Insecticidal Potential of Indigenous Flora of Soon Valley against Asian Citrus Psyllid Diaphorina citri Kuwayama and Cotton Aphid Aphis gossypii Glover

Sap-sucking insect pests have been a severe threat to horticultural and agricultural crops all over the world. Asian citrus psyllid Diaphorina citri Kuwayama (Psyllidae: Hemiptera) and cotton aphid Aphis gossypii Glover (Aphididae: Hemiptera) are destructive sap-sucking pests of citrus and cotton, respectively. Extensive use of persistent synthetic insecticides against these pests poses issues of environmental contaminations and health hazards and suggests looking for alternate biorational plant protection measures such as botanical pesticides. This study evaluated the potential toxicity of acetone extracts of 40 indigenous plant species of Soon valley and surrounding salt range (Punjab, Pakistan) against D. citri and A. gossypii using standard twig-dip and leaf-dip bioassay methods, respectively. Results of initial screening bioassay showed the highest mortality of D. citri by 10% extracts of Mentha longifolia (L.) Huds. (93%), Melilotus officinalis (L.) Pall. (91%), Nerium indicum Mill. (89%), Datura alba L. (88%) and Salvia officinalis L. (81%). Second bioassay conducted against A. gossypii using different concentrations (5, 10, 20 and 40%) of the most effective botanical extracts revealed that the extract of S. officinalis was most toxic (LC₅₀ = 18.59%), followed by N. indicum (LC₅₀= 20.27%) and M. longifolia (LC₅₀ = 20.73%). Similar trend of effectiveness was observed regarding their LT₅₀ values. Overall study results demonstrated the biocidal potential of the extracts of indigenous plant species of Soon valley against D. citri and A. gossypii, and suggest their further biochemical characterization and practical implication in future IPM programs against these and other sap-feeding insect pests.