
- Repeat sprays at 10-day intervals for severe infestations.
Leaf Roller (Sylepta derogata) – Identification and Damage
- Family: Pyralidae; Order: Lepidoptera.
- Caterpillars fold leaves from tip upwards and feed within the folded area.
- Infested leaves wither, dry up, and larvae remain concealed in leaf folds.
Management of Leaf Roller
- Remove and destroy folded leaves along with larvae to reduce pest population.
- Apply carbaryl 0.2% spray or dust 10% carbaryl at 20 kg/ha for chemical control.
Objective Questions
Q1. Which distinguishing feature is correct for the adult Earias insulana moth?
A. Forewings are uniformly silvery green
B. Forewings are pale with a wedge-shaped green band
C. Forewings are brown with white streaks
D. Forewings are sky blue in color
Answer: A
Q2. What is the approximate number of generations per year for Earias spp. on okra?
A. 4
B. 8
C. 12
D. 16
Answer: C
Q3. Which insecticide and dose is correctly matched for whitefly management on okra?
A. Acetamiprid 0.4 g/l
B. Carbaryl 10% DP 25 kg/ha
C. Dicofol 2.7 ml/l
D. Imidachloprid 5 kg/seed
Answer: A
Q4. Which parasitoid is released for biological control of okra shoot and fruit borer?
A. Trichogramma chilonis
B. Chrysoperla carnea
C. Distina albina
D. Chrysopa cymbela
Answer: A
Q5. What is the main symptom of leafhopper (Amrasca biguttula biguttula) infestation on okra?
A. Hopper burn
B. Sooty mould
C. Yellow vein mosaic
D. Webbing on leaves
Answer: A
Q6. Which pest acts as a vector for yellow vein mosaic virus in okra?
A. Bemisia tabaci
B. Amrasca biguttula biguttula
C. Aphis gossypii
D. Sylepta derogata
Answer: A
Q7. Which management practice is NOT recommended for red spider mite control?
A. Spray with 0.2% sulphur
B. Spray with 0.03% dicofol
C. Spray with Bacillus thuringiensis
D. Dusting with sulphur @ 20-25 kg/ha
Answer: C
Q8. Which is a correct host plant for Earias spp. besides okra?
A. Cotton
B. Tomato
C. Potato
D. Apple
Answer: A
Q9. Which statement is true regarding the larva of Earias vitella?
A. Brownish with white streaks dorsally and pale yellow ventrally
B. Brown with a white median longitudinal streak
C. Green with black spots
D. Yellow with red bands
Answer: A
Q10. Which control measure is specific for leaf roller (Sylepta derogata) on okra?
A. Removal and destruction of leaf fold along with caterpillar
B. Spray with acetamiprid 0.4 g/l
C. Release of Trichogramma chilonis
D. Use of yellow sticky traps
Answer: A
This presentation provides an overview of major insect pests affecting tomato crops, focusing on their identification, nature of damage, life cycles, and integrated management strategies. Emphasis is placed on the economic impact, pest biology, and effective control measures, including cultural, biological, and chemical methods. Key topics include the management of Helicoverpa armigera, Liriomyza trifolii, Tuta absoluta, Bemisia tabaci, and Thrips tabaci, which are crucial for sustainable tomato production and pest resistance management.
Introduction to Tomato Pests
- Tomato is susceptible to several major insect pests causing significant yield losses.
- Pests affect all growth stages, from seedlings to fruiting plants.
- Effective management requires understanding pest biology and integrated control methods.
Tomato Fruit Borer (Helicoverpa armigera)
Scientific Name: Helicoverpa armigera
Family: Noctuidae
Order: Lepidoptera
Distribution: Widely found in tropics, subtropics, and warm temperate regions.
Economic Importance:
- Major pest of tomato, also attacks tur and gram.
Identification:
- Caterpillars: Variable color, radiating hairs, brown to greenish with dark lines.
- Moth: Medium-sized, light yellowish brown, forewings with dark spot, hindwings smoky white with black border.
Life Cycle:
- Eggs laid on tender plant parts.
- Larval period: 18–25 days; pupates in soil.
- Total life cycle: 30–40 days.
Nature of Damage:
- Larvae bore circular holes in fruits, feed on inner contents.
- Secondary infection by fungi and bacteria.
- One larva can damage 2–8 fruits.
Management:
- Collect and destroy infested fruits and larvae.
- Intercrop with marigold (1:16 rows) to attract pests.
- Deep ploughing after harvest to expose pupae.
- Install pheromone traps (Helilure) at 12/ha.
- Grow resistant varieties (Rupali, Roma, Pusa Red Plume).
- Spray Bacillus thuringiensis (2g/lit).
- Release Trichogramma spp. and Chrysoperla carnea as biocontrol agents.
- Spray HaNPV @ 250 LE/ha for biological control.
- Chemical options: Azadirachtin, Indoxacarb, Flubendiamide, Novaluron, Phosalone, Quinalphos (as per recommended doses).
Serpentine Leaf Miner (Liriomyza trifolii)
Scientific Name: Liriomyza trifolii
Family: Agromyzidae
Order: Diptera
Identification:
- Larva: Minute, orange-yellow, apodous maggots.
- Pupa: Yellowish brown, found in soil or leaves.
- Adult: Pale yellow, small fly.
Life Cycle:
- Eggs laid singly on upper leaf surface.
- Larval period: 7–10 days; total cycle ~3 weeks.
Nature of Damage:
- Larvae mine between leaf epidermal layers, creating serpentine trails.
- Severe infestation causes leaf drying and drop.
Management:
- Collect and destroy mined leaves.
- Spray neem seed kernel extract (NSKE) 5%.
Tomato Leaf Miner (Tuta absoluta)
Scientific Name: Tuta absoluta
Family: Gelechiidae
Order: Lepidoptera
Identification:
- Small greyish moth; larvae are cream to greenish with dark head.
Nature of Damage:
- Larvae mine leaves, stems, and fruits, causing blotches and fruit damage.
- Can cause up to 80–100% yield loss if unmanaged.
Management:
- Use pheromone traps for monitoring and mass trapping.
- Remove and destroy infested plant parts.
- Release natural enemies (Trichogramma spp., Nesidiocoris tenuis).
- Apply Bacillus thuringiensis or selective insecticides as per recommendations.
Whitefly (Bemisia tabaci)
Scientific Name: Bemisia tabaci
Family: Aleyrodidae
Order: Hemiptera
Identification:
- Eggs: Pear-shaped, light yellow.
- Nymphs: Oval, scale-like, greenish white.
- Adults: Tiny, white, scale-like.
Nature of Damage:
- Nymphs and adults suck sap, causing chlorosis and leaf curling.
- Vector of tomato leaf curl virus.
Management:
- Uproot and destroy infected plants.
- Remove alternate weed hosts (e.g., Abutilon indicum).
- Use yellow sticky traps (12/ha).
- Apply carbofuran 3% G @ 40 kg/ha or recommended insecticides (Dimethoate, Malathion, Oxydemeton-methyl, Thiamethoxam).
Aphids (Aphis gossypii, Myzus persicae)
Scientific Names: Aphis gossypii, Myzus persicae
Family: Aphididae
Order: Hemiptera
Nature of Damage:
- Nymphs and adults suck sap from leaves and stems.
- Plants turn yellow, become deformed, and may dry up.
- Honeydew secretion leads to sooty mould, reducing photosynthesis.
Management:
- Seed treatment with imidacloprid or thiamethoxam.
- Use yellow sticky traps.
- Spray recommended systemic insecticides if needed.
Thrips (Thrips tabaci)
Scientific Name: Thrips tabaci
Family: Thripidae
Order: Thysanoptera
Identification:
- Nymphs: Yellowish.
- Adults: Dark with fringed wings.
Nature of Damage:
- Silvery streaks on leaves, premature flower drop, bud necrosis.
- Vector of tomato spotted wilt virus.
Management:
- Uproot and destroy diseased plants.
- Use yellow sticky traps (15/ha).
- Release Chrysoperla carnea larvae (10,000/ha).
- Spray methyl demeton or dimethoate as per recommendations.
Red Spider Mite (Tetranychus spp.)
Scientific Name: Tetranychus spp.
Family: Tetranychidae
Order: Acarina
Identification:
- Eggs: Hyaline, globular, laid in masses.
- Nymphs: Yellowish.
- Adults: Small, red.
Nature of Damage:
- Leaves turn reddish-brown and bronzy.
- Webbing on leaves; severe cases cause leaf drying and reduced fruit set.
Management:
- Spray wettable sulphur 50 WP (2g/lit).
- Spray dicofol 18.5 EC (2.5 ml/lit) if needed.
Summary: Integrated Pest Management in Tomato
- Combine cultural, biological, and chemical methods for effective pest control.
- Monitor fields regularly for early pest detection.
- Promote use of resistant varieties and natural enemies.
- Minimize pesticide use to delay resistance and protect beneficial organisms.
Objective Questions
Q1. Which family does the tomato fruit borer, Helicoverpa armigera, belong to?
A. Noctuidae
B. Gelechidae
C. Agromyzidae
D. Aleurodidae
Answer: A
Q2. What is the recommended ratio of American tall marigold to tomato seedlings for managing tomato fruit borer?
A. 1:10
B. 1:16
C. 1:20
D. 1:25
Answer: B
Q3. Which insecticide and dose is recommended for chemical control of whitefly on tomato?
A. Indoxacarb 8 ml/10 lit
B. Dimethoate 1.0 ml/lit
C. Flubendiamide 5 g/10 lit
D. Azadirachtin 2.0 ml/lit
Answer: B
Q4. Which pest is the vector of tomato leaf curl disease?
A. Thrips tabaci
B. Bemisia tabaci
C. Tetranychus spp
D. Liriomyza trifolii
Answer: B
Q5. What is the total life cycle duration of the serpentine leaf miner?
A. 5-6 days
B. 7-10 days
C. 3 weeks
D. 18-25 days
Answer: C
Q6. Which biological control agent is released at 1 lakh/ha for tomato fruit borer management?
A. Trichogramma chilonis
B. Trichogramma pretiosum
C. Chrysoperla carnea
D. Bacillus thuringiensis
Answer: B
Q7. Which pest causes silvery streaks on tomato leaves and is a vector of tomato spotted wilt virus?
A. Aphis gossypii
B. Tuta absoluta
C. Thrips tabaci
D. Helicoverpa armigera
Answer: C
Q8. Which of the following is NOT a recommended chemical for tomato fruit borer control?
A. Novaluron
B. Quinalphos
C. Malathion
D. Flubendiamide
Answer: C
Q9. What is the main symptom of red spider mite infestation on tomato leaves?
A. Silvery mines
B. Reddish brown and bronzy leaves
C. Downward curling
D. Circular holes in fruits
Answer: B
Q10. Which pest's larvae are described as minute orange yellowish apodous maggots?
A. Helicoverpa armigera
B. Tuta absoluta
C. Liriomyza trifolii
D. Aphis gossypii
Answer: C