Potential of Bioactive Plant Extracts against the Desert Locust (Schistocerca gregaria)

The severe agricultural pest is the Schistocerca gregaria, caused damages to all grasses. This study is to assess effects of plant extracts, Sabadilla (Schoenocaulon officinale), Limonene (Orange peels), Rotenone (Derris elliptica), Azadirachtin (Azadirachta indica) and IGR, precocene II against Schi. gregaria. The findings of 4th and 5th nymphal instars were impacted by the tested extracts where higher LC50 was 5.4 and lower LC50 was 7.7% by the effects of azadirachtin, rotenone and limonene, respectively, on 4th nymphal stage. While LC90 was 22.1 and 38.8%, of the previous extracts respectively. The higher and lower LC50 on 5th nymphal instar showed 4.1 and 6.2% while LC90 was 25.4 and 31.3% by effect of azadirachtin and limone, respectively. Longest 4th nymphal duration was 15.1 day by limonene at concentration of 20% and shorter, 10.4 days with rotenone at a concentration of 5%. Additionally, the highest lose weight was 256.5mg due to effect of limonene at concentration 20% while lowest weight of 4th instar was 351.2mg at oncentration 10% of limonene. Lowest weight of 5th nymphal instar was 356.2mg due effect of limonene at concentration of 5% and weight was 218.6mg by effect of rotenone at concentration at 20%. 4th Nymphal deformation was 29.4% at 1000 ppm and at lower concentration, 50 ppm caused 15.2%. Deformation of 5th instar was 33.6% and 12.2%, respectively at the previous concentrations. Adult deformation was 46.2% after treatment of 4th nymphal stages and 52.3% after treatment of 5th nymphal instars with the 1000 ppm.