Insect Pests
Whiteflies
Whiteflies are oval shaped, tiny flies with mealy white wax covering their wing and yellow body. Eggs are laid on the undersurface of the leaves, in circular or semicircular fashion depending on the species. The early stages of nymphs resembles scale insects and there are four nymphal instars. Most whiteflies are confined to undersurface of the leaf and continuously suck the sap from leaves. High population causes yellowing and shriveling of leaves, affects plant health and flower quality. Whiteflies are most common and perhaps most difficult pests to control under polyhouse. Common species found under polyhouse are greenhouse whitefly, Trialeurodes vaporariorum and cotton whitefly, Bemisia tabaci.
Aphids
Aphids are small, 1.5 – 3.2 mm long, soft bodied insects. They range in color from green to brown, red, black or purple. Aphids excrete sugary liquid called honeydew. This honeydew drop into plant foliage and provide suitable place for development of back mold.
Leafhopper
Leafhopper are minute insects which are plant feeders that suck plant sap from grass, shrubs, or trees. Their hind legs are modified for jumping, and are covered with hairs that facilitate the spreading of a secretion over their bodies. Leafhoppers have various host associations, varying from very generalized to very specific, some species have a cosmopolitan distribution. Some species are pests and some are vectors of plant viruses and phytoplasmas.
Thrips
Thrips are tiny insects which feed on mainly new growing points of the plant. Both nymphs and adults suck cell sap resulting in curled or bronzed leaves, deformed buds with burnt margins and some species can also from galls on plant parts. Some specific species may transmit plant viruses as vectors.
Scales insects
Scales insects are flat, circular and reddish in colour and measures about 2 mm in diameter. They appear in severe form before and after the monsoon season. Both adults and young ones suck the sap from mature shoots and deplete vigor of the plant. The infested plant bears a few small flowers.
Leaf miner
Small, black and yellow colored flies. Adult Leaf miner lay eggs on upper surface of leaves by making a small puncture. Eggs can be seen as small white specks on the leaves. After hatching, larva mines into the leaf and form a characteristic serpentine tunnel in the leaf.
Insect Pest