Insect Pests of Vegetable, Ornamental and Spice Crops (2+1)

Gladiolus thrips and Bud borer

1. Gladiolus thrips, Taeniothrips simplex (Thripidae: Thysanoptera)

Damage:

• Both nymphs and adults are damaging
• Rasp the tissue and suck the oozing sap
• Affected parts develop silvery streaks which later on turn brown
• Attacked leaves get deformed and ultimately dries up
• If young plants are attacked, there is a reduction in flower production and quality
• Thrips also attack corms under storage
• Infested corms become sticky, shrivel and produce weak plants when planted.

Identification

• The nymphs are light yellow
• Adults are black in colour
• Wings have hairs which are arranged like the parts of the feather

Life cycle:

• Adults emerge in early spring and begin to feed on leaves and spikes
• After about 3 weeks they start laying eggs in the tissue of foliage
• On hatching young ones start feeding on the leaves and spikes
• Nymphs become full fed in about two weeks
• Pupate in soil.
• Pupal period is for about one week

Management:

• Field:
• Monitoring with‘Blue’ sticky cards
• Spray oxy- demeton methyl (0.025%) or dimethoate (0.03%) at 10 day interval.
• Soil application of phorote @ 1.0 kg a.i./ha
• Drenching with chlorpyriphos (0.04%) or deltamethrin (0.0028%) to kill the pupae
• Storage:
• Corms infested with thrips should be stored at 2o C for 6 weeks and later should be treated in hot (46°C) for 15 minutes.

2. Bud borer, Helicoverpa armigera (Noctuidae: Lepidoptera)

Damage:

• Larvae feed on leaves by eating leaf lamina.
• Caterpillars enter into the developing spikes and feed inside by damaging the flowers.

Bio-ecology:

• As described under carnation.

Management:

• As soon as the eggs or caterpillars are seen in the field, spray the crop with cypermethrin (0.0075%) or fenvalerate (0.01%) or deltamethrin (0.0028%).
• The pest can also be controlled by the application of Btk formulation (dipel) @ 0.5 kg/ha in the early stage of infestation.