Ultraviolet light traps Sticky traps Jar or bag traps Window traps

Public Health Significance of Urban Pests 227 Perimeter treatments that use vaporized or liquid repellents or pesticides are just now being developed for flies, although various products on the market also claim effective- ness against mosquitoes. Jar traps and sticky traps have been used successfully to prevent or minimize the passage of flies, but the former would not be recommended for use in urban areas. Some pest management companies apply various pesticides and growth regulators to out- side walls of commercial buildings that might be used by flies as resting sites. Some of these sites are near rear entry doors and treatments are thought to prevent fly entry into the structure. The effectiveness of such treatments has not been evaluated.

7.8.8. Crack-and-crevice treatments

As the name implies, crack-and-crevice treatments are usually treatments with pestici- des placed in cracks and crevices of walls. Generally, however, these treatments do not apply to flies, because in most instances flies are not found in such locations. The excep- tion might be overwintering flies. If this is the case, standard liquid-formulation pestici- des could be used to kill the flies. If flies are entering a structure, the entryways should be closed, as suggested in subsection 7.8.3. If cracks in walls, around windows and under doors are large enough to allow fly entry, these should be repaired by the party respon- sible for maintenance.

7.8.9. Biological control

Biological control is not recommended at present for urban settings. This is because most of the available options work best against the immature stages of the fly and essentially, it is the adults that are causing the problems. If immature stages are found in temporary urban habitats, these can usually be eliminated quickly by nonbiological means. The exception might be their elimination in compost piles. The most promising biological organisms being investigated for urban use against adult flies are entomopathogenic fungi. A number of these have been identified and tested, but spore preservation techniques need to be improved, so spores remain viable in the field for long periods. This will allow the use of feeding or infection stations, where flies are attracted to bait and become infected with a fungus.

7.8.10. Attractants

Attractants are desperately needed for fly management in urban areas. Several housefly attractants are available for agricultural use, but these are in many cases too odoriferous for use indoors. Attractants for use indoors must compete well with common indoor odours, such as those from pastries in bakeries and meats in delicatessens. Commercial buildings in some locations are air-conditioned and the air inside can be completely repla- ced up to five times an hour. Thus, any attractants designed to be used with indoor traps must be dispensed in appropriate quantities. Various pest control companies have added housefly sex pheromones to the glue boards in their light traps as attractants; however, Flies 226

7.8.6. Traps

Many types of trap are used in urban areas for managing flies inside and outside of com- mercial and private dwellings. These include: ultraviolet light traps; sticky traps; jar or bag traps; window traps; and sticky tubes, tapes and ribbons.

7.8.6.1. Ultraviolet light traps

These traps attract flies with long-wavelength ultraviolet light and then either kill them by electrocution or trap them on boards covered with glue. These traps are the main method used by many commercial pest management companies to control flies in com- mercial establishments, particularly supermarkets and restaurants. They are not recom- mended for individual houses or apartments. There are many trap models to choose from; however, to maximize the number of flies captured, the location of their placement is critical. Whenever possible, traps should be mounted within a metre of the floor, and models having an open front with a direct display of the lights are generally most effec- tive. Traps that kill by electrocution should not be used indoors, especially in food pre- paration or consumption areas. When electrocution occurs, very small particles of the insects and any associated microorganisms are projected into the air where they may contaminate food or be inhaled by people Urban Broce, 2000.

7.8.6.2. Sticky traps

Several sticky flytraps are commercially available. These can be used in commercial loca- tions or in backyard garden areas to capture flies outside without pesticides. These traps are also suitable for surveillance work.

7.8.6.3. Jar or bag traps

These traps are charged with an attractant mixed with water to draw flies inside the trap, where they die. These traps can be used by commercial establishments, around trash com- pactors and in garbage collection areas. They can also be used outdoors by private indi- viduals – for example, in garden areas. No pesticides are used these traps.

7.8.6.4. Window traps

These traps can be used in commercial establishments and in homes, to capture flies that enter buildings and eventually come to the closed, glass windows. These are passive traps and flies attracted to windows eventually fumble down into the traps and become cap- tured on a sticky strip. Some of the traps fit in the corners of the windows, and others merely fit along the sill. Window traps capture the flies on glue boards out of view and without pesticides.

7.8.6.5. Sticky tubes, tapes and ribbons