| Popis: |
The cotton leaf worm Spodoptera littoralis (Biosd) treated as 4th instar larvae by LC50 of some plant oil formulations as neem, jojoba and orange oils to study the histopathological changes in male testes and female ovaries of adult moths. The experiments started by some biological studies on the 4th instar S. littoralis larvae, the results showed that all the tested plant oil formulations achieved the greatest percent of adult malformations. Also, the previous formulations caused strongest effect in the adult fecundity and fertility reduction. This was followed by toxic impact studies on 4th instar S. littoralis larvae that fed on castor bean leaves treated by a series of successive concentrations of each formulate to determine LC50 and LT50 and calculated toxicity index for each formulate. The results concerning neem force (neem oil) was found to be the most effective plant oil formulate that recorded LC50 (0.095%) and the shortest LT50 (2.88 days). The results could be summarized as follows: 1) Neem oil formulation: Testicular follicle were indistinguishable, the contents of male testes separated from the epithelial membrane, in addition, sperm bundles were degenerated and scattered in testes compared with the control. Also, it reduced the size of female ovaries and appeared as clustered, while the nurse cell nucleus was dissolved or absent, the ovarian vacuoles appeared in the shrinkage oocyte compared with normal female ovaries. 2) Jojoba oil formulation: The histopathological effects were clearly observed in male testes and female ovaries of moths. Complete necrosis of all zones and germ cells became indistinct and the vacuoles were clearly seen along the whole testes. Also, ovaries exhibited different shapes and sizes. On the other hand, small vacuoles were found. Moreover, some oocytes nurse cells and their nuclei were shrinkage compared with male testes and female ovaries of the control. 3) Orange oil formulation: The epithelial membrane was separated from testes and became unclear as compared to some sperm bundles degenerated and the rest become scattered. While, the follicular epithelial of female ovaries were completely separated more than oocytes and the nurse cells were absent with abnormal oocyte shape. Also, the ovaries appeared in abnormal shape. |
