|
New Invader: Chili
Thrips, Scirtothrips
dorsalis Hood
Picture of adult chili
thrips.
Photo credit: Dr. Lance
Osborne, University of
Florida
http://mrec.ifas.ufl.edu/lso/thripslinks.htm
Just as a
bowl of chili will warm
your body, chili thrips
will also make you
“heated,” if they are
found in the landscape.
This thrips is commonly
found in such areas as
South Africa, Pakistan,
India, Bangladesh, Sri
Lanka, Thailand, Malaya,
Indonesia, New Guinea,
Solomon Islands,
Australia, Taiwan,
Japan, Hawaii, and
Venezuela. It is also
commonly found in the
Caribbean. However, they
were spotted in south
Texas within vegetable
transplants this year.
Therefore, it will only
be a matter of time
before they are seen in
North Texas. Adult chili
thrips have a pale body
with dark colored wings
and are less than 2 mm
in length. The immature
thrips are pale in
color. Their lifecycle
can be completed in
14-18 days, with the
adults living about 11
days. Chili thrips have
a wide host range
including many crops.
They can be found on
over 100 host plants,
including beans,
chrysanthemums, citrus,
corn, cotton, eggplant,
grapes, onions, peanuts,
pepper, roses and
tomatoes. They attack
the terminal growing
points of plants, mainly
feeding on young leaves,
buds and fruits. This
surface feeding usually
appears shiny silver at
first and then becomes
yellow to greenish-brown
in color. Dry conditions
can cause population
increases, and feeding
damage appears more
quickly when plants are
water stressed. Chili
thrips are also capable
of spreading tomato
spotted wilt virus,
peanut necrosis virus (PBNV),
peanut chlorotic fan
virus (PCFV) and tobacco
streak virus. If large
populations exist, total
defoliation and
potentially heavy crop
loss can occur.
Some Control Tactics:
Non-Chemical Control
Options: Inspect plant
materials to prevent
infestations. Preserve
natural enemies, which
include minute pirate
bug, green lacewings,
parasitic wasps,
predatory mites and
nematodes (Thripinema
spp.).
Some Chemical Control
Options:
Monitor
for thrips and treat at
first sign of damage.
The use of foliar
insecticides is more
effective at controlling
this thrips, since they
are usually feeding on
exposed plant surfaces.
Some foliar sprays can
include such chemicals
as azadirachtin,
spinosad, novaluron,
bifenthrin, permethrin.
Systemic insecticides
will also provide
control, such as those
containing imidacloprid.
Noticing
Early
Populations
of Spider
Mites Will
Help with
Control
Measures
Two-spotted spider mites,
Tetranychus urticae
Koch.
Photo by: University of
Florida
The
two-spotted spider mite
is a common pest of many
landscape and nursery
plants. Adult
two-spotted spider mites
are small, arachnids
with dark spots on each
side of their bodies.
They feed on the phloem
on the underside of
foliage, causing a
speckled appearance.
They will construct a
web where all the life
stages develop and are
well protected. The
plant nutrients allow
these mites to multiply
rapidly. If large
numbers of mites are
feeding, the foliage
will turn yellow and the
leaves will drop. Heavy
infestations can even
cause death to the
plant. New generations
will continue to develop
until cool weather
occurs, leading to a
reduction of activity.
Some
Control Options:
Non-Chemical Controls:
There are
many predators of the
two-spotted spider mite
that can be introduced
or conserved, such as
the minute pirate bug,
big-eyed bug, green
lacewing, and a variety
of predatory mites such
as Galendromus
occidentalis,
Phytoseiulus persimilis,
and Neoseiulus
californicus. Some
predatory mites require
high humidity levels, so
are more effective
indoors.
Chemical Controls:
Some
options include dormant
oils for use in the fall
to early spring to kill
eggs and dormant adults.
Some other options
include insecticidal
soap, bifenthrin,
cypermethrin, or a
combination of
imidacloprid and
bifenthrin. A thorough,
repeat application of
insecticides to the
underside of the foliage
is needed to gain
control.
Mention
of commercial products
is for educational
purposes only and does
not represent
endorsement by Texas
Cooperative Extension or
The Texas A&M University
System. Insecticide
label registrations are
subject to change, and
changes may have
occurred since this
publication was printed.
The pesticide user is
always responsible for
applying products in
accordance with label
directions. Always read
and carefully follow the
instructions on the
container label.
|