Trap crops in integrated pest management

Trap crops are plants grown to attract insects or other pests that destroy the main crops. The principle of trap cropping rests on the fact that virtually all pests show a distinct preference to certain crops during growing stages.

Trap cropping is economical and environmental benefits are often associated with this strategy. Its potential role in improving the environmental soundness cannot be undermined.

Pest attraction

Yet another function of trap crops is their use of attracting natural enemies of pest insects to the fields and concentrating them there to enhance naturally occurring biological control.

Essential features of the trap cropping are that the trap crop must be more attractive to the pest than the main crop, should occupy a small area as far as possible and must be established at an early or later stage or along with the main crop.

Some important trap crops commonly used in pest management include bhendi/okra in cotton to trap bollworms and marigold at the border of the field. Sesamum is commonly being used as trap crop to attract pests such as diamondback moth in both cabbage and cauliflower. Two rows of sesamum for every 25 rows of cabbage or cauliflower can be planted to trap the pest. In groundnut, castor or sunflower can be used to attract leaf eating caterpillar on the field borders.

In tomato marigold or cucumber is commonly used as trap crop for every 15 rows of the main crop to attract tomato fruit borer. In case of field beans, chrysanthamum acts as a trap crop against leaf minor.

Marigold is a potential trap crop in potato and rice against nematodes and snails, respectively.

To trap corn stalk borer in maize sorghum has been exploited as trap crop. Bihar hairy caterpillar in cowpea can be trapped by planting gingelly.

Economic benefits

Trap cropping has indicated benefits in terms of economic returns on an average of 10-30 per cent increase in net profits mainly resulting from reduced insecticide use and pest attack. It is a useful strategy in managing several pests in various cropping systems.

(D. N. Kambrekar, Asst prof, S.B.Kalaghatagi, Prof, Regional Agricultural Research Station, Bijapur, UAS, Dharwad, Email: kambrekardn@gmail.com, phone: 08352- 230568.)