Pest of Tobacco

1. Tobacco 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 gregarously on tender leaves and juicy stems at 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 become 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 eggs 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. Stem borer:
Gnorimoschema heliopa L.
Family:- Gelechidae
Order:- Lepidptera

Marks of identification: - The moths are small, active, pale-brown closely allied to the potato tuber moth. The caterpillars are small and brownish-white in colour with as dark head and are about mm long when full-grown.

Nature of damage: - The caterpillars bore into stems and caused characteristics gall-like swellings on them.

Life history: - Elongated eggs are laid on leaf stalks and the lower side of leaves of tobacco plant and they hatch in about six to seven days. Tiny caterpillars, on hatching, burrow along the leaf stalks into the stems and feed on the internal tissues. The irritations caused inside the stems by larvae create gall-like swellings on them. The caterpillars become full-grown in about six to seven weeks’ time and pupate inside the larval burrowns. Their pupal period lasts about 10 days and the total period of their life cycle is seven to eight weeks.

Control measures: -Preventive measures include the removal and destruction of the affected stems during the growth of the crop also after harvesting the crop-stray and wild tobacco plants should be destroyed. Care should be taken to plant healthy seedlings from the seed-bed if infestation is noticed at the seeding stage.

Cut worm: - This pest has been discussed under the pests of patato.

White fly: - Bemisia tabacigen is the known vector for transmitting some of the persistent viruses. Control measures for the pest is dealt under citus.

3. Aphids: - Myzus parsicae sulz.
Family: Aphidae
Order: Hemiptera

Marks of Identification: - These aphids are commonly known as green peach aphids. The wingless adults are yellowish green, light purpul or brownish pink in colour. Wingless and winged forms are also seen. These are reproducing viviparously and pathenogenetical. The wing of a female has a black head and greenish abdomen with one or two transverse dark bands and four lateral dark spots.

Host plants: - Cabbage, brinjal, raddish, potato, chillies, shepu, tomato, tobacco sanhemp, sweet potato, hibiseus sp. etc.

Nature of damage: -During heavy infestation, thousands of aphids can be seen feeding on lower surface of the leaves. By constant feeding on sap, the leaves look sickly and become unfit for curing. They excrete out honeydew while feeding on plant sap, where the sooty mould (fungus) also develops. The quality of such leaves thus deteriorated. Apart from this direct damage, these aphids have remarkable ability to transmit non-persistent type of viruses. The Rosettee disease of tobacco is know to be transmitted by these aphids.

Control measures: - Spraying with 0.02% phosphamidon, parathion, methyl demeton, thiometon or menazen effective for controlling the pest.