Mosquito Borne Viruses Pose Potential Threat to Florida/Polk County

Aedes albopictus - Asian tiger mosquito
(photo by James Gathany)

Aedes aegypti adult (photo by James Gathany)

Both dengue and chikungunya are viral diseases whose vector is the yellow fever mosquito - Aedes aegypti. Chikungunya has as an additional vector, the Asian tiger mosquito (Ae. albopictus). Both Ae. aegypti and Asian tiger mosquito occur in Polk County but Ae. aegypti is much more common in the urban areas of south Florida.

Both species are container-inhabiting mosquitoes; often breeding in unused flowerpots, spare tires, untreated swimming pools, and drainage ditches. They thrive in urbanized areas, in close contact with people making them exceptionally successful vectors. Ae. aegypti bite during the day both indoors and outdoors while the Asian tiger mosquito bite mostly at dawn and at dusk.

The Florida Department of Health, recently reported that dengue fever had been confirmed in 24 people in Florida and chikungunya confirmed in 18 people. All of the infected people in Florida had traveled to the Caribbean or South America and could have become infected there, according to Walter Tabachnick, director of the Florida Medical Entomological Laboratory in Vero Beach.

The Florida Department of Health fear that individuals who become infected while traveling could pass the disease on to localized populations of either vector when they return to Florida which could result in a state epidemic.   

Localized epidemics of dengue occurred in 2013 in a small neighborhood in Jensen Beach where 24 people were infected, and in 2009 and 2010 in Key West where 28 people were infected, according to state and federal reports.

The Caribbean Public Health Agency said this week that authorities in 18 Caribbean countries or territories had reported more than 100,000 confirmed or suspected cases of chikungunya.

A key feature shared by both dengue and chikungunya is that the fever comes on sharply about a week after exposure and lasts about a week. Dengue fever classically is accompanied by a headache, eye pain, prominent muscle aches, and swollen lymph nodes. Similarly, chikungunya features prominent headache and swollen lymph nodes, but instead of the muscle pain that is so characteristic of dengue, chikungunya entails marked joint pain and arthritis. A flat red rash that is covered with small confluent bumps is common beginning on about day 3 in patients with chikungunya, especially so in children.

At the present time there is no vaccine for either of these two virus diseases. Unfortunately some infected individuals may experience symptoms for months even years after infection. There are no specific medicines for these diseases. Using medicines other than aspirin may help to lower joint pain and fever.

There are several steps individuals can take to reduce localized mosquito numbers. Because these mosquitoes are container-inhabiting mosquitoes, one of the most successful and cost-effective methods to reducing populations is by preventing containers around the home from collecting water. By turning over empty flowerpots, properly maintaining swimming pools, and removing unused tires, you can greatly reduce the number of places mosquitoes have to lay eggs. Aerate birdbaths and make sure gutters are free of blockages. Clean pet bowls every day and always empty overflow dishes for potted plants.

For personal protection from bites, apply an insect repellant (DEET, picaridin, IR3535 and oil of lemon eucalyptus), and wear long pants and long sleeves when outside. Wear permethrin-treated clothing to repel and kill mosquitoes. Make sure door and window screens are intact. For more information on mosquito management, please visit the Florida Medical Entomology Laboratory mosquito management website at: http://mosquito.ifas.ufl.edu/Mosquito_Management.htm.

For information regarding mosquito management devices for the home, see http://edis.ifas.ufl.edu/in171

 

 

 

 

 

Flatid Planthopper on Cabbage Palm - A Vector for Texas Phoenix Palm Decline?

Flatid planthopper (photo by D. Hazelbaker)

This flatid planthopper, Ormenaria rufifascia, is a common insect on some species of palms in Florida. The natural hosts of this planthopper in Florida are probably cabbage palmetto, Sabal palmetto, and saw palmetto, Serenoa repens, both native to this state, but this insect is sometimes seen on other palms.

 Although it is usually not a serious pest, it sometimes indirectly causes aesthetic damage when dense populations produce honeydew that supports extensive coatings of sooty mold on the host plants. Both the adults and nymphs are conspicuous insects that often arouse people's curiosity.

It has been reported throughout the Florida peninsula and in Georgia. It may occur throughout the range of cabbage palmetto and possibly of saw palmetto - Florida and the Gulf Coast west to Louisiana and the Atlantic Coast north through the Carolinas.

The adults are rather large for planthoppers i.e., about 1/2 in length. They are highly conspicuous when seen on their usual feeding site, the lower surface of fan-leaf palms. They appear as tiny colorful sailboats. Their color is light blue-green, with various orange to reddish markings. There are no other species of similar appearance known to occur on palms in Florida, and very few species of Flatidae occur on palms anywhere in the world.

Both the nymphs and adults tend to occur on older rather than younger leaves, a behavioral trait that is characteristic of many insects that feed on palm leaves. The fact that the older fronds of palms are more or less horizontal and thus offer protection from sun and wind may be a factor in their being preferred by many kinds of insects.

Like the vast majority of species of the insect order this planthopper feeds by sucking plant juices, and thus draws energy from the plant. The populations of this insect usually do not consist of more than several individuals per frond, but dense populations may occur from time to time. As evidence, highly infested fronds are sticky with honeydew which supports thick crusts of sooty mold.

Populations of this insect are generally sparse and control measures would seldom be needed. The species has not been considered economically important enough to justify research on chemical or other methods of controlling it. In cases in which a few specimen palms become highly infested with this insect, it may be possible to eliminate them by simple physical means, such as a strong water spray.

This planthopper has recently has been suspected as a vector of Texas Phoenix Palm Decline of cabbage palms, but certainly not proven. If this insect is a vector for TPPD, it would be very bad news for cabbage palms as their range extends up through Florida into Georgia, the Carolinas and west to Louisiana as does this insect. So in effect every cabbage palm in the above areas could eventually be in danger of infection.  

Flying Stinging Ants

Winged Swarmer With Stinger

A few years ago, 2007 I believe, many Polk County residents were pestered by a stinging flying ant. I don’t think this insect has officially been given a common name, but the scientific name is probably Hypoponera punctatissima or a related species. This species is pretty common in many counties in Florida, but is seldom noticed or posed a problem for humans.  The Extension Service was first alerted by residents in the City of Auburndale about being attacked by flying stinging ants. Little League baseball games in northern Polk County had to be cancelled and the Juvenile Assessment Center in Bartow had to have outside activities cancelled just to name a few occurrences. Since 2007 no other complaints about this insect have been reported to the Polk County Extension Service. However, this last weekend I received an e-mail from a resident of Punta Gorda who had been stung by flying ants - probably the same species. So, we may see them again this year in Polk County.

This is one of the very few swarming ants in Florida which have stingers and can inflict a painful sting. They are very aggressive during mating flights and can work their way under human clothing and sting at will. The sting can lead to a painful welt. They are not specificaly attracted to people as are mosquitoes, yellow flies, etc., they are just looking for a new nesting site and people happen to get in the way. They normally nest in soil or under objects resting on the ground, like potted plants, bags of soil, and toys. They also will nest in trash piles, rotten wood, and grass tussocks.  They often are found in wet areas. The workers do not sing or bite as fire ants do. They hunt live insects for food.

There really aren't any control recommendations for this ant in the winged stage, unless you can find the colony where they are coming from.  Since they are just dispersing from their nest and are not attracted to people, repellents are not going to be very effective.  Their flight season is during warm, humid weather – the duration of the dispersal flight is not known. During 2007 in Polk County, the problem subsided after a week or two - maybe less.

 

Don’t confuse this ant with the elongate twig ant which is long and skinny and spends much of its time in trees. They commonly drop out of trees and land on people and can make their way under clothing. They have a ferocious bite something similar to fire ant bites. These are worker ants foraging for food – they do not have wings. The elongate twig ant winged swarmer’s do not sting.

 

Azalea Caterpillar

Adult azalea caterpillar moth
(photo by James Baker)

The azalea caterpillar, Datana major G & R, is found in Florida from July through October on azaleas. Often, the caterpillars completely defoliate much of the plant before they are detected. So, take a good close-up look at your azaleas right now! While the caterpillar appears hairy, it is harmless to humans and can be picked off the bushes by hand.

The caterpillar is found in Florida as far south as Polk and Hillsborough Counties and azaleas are the only known hosts in Florida.

Eggs are deposited by the female moth in late spring in masses of 80 to 100 on the underside of the leaf. 

azalea caterpillar (UF photo)

The first instar caterpillars feed in a cluster side by side unless disturbed. The first instar caterpillars are approximately 3/8 inch long after feeding for eight to ten hours. They remain gregarious and soon devour the entire leaf.   

The first instar caterpillar is yellow with seven red longitudinal stripes and a black head. As the larva matures it becomes highly colored. The mature caterpillar is about two inches long, and predominately black, with a red last segment and eight broken yellow (occasionally white) lengthwise stripes. The head and legs are mahogany-red.

The adult moth is light brown with a wing expanse of 1 3/4 inches. 

The semi-skeletonized leaves dry up, turn brown, and remain on the plant for several days. If disturbed some of the caterpillars drop one or two inches below the infested leaf and hang by a silken thread. When it is disturbed, the caterpillar raises its front and rear ends into the air. Young larvae skeletonize the leaves and the larger ones eat the entire leaf. In some parts of the South there may be a partial second generation, but one generation is usually the rule. It is thought to overwinter in the pupa stage.

Severe damage by azalea caterpillar
(photo by D Shibles)
 

Healthy azalea (photo by D. Shibles)

Most of the damage in the southeast United States occurs in August and September, but in Florida it continues through October. This caterpillar is pretty easy to control with commonly available pesticides such as Bug-Be-Gone Max (bifenthrin), Sevin (carbaryl), Orthene Insect Killer (acephate), Permetrol (peremethrin) and several others. More environmentally friendly products include Thuricide and Dipel (B.t. containing products) and Conserve (spinosad).

This time of year carefully inspect your azaleas for this pest. The caterpillars often go unnoticed until the damage is quite severe. Do not prune off branches with no leaves as the leaves will grow back in a few weeks. Any pruning at this time of the year will result in a loss of flower buds which are already forming on the leaf-eaten branches.

  



Caterpillars That Sting

The four major stinging caterpillars occurring in Florida are the puss caterpillar, saddleback caterpillar, Io moth caterpillar and hag caterpillar. Some less common ones also occur in the state. These caterpillars do not possess stingers, but have spines (nettling hairs) that are connected to poison glands. Some people experience severe reactions to the poison released by the spines and require medical attention. Others experience only an itching or burning sensation.

Saddleback Caterpillar

Saddleback Caterpillar (UF photo)

This is a very unusual and striking insect. It is brown with a green back and flanks, on which there is a brown, oval, central area that usually is bordered with white. The brown spot looks like a saddle, and the green area looks like a saddle blanket; hence, the common name. It may exceed an inch in length and is stout-bodied. The primary nettling hairs are borne on the back of paired fleshy protuberances toward the front and hind ends of the body. There is also a row of smaller stinging organs on each side. This caterpillar feeds on many plants, including hibiscus and palms.

Puss Caterpillar

Puss Caterpillar (UF Photo)

The larva is convex and stout-bodied, almost 1 inch long when mature, and completely covered with gray to brown hairs. Under the soft hairs are stiff spines that are attached to poison glands. When touched, these poisonous spines break off in the skin and cause severe pain. Puss caterpillars feed on a variety of broadleaf trees and shrubs, and are most often found on oaks and citrus. In Florida there are two generations a year, one in spring and the other in fall. Natural enemies keep these caterpillars at low numbers during most years, but they periodically become numerous.

 

IO Moth Caterpillar (UF photo)

Io Moth Caterpillar

This is a pale green caterpillar with yellow and red stripes. It often exceeds 2 inches in length and is fairly stout-bodied. The nettling organs are borne on fleshy tubercles, and the spines are usually yellow with black tips. They feed on a wide range of plants, but ixora and rose are their favorite hosts.

Hag Caterpillar



Hag Caterpillar (UF photo)

This caterpillar is light to dark brown. It has nine pairs (sometimes fewer) of variable-length, lateral spines, which bear the stinging hairs. These spines are curved, twisted and likened by some to the disheveled hair of a hag, for which it is named. It is found on various forest trees and ornamental shrubs, but is not as common as the other stinging caterpillar species.

 

Less Well Known Venomous Caterpillars

Flannel Moth Caterpillar



Buck Moth Caterpillar

Spiny Oak-slug caterpillar (UF photo)


 




 

 

First Aid

Place clear tape over the affected area and strip off repeatedly to remove spines. Apply ice packs to reduce the stinging sensation, and follow with a paste of baking soda and water. If the victim has a history of hay fever, asthma or allergy, or if allergic reactions develop, contact a physician immediately.