Biological
Controls
Foster
Creek is targeting four invasive species using five biological
control species. These "bugs" are part of an
overall strategy to control and eradicate Dalmatian toadflax,
Diffuse knapweed, Canada thistle, and Common mullen. By
themselves they can contain these weed species but when coupled
with other cultural practices (cultivation, mowing, herbicides,
and planting competitive beneficial plants) are part of a
comprehensive approach to weed control.
The
District cost shares up to 50% on biological controls for our four
main weed species. If you are interested, please contact the
district office or download our request form here
and mail/email it back to us. Staff will follow up to
confirm your request.
Mecinus janthinus adult.
R. Richard, USDA-APHIS |
Dalmatian
toadflax
Mecinus
janthinus adults are shiny black, slender weevils about 3-4
mm long, with a pronounced snout. Beetles are found on
toadflax foliage. The legless larvae are creamy-white in
color with a light-brown head capsule, and appear C-shaped
when viewed from the side. M. janthinus larvae are found
tunneling within toadflax stems. |
|
Larinus
minutus adult.
R. Richard, USDA-APHIS |
Diffuse knapweed
L.
minutus is a brown-grey weevil with a very large, bulbous
snout. L. minutus measures 4-5 mm in length. They are strong
fliers and disperse throughout the entire knapweed patch in
several years. When the adults first emerge from the
knapweed seed head they are light grey with some yellow fuzz
on their bodies. |
.jpg)
Larinus
Planus adult.
Dale Whaley, WSU Extension |
Canada Thistle
L.
planus is an oval weevil, 5-8 mm long, with almost parallel
sides to its body. Wing covers are marked with punctures,
furrows and hairs making grayish-white spots. Rostrum
(snout) is shorter than the thorax, which is distinctly
narrower than the wing covers. Rhinocyllus conicus is also
found on Canada thistle, but it is smaller and has a short
rostrum that it barely visible from above. In Larinus planus
the rostrum long, held forward and has conspicuous antennae
about the mid point |
|
Rhinocyllus
conicus adult.
Dale Whaley, WSU Extension |
Canada Thistle
R.
conicus is an oblong black weevil, 3-7 mm long and just over
1/3 as wide, with patches of brown and pale grey hairs and
short rostrum (snout). |
|
Gymnetron
(Rhinusa) tetrum adult. |
Common Mullen
Adults
of mullein seed head weevil are broad, round-oval and
flattened above. They are small (> 2.0 mm < 4.5 mm
long) in size. The erect and recumbent, dense pubescence
nearly conceals the shining black body. The setae and
scale-like setae often have a brassy metallic color. The
rostrum is straight and very strongly attenuate, and nearly
as long as or longer than the pronotum. The erect to
sub-erect pubescence is equally dense on the basal half of
the rostrum, the legs, and the underside of the body. The
femur of the front leg is toothed strongly only in the
males. The femora are strongly dilated and toothed. |
|
|
