Abstract:
Laboratory experiments were conducted in the Department of Plant protection, College of Agricultural Studies- Shambat, Sudan University of Science and Technology (SUST).
The objectives of the study were to evaluate the lethal effects of the aqueous extracts and powders of Jatropha (Jatropha curcas L.) seeds, and Argel (Solenostemma argel (Del.) leaves, against the 3rd larval instars of the spiny boll worm, Earias insulana (Boisd), to test their effects on the rate of egg hatchability of the spiny boll worm.
Three concentrations of each of the powder and aqueous extracts of each plant were used in this study (5%, 10%, and 15%). The results of treatments of the powder from both plants Jatropha seeds and Argel leaves showed no effect on eggs hatching and larval mortality at all concentrations after 72 hrs. Concerning of the results of application of aqueous extracts on the larvae, the results showed that, all tested concentrations of both plants caused higher mortality percentage of the 3rd instars larvae of the spiny boll worm, in comparison with the control. The lowest concentration (5%) of seeds aqueous extract of J. curcas gave 50% mortality, and highest concentration (15%) gave 80%mortality after 72 hrs of exposure. Leaves aqueous extracts of S. argel at 5% and15% concentrations generated 46.6 % and 73.3% mortality, respectively after 72 hrs of exposure. The mortality percentage given from the standard insecticide was (100%).
Also, the results showed reduction of egg hatchability percentage on extracts than the control. The lowest and highest concentrations 5%, 15% of seed aqueous extracts of J. curcas reduced hatching to (35.5%, 13.3%) respectively after 72 hrs of exposure. The lowest and highest concentrations 5%, 15% of Leaves aqueous extracts of S. argel reduced hatching to (38.8%, 21%) respectively after 72 hrs of exposure, compared with the control which showed hatching percentage (82.1%).
The results of the present study indicated that, the aqueous extracts of the two plants Jatropha and Argel could be considered a cheaper source for active substances for the spiny boll worm.
