Chemical-Free Mosquito Control

Using nature to solve natural problems is a sound idea. This is particularly true for . .

A mosquito develops through four stages—egg, larva, waterborne pupa, and emerging adult—and it's helpful to know where the life cycles of various types of mosquitoes take place in order to understand how to deal with -our particular insect problem. Species can be grouped more or less into three categories, according to breeding-site preferences.

The Permanent Pool Group: Most species in this class inhabit bodies of fresh water—particularly quiet pools with abundant surface vegetation. Such spots include not only permanent ponds but also semipermanent sites such as roadside ditches, pits, canals, clogged streams, and irrigated lands. Breeding is continuous, and several generations are produced each year. The adults' flight range extends one to two miles tom the breeding site. Species in this group can carry encephalitis, dog heartworm, and in some cases malaria.

The Floodwater Group: These mosquitoes usually appear early in the season, with most species producing several broods per year. They breed in receding pools, on damp soil in grassy depressions, or along grassy shorelines that are intermittently flooded. The eggs are laid, the wet area dries out, and large numbers of larvae hatch with the next flooding. The adults' flight range extends five to twenty miles from the breeding site, and species in this group have been known to carry dog heartworm.

The Artificial Container/Tree Hole Group: These insects prefer to lay their eggs in small, water-filled places—birdbaths, such litter as old cans and jars, and other man—made containers, as well as holes in trees. Species in this group produce several broods per year. The eggs are laid on the inner surface of the container or tree hole at or above the waterline, and they hatch when inundated after a dry period. In general, the habits of these mosquitoes are similar to those of the floodwater group.

PHYSICAL CONTROL

The destruction of breeding habitats is one of the most basic ways to combat mosquitoes. Several courses of action, such as the following, can be taken.

[1] Making a pond's shallow shore steeper or deeper is effective, since it's unlikely that mosquitoes will breed in water over six inches deep. Dredging to this depth or attaining a slope ratio of 3:1 has been found to deter the establishment of vegetation and breeding conditions.

[2] Remove weed growth in shore areas to destroy the larvae's protection and food source.

[3] Fill in depressions and potholes with soil or other compactible material to eliminate these breeding areas.

[4] Drain standing water. This can be accomplished through open ditching, the use of subsurface drains, or pumping.