SY U. S. EPAR ET OF AGRICULTUE
.iBUREkU OF ENTOMOLOGY
D .. ivision of Insects Affecting hMan and Animals,
g p)49 F.C. Bishopp. In Charge
"SAND FLIES" AYID "PU.IES"
Biting midges, known as sandd flies," "sand gnats," "no-see-ums," "punkies," and by other names, comorisoe about 30 species of tiny blood-sucking insects. The most important of these occur where fresh-water streams permit entrance of salty tidal water. At different points along the South Atlantic and Gulf coasts the annoyance caused by blood-sucking midges seriously affects values or prevents development of water-front properties. Many inland localities, especially in the mountains, are infested with different species of midges which also limit outdoor seasonal activities and cause much discomfort to people. These insects also attack livestock and game animals. All of these midges are small enough to pass through the ordinary wire screen of windows and most of them are attracted to lights in residences. They are easily killed with the Commonly sold pyrethrum spray, but
suhamasr sreomne It is
such a measure is recommended only as a means of te.-ocrary relief from then. It is
much better to prevent development of these pests by measures directed against thei: breeding places.
There is mucnh yet to be learned about sand flies and their control, as it is only recently that the Bureau of Entomology began a systematic study of this problem. The work is still under way, and some of the methods of control suggested have not been tested thoroughly. No doubt others will be developed in the course of the work.
In general, the breeding places of blood-sucking midges are of two types-those in salt marshes and those in rot holes of trees. A hole in a shade tree can furnish a sufficient number of midges to amoy' the members of an entire household. It is a good idea to examine the shade trees about the house very carefully. If rotted holes are found they can be trimmed so as to permit them to drain. The trimmed surface should then be treated with creosote so as to prevent further rotting and permit healing, or the cavity can be filled with concrete. Creosoted pine sap, a waste product from plants which creosote pine lumber, can be used in treating rot holes. It is inexpensive and is highly toxic to midge maggots and mos-uito larvae. Tree holes which hold water are capable of breeding both mosquitoes and midges, but holes containing only the wet soil or decaying wood can breed bloodsucking midges. If kerosene or other surface-floath-ing oils are applied to rot bolef in trees for mosquito larvae, the midge larvae are not killed by the treatment. This is due to the fact that midge larvae infest wet decayed portions of the trees and are not obliged to come to the surface of the water.
The salt-marsh sand flies do not develop in rot holes of trees, but their
larvae are found in decaying leaves and silt along the edges of salt marshes, where there is dense shade and where there is no violent daily tidal action. Some larvae occur in crab holes of seepage areas near the edges of the marshes. The areas which produce sand flies are reached by salt water during the highest tides which "spring" up about once each month. Since the larvae require about 6 months or Longer for development into sand flies, it is practicable to direct control measures against the larvae in their breeding places. If trimming the trees so as to admit sunlight is considered undesirable, the shaded areas can be sprayed with creosote pine s. I should be us d at the rate of 50 gallons to 00 sq
feet of marsh1 me MAMAAM mmiS
UNIVERSITY OF FLORIDA
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Breeding areas in towns and cities, where the number of people affected and the property values warrant the expense, can be permanently eliminated by bulkheading and filling.
Some of the experiments of the Bureau of Entomology are showing that drainage ditches designed to prevent mosquito breeding in salt marshes tend to concentrate large numbers of sand-fly larvae in places where many of them are killed by drying or by the heat of the sun. It seems advisable to supplement such a natural control with a spray treatment. In wet ditches and along their banks in salt marshes most of the sand-fly larva can be killed by spraying with creosote oil thinned with kerosene, or by spraying with creosoted pine sap. At the present time it appears that one treatment during the autumn and one during the spring months should effect a high degree of control.
In a small experiment at Fort Pierce, Fla., the Bureau is using a dike to impound tidal waters on a mangrove marsh. The capturedwater keeps the sand-fly bre ing area (consisting of salt seepages) submerged so that sand-fly larvae are forcedto the edges of the water. The soil near the edges of the water is being sprayed with creosote oil thinned with kerosene. This diking and flooding experiment ap8&r promising for control of mosquitoes as well as satd flies, because minnows that are trapped in the impounded water feed upon mosquito larvae. Such a control method
promises to be helpful also in reclaiming a marsh by allowing the impounded area to collect soil.
Sand-fly breeding near small streams may be prevented by the use of tide gates across the streams. Such gates permit the fresh-water streams to flow during low tides but automatically close during the rise of tidal waters.
In the experience of this bureau, the use of repellents on the skin and on
window screens for protection against sand flies is not very satisfactory. If o dinary kerosene is applied to the screens it keeps some of the flies away for one
night. An application of pine oil is more satisfactory. Sand-fly annoyance is duced if the use of lights in bedrooms is avoided. Some oils applied to the s will give protection for 30 minutes to an hour or two. The oil of citronella
-monly employed against mosquitoes is not as effective as oil of camphor, oil of sassafras, or oil of pine. If glycerine is applied to the neck, face, and han it serves as a mechanical barrier in preventing sand flies from biting and ta the blood of man. As a lotion to relieve burning sensations which follow the of sand flies, 5 percent carbolic acid thoroughly mixed in glycerine maybe used,.
Experiments for control of salt-marsh sand flies are being carried on by D W. E. Dove, U. S. Bureau of Entomology, 403 P. 0. Building, Savannah, Ga.
June 15, 1933.