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

Cotton aphid

1. Cotton aphid, Aphis gossypii (Aphididae: Hemiptera)

• Nymphs and adults suck sap from Hibiscus rosa sinensis, Cossia glance, Tecoma capensis
• Bioecology and management have been discussed earlier

2. Dusky cotton bug, Oxycarenus laetus (Lygaeidae: Hemiptera)

Hosts: Hibiscus rosa sinensis, Malvaviscus arboreus, Bougainvillea spp, Jasminum spp., Plumeria acuminata.

• The nymphs and adults are commonly found feeding on its hosts throughout the year except during winter months
• H. rosa sinensis is the most preferred host
• Maximum population is found from March to May
• The flower buds of Hibiscus plants become pale as a result of its feeding and fall down without opening
• The adults usually feed on the terminal portions
• They hide in clusters of dry leaves and flowers during winter.

Life cycle and management of this pest has been discussed under insect pests of okra.

3. Hollyhock tingid bug, Urentius euonymus (Tingidae: Hemiptera)

Hosts: Garden holy hock, Althaea rosea, Abutilon indicum, Sida cardifolia and Chrozophora rotilesi.

Damage:

• Both nymphs and adults suck the cell sap from the under surface of leaves
• The infested leaves become pale yellow then turn brown and ultimately dry up after shriveling.

Identification

• The bugs are about 5-6 mm in length having densely reticulate body and wings
• The nymphs are spiny in appearance.

Life cycle

• This pest appears from March to June
• Adult females lay eggs on the upper surface of leaves
• The incubation period is 8-10 days
• There are five nymphal instars
• Larval period is 15-27 days
• The pest over winters in egg stage.

Management:

• Spray dimethoate @ 0.05%

4. Sunflower lace wing bug, Cadmilos rotiarius (Tingidae: Hemiptera)

Hosts: Many garden plants like sunflower, gaillardia, daisy, chrysanthemum, marigold, etc.

Identification

• It is a small insect measuring about 4 mm
• Transparent shiny, reticulate wings
• Body is black

Damage:

• Both nymphs and adults suck the sap and the infested leaves turn yellowish brown and finally dry up.

Life cycle:

• Pest appears during July and remain active up to September
• Adult females lay eggs on the upper surface of the leaves
• The eggs are inserted strongly into plant tissue
• Only opercula exposed, which appear like white or brown dots
• The eggs hatch in 5-7 days
• Moult five times during 2-3 weeks.

Management

• Spray the crop with malathion @ 0.05%.