Figure 1 : Pupa - Larvae - and Adult of the Midge
Midges
In Manatee County, there is an insect most commonly mistaken as a mosquito called the midge. The midge belongs to the family of flying insects called CHIRONOMIDAE . They are small (some are very small), delicate, and somewhat mosquito-like in appearance (See Figure 1). The larvae of midges are aquatic, living in the soft organic bottoms of bays, lakes, ponds, even lagoons. The adults often occur in swarms in areas near to their larval aquatic habitat. Although harmless and non-biting, chironomid midges are readily attracted to lights and some can easily penetrate ordinary window screens. Lake-front homes, sporting facilities, recreational areas and businesses can be blanketed with the insects after times of peak emergence. Since they have a short life span the accumulation of dead midges around a home can cause some distress. Because of these reasons, midges become a matter of public concern.
While the Chironomid midge family has about 670 North American species, they all have the same general life cycle. The life cycle consists of the egg, 4 larval instars (growth stages), the pupa, and the free- flying adult. The eggs are dropped in masses (up to 3,000 eggs) onto the surface of the water. Here they absorb water, swell and eventually sink to the bottom. Young larvae hatch and are usually mobile. Eventually they build silken tubes to live in and dwell within the first 2-3” of fine muck bottom. Algae, plankton and detritus serve as a food source for larval midges. This larval stage constitutes the longest part of the life cycle, lasting from several days to over a month long in some cases. Larvae cease feeding at the end of the larval stage and pupate within their tubes. (The pupa stage is similar to the cocoon stage of a butterfly). Pupae rise from the tubes and actively swim about before rising to the surface for emergence into the adult stage. Adults fly with the wind to the nearby shores where males form swarms. Females fly up into the swarms, where they are clasped by the male to mate. Upon release they return toward the water to lay their eggs. The females die shortly after egg deposition, living only a few days. Although there are generally synchronous emergences of adults resulting in peak nuisance numbers, first generation emerges with the warmer temperatures of spring, followed by two or more generations during the summer months. The intensity of the midge populations seem to fluctuate from year to year, probably due to the difference in weather or environmental conditions.
Control of midges has been very ineffective. Nearly all attempts at control have yielded poor results at best because of the types of habitat that they breed in and their habits once they are adults. The problems with larval control are tha, in general, the larvicides available are relatively ineffective against midges. This is probably because they are protected within their tubes in the soft mud and the pesticide is diluted by the large amounts of water in the breeding habitat. Likewise, adult control is also nearly as impossible. The adult midges tend to congregate on the lee-side of any obstruction (i.e., Homes, bushes, cars, etc.). Any type of area wide spray, even aerial spraying, does not reach the adults where they are swarming, and thus has no effect. An additional problem is that, since the adults are continuously emerging and replacing any that would be killed, any reduction would be short lived. Area type spraying has been tried in many areas around the country with virtually no success. All things considered, the most effective measures against midges are ones that the homeowners can do themselves. Most of these do not require the use of pesticides.
1. Avoid outdoor and bright lighting near open windows. Midges are attracted to light and would be more likely to come in a window by a light.
2. Close windows on the leeward side of house. Remember - they are trying to get out of the wind. So make it less accessible for them in these areas.
3. Spray resting & swarming midges with water from a garden hose & nozzle. Water pressure out of such a nozzle can kill resting midges. This will give some temporary relief from the adults that are swarming on structures and wash away the dead ones.
4. Temporary spraying of swarming midges. Spray swarming midges and yard area with “Yard Guard” or other area type spray. (Use as directed on the label.) This will kill the existing adult midges just as #3 above, however, this becomes more expensive than using a hose and water.
5. Residual spray of resting areas using insecticides. Spray resting areas such as bushes, grass. etc. where adult midges would rest, with a more residual pesticide. These can be purchased at a hardware or home & garden (Lowes, Home Depot) center for homeowners use. Follow the directions for treating adult flies. This should control the midges that are there and provide some residual to kill incoming midges.
Figure 1 : Pupa - Larvae - and Adult of the Midge
For More Information: http:edis.ifas.ufl.edu/IG092
No-See-Ums (Sand Gnats)
No-See-Ums belong to a group known as the Culicoides. They are a small dark colored fly about the size of a pinhead. Mostly, they aren't seen, but their presence is noticed by the painful, burning sensation produced by their bite. No-See-Ums can be found throughout Manatee County, however larger numbers predominate where there is significantly more breeding habitat (coastal salt marshes). While peak activity times are dawn and dusk, they seem to remain active during periods of high humidity.
Stable Flies
Also known as the Horse Fly, the Stable Fly is a small biting fly very similar in appearance to the common House Fly. Stable flies can be intolerable inflicting their painful bite on humans; they can become a major problem to many of the horse farms. Large numbers of Stable Flies can be produced in piles of straw or hay that become moist from decay. Additionally, coastal areas can breed Stable Flies in piles of eelgrass that wash up along the shoreline.
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