Thrips can infest and build up on numerous garden plants. But are
seldom seen due to their minute size (Average of 0.04 inch long) as well
as the fact that they spend most of their time concealed between foliage
and imbedded in flowers.
Adult thrips have two pairs of narrow wings which are fringed with
hairs.
Unlike many insect species Immature thrips that have not yet "earned
their wings " closely resemble the Adult stage. Adults have wings and
can fly.
Thrips have a unique life cycle. The adult lays her eggs in plant
tissue. Thrips are relatively primitive insects, having " incomplete
metamorphosis"... Primitive or not , as a species they thrive.
The larvae hatch and enter two or more stages before entering the
prepupal and pupal stage in the soil. The pupae emerge as winged adults
and migrate back to the plants or out of the field. The entire cycle
from egg to adult requires slightly over two weeks.
There are multiple generations annually.
Thrips are among the most abundant insect pests of ornamental plants,
many varieties of vegetable plants, small fruits and berries. The list
of host plants is way too numerous to catalog here.
Among the most favored ornamental plants are roses, peonies, daisies,
gladiolus, chrysanthemums, cotton blossoms, and day lilies. These tiny,
active insects may be seen flying or hopping between flower petals when
disturbed.
During warm weather, thrips often fly in swarms in late afternoon.
For whatever reason they seem to prefer light-colored blossoms. They
feed on petals and buds by rasping soft plant tissue and sucking the
juices.
Numerous beneficial insects are useful in suppressing thrips. These
include lady bugs, minute pirate bugs, ground beetles, and spiders.
Unfortunately, these predators and parasites may be hampered by the fact
that thrips feed under close-fitting leaves and down in the leaf sheaths
where they are difficult to access. Minute pirate bugs (Orius
tristicolor) play a major role in controlling thrips populations
See: Bioneem
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