Limothrips cerealium (Haliday), the grain thrips,
is a common insect in small grains.
While it normally does not infest vegetable crops, it is included
here because of possible confusion with tobacco thrips, Frankliniella fusca
(Hinds), or with dark forms of other species, such as Frankliniella schultzei
(Trybom).
The female grain thrips is 1-2 mm in length and dark brown to
black in color. Antennal segments
III-V and the legs may be a pale yellowish brown color. The male
is slightly smaller and paler than the male, and lacks wings.
The head is slightly elongated. Antennal segment II is simple,
while segment III is slightly expanded at the apex.
The prothorax has only the posteromarginal
setae well developed. This differs
from the other Terebrantia discussed here.
The abdomen lacks distinct markings.
The grain thrips infests small grains such as wheat and oats,
as well as other grasses (Stannard 1968).
The grain thrips is not known as a pest of vegetable crops. During
migrations, however, it may land on vegetable crops. Due to the
trips' dark color, confusion with dark-colored pest species
may occur.
As their host plants mature, these thrips often migrate in massive
numbers. Agricultural workers may be annoyed by the tickling and
biting associated with thrips landing on exposed skin.