Frankliniella tritici, the flower thrips or eastern
flower thrips is the dominant thrips species
in temperate North America east of the Rocky Mountains. In some
areas it is being replaced by the recently introduced Western
flower thrips, Frankliniella occidentalis.
The female flower thrips is about 1.0 mm long, yellow and may
have pale gray bands or blotches on each segment
of the abdomen. The male is pale
white to yellow and smaller than the female. Stannard (1968)
notes that dark forms may occur.
The postocular seta
is about half the length of the interocellar
seta. The second antennal segment
is simple, with two normal setae. The pedicel
of the third antennal segment has a thickened, rounded annulus
(ring), which will distinguish it from the other species
in this knowledgebase.
The anteroangular and anteromarginal
setae are well developed, as are the posteroangular and posteromarginal
setae. The anteromarginal setae are shorter than the anteroangular
setae.
The comb on abdominal segment VIII is incomplete.
It has a very wide host range, including
members of the grass, legume, rose, composite and crucifer families
(Beckham et al. 1971, Beshear 1973, Watts 1936).
Frankliniella tritici has been known as a significant
economic pest in the past (Quaintance 1898, Watson 1912). However,
in recent years, it has been surpassed in importance by the western
flower thrips, Frankliniella occidentalis.
Even so, high numbers of F. tritici should not be
tolerated in sensitive crops, such as strawberries or floral crops.
They are most often found in the blooms of vegetable crops. Therefore,
monitoring their numbers in blooms is important.
Where a mixed population of western and eastern flower thrips
occurs, the eastern flower thrips may provide some suppression
of western flower thrips through competition, much as the Florida
flower thrips does. This underscores the importance of identifying
the species infesting your crops
periodically throughout the season, but especially during the
critical bloom stage. In Florida, the eastern flower thrips is
susceptible to a number of insecticides
applied for control of the more damaging tobacco and western flower
thrips.