First report of thiamethoxam resistance selection, cross resistance to various insecticides and realized heritability in Asian citrus psyllid Diaphorina citri from Pakistan

Abstract Diaphorina citri Kuwayama (Hemiptera: Liviidae) is one of the devastating pests of citrus orchards in different regions of the world and its management depends upon the use of insecticides. The work was conducted to evaluate the toxicities and resistance levels to various insecticides in a field collected population of citrus psylla from an area of Pakistan. The field population was also kept under selection pressure with thiamethoxam for several generations to study the impact of selection on thiamethoxam resistance development. The resistant population was then studied for cross-resistance with insecticides from different groups and realized heritability of thiamethoxam resistance was determined to assess the potential of resistance development. Selection of D. citri from G 1 -G 7 with thiamethoxam produced 229-fold resistant strain in the laboratory. Selected strain exhibited very low cross-resistance with flonicamid, buprofezin, and spirotetramat; low cross-resistance with diafenthiuron and fenpropathrin, moderate cross-resistance with nitenpyram and pyriproxyfen, and a very high cross-resistance with acephate and methomyl. The estimated realized heritability of thiamethoxam resistance was 0.36. This study provides information on the impact of selection on resistance development and its management by restoring the susceptibility of D. citri through rotation of insecticides with low level of cross-resistance.