Watch for the Bagrada Bug
Rick Gibson
Cooperative Extension Agent, Agriculture
Pinal County, Arizona
Have you heard about the
bagrada bug? It is a relatively new
garden pest here in Pinal County.
The bagrada bug, Bagrada
hilaris is sometimes known as the painted bug. Native to Africa, India and Pakistan, it was
first spotted in California in June of 2008 and arrived in Yuma in September of
2009. It has since spread to other parts of Arizona including La Paz, Maricopa,
Pima, and Pinal counties.
Feeding sites have been found
on corn, cotton, potatoes and other crops, but plants related to cabbage seem
to be favorite targets. Cabbage
relatives include: kale, mustard, cabbage, arugula, broccoli, cauliflower,
radishes and Brussels sprouts. Look for
yellow spots, we call it stippling, along the margin or edges of the
leaves. As feeding gets heavier, the
stippled areas merge and the leaf can eventually wilt and die.
Another more serious symptom
is “blind head,” a problem in heading species like broccoli and
cauliflower. These vegetables develop a
flowering head, which is the part that we eat.
Bagrada bug feeding can keep the head from developing.
The bagrada bug is a true
bug, that means that it is classified in the order Hemiptera. Like all true bugs, it has a piercing-sucking
mouthpart, six legs and a triangular-shaped shield on its back. Other true bugs include the lygus bug, the
stink bug and the leaf-footed plant bug.
All are major agricultural pests in Pinal County.
The insect piercing-sucking
mouth part is most easily compared to our familiar soda straw. The straw is a tool to get liquid from a cup
or can to our mouths. Likewise, the insect
uses its mouth part to pierce the outer defenses of the plant and slurp up the
nutritious plant juices. This is
obviously not healthy for the plant because it is losing important nutrients
and fluids to the invading insect. A
heavy population of insects can drain a plant in short order.
The insect is about
one-quarter of an inch long with a black body that is splotched with orange and
white markings. Some of the markings are
distinct, large spots. Those along the
center of the back, however are stretched into long lines. The colors are distinctive, but resemble those
of a harlequin bug, another distant relative. Be careful that you do not
confuse the two. If you are into gardening, you may want to get a copy of a
good color photograph and keep it handy so that you can compare what you have
with the photo.
To download a photograph and
get additional information, go to the
University of Arizona Cooperative
Extension website at http://cals.arizona.edu/pubs/insects/az1588.pdf
and type in bagrada in the search line.
You can print off the PDF version of the publication without
charge. Another option is to go through
your web browser and search for the name of the insect. There are many sites with good photographs.
While the bagrada bug does
have wings, it seems to prefer walking more than flying. Once the insect finds a good place to feed,
it tends to settle down and stay a while.
The life cycle of the insect begins with an egg laid by a female
adult. She generally will lay the egg on
the ground underneath the plant but sometimes she will select a site on the
plant itself. Look for creamy-white,
oval-shaped eggs with a band around it that make it look like a lid. The eggs change in color to orange as they
mature.
As a true bug, it does not
produce a caterpillar stage that looks completely different from the adult,
like moths and butterflies. Instead, the
newly hatched insect closely resembles the adult stage. The young are called nymphs. In the immature stages of growth, they lack
wings and can only walk to move around.
There are five juvenile stages that each insect must pass through before
they become adults. These newly hatched
nymphs are colored orange-red and get darker as they mature into the later
juvenile stages.
If they show up in your
garden, be ready for a blitz. They like
to gather together in large clusters and as many a 2,000 nymphs of different
stages have been seen feeding on a single cabbage plant. Talk about stress! No wonder affected plants
go into shock. If we want healthy
plants, we should never let a population get that big.
So, how do we do that? A good plan of action will include frequent
monitoring of plants and a careful balance of cultural control methods
including the use of a mixture of nonchemical and chemical control tools. Here are some specific guidelines recommended
by entomologists down in the Yuma area where they have been battling the
bug.
First, make sure that you
check your plants regularly, at least weekly, to look for eggs on the leaves or
soil. Allyssum is a known host for the
bagrada bug and that is a good place to start looking if you have some planted
in your yard.
Second, hand pick the insects
early in the season to help keep populations down. If you are squeamish, use gloves or a tool
like a pocket comb or small paint brush to pick them up and drop them into a
container where they can stay until you destroy them. They are relatively easy to find because they
tend to group together.
Third, cultivate the soil
around your plants with a hoe or other tool to break the crust of the soil and
bury or destroy any eggs that might be lurking on the soil. At the same time, get rid of any crop debris
and weeds that might be harboring the insects.
Fourth, use a soapy water
solution to spray the insects, especially nymphs. Insecticidal soap sprays tend to clog the
breathing holes of the insects and break down the soft, outer protective layers
of the insect leading.
Fifth, use an insecticide
containing a pyrethroid to clean up residual populations. I know that for some that this may not even
be an option, and I suggest this as a last resort because no one really enjoys
dousing something that they will eventually eat with pesticides. However, used correctly, these pesticides are
safe to use. Just be sure that you
follow label instructions when mixing, applying and waiting the proper interval
before you pick and eat the produce. If
populations explode on you and you cannot seem to get ahead of them this may be
your best option.
If you end up with a heavy
dose of the bug on your plants and can’t seem to get them under control, it
will be important to cut your losses and get rid of the infested plants. Pull them up and toss them out. If you don’t, the adults will keep laying
eggs until the end of the season and you will end up with an insect population
waiting in the soil until you plant again.
Not a pleasant thought.
The Bagrada bug is a new
garden pest that could complicate our efforts for high quality, home grown
vegetables. However, by carefully
monitoring our gardens and treating for these pests in a timely manner, we
should be able to prevent serious problems.
If you have questions, you
can reach one of the Master Gardeners at the Cooperative Extension office, 820
E. Cottonwood Lane, Building C, in Casa Grande.
The telephone is (520) 836-5221, extension 204. The author’s email address is gibsonrd@ag.arizona.edu.
The University of Arizona is
an equal opportunity, affirmative action institution. The University does not discriminate on the
basis of race, color, religion, sex, national origin, age, disability, veteran
status, or sexual orientation in its programs and activities.
Rick Gibson
Extension Agent, Agriculture
University of Arizona
Cooperative Extension
820 E. Cottonwood Lane,
Building C
Casa Grande, Arizona 85222
Voice: (520)
836-5221
Fax: (520)
836-1750
Cell: (520)
705-1141
email: gibsonrd@ag.arizona.edu
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