الفهرس 
MATERIALS AND METHODS
Seed-germinationOnly 14 pages are availabe for public view
 |  | from | 124 |  |  |
| | | from | 124 | | |
Abstract
Since the first successful development of the synthetic
Pyrethrin, Allethrin by Dr. La Forge in 1947, a number of
workers has started the modification of the natural pyrethrin
which resulted in a remarkable change in its property.
Particularly, the potent and photostable pyrethroids have
been disclosed by the ~1orkers in Great Britain and Japan.
Thus these pyrethroids are able to use for agricultural pest
control in a large scale. (Nakajima, 1982).
The synthetic pyrethroids such as
Cyperrnethrin,
broad-spectrum
and Deltarnethrin are extremely
insecticides. Although their
permethrin,
potent and
toxicity to
mammals and birds is relatively low, they are extremely toxic
to fish and a variety of aquatic invertebrates. These
chemicals have low water solubilities and are photostable.
In , they are degradable via microbial hydrolysis at the
ester linkage (Khan, 1982).
Miyamoto and Mikami (1982) discussed the degradation of
the synthetic pyrethroids (Permethrin, Cypermethrin,
Deltamethrin, Fenvalerate and Fenpropathrin) in plant, soil
and the aqueous environment. The pyrethroids undergo a
variety of photochemical reactions including trans/Cis and~R
/O(S interconversions except Fenvalerate. ~!hen applied to the leaves of plants, they were
penetrated to the ssues to almost the same degree, but
little translocation to the untreated area occurred. When
plants are grown in the treated soil, again little
translocation of chemical to aerial parts of the plant
occurs.
The pyrethroids are degraded in soil mainly by
micro-organisms. Hydrolysis of the ester linkage together
with oxidation are the major degradation routes. The
products are further decomposed yielding from
radiolabeles at various positions of the molecules. The
pyrethroids are immobile and can not be leached with water
through soil, In the aqueous environment, pyrethroids were
rapidly removed from the aqueous phase by adsorption on to
sediments. (Miyamoto and Mikami, 1982},
Synthetic pyrethroids are toxic to the house flies,
Musca domestica L. (Taylor~ al., 1981), with no irritation
to nasal passage (Adkins e-t -al., 1971) and with no symptoms
of irritation to animals [Faraone ~ al., 1978}.
Synthetic pyrethroids are effective against larvae of
various species of mosquitoes {Mulla et al, 1980, and
Priester~ al., 1981), and to larvae and adults of the
Egyptian mosquito ~ pipiens k· (Gaaboub, and Abu-Hasbisb,
1981 ).Cypermethrin is also toxic to: larvae of the fall
armyworm (Mcclanahan, 1978), house flies and German
cockroaches (Scirocchia and Cesaroni, 1979); onion, seed-corn
maggot flies and dark sided cut vmrm (Harris and Turnbull,
1980).
In the fields of wheat, shoot fly,
Steyskal damage was effectively controlled
of Cypermethrin during the early growth
crop. (Singh and Saxena, 1 981 ) •
Atherigona nagvii
by foliar sprays
phases of wheat
Cypermethrin used as field treatments of silage
significantly reduced corn borer damage (Ostrinia nubilalis)
and increased dry matter yield than untreated plots (Raemisch
and Walgenbach, 1983 and 1984).
In mamals, Cypermethrin is
distributed, and metabolised.
ester linkage and subjected to
It is
readily absorbed,
readily cleaved at the
oxidative degradation and
conjugation of the metabolic products. Elimination from the
body following acute and subecute administration is rapid.
(JMPR, t 979).
In a wide variety of studies, there was no carcinogenic
or mutagenic potential as evidenced by short-term bioassays
or long-term chronic study (JMPR, 1979). However,
Cypermethrin showed mutagenic potential in our studies. In
6one study, oral administration of the insecticide at a
dietary level of 900 ppm for 7 and 14 consecutive days as
well as double and multiple (Total 41 dermal treatments (360
mg/kg body wt.) induced a statistically significant increase
in the frequency PEs •~i th micronuclei in mouse bone marrow
(Amer and Aboul-Ela, 1985).