Control of leaf miner menace in watermelon

Control of leaf miner menace in watermelon

Watermelon crop is attacked by many insect pests, of which leaf miner, assumes significance as it causes greater damage.

The larvae feed on the leaves by mining into them. Smaller leaves with limited feeding space are characterised by a secondary blotch.

Damage caused by a single larva is minimal; however, when the population is heavy they are capable of destroying more leaves and affect the plant growth.

Larvae are easily visible. Yellow and white to brown tunnels or blotches are noticed between the upper and lower surface of leaves. These tunnels spread all over the leaf making loops. Severely affected leaves curl, turn brown and die.

Pest biology

Eggs are oval in shape and creamy white in colour and are laid singly in punctures on the epidermis of the leaf. Entire larval period lasts for 7-9 days.

Pupae are yellowish brown in colour and distinctly segmented. Pupae are oval shaped with narrow ends. Adults are small grey coloured flies with black and yellow markings and live for about 10-20 days depending on the environmental conditions.

Management

— Collect and destroy damaged leaves along with larvae.

— Maintain the field and bunds free from weeds.

— Install yellow sticky traps to attract and kill the adults. These should be placed in and around the field at about 10 cm above the foliage. Replace the trap at least once a week.

— Avoid water stress in irrigated crop. Set up light traps to monitor and attract the leaf miner moths.

— Dusting leaves with phosalone 4D at 25 kg/ha or Carbaryl 10D at 25 kg/ha will be effective.

V. Radhakrishnan

& K. Ramaraju

Department of Agricultural Entomology

Tamil Nadu Agricultural University, Coimbatore