UF/IFAS
Okeechobee County Extension Service
458 Highway 98 North
Okeechobee, FL 34972-2578
Phone: (863) 763-6469
E- mail: dfculbert@ifas.ufl.edu
February 9, 2005
Feature
Article - for release the week of
Dan
Culbert - Extension Horticulture Agent
ARE YOUR MEALYBUGS PINK?
Pink is the color for Valentine’s Day and just in time is a new pink bug
in town. Although its soft and
pink, it won’t be very cuddly on many of our landscape and house plants.
This new insect invader from
Unfortunately, the what to do about it part of the story is still
being written.
Hedge defoliated by PHM |
|
Female PHM (arrow) and small immature pink nymphs |
photo: USDALifestyles of the Pink and Puffy
This pest is generally called by the common name, pink hibiscus mealybug (Maconellicoccus
hirsutus), even though it attacks many plant species, including citrus. It
has also been called pink mealybug and hibiscus mealybug.
Over 275 species of mealybugs are known in the US. Mealybugs are related to aphids, whiteflies, and the scale insects. Most of
these insects use a straw-like mouth part to feed on the sap of their host
plant. In the process of feeding, they can inject plant toxins or diseases.
Adult PHM mealybugs are small (about
1/16 inch long) and pink in body color, but covered with a waxy secretion. The
waxy filaments are short and females may be hard to see because of this white
mealy wax. Adult males are smaller, reddish brown and have one pair of wings
and two long waxy "tails." When squashed, a pink to red fluid is
observed - that is the identifying feature that distinguishes PHM from other
mealybugs.
The pink hibiscus mealybug females can lay up to 600 eggs during their 23
to 30 day life cycle, and with up to 15 generations of PHM
per year, pest populations can become very large, very fast. The PHM may be
spread naturally by wind, birds, and other wildlife, or by people moving
infested plant material. The USDA has been working valiantly to keep this pest
out of our county for many years, but because of the wide host range, PHM
are expected to colonize all of Florida and spread into southern Georgia.
Look for PHM on all parts of plants, but
focus in on the buds, undersides of leaves, inside the joints between twigs,
and even down in the feeder roots in the soil. The PHM
injects toxic saliva as it feeds, and distorts and stunts growth. Mealybug
feeding can kill the plant. One or more of the following symptoms on host
plants may be seen:
· Crinkled or twisted leaves and shoots
· Bunched and unopened leaves
· Distorted or bushy shoots, called "Bunchy top"
· White fluffy mass on buds, stems, fruit, and roots
· Presence of honeydew, black sooty mold, and ants
· Unopened flowers which often shrivel and die
·
Small deformed fruits
While the PHM does attack Hibiscus, the
list of other plants that it can infest is very long. UF entomologists have
identified more than 332 host plants. Here is a short list of some of our
local plants that are known to be affected by the PHM:
· Fruit trees: Avocado, Banana, Carambola (Star Fruit), Citrus, Grape, Guava, Mango Papaya, Passion Fruit.
· Vegetables: Tomato, Peppers, Beans, Cucumber, Pumpkin, Squash, Okra, Lettuce, Cabbage.
·
Ornamentals: Allamanda, Anthurium, Bougainvillea, Croton, Ficus,
Ginger Lily, Heliconia, Hibiscus, Ixora, Lantana, Oleander, Schefflera,
Seagrape.
Predators,
parasites and pesticides
The best hope for coping with this unwanted visitor seems to be the release
of predatory and parasitic insects which will keep the numbers to tolerable
levels. The successful introduction of these good guys will depend upon the
release of and establishment of populations of hungry helpers. And, the use of
pesticides in our Florida Yards to control the PHM
may also kill these predators and parasites. Bottom Line: at this
point, don’t spray pesticides for this pest without following the specific
homeowner recommendations developed by Dr. Osborne
Several good guys are being proposed to put the bite on PHM.
One is a very small parasitic wasp (Anagyrus kamali) that lays an egg
inside adult mealybugs. One female wasp can take care of 40-60 mealybugs in 15
days. The adult also pierces the mealybug shell and feeds on the pest’s body
fluids.
The wasp does not sting people and feeds only on mealybugs. The USDA has
reported a 94 percent reduction in PHM in
the year and a half since these wasps were introduced in St. Kitts and more
than an 80 percent reduction in only four months in
Another good guy is the redheaded ladybird beetle (Cryptolaemus montrouzieri), whose larvae is sometimes called the mealybug destroyer. A voracious feeder on mealybugs, this predaceous beetle is capable of eating 3,000-5,000 mealybugs during its lifetime. Because of their heavy wax coating, the larvae of this beetle are often mistaken for large mealybugs. But, these beetles can interfere with the parasitic wasp because the beetles will also feed on parasitized mealybugs. This is another reason why the local pest management strategies are not yet clear.
|
Anagyrus kamali, a parasitic wasp from China lays an egg inside the mealybug adult. Photo by: Tony Cross International Institute of Biological Control |
|
This
"mealybug destroyer", a larva of the ladybug Cryptolaemus
sp., is covered with white secretions. It may be
confused with PHM but is an important predators and
should not be destroyed.
Photograph by: Lance Osborne, UF/IFAS
|
Predatory ladybugs, may provide some suppression of
PHM pest populations, but are not expected to provide adequate control because the beetles will require large numbers of mealybugs to survive.
Photograph by: Lance Osborne, UF/IFAS How
you can help
If you travel outside the country, make sure that all plants, are properly
inspected and cleared at
Monitor your landscape, fruit and vegetable plants for signs of this
insect. Look at any new plants before you bring them into your landscape. Be
on the lookout for white fluffy masses on buds, stems, fruit, and roots.
Because pesticides cannot easily penetrate the heavy wax layers on PHM,
many pesticides will be ineffective against this mealybug. Follow pesticide
recommendations exactly.
Report suspected PHM infestations to our
Extension office; our staff will be able to give you contact information for
Department of Agriculture officials.
Our office can provide you with copies of fact sheets about the Pink
Hibiscus Mealybug. In the mean
time, be on the lookout and bring suspected samples fully enclosed in
containers to our office if you suspect it is on your plants. As soon as
further recommendations on how to best manage this pest are available, we will
pass it along through this paper and on our
I’ve
placed more information on our Okeechobee web page, http://okeechobee.ifas.ufl.edu.
If you need additional information on PHM,
please email us at okeechobee@ifas.ufl.edu
or call us at 863-763-6469. Local
residents can stop by our office at 458 Hwy 98 North in Okeechobee, and visit
our
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For more information:
