Hemipteran have their mouthparts adapted to suck internal liquids of animal or vegetable tissues (mouth stilettos). Whitespotted stink bug, in particular, feed exclusively on grains of grasses.
In order to feed themselves, whitespotted stink bug stick their stiletto into the grain and suck part of its content. The symptoms noticed on the rice grains once they are ripe are:
- A sting on the grain.
- A Grain a little or very distorted, the spot with the sting being more depressed.
- Brownish stain around the sting as a consequence of a subsequent fungal infection.
Although in general weight losses are not usually very significant, the problems come because of a loss of quality (commercial value) of the affected grains.