Whitespotted stink bug (Eysarcoris inconspicuus) is an Hemiptera from the Pentatomidae family. Both adults and immature ones (newborns and nymphs) feed themselves with grains of grasses. The harm they do to the rice is the consequence of them biting the grains in order to suck its content.
This insect has been known in the Delta for many years and even though it is not considered a pest, there have been years when an effect of its attack to the crops has been noticed. It should be noted that on the Andalusian rice fields (Guadalquivir plain) it is one of the most important pests.
In the Delta, its presence on the rice fields coincides with the earing season and the ripening of the rice plants. Therefore, this presence is extended from late July until harvest time. Before these dates, the whitespotted stink bug population is attached to the spontaneous grasses in the area.
Works by PROBODELT in the area (sampling maps) show that, as the season moves forward, there is a certain migration of whitespotted stink bug individuals from grasses near the fields towards the rice. In addition, it does not only invade the nearby rice; it spreads in a more or less homogeneous way throughout the whole plot.
Whitespotted stink bug spends the winter in the shape of an adult almost inactive, hidden under herbaceous vegetation, under dead vegetable matter or under stones. In the spring, individuals get out of their refuges and they occupy adventitious plants in the surroundings of the rice fields until the moment when they can already use the rice spikes as food. Although it is not known in detail, it seems that in the Delta, whitespotted stink bug may develop a minimum of 4 generations. The last two of them being probably connected to the rice plant.