Many environmental factors, biotic and abiotic interact to
influence organismal development. Aquatic plants are considered as
important environmental factors. Duckweed considered plants and
grasses aquatic that most widely used water in the world for its ability
to grow and reproduce greenery in aquatic habitats and various
breeding sites of mosquitoes. Effect of the aquatic Lemna minor on
the development and survival of Culex pipiens mosquito immature
was investigated under laboratory conditions. Duckweed plants were
used as low (15 plants/cm2), medium (25 plants/cm2) and high (35
plants/cm2) density on the surface of the water. The results showed
the presence of aquatic plants duckweeds was affected larval
development and survival of Culex pipiens, where they reach 11.4, 12
and 19 days of larval duration at non-plant, low and high plant
density, respectively. Survival of larval and larval-adult stages of
mosquito shortened as the plant density interval increased (%:
47.16±2.84 and 32.93±0.87) compared to the absence of plant
(94.83±0.83 and 95.87±1.35). Analyses data indicated a high density
mats of duckweed plant was marked inhibitory effect on mosquito
breeding. The attractiveness of oviposition site for vector mosquitoes
is dependent upon a number of physical and chemical factors. Cage
tests in the laboratory indicated that the plant could be a suitable
breeding place for gravid females especially at polluted sites (F=
19.705, P= 0.0001). The suggestion is made that the aquatic plant
might be considered as a natural vector control measure in certain
types of breeding places.