3. Flower thrips

3. Flower thrips - Scirtothrips dorsalis (Thripidae: Thysanoptera)
    Damage
    • Both nymphs and adults lacerate the tender tissues and suck the exuding sap.
    • The infested leaves begin to curl downwards from the margin towards the mid rib.
    • Heavily infested trees exhibits sickly and faded appearance, which can be recognized even from distance.
    Bionomics
    • The adult is minute measuring 1 mm in length.
    • It is yellowish brown insect, with fringed wings. It reproduces parthenogenetically.
    • The fecundity is 30-50 eggs per female.
    • It lays eggs on the lower surface of leaves by inserting them singly in the tissues along the mid rib of tender leaves.
    • The eggs are reniform and hyaline when laid but turn pale yellow just before hatching.
    • The egg period is about 4-6 days.
    • The nymphs are pale yellow and wingless.
    • They moult 2-3 times passing through 3-4 instars in 12-18 days according to the prevailing temperature.
    • Full grown nymphs undergo two resting stages called pre-pupa and pupa.
    • The pupal period lasts for 6-10 days.
    Management
    • Sprays water twice or thrice during thrips out break helps to reduce its population load appreciably.
    • Spray monocrotophos 36 WSC 1.5 ml or endsulfan 35 EC 2ml/ml or quinalphos 25 EC 2.0 ml / litre of water.

Last modified: Monday, 30 January 2012, 5:36 PM