Photodegredation and mineralization of
pesticides has becomes the key concern of scientific community. The main cause
of Pesticide pollution is the excessive use of pesticides. Mainly in
agriculture Estimated 1 to 2.5 million tons of active pesticide ingredients are
used each year causing environmental pollution Pesticide pollution emerges as
the serious environmental concern. The nanotechnology plays an important role
for solving this problem using TiO₂ nanoparticles which could
successfully eliminate the harmful pesticide toxicity under the sunlight
radiation within a very short time. In this study three treatments of the 2^nd
and 4^th instars of laboratory strain of Spodoptera littoralis larvae
used and feed on three groups of cotton leaf plant the first group sprayed with
solution mixture of the methomyl and TiO₂ nanoparticles the second
group sprayed with methomyl alone the third group sprayed with distilled water
as control. The experiment was evaluated at 0, 3, 5, 7, 9 and 12 days after the
treatment. It is noticed that the insect feed on methomyl alone has large
percentage of mortality than the insects treated with mixture compared by zero
mortality % for the insects treated with distilled water. The mortality %
varied accord to the larval instar as for methomyl
alone the mortality % was 100, 100, 100, 100, 100, 80 and 100, 100, 100, 100,
100, 75 for 2^nd and 4^th instars
respectively. And mortality % for methomyl (TiO₂) NPs
mixture was 80, 70, 65,    60, 55, 50 and
100, 75, 60, 55, 50, 50 for 2^nd and 4^th
instars respectively. The
treatments had a latent effect on the biological activities of the insect as
adult and pupa longevity, fecundity, hatchability morphogenic abnormality and
pupal weight.