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 biological, cultural, and chemical methods. Key concepts include pest identification, damage symptoms, life cycle, integrated pest management, and chemical control.
Introduction to Tomato Pests
- Tomato is affected by several major insect pests causing significant yield loss.
- Pests attack various plant parts: leaves, stems, flowers, and fruits.
- Effective management requires understanding pest biology and damage symptoms.
Tomato Fruit Borer (Helicoverpa armigera)
Taxonomy:
- Family: Noctuidae; Order: Lepidoptera
Economic Importance:
- Serious pest in tropical and subtropical regions.
- Also attacks other crops like pigeon pea and chickpea.
Identification:
- Caterpillar: Variable color, radiating hairs, greenish with dark lines.
- Moth: Medium-sized, light brown, forewings with dark spot, smoky hindwings.
Tomato Fruit Borer – Biology and Damage
Life Cycle:
- Eggs laid on tender plant parts.
- Larval stage lasts 18–25 days; pupates in soil.
- Complete life cycle: 30–40 days.
Nature of Damage:
- Young larvae feed on foliage; older larvae bore into fruits.
- Bore circular holes, feed inside fruits, causing secondary infections.
- One larva can damage multiple fruits.
Tomato Fruit Borer – Management
Cultural Control:
- Collect and destroy infested fruits and larvae.
- Deep ploughing after harvest to expose pupae.
- Intercrop with marigold (1:16 ratio) to attract egg-laying adults.
Biological Control:
- Release Trichogramma spp. and Chrysoperla carnea.
- Spray Bacillus thuringiensis or HaNPV.
Chemical Control:
- Use pheromone traps (Helilure) at 12/ha.
- Apply insecticides: Azadirachtin, Indoxacarb, Flubendiamide, Novaluron, Phosalone, Quinalphos as per recommended doses.
Serpentine Leaf Miner (Liriomyza trifolii)
Taxonomy:
- Family: Agromyzidae; Order: Diptera
Identification:
- Larva: Minute, orange-yellow, apodous maggots.
- Adult: Pale yellow, small fly.
Life Cycle:
- Eggs laid singly on upper leaf surface.
- Larval period: 7–10 days; pupation in soil or leaves.
- Total life cycle: ~3 weeks.
Nature of Damage:
- Larvae mine between leaf epidermis, creating serpentine trails.
- Severe infestation leads to leaf drying and drop.
Management:
- Remove and destroy mined leaves.
- Spray neem seed kernel extract (NSKE) 5%.
Tomato Leaf Miner (Tuta absoluta)
Taxonomy:
- Family: Gelechiidae; Order: Lepidoptera
Nature of Damage:
- Larvae mine leaves, stems, and fruits, causing blotches and galleries.
- Leads to fruit damage and yield loss.
Management:
- Use pheromone traps for monitoring and mass trapping.
- Release natural enemies (Trichogramma spp.).
- Apply Bacillus thuringiensis or selective insecticides as needed.
Whitefly (Bemisia tabaci)
Taxonomy:
- Family: Aleyrodidae; Order: Hemiptera
Identification:
- Egg: Pear-shaped, light yellow.
- Nymph: Oval, scale-like, greenish-white.
- Adult: Tiny, white, scale-like.
Nature of Damage:
- Nymphs and adults suck sap, causing chlorosis and leaf curling.
- Vector of tomato leaf curl virus.
Management:
- Remove and destroy infected plants and weeds.
- Use yellow sticky traps (12/ha).
- Apply carbofuran or recommended insecticides: Dimethoate, Malathion, Oxydemeton-methyl, Thiamethoxam.
Aphids (Aphis gossypii, Myzus persicae)
Taxonomy:
- Family: Aphididae; Order: Hemiptera
Nature of Damage:
- Nymphs and adults suck sap, causing yellowing and deformation.
- Honeydew secretion leads to sooty mould growth, reducing photosynthesis.
Management:
- Seed treatment with imidacloprid or thiamethoxam.
- Use yellow sticky traps.
Thrips (Thrips tabaci)
Taxonomy:
- Family: Thripidae; Order: Thysanoptera
Identification:
- Nymphs: Yellowish; Adults: Dark with fringed wings.
Nature of Damage:
- Silvery streaks on leaves, bud necrosis, flower drop.
- Vector of tomato spotted wilt virus.
Management:
- Uproot and destroy diseased plants.
- Use yellow sticky traps (15/ha).
- Release Chrysoperla carnea larvae.
- Spray methyl demeton or dimethoate as per recommendations.
Red Spider Mite (Tetranychus spp.)
Taxonomy:
- Family: Tetranychidae; Order: Acarina
Identification:
- Eggs: Hyaline, globular, laid in masses.
- Nymphs: Yellowish; Adults: Small, red.
Nature of Damage:
- Leaves turn reddish-brown, bronzed, and dry.
- Webbing on leaves; affects flower and fruit formation.
Management:
- Spray wettable sulphur (50 WP, 2g/lit) or dicofol (18.5 EC, 2.5 ml/lit).
Summary: Integrated Pest Management in Tomato
- Combine cultural, biological, and chemical methods for effective pest control.
- Monitor fields regularly for early pest detection.
- Use resistant varieties and crop rotation.
- Promote natural enemies and minimize pesticide use.
Objective Questions
Q1. Which family does the tomato fruit borer, Helicoverpa armigera, belong to?
A. Noctuidae
B. Gelechidae
C. Agromyzidae
D. Thripidae
Answer: A
Q2. What is the recommended ratio of American tall marigold to tomato rows for managing tomato fruit borer?
A. 1:10
B. 1:16
C. 1:20
D. 1:25
Answer: B
Q3. Which insecticide is recommended at a dose of 8 ml/10 lit for tomato fruit borer control?
A. Flubendiamide 20 WG
B. Indoxacarb 14.5% SC
C. Novaluron 10% EC
D. Azadirachtin 1.0% EC
Answer: B
Q4. Which pest is identified by minute orange yellowish apodous maggots as larvae?
A. Helicoverpa armigera
B. Liriomyza trifolii
C. Tuta absoluta
D. Bemisia tabaci
Answer: B
Q5. Which pest is the vector of tomato leaf curl disease?
A. Aphis gossypii
B. Bemisia tabaci
C. Tuta absoluta
D. Thrips tabaci
Answer: B
Q6. Which chemical is recommended for spraying against red spider mite at 2g/lit?
A. Dicofol 18.5 EC
B. Wettable sulphur 50 WP
C. Dimethoate 30% EC
D. Malathion 50% EC
Answer: B
Q7. Which pest's nymphs and adults cause silvery streaks and bud necrosis on tomato?
A. Aphis gossypii
B. Tetranychus spp
C. Thrips tabaci
D. Liriomyza trifolii
Answer: C
Q8. 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
Q9. Which order does the tomato leaf miner, Tuta absoluta, belong to?
A. Diptera
B. Hemiptera
C. Lepidoptera
D. Acarina
Answer: C
Q10. Which pest's infestation leads to sooty mould growth due to honeydew secretion?
A. Thrips tabaci
B. Tetranychus spp
C. Aphis gossypii
D. Liriomyza trifolii
Answer: C
