It is not a Pakistani invasion but a species of insect that originated from Pakistan's Southern Sindh provience is giving sleepless nights to the Indian scientists in Rajasthan. The insects - Derolus Discicollis Gahen - has infected Rajasthan's life tree - Khejri or Prosopis Cineraria resulting in drying of a large number of trees in the State. Scientists from the Arid Forest Research Insititute (AFRI), Jodhpur, say the insect had a devastating effect on the trees in four districts of Northwest Rajasthan.