The cotton leafworm, S. littoralis, is a major pest in Egypt
causes severe quantitative and qualitative losses of cotton and
other economic crops. This study examined the effect of chitin
synthesis inhibitors, lufenuron (match 5%) on the 2nd instar larvae.
The results showed that lufenuron caused not only mortality in
larval stages, but also caused effect on pupal and adult duration,
adult fecundity and egg fertility. Also lufenuron treatments have
resulted in emergence of deformed pupae and adults. PCR-RFLP
technique was used in this study to investigate the effect of
lufenuron on the vira-like chitinase gene, one of the genes
involved in the formation of chitin and concerned with
development of insect. The endonucleases Spel, EcoRI and
Bbsl were used to detect the molecular changes at different
time intervals 6, 12, 24 and 48hrs post treatment with
sublethal doses LC25, LC50 and LC90.The results showed
significant changes in the sequences of the treated groups
which were dose and time dependants. Moreover the number of
RNA secondary structure stems was varied in the different studied
groups and most of them differed in their nucleotide sequences,
positions and free energy. |
