Contact and feeding effects of chlorantraniliprole, methoxyfenozid and spinosad on some histological changes in cotton leaf worm Spodoptera littoralis (Lepidoptera : Noctuidae)‎

الملخص EN

The contact and ingestion effect of chlorantraniliprole, methoxyfenozid and spinosad on the 4th larval instar of Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae) were studied.

Half and a quarter off the recommended rates of three insecticides (Coragen, runner and spinosad) were prepared, and the two methods of contact and food contamination were applied in laboratory to compare their effects on the histo-formation of both the midgut and the integument of the 4th instar larvae S.

littoralis.

Histomorphological changes have been observed within 48 hrs.

in both applications (contact and/or ingestion) on the midgut and integument tissue formation of the treated larvae.

The treatment with the tested insecticides caused in general, destruction of both goblet and columnar cells of midgut.

Epithelial layer showed detached of the basement membrane, disorganized and accompanied by major vacuolization.

Separation of both basement and peritrophic membrane.

Lysis in the peritrophic membrane led to the mixing of the components of the lumen with the lysis cells of the midgut membrane.

It progressively degeneration in the epithelial lining of the midgut.

The tested insecticides affected the integument as disturbance with abnormal deposition showing different thickness, fissure in hypodermal cells and endocuticle distortion.

These histopathological effects are presumed to be responsible for the food utilization and reduction in growth caused by Runner, coragen and spinosad.

Therefore, be concluded that these insecticides have sublethal effects on S.

littoralis that may affect on the dynamic population.