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59. KRULIK, GERALD, WHAT WILL YOU DO WHEN THE EVIL WEEVIL APPEARS?, PUP TALK
(Saddleback Valley Bromeliad Society), 16(2), p. 5-8 , February, 2009.

By Jerry Krulik

                                           THIS IS THE 'EVIL WEEVIL'

The natural size of Metamasius callizona is 0.4-0.6 inches. (Reference 1 for the photo)























We Californians live in a ‘Fool’s Paradise’. We have a variety of sub-tropical and warm temperate
climates, which are hospitable to a large number of exotic plants. Many of them grow very well,
seemingly trouble-free. At least, until some pests of the exotic plants appear.

Up to a decade or so ago, Eucalyptus with all its species, was a wonder plant here. It grew without
care or concern, in good soil or bad, in wet and dry areas. Then the Eucalyptus borer beetle
appeared, concealed as larvae in untreated wood. And the lerp psyllid, a sucking insect from
Australia, showed up too. Between the two pests, innumerable trees were rapidly wiped out.
Oleander is another example. Remember those huge hedges which lined the highways all the way
from San Diego to the indefinite north? They are gone, victim to a plant sucker, a leafhopper which
carried a virus. Evidently this was imported on nursery plants from Florida. There are many others,
which have appeared or which will, eventually, appear here.

Why are we so blessed with a lack of native pests? It is because climatologically, California is an
island. We are protected by the immense dry and cold deserts of northern Mexico, New Mexico,
Arizona, and Nevada, plus our own inland deserts. There are no corridors of water loving,
subtropical vegetation running up to our borders. Thus there is no natural way for pests to spread
to Heliconias, Bromeliads, Plumerias, and so many other plants. When plants are grown without
their normal pests, they usually grow very well and present no problems in cultivation. Our
favorite plants, Bromeliads, are typical. California plants have, essentially, no natural enemies.
Yes, we can rot them, or lose them to cold, but we rarely have anything more disturbing than some
errant mealie bug or aphid-ridden inflorescence.

This happy state of affairs will soon change. Perhaps the Evil Weevil has already appeared here,
though I could find no articles on it. However, it WILL be here and probably in the near future. All it
will take is some infected plant or two, collected in Florida by a hobbyist, brought in by a random
tourist, sent from a nursery, or on a truck with other mass-produced vegetation for the big stores
here. There really is no way to prevent its appearance.

What is the exact concern anyway? Most people seem to know little about it, except for its catchy
name. Let’s start at the beginning. It lives in warm to cool tropical parts of Central America, as
shown on the map (2).





















This weevil was first discovered in November 1989, less than 20 years ago, in a brom nursery in
Fort Lauderdale, and was soon discovered in nearby forests and yards (3). After that, its spread
has been phenomenally rapid. NOTE THAT MUCH OF THIS SPREAD WAS DUE TO MOVEMENT OF
NURSERY GROWN PLANTS! There is a native, smaller species of Metamasius which has never
been observed to do much damage, apparently held in check by native parasites, predators, and
diseases. The new weevil has no natural enemies in Florida, but has/had an immense population
of Tillandsias to devour.
One person, Olan Creel, has spent an incredible amount of effort in documenting its spread. You
need to check out his illustrated articles to comprehend the destruction, with his BW and AW
(before weevil, and after weevil) photographs. For example, less than a year after the weevil was
discovered, it destroyed about 80% of the biomass of Tillandsia spp. in Hidden Forest, Broward
County, during a 4-6 week period late in 1990 (4, 5)
The Florida map shows where the beetle has now been documented (2).




























Of all the Tillandsias in the state, only Spanish Moss, T. usneoides, is safe, and maybe some other
smaller species like T. recurvata and the cultivated T. ionantha. Adults will even nibble on those,
but the weevil larvae need a stem to hide in and to devour. There has to be sufficient succulent
meristematic tissue, the actively growing part of plant, to support the larvae. This is what a
Tillandsia looks like after the larvae are done with it. (2) The adults lay eggs in the succulent tissue
of the stem. The larvae burrow through the stem, destroying all the growing tissues, and then
pupate within the remains of the plant body. An affected forest is a wasteland, with dead and dying
plants collapsed and toppled from their trees. The largest plants are the most desired by the
weevil.
















The weevil takes only 2 months from egg to adult. Each adult female lays about 40 eggs. They fly
very well. Unfortunately, it also seems to have been spread around the state by transportation of
infected plants.  

By the way, this pest likes Tillandsias, but it is a pest of many other Bromeliads too. In its home in
Mexico, this weevil attacks Vriesia, Aechmea, and Catopsis, in addition to many Tillandsias. In
Florida, it has attacked Aechmea, Vriesia, Ananas, Canistrum, Dyckia, Fernseea, Guzmania,
Quesnelia, Nidularium, Orthophytum, Hohenbergia, Pitcairnia, Neoregelia, and Tillandsia, but no
non-bromeliads. I was scared before when it sounded just like a pest of Tillandsias. Now I am
terrified!

Fortunately a few scientists are fighting back. Wood and Cave (6) searched the jungles of
Honduras and Guatemala for dying Tillandsias. They discovered a previously unknown parasitic fly
in collected cocoons of Metamasius callizona. A long period ensued during which they had to
learn how to mass-produce them in captivity, check them for compatibility with native Florida
insects, and acquire all the necessary permits. (7,8)  Dr. J. Howard Frank has been involved in the
continuing release of hundreds of these flies around Florida, starting in the middle of 2007 (9).
There has been little published word on its success, but everyone is hopeful that it will slow the
spread of, and decrease the numbers, of the Evil Weevil.

Why am I so terrified, if there is a known parasite of the Evil Weevil? There are numerous reasons.
Once an insect pest has spread to a new territory, it has never been wiped out. No matter how
many predators and parasites and diseases are introduced, they only reduce the numbers (i.e.,
this is called ‘control’) of the targeted pest. We need more than just one fly, which only lays eggs
in the weevil larvae. The parasitized larvae continue their merry way, eating and destroying the
Tillandsia they started in, and finally turning into pupae. The flies emerge from the weevil pupae,
and go after more weevil larvae, but the damage has been done. The only thing this parasitic fly
can do is cut down on the number of larval, and eventually adult, beetles. Further searches need
to be done to bring in more pests to control this weevil, such as parasitic wasps, predaceous
mites, pathogenic nematodes, viruses, fungi, and weevil bacteria. There has to be a way to
drastically reduce the weevil population and to destroy both adults and larvae as quickly as
possible.

How do you tell if you have this pest? If your larger Tillandsias start to collapse, check them
thoroughly for signs of insect attack, small pupae and beetle larvae inside, and the adult beetles.
Make sure the plant collapse was not just due to over watering or old age. Call for help too, as
quickly as possible. The only way we can control this pest is by use of pesticides, both contact and
systemic poisons, to kill both adults and larvae. With a 2 month life cycle, if this weevil gets
established we may have to thoroughly treat our collections several times a year. I am not
enthusiastic about this prospect, as I use pesticides as little as possible in my garden.

And a final note. We call this pest the ‘Evil Weevil’ as if there is only one kind of weevil which
attacks bromeliads. I found a web page which shows color photos of about 2 dozen species of
weevils, from many different countries, which attack the native bromeliads. (2). These are only a
few of the doubtless thousands of tropical weevils which are potential destructive pests of our
favorite plants. It only takes a few adults or hidden larvae brought into California to start our own
infestation, and there is no way to know in advance which insect will prosper. For reference, the
weevil family is the biggest family of insects, in the biggest group, beetles. There are over 300,000
named types of beetles, and over 60,000 are weevils.


References:

1. www.doacs.state.fl.us

2. http://bromeliadbiota.ifas.ufl.edu/wvbrom13.htm

3. O'Brien, C.W., Thomas, M.C., Frank, J.H. 1990. A new weevil pest of Tillandsia in south Florida.
Journal of the Bromeliad Society 40: 203-205, 222.
http://bromeliadbiota.ifas.ufl.edu/wvbrom12.htm#obrienthomas

4. Olan Ray Creel, August, 2000, at http://fcbs.org/

5. Olan Ray Creel, Winter 99-2000 Issue of "The Palmetto", The Quarterly Magazine of the Florida
Native Plant Society; found at http://fcbs.org/

6. Wood, D. M., and Cave, R. D., Description of a new genus and species of weevil parasitoid from
Honduras (Diptera: Tachinidae). Florida Entomologist 89: 239-244 2006.

7. Suazo, A, Cave, R. D., and Frank, J.H., Reproductive Biology and Development of Lixadmontia
franki (Diptera:Tachinidae) (Diptera: Tachinidae), A Parasitoid of Bromeliad-Eating Weevils, Florida
Entomologist 91(3) 453-459 September 2008

8.  Suazo, A, Arismendi, N, Frank, J.H., and Cave, R.D., Method For Continuously Rearing
Lixadmontia Franki (Diptera:Tachinidae), A Potential Biological Control Agent of Metamasius
callizona (Coleptera: Dryophthoridae) Florida Entomologist 89(3) 348-353 September 2006.

9. Local scientists say they have plan to battle 'evil weevil'. “Insect feasts off Florida bromeliads”
By JEREMY COX 6:43 p.m., Sunday, June 24, 2007, Naplesnews.com, Naples Daily News.htm
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