A Comparative Study Between Neem (Azadirachta indica Juss) Seed Kernel Oil and Eucalyptus (Eucalyptus camadulensis Dhn Leaves Oil as Insecticide Against the Tree Locust (Anacridium melanorbodon melanorbodon Walker: Acrididae).

Abstract

This study investigated the effect of oil extracted from Eucalyptus camadulensis Dehn. Leaves, and neem (Azdirachta indica Juss) seed kernel oil on the frequency of moulting, feeding, deformation (%), oviposition % and mortality (%) of the treelocust Anacridium melanorhodon melanorhodon, reared inside breeding cages under field conditions in Northern Kordofan (Umruaba), in seasons 1996, and 1997. Eucalyptus crude oil was extracted by the steam distillation technique, and neem crude oil. was extracted manually. The 1st, 2nd, 3rd and 4th instars were bred inside small cages (diameter 30  30  30 cm ), and the 5th, 6th and mature stages were bred inside big cages (diameter 30  30  50 cm). All instars of the tree locust were treated with various concentrations of botanical oils. The 1st instar was treated with botanical oils at concentrations 0.5, 0.7, 1.0, 5.0 (%). The 2nd, 3rd, 4th, and 5th instars were treated with botanical oils at concentrations 0.5, 1.0, 5.0 and 10.0 (%). The 6th and mature stage were treated with 1.0, 3.0, 5.0 and 10.0 (%) in season 1996. In season 1997, 1st and 2nd instars were treated with Eucalyptus oil at concentrations 2.0, 5.0, 8.0 and 10.0 (%). The 3rd and 4th instars were treated with Eucalyptus oil at concentrations 3.0, 5.0, 7.0 and 12.0 (%). The 5th, 6th, and mature stage were treated with 4.0, 7.0, 12.0 and 15.0 (%) of Eucalyptus oil. Neem oil treatments were replicated as in season 1996. The results indicated that, the frequency of moulting of the 1st instar was significantly P (<0.0 I) reduced by neem and Eucalyptus oils treatments. The frequency of moulting of the 2nd, 3rd, 4th and 5th instars was significantly p (<0.001) reduce when treated with neem and Eucalyptus oils (10.0%). There was a significant correlation (r = 0.91, p < 0.00I) between Eucalyptus oil treatments and frequency of moulting of the 3rd instar. Eucalyptus oil treatments showed significant correlation ( r = 0.91, p < 0.001), ( r = 0.89, p < 0.01), ( r = 0.95, p < 0.01) and (r = 0.91 p < 0.001) with the frequency of moulting of the 3rd, 4th , 5th , and 6th instars respectively. Feeding of the 4th instart was significantly p(< 0.00I) decreased at 10.0% neem oil. Neem oil treatments also showed significant (r = 0.88, p < 0.01) correlation with the amount of feeding of the 4th instar. Deformation (%) of the 41.11, 51.11, and 6th instars was significantly increased P (< 0.00I), when treated with neem oil (10.0%). Ovipositor (%) of females was significantly decreased P (< 0.01) at 10.0%. Mortality (%) of the 2nd, 3rd, 4th, 5th, 6th and mature stage significantly increased P (< 0.00 I), at neem oil 10.0% treatment Neem oil treatments showed significant correlation ( r = 0.89, p < 0.01), (r = 0.82, p < 0.05), = 0.93, p < 0.01), and (r = 0.93, p < 0.01) with mortality (%) of the 1st, 2nd, 4th and 6th instars respectively, season 1996. Frequency of moulting of the 1st, 2nd, 3rd 4th and 5th instars was significantly decreased, when they were treated with botanical oils. There were significant correlation ( r = 0.94, p < 0.01 ), ( r = 0.91, p < 0.03 ), ( r = 0.96, p < 0.008 ) and (r = 0.90, p < 0.03) between Eucalyptus oil treatments and frequency of mortality of the 2nd, 3rd, 4td and 6th instars, respectively. Amount of feeding of the 4th and 5th instars was significantly p (< 0.001). decreased at neem and Eucalyphis oils (10.0%) treatment. Neem oil treatments at concentrations 1.0, and 5.0% significantly p(< 0.05) increased the deformation % of the 5th instar. However, neem oil treatment at concentration (1.0%) has a significant p (< 0.05) effect on deformation (%) of the 6th instar. Neem oil treatments showed significant correlation (r = 0.90, p < 0.03) with deformation (%) of the 4th instar. Ovipositor (%) of the females decreased with increasing concentration of neem and Eucalyptus oils. Oviposition of females was completely prohibited, when they were treated with Eucalyptus oil (15.0%). Neem oil at 10.0% showed the same impact. Mortality (%) of the 1st, and 2nd instars significantly increased at all neem and Eucalyptus oil treatments. The 1st and 2nd instars showed 45-90% mortality, when they were treated with 10 % botanical oils. Mortality (%) of the 3rd instar significantly P (z< 0.005) increased at Eucalyptus oil (12.0%) treatment, and the mortality of the 2nd instar significantly P (z< 0.001) increased at neem oil (10.0%) treatment. Mortality of the 4th instar significantly increased at P (z< 0.01), and P (z< 0.005) when treated with Eucalyptus oil (10.0%), and neem oil (12.0%) treatments respectively Mortality (%) of the 5th, 6th, and mature stage significantly increased P(z<0.01), P(z<0.002), and P(z<0.001) at Eucalyptus oil (l5.0%) treatments respectively. Mortality of the 5th, 6th and mature stage significantly increased P(z< 0.001) at neem oil (10.0%) treatment respectively. Neem oil treatments showed a significant correlation ( r = 0.93 , p < 0.03), (r = 0.77, p < 0.004) with mortality of the 1st, and 5th instars respectively season 1997. Eucalyptus oil treatinents showed significant correlations (r = 0.96, p < 0.007), (r =0.97, p< 0.006), (r = 0.88, p< 0.04), and (r = 0.97, p < 0.003) with the mortality of the 2nd, 3rd, 5th and mature stage respectively, season 1997.