Pests of Turmeric and Ginger

1. Rhizome fly
Mimegralla coerrulelfrons Mocquart
Family: -Micropisidae
Order: - Diptera

Economic importance

Rhizome fly is becoming a serious menace to the cultivation of the turmeric and ginger crops in recent years in Maharashtra State.

Marks of identification

The flies are fairly large with slender body and long legs. The body is black in colour and wings are transparent with ashy spots. The wing expansion of flies varies from 13 to 15mm. The eggs are small, white, cigar shaped, tapering at either side. The full grown larva is creamy white in colour, apodous and measures 9.5mm in length an d1.95mm in breadth.

Host plants

Turmeric and ginger

Nature of damage

The maggots feed on the rhizome as a result of which yellowing of plants and rotting of rhizomes takes place.

Life history

Fliers are noticed in the fields in the months of August and September. Female fliers lay eggs singly or in clusters of 6-10 near the base of the plants under small lumps of soil, in cracks and on the surface or soil. The incubation period lasts for 2-5 days. The larval period lasts for 13.18 days. The full-grown maggots pupate into rotten rhizomes. The pupal period lasts for 110-15 days. The pupal period lasts for 10-15 days. The total period of life cycle is about 4 weeks.

Control measures

Preventive measures like destruction of stray plants in off season, selection of healthy rhizome for planting, removal and destruction of rotting rhizomes along with the maggots from the field after the harvest of the crop may help to check the breeding of the pest. Spraying with 0.05% fenitrothion of monocrotophos of 0.02% diazinon was found to be effective.

Besides, recently the turmeric crop is also found infested by scale insects viz. Aspidiella sp. Responsible for deteriorating the quality and germination percentage of turmeric and ginger rhizomes.