Collecting Bromeliads and Orchids in Florida

Subtitle

 

Mosquitoes

Adult mosquitoes (flies belonging to the family Culicidae) are winged terrestrial insects, while their immature stages, eggs, larvae and pupae, are aquatic. Larvae and pupae are strictly aquatic, but the eggs of some mosquito species are laid in damp places to await flooding before the larvae can hatch from them.

Larvae molt their skins four times during their development and, at the fourth molt, they become pupae. Adult females of most mosquito species take blood from warm-blooded animals. This provides proteins needed for the development of eggs. Adult male mosquitoes, and females of some species, do not take blood. Adult mosquitoes of both sexes feed on the plant nectars which they use for energy. Mosquito larvae feed by filtering particles from the water, by rasping particulate debris from underwater surfaces, or by preying on other small organisms depending upon the species. Eggs and pupae do not feed, in general, all stages; eggs, larvae, pupae and adult mosquitoes are short lived, but there are exceptions.

As of 2004, 78 mosquito species in 12 genera inhabit Florida. Almost all are considered natives. Few of them are associated in any way with Bromeliads. In the United States, two journals are dedicated to publishing information about mosquitoes. They are the Journal of the American Mosquito Control Association, and the Journal of the Florida Anti-Mosquito Association.

Mosquito-Borne Diseases

The animal (or person) on which an adult female mosquito feeds is called the host. Adult female mosquitoes of some species are capable of transmitting certain infectious diseases from host to host. These diseases are caused by protozoa, nematodes and viruses.

Malaria is caused by parasitic protozoans and is transmitted by some of the Anopheles mosquitoes. Filariasis and dog heartworm are caused by parasitic nematodes and are transmitted by some Aedes and Culex species. Yellow Fever and Dengue are caused by viruses and are transmitted mainly by some Aedes mosquitoes. Viral Encephalitides such as Eastern Equine Encephalitis (EEE) and St. Louis Encephalitis (SLE) have been transmitted in Florida by some Culex mosquitoes. Whether a particular female mosquito carries such a disease organism depends on its previous exposure to the disease. Yellow Fever, Malaria and Dengue have been eradicated from Florida by control of the mosquitoes carrying them, but all three diseases exist in parts of South America. Though the diseases are no longer present in Florida, the mosquito species which might transmit them (if they were here) are still present.

The viral Encephalitides (EEE and SLE) are not uncommon in wild birds in Florida. From time to time these diseases are transmitted from bird populations to human and horse populations by Culex mosquitoes. There were huge outbreaks in Florida of SLE in 1990 and EEE in 1991. During outbreaks of these dangerous doseases, personel from Florida's mosquito control districts monitor the diseases and use all means to supress the mosquitoes capable of transmission.
  Monitoring the diseases is accomplished by the use of "sentinel chickens." These chickens are placed in outdoor cages and their blood is tested for the presence of the virus. Also, mosquitoes are caught in traps and checked for the presence of virus. Medical practitioners are required by law to report cases of these diseases.

Physical methods are used to reduce the habitat available to mosquito larvae and pupae wherever possible. Chemical pest-icides, microbial pesticides and biological control agents are also used against the larvae and pupae stages. Chemical pesticides applied by aircraft, trucks, and manually-operated sprayers are used against adult mosquitoes. Mosquito control district personnel have the right to inspect private properties for sites producing disease mosquitoes and they can take legal action against property owners who allow conditions conductive to the production of such mosquitoes.

The Asian Tiger Mosquito

Before 1985, the distribution of Aedes albopictus, the Asian Tiger Moaquito, was confined to Asia amd many islands in the Pacific Ocean, including some of the Hawaiian Islands. Yet, in recent years, the range of this mosquito has greatly expanded to include North and South America, Africa and Europe.

The Asian Tiger Mosquito (ATM) was most likely introduced into North America through the importation of used tires from Japan or Taiwan. During the 1980s there was a large increase in the number of used tires imported into the United States from countries where ATM is indigenous. Most imported used tires come to the US in containerized shipments that are not adequately inspected for mosquitoes at the ports of entry. These conditions have enabled ATM to become well-established in the United States and to date, they are known to exist in 25 states extending from Texas and Florida in the south, to New Jersey and Nebraska in the north.

In 1986, the Asian Tiger Mosquito was discovered in Florida at a tire dump site in Jack-sonville (Duval County). Over the next 10 years, this exotic mosquito spread to all of Florida's 67 counties. Currently, it is the dominant 'Aedes' mosquito in artificial containers throughout Florida. An exception to this pattern occurs in the Florida Keys, where the Yellow Fever mosquito (YFM), Aedes aegypti has a widespread distribution but where there are as yet, no Asian Tiger Mosquitoes.

Aquatic Habitats of the Asian Tiger

Although immature Asian Tiger Mosquitoes inhabit many different types of containers, scrap tires harbor this mosquito more frequently and in greater numbers than any other type. Approximately 15 million waste tires are generated every year in Florida. The Florida Department of Environmental Protection has new regulations concerning the storage, movement and disposal of waste tires. Authority to issue the so-called Waste Tire Rule is provided in Section 403.717 of the Florida Statutes passed in 1988 and amended in 1990. If this law is enforced, the regulations on waste tires will reduce the availability of used tires as habitats for the Asian Tiger Mosquito and other related pests.

Other common man-made habitats for these mosquitoes are bird baths, water bowls for pets, buckets and plates under potted plants, clogged rain gutters and vases used to hold fresh-cut or silk flowers. The Asian Tiger Mosquito shows a much greater propensity for using natural and man-made containers than does the Yellow Fever mosquito, Aedes aegypti.

In more than a dozen Florida counties, the initial discovery of the Asian Tiger was made at cemetery sites. Plastic floral baskets with fresh cut flowers are often placed at a grave site at the time of burial. After a few days, the wilted flowers are discarded, but the baskets are usually recycled. They may return to the same or to a different cemetery holding fresh or silk flowers. Mosquito eggs laid while the basket is in one cemetery may hatch in another. This invasion route may explain why the ATM became well-established in some cemeteries before appearing in nearby sites of waste tires.

Distinguishing Asian Tiger and Yellow Fever Mosquitoes

The spread of the Asian Tiger Mosquito seems to have occurred at the expense of the YFM (Yellow Fever Mosquito, or the Aedes aegypti). The abundance of the YF mosquito in several Florida cities declined drastically with the introduction of the Asian Tiger Mosquito (ATM). Additional field studies are needed to more clearly document the types of habitats and the geographical regions in which populations of YF mosquitoes have undergone a decline and to assess the role the Asian Tigers may have had in bringing about these changes. In southern parts of both Florida and Texas, YF mosquitoes have continued to thrive in some habitats long after the arrival of the ATM. Since these two mosquito species inhabit the same types of artifical containers, a decline in one species would make more resources available for the other.

Adult AT and YF mosquitoes are active during the daytime. They usually can be disting-uished with ease in the field by differences in the patterns of the scales on their backs. In addition, the clypeus, a structure located on the head between and above the proboscis, is covered with white scales in female YF mosquitoes and with only black scales in female ATM mosquitoes. Scales on the back may be rubbed off, especially in specimens taken in traps, where the scales on the clypeus are seldom missing.

Status of the Asian Tiger Mosquito as a Pest and Vector of Disease

The Asian Tiger Mosquito has quickly become a serious pest problem in many Florida communities where the pest level generated by populations of this mosquito is considerably greater than that caused previously by the Yellow Fever Mosquito (Ardes aegypti). The wider range of habitats occupied by the ATM would tend to make it generally more common than YF mosquitoes.

In Florida, the Asian Tiger Mosquito has not been implicated in the transmission of any human pathogens. Elsewhere, it is a major vector of dengue and yellow fever. Results of laboratory tests indicate that the ATM is capable of serving as a vector for several other viruses that are pathogenic to man or animals.

Control

The best approach for controling AT and YF mosquitoes is by eliminating larval habitats. With improved legislation and better informed people, it should be possible to greatly reduce the abundance of container-inhabiting mosquitoes throughout Florida. The current requirements for the storage of waste tires are grossly inadequate for mosquito control. The waste tire rule should be revised to require that all tires be stored in dry areas.

Educational programs which inform citizens about the important role they can play to prevent mosquito production in containers around their homes, should be expanded and offered on a continuing basis. By eliminating unneeded containers and by frequently emptying the water in other containers, e.g. bird baths and pet dishes, residents can help in the local control of mosquito programs.

Achieving permanent mosquito control in natural containers such as tank bromeliads, may be a bit more difficult. Chemical and microbial larvicides work great. I use a safe bacterial toxin that kills the larvae. Called "bacillus thuringiensis israelenses" (BTI), this product is available in granular and doughnut-shapped pieces at nurseries and on-line suppliers. Brand names include Mosquito Dunks, Quick Kill and Aquabac. I prefer using the granules applied once a month with a broadcast spreader or thrown by hand for the hard to reach bromeliads, such as in trees. Most homeowners need only a few granules per plant, sprinkled into the cups every 45 to 60 days.
Another less expensive method is the use of liquid dishwashing soap. This breaks-down the surface tension of the water which in turn does not permit the mosquito eggs to hatch.
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Footnotes:
This document is ENY632, one of a series of the Entomology and Nematology Department, Florida Cooperative Extension Service, Institute of Food and Agriculture Sciences, University of Florida. Origninal publication date September, 1997. Revised July 2005.
Visit the EDIS Web Site at> http://edis.ifas.ufl.edu/ 

G.F. O'Meara, professor, Florida Medical Entomology Laboratory, University of Florida,
Vero Beach, Florida 32962
U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A.&M. University Cooperative Extension Program, and Boards of County Commissioners. Larry Arrington, Dean

Copyright Information:
This document is copyrighted by the University of Florida, Institute of Food and Agriculture Sciences (UF/IFAS) for the people of the State of Florida. UF/IFAS retains all rights under all conventions, but permits free reproduction by all agents and offices of the Cooperative Extension Service and the people of the State of Florida. Permission is granted to others to use these materials in part or in full for educational purposes, provided that full credit is given to the UF/IFAS, citing the publication, its source, and date of publication.

 

Weevils in Florida and the Damage

At present, 576 weevil species and known from Florida of which 526 and natives, and a few of them are pests. Among the 50 species of foreign orign, 5 were introduced as biological control weevils of weeds. These five weevils were introduced and released to control hydrilla, 
waterhyacinth, waterlettuce, and watermilfoil (Frank & McCoy 1993), and another more recently for control of Melaleuca. Each of them is a specialized feeder on one of those weed species.
Florida now has three species of the genus Metamasius. One, M. mosieri, is a native or at least has been in Florida a long time. The second, M. hemipterus, is an immigrant detected in 1984 and attacks palms, banana plants, sugarcane, and occasionally the pineapple. The third, M. callizona, detected in 1989, is also an immigrant and attacks bromeliads. A fourth, M. monilis, which attacks orchids, was also an immigrant but was soon eradicated after it was detected in 1972.
The Division of Plant Industry (DPI), of the Florida Department of Agriculture and Consumer Services eradicated M. monilis soon after it was detected, but it was too late for M. hemipterus and M. callizona.

Origin of the weevil Metamasius callizona

Metamasius callizona (left) was orignally described from the state of Veracruz, Mexico in 1883. In July, of 1992, Howard Frank and Michael Thomas went to Veracruz, Mexico in search of M. callizona and found it to be very uncommon, and found no potential biological control agents.

In June 1994, H. Frank and Al Muzzell went to Panama and were unable to find M. callizona in bromeliads in Chiriqui. In April - September 1995, Howard Frank spent 6 months in Veracruz Mexico, and again found Metamasius callizona to be very uncommon, and he also found Cactophagus validirostris and Metamasius flavopictus attacking bromeliads. He found no potential biological control agents for M. callizona.

Enormous numbers of insects are intercepted each year by USDA-APHIS inspectors at US ports and airports in shipments of plant material (Frank & McCoy 1992). Between 1973 and 1987, specimens of M. callizona were found 14 times by inspectors, on all but one occasion on Tillandsia spp., and all from Mexico (Frank & Thomas 1994b). Importers have reported finding living specimens in shipping containers from Mexico and provides a high probability that the Metamasius callizona population, which is now established in Florida, came from Mexico in shipments of Tillandsia spp. One of the USDA-APHIS records identified Tillandsia tricolor as the plant in the shipping container, but most of the interception records do not identify the plants to species (Frank & Thomas 1994b).

Florida Bromeliad Weevil (suggested common name), Metamasius mosieri Barber (Insecta: Coleoptera: Dryophthoridae)

Barbara Larson, J. Howard Frank, and Olan Ray Creel

Introduction and Cistribution
Metamasius mosieri Barber is native to Cuba and the Dominican Republic and likely to southern Florida. Until recently, it was rarely collected in Florida, most likely because until recently no effort was made to find it. It has been reported from Collier county (Corkscrew Swamp, Rookery Bay, Collier-Seminole State Park, Fakahatchee Strand), Glades county (Fish-Eating Creek), Hendry county (LaBelle, Big Cypress Seminole Reservation), Sarasota county (Laurel), Lee, Dade, St. Lucie and Osceola Counties.

The Florida bromeliad weevil is an occasional and minor pest on ornamental bromeliads and occurs at very low population densities in its natural habitat. It should not be confused with the Mexican bromeliad weevil, Metamasius callizona, which is currently attacking five species of native bromeliads in 16 counties and will likely destroy populations of six additional species of already threatened or endangered species of bromeliads if not brought under control. 

Description

The Florida bromeliad weevil is smaller than the other two species of Metamasius weevils currently found in Florida with the males slightly smaller than females. Adults are red and black with most of the thorax and upper half of the elytra being red, and they have two black spots about midway on the elytra.

There is some variation in the size and shape of these spots, and occasionally two additional smaller black spots are present above them. In Osceola County, a darker color form has been seen, which is nearly all black except for a thin red line on the thorax dorsally and red coloration on the head.

The Florida bromeliad weevil can easily be distinguished in the adult stage from the Mexican bromeliad weevil, Metamasius callizona, and the cane weevil, Metamasius hemipterus, by both size and coloration. Larvae of the three species are similar in appearance, except that mature larvae of M. mosieri are smaller than those of the other two species.
Credits: B. Larson, University of Florida Adult Metamasius mosieri, the Florida bromeliad weevil.

Host Plants

In Florida, the weevil has been found most commonly on Tillandsia balbisiana, T. utriculata, T. variabilis, and T. setacea, although it also occurs on several additional species of native bromeliads, including T. fasciculata, T. simulata, T. paucifolia, T. flexuosa, T. bartramii and the natural hybrid T. x smalliana.

When it occurs on larger species such as Tillandsia utriculata and T. fasciculata, it appears limited to seedlings and immature individuals of those plants.

It has also been observed in growers shade-houses to attack some small species of Tillandsia exotic to Florida, including T. bergeri, T. bulbosa, T. concolor, T. geminiflora, T. gardneri, T. hondurensis, T. ionantha, T. jucunda, T. rhomboidae, T. streptophylla, T. stricta and T. vernicosa.
B. Larson, University of Florida
Pictured; Tillandsia balbisiana Schultes, one of the principal host plants of the Florida bromeliad weevil, Metamasius mosieri Barber.
For more information, see Florida Native Bromeliads Illustrated.

Biology and Damage

Development time appears to be longer than that of the Mexican bromeliad weevil. Observed development time under ambient conditions in St. Lucie County from egg to adult has ranged from 18 to 22 weeks. All stages of M. mosieri maintained in St. Lucie County have been observed to survive four-to-six-hour periods of freezing temperatures, 30 degrees F, as well as temperatures up to 96 degrees F. The weevil remains active at temperatures between 55 degrees F and 90 degrees F.

Adults feed externally on leaves, and they may also feed on flowerstalks and inflorescences as do adults of other weevils that are specialists on bromeliads. Females of the Florida bromeliad weevil deposit eggs singly.

The eggs, which are approximately 3 mm in length, have been found both on the surface of leaves in the center of the plant and within slits in the leaf made by the female.

Females generally lay one egg per plant, and when more than one are laid on a single plant, cannibalism in the larval stage usually reduces the number of individuals to one plant. Adults are known to survive at least eight months under ambient conditions in St. Lucie County, and females have been observed to continue laying eggs for at least seven months.

Upon hatching, the larvae eat through the outer layer of leaf tissue. Larger larvae, which grow to approximately 11 mm in length, chew through the leaves in the center of the plant, less frequently tunneling into the base of the plant as do the larvae of the Mexican bromeliad weevil. Larvae have also been observed mining the flowerstalks of mature plants without killing them.

As the larvae feed in the center of the plant, they push shredded leaf material up, forming a plug between the leaves, which probably serves as protection against desiccation or natural enemies.

Pupation occurs within the plant, often just below the plug, inside a cocoon constructed by the larva from shredded leaf tissue.

Approximate time in the pupal stage under ambient conditions in St. Lucie County has been observed to be two to three weeks.

While damage to individual plants from Metamasius mosieri is considerably less than that from Metamasius callizona, the Florida bromeliad weevil has been reported killing plants of several native bromeliads in Florida. However, its effects on bromeliad populations are generally insignificant, because the Florida bromeliad weevil is found in low population densities and largely attacks seedlings and immature plants. Greatest damage in natural areas has been observed in St. Lucie County in bromeliad populations already affected by the Mexican bromeliad weevil, M. callizona. The effects of M. callizona presence on population dynamics of M. mosieri are still unclear. In addition to the plug that can be seen in the center of most infested plants, chewing on the base of central leaves serves as a sign of the presence of the Florida bromeliad weevil.
Credits: B. Larson, University of Florida

Management


In natural areas. the Florida bromeliad weevil does not damage host plant populations enough to warrant management efforts. In bromeliad nurseries or private collections, it is a very infrequent and minor pest.

If necessary, it can be controled with a reduced concentration of an insecticide labeled for beetle adults and grubs, applied as a spray or dip every two to three months to prevent infestations.

This recommendation is based on general principles and not on specific efficacy data, since no chemical trials of any pesticide have been carried out against the weevil.

Selected References

Howard Frank [email protected] 

Barber, H.S. 1920. A new tropical weevil from Florida and Cuba.
Proc. Ent. Soc. Washington 22:150-152

Creel, O.R. 2000. Up-close and personal with the evil weevil:
One man's encounters with Metamasius callizona. April 2, 2001
http://www.fcbs.org/articles/olan_creel.htm

Frank, J.H. 1999. Bromeliad-eating weevils.
Selbyana 20:40-48

Frank, J.H. and M.C. Thomas. September 2000.
Weevils that eat bromeliads.
http://bromeliadbiota.ifas.ufl.edu/wvbrom.htm

O'Brien, C.W. and M.C. Thomas 1990.
The species of Metamasius in Florida (Coleoptera, Curculionidae).
Fla. Dept. of Agric. & Consumer Services, Division of Plant Industry,
Entomology Circular No. 330.

Vaurie, P. 1966. A revision of the Neotropical genus Metamasius
(Coleoptera, Curculionidae, Rhynchophorinae). Species groups I and II. Bull.
American Mus. Natural History. 131:213-337.

Footnotes

1.This document is EENY-209 (IN366), one of a series of Featured Creatures from the Entomology and Nematology Department, Florida Cooperative Extension Service, Institute of Food and Agriculture Sciences, University of Florida. Published: May 2001.
Revised: August 2007. Reviewed: March 2008. This document is also available on the Featured Creatures Website at:
http://creatures.ifas.ufl.edu
Visit the EDIS Website at http://edis.ifas.ufl.edu

2. Barbara Larson, J. Howard Frank, Entomology and Nematology Department,
University of Florida, and Olan Ray Creel.

The Institute of Food and Agriculture Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national orign, political opinions or affiliations. For more information on obtaining other extension publications, contact your county Cooperative Extension service.

U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Larry Arrington, Dean.
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Copyright Information

This document is copyrighted by the University of Florida, Institute of Food and Agriculture Sciences (UF/IFAS) for the people of the State of Florida. UF/IFAS retains all rights under all conventions, but permits free reproduction by all agents and offices of the Cooperative Extension Service and the people of the State of Florida. Permission is granted to others to use these materials in part or in full for educational purposes, provided that full credit is given to the UF/IFAS, citing the publication, its source, and date of publication.