Insect Pests of Vegetable, Tuber and Spice Crops

Greenhouse whitefly

3. Greenhouse whitefly, Trialeurodes vaporariorum (Aleyrodidae: Hemiptera)

Distribution: Cosmopolitan

Hosts: Polyphagous

Damage:

• Caused by nymphs as well as adults
• Suck the cell sap from leaves
• Leaves turn yellow and dry away.
• Nymphs also excrete honey dew on which sooty moulds develops
• Photosynthesis of the plant is reduced.

Identification:

• Greenhouse whiteflies are small insects with white coloured wings
• The eggs are 0.2 to 0.25 mm x 0.08 to 0.12 mm
• Newly emerged nymphs are light yellow in colour
• Last nymphal instar is 0.70 to 0.90 x 0.40 to 0.60 mm

Life cycle:

• Incubation period is 3 to 8 days
• Development of first, second, third and fourth instar nymph is completed in 2 to 6, 5 to 8, 3 to 5 and 3 to 6 days, respectively.
• The total life cycle is completed in 15 to 32 days.

Salient features:

• Remain hidden on the under surface of leave.
• Eggs are stalked and remain suspended on the lower surface of the leaf
• Four nymphal stages
• Full grown nymph pupates in a yellow pupal case surrounded by a waxy palisade and waxy fringe.
• Many generations in a year

Management:

• Removal of weed hosts is important to reduce the incidence.
• Protect the nursery by using nylon nets (200 mesh) for 25-30 days.
• The pest can be controlled by need based spraying of crop with imidacloprid (0.0075%) or triazophos (0.15%) or deltamethrin (0.0028%).