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

Cotton whitefly

1. Cotton whitefly, Bemisia tabaci (Aleyrodidae: Hemiptera)

• Distribution: Throughout the northern and western regions of the Indian sub-continent
• Hosts: Cotton, okra, cabbage, cauliflower, melons, potato, egg plant, coriander and several weed plants.

Damage

• Caused by nymphs and adults
• Suck the cell sap from leaves and other tender plant parts
• Vitality of the plant is reduced
• Nymphs also excrete honey dew on which sooty mould grows
• Interferes with photosynthesis
• Also transmit viruses.

Identification

• The eggs are stalked, sub elliptical and light yellow initially and turns brown before hatching
• Nymphs are elliptical
• Adults are small white coloured insects

Life cycle

• Eggs hatch in about 3-5 days
• Nymphs grow through three stages
• Become pupae in about 9-14 days during summer and 17-81 days during winter
• Pupal period is of 2-8 days
• Total life cycle is completed in 14-122 days.

Salient features

• The pest breeds through out the year
• During cold seasons only adults are noticed
• Females lay eggs singly on the under surface of the leaves
• Suck the sap from tender ports of the plant.

Management:

• Use of yellow sticky traps
• Need based spray of phosphamidon (0.04%) or oxy-methyldemeton (0.025%) or dimethoate (0.03%).
• Observe a waiting period of 7 days

Minor pests of coriander

• Aphid, Hyadophis coriandri (Aphididae: Hemiptera)
• Bug, Agonoscelis nubila (Pentatomidae: Hemiptera)
• Indigo caterpillar, Spodoptera exigua (Noctuidae: Lepidoptera)