Identification

Adults of this beetle have a dark blue or blackish colour with spines all over the body and are 4-5 mm long (Fig 1). The larva is whitish yellow and flattened with the size of 3.5 mm (Fig 2).

Damage

The larva mines into the leaf blade and feed on the green tissue between the veins. Adults also feed in the green tissue; they scrape green matter of the tender leaves. Generally the plants are affected at young stages from the nursery bed up to panicle initiation. Tunneling of larvae through the leaf tissue causes irregular translucent white patches that are parallel to the leaf veins (Fig 3). The damaged leaves wither off.

It can be found the nursery and rice field as well as the monsoon rice and the summer rice fields. Six generations can be completed in one year.

Control options

Cultural control: Avoid over use of fertilizer and too close plant spacing. In the nursery, destroy the leaf tip containing blotch mines on the leaf before transplanting to the field.

Biocontrol: Reduviid bugs, as well as other natural enemies prey upon this pest. Therefore, conservation of natural enemies should be strongly considered by judicious use of insecticides.