The efficacy of Datura ferox (Fierce Thorn apple) leaf extracts against Yellow Sugarcane Aphid (Sipha flava) in the Zimbabwe Sugar Industry

The study was carried out to test the efficacy of Datura ferox (fierce thorn apple) leaf extracts against Yellow Sugarcane Aphid (Sipha flava) in the laboratory. Sequential exhaustive extraction was performed using three solvents of varied polarities and these included ethanol, hexane and ethylacetate. This was done to obtain crude extracts with components of a wide range of polarity. The most polar solvent yielded the highest followed by an intermediate polar and then non polar. This showed an increase trend in yield with solvent polarity. The laboratory experiment had three treatments which were extracts from different solvents. Different concentrations were prepared using the N₁V₁₌ N₂V₂ method. Acetamprid (Allice) was used as the standard/ positive control and pure solvents were also used as negative controls. To test for the toxicity of the extracts, the filter paper method was adopted and petri dishes were used to confine the aphids. Aphid numbers between 50 and 70 were chosen. Mortality was recorded after 3, 24 and 36 hours. LD₅₀ and LD₉₀ were calculated in excel. Ethanol extracts showed the highest efficacy against the aphids. Alkaloids which are the main active ingredients in Datura ferox are polar and they tend to be extracted by more polar solvents which explains why ethanol extracts showed the highest efficacy against the aphids.The extracts that showed the highest insecticidal activity were taken for phytochemical screening. Alkaloids were phytochemicals of interest in this survey. However, screening was also done for flavonoids, tannins, phenols, coumarins, saponins anthraquinones and terpenoids. Alkaloids and flavonoids were also confirmed using Thin Layer Chromatography.