Pest of Leafy vegetables

1. Leaf-eating caterpillar
Spodoptera litura F.
Family: -Noctuide
Order: - Lepidoptera

Marks of identification

The moths are medium sized and stout bodied, with front wings pale Grey to dark brown in colour having wavy marking and whitish hind wings. The caterpillars are pale greenish-brown and smooth, with dark markings and a prothoracic plate and are about 37.5mm long when full-grown.

Nature of damage

The caterpillars, when young, feed gregariously on tender leaves and juicy stems. It become isolated at the later stages of growth.

Host plants

Tobacco, peas, brinjal, castor, banana, agathi are the main hosts.

Life history

Numerous eggs are laid in masses covered with brown hairs on tender leaves and they hatch in a period of four to five days. The caterpillars, which are darkish in appearance, on hatching start feeding on the soft green layers of leaves gregariously during the night, both in seedbeds and planted fields. They pupate in rough earthen cocoons. Their pupal period lasts from nine to fourteen days and the total period of their lifecycle is 30 to 40 days.

Control measures

Preventive measures such as collection and destruction of egg masses and caterpillars and thorough ploughing after the harvest of the crop to expose pupae may be launched with a fair degree of effectiveness. At the early stage of infestation dusting with 10% carbayl at 20-25 kg/ha controls the pest satisfactory. When the caterpillars are about to pupate it is better to collect and destroy them on large scale.

2. Aphids
Myzus persicae Sulzer
Family: -Aphididae
Order: - Hemiptera

Marks of Identification

Aphids are tiny yellowish soft-bodied insects, the adult is along 1mm long and has two projections called cornicles on the dorsal side of abdomen.

Nature of damage

Aphids are found in large colonies on underside o leaves and tender shoots. The nymphs and adults suck the sap. Therefore, the affected leaves turn yellow, get wrinkled and destorted. The insect also exude honeydew on which fungus develops, rapidly covers the plant with sooty mould that interferes with the photosynthetic activity of the plant. As a result, the growth of plant is stunted and yield is affected adversely. Besides, they act as a vector for transmitting by aphids. The loss caused on this account is far more severe than by their feeding and devitalizing the plant.

Life history

Adults and apterous forms reproduce parthenogenitically. Single female produces 8-22 nymphs/day. The nymphs are completed in 7 to 9 days and several generations are completed in a season.

Host plants

It is a polyphagous species have been recorded on cabbage, brinjal, radish, chilly, tomato, tobacco, sanhemp, sweet potato etc.

Control measures

Spraying with 0.05% endosulfan, 0.02% phosphamidon, 0.03% dimethoate, methyl demeton or thiometon

Ag.
Technologies
(Pest Mgmt.)