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DITCHLING CORPORATION LIMITED
"Supplying professional Pest Control products since 1964"
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DITCHLING CORPORATION LIMITED
"Supplying professional Pest Control products since 1964"
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Blackflies
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The Blackfly has four life stages - egg, larva, pupa and adult. The first three stages can only develop in free flowing water; they are found in rapids and even just below waterfalls. In the spring every stream and rivulet is a potential breeding place for Blackflies. Unlike the Mosquito which breathes at the water surface, Blackfly larvae and pupae obtain oxygen directly from the water. This explains the need of the Blackfly for well-aerated flowing water, whilst the Mosquito thrives in still water.
Breeding and developnig in running water make the Blackfly difficult to control, as most jurisdictions ban the use of Larvicides and Insecticides in running water.
Different species of Blackfly differ greatly in details of development, such as stage in which they overwinter, preferred water temperature for development, types of stream in which they live, number of generations per year, etc. Depending on species , Blackflies may have one or several generations per year. In the latter case. The number of generations may overlap , so that at a given time any of four life stages of a species may be present.
The very small eggs are laid on or in the water, or on rocks, weeds and other materials at or just under the water surface. Depending on species, each female can lay 200 to 500 eggs. Some species overwinter in the egg stage, and others as larvae. Eggs hatch into larvae which attach to stones, sticks or vegetation under water. Larvae may be dark brown, green or pale in color. When very numerous they cause the object to which they cling to have a slimy appearance. Larvae feed on organic matter they filter from the water; they shed their skin six times during development and when full grown are about 3/8" long.
Larvae spin cocoons which are attached to objects in the water. Cocoons vary in form. Larvae change into pupae within the cocoon. Pupae obtain oxygen from the water by means of filaments projecting from the cocoons. Depending on species and environment, total length of time spent by a Blackfly in water stages may be as short as two weeks or as long as several months.
The adult Blackfly emerges from the pupal skin and takes flight almost immediately. The adults are small, stout-bodied and hump-backed with short, broad wings and short legs.
There are about 100 species of Blackfly in Canada , but only a few are a major pest to man and domestic animals. Some species that seldom bite can be very annoying because of their habit of flying about the head and face. However, if they are not biting they are more of a psychological problem than a physical one. The life span of the adult Blackfly ranges from a few days to several weeks.
Like Mosquitoes, both sexes feed on the nectar of flowers. The female starts looking for a blood meal within two or three days after emerging. Unlike the Mosquito, the Blackfly bites only during the day. They bite not only the exposed skin of animals, but also invade the ears and nostrils and may even be the cause of death. In addition to biting exposed areas on man, they also crawl through small openings in clothing. Although the actual bite ma\y not be painful, swelling may occur later, and the area may remain sore and itchy for several days or even longer. In severe cases medical attention may be required.
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