Controlling giant African snail menace

The Giant African Snail Achatina fulica is an exotic pest introduced from East Africa to India in 1847 itself. This is the biggest land snail having a protective shell, measuring about 19 cm in length.

It is very active during monsoon, nocturnal in behaviour and damages crops like papaya, brinjal, beans, okra, cole crops, areca nut, rubber buds, coffee seedlings, orchids, etc.

Contamination

The snail eats the leaves, stems, fruits and flowers of host plants causing severe damage to the young saplings especially in nurseries. It also contaminates leafy vegetables with its excrement.

It frequently climbs on papaya and banana plants and clings on the leaf surface thus interfering with cultural operations and affecting the aesthetic value of kitchen gardens and roof gardens too.

This snail is a hermaphrodite and lays 50-200 yellowish eggs on soil surface. Hatching takes place in about a week’s period and the young ones grow up to a year and reach sexual maturity.

The life span of this snail is 3-5 years. And those hatching towards the end of rainy season take a long time to mature as they undergo hibernation and aestivation.

Management:

The locations of hiding places and snails are to be destroyed.

Hand collection and destruction will be effective during early phase of infestation.

Cut pieces of papaya stems may be placed for attracting and trapping the snails.

Use wet gunny bags and papaya leaves as bait to collect and destroy them.

Marigold can be raised as trap crop around vegetable fields.

Lime or bleaching powder may be sprinkled in the infested area.

Common salt may also be spread on the snail infested area. Predatory snails, hermit crabs and millipedes are found to feed on this snail and check the increasing population.

Spread the bait mixture of rice bran and metaldehyde (5 per cent) to cover the paths of snails or sprinkle 5 per cent metaldehyde pellets around the infested plants.

(Dr. J. Jayaraj is Professor of Entomology, Agricultural College and Research Institute, Madurai 625 104, Email: vu2jrj@rediffmail.com, Phone No. 0452-2422946.)