Impact of gamma irradiation and phenol on the biological activity of the cotton leaf worm, spodoptera littoralis (Boisd.)‎

Abstract EN

Gamma irradiation and Simple Phenole could potentially be used as a new approach to control the cotton leaf worm, Spodoptera littoralis (Boisd.).

Inherited sterility (IST) technique using sub-sterilizing doses of gamma irradiation and/or different concentrations of phenol were tested on the biological activity of S.

littoralis.

The biological aspects included egg hatchability; larval mortality pupation, survival, adult emergence, sex ratio and longevity were tested.

It was noticed that the phenol concentrations (2.5 and 5%) and sub-sterilizing dose of gamma irradiation 100Gy were the most promising for combination treatment.

The results indicated that the combined treatments drastically decreased the percentages of pupation and survival more than separate treatments, to reach 3.0 and 2.0%, respectively in the case of 100Gy+ 5%.

Also, the deleterious effect of combined treatments on growth inhibition, relative growth index, growth index was sharply decreased in F1 generation than each treatment.

The reduction of F1 progeny in combined treatments was higher than could be expected from the sum of .the two treatments.

It was concluded that insect suppression was more pronounced in the case of 100Gy+ 5% phenol than in the case of 100Gy+ 2.5 % phenol.

These findings indicate that the IS technique might be considered as an environmentally compatible alternative or supplement to the phenol for Spodoptera littoralis pests management.