Major Insect-Pests in Protected Cultivation

a. Aphids

• Common Species: Myzus persicae, Aphis gossypii.
• Crops Affected: Tomato, cucumber, capsicum, ornamental plants.

Symptoms

• Curling, distortion, and yellowing of young leaves.
• Stunted shoot growth.
• Honeydew excretion leading to sooty mold.

Biology: Rapid reproduction through parthenogenesis, several generations per season.

Integrated Management:

• Cultural: Remove alternate hosts, maintain spacing for ventilation.
• Mechanical: Yellow sticky traps to monitor and trap adults.
• Biological: Release Aphidius colemani, ladybird beetles (Coccinella septempunctata).
• Chemical: Imidacloprid, acetamiprid; use carefully to protect natural enemies.

b. Whiteflies (Bemisia tabaci)

• Crops Affected: Tomato, capsicum, cucumber, ornamental crops.

Symptoms:

• Yellowing of leaves, stunted growth.
• Honeydew secretion leading to sooty mold.
• Transmission of plant viruses (e.g., Tomato Yellow Leaf Curl Virus).

Biology: Tiny, winged insects; develop from egg to adult in 2–3 weeks.

Management:

• Cultural: Remove weed hosts; maintain clean environment.
• Mechanical: Yellow sticky traps, reflective mulches.
• Biological: Release Encarsia formosa, Eretmocerus eremicus.
• Chemical: Use IGRs (pyriproxyfen) or neem formulations.

c. Thrips (Thripidae)

• Crops Affected: Tomato, cucumber, capsicum, flowers.

Symptoms:

• Silvering or streaking of leaves.
• Deformed flowers and scarred fruits.

Biology: Small, slender insects with rapid reproduction; vectors for tomato spotted wilt virus.

Management:

• Cultural: Sanitation, remove crop residues.
• Mechanical: Blue sticky traps.
• Biological: Predatory mites (Amblyseius swirskii, Neoseiulus cucumeris).
• Chemical: Selective insecticides such as spinosad, cypermethrin

d. Spider Mites (Tetranychus urticae)

• Crops Affected: Tomato, cucumber, capsicum, ornamentals.

Symptoms:

• Yellow specks on leaves, bronzing, webbing.
• Leaf drop under severe infestation.

Biology: Prefer hot and dry conditions; rapid life cycle (7–14 days).

Management:

• Cultural: Maintain humidity, avoid drought stress.
• Mechanical: Spraying water to dislodge mites.
• Biological: Release Phytoseiulus persimilis, Neoseiulus californicus.
• Chemical: Miticides like abamectin, spiromesifen.

e. Caterpillars and Leaf Miners

• Crops Affected: Tomato, cucumber, capsicum, leafy vegetables.

Symptoms:

• Leaf chewing, tunneling inside leaves, defoliation.
• Fruit scarring in severe cases.

Management:

• Cultural: Remove infested leaves.
• Biological: Parasitoids (Trichogramma chilonis).
• Chemical: Bacillus thuringiensis formulations, selective insecticides.