questions: query regarding trunk borer in lemon. 
 answers: spray acephate 75 sp or carbaryl 2ml/2 gram per liter of water 3 times at 5 days interval in the evening time and then block the holes with cotton plug deep in kerosene. after that smearing of carbaryl with lime and water (3 gram carbaryl/liter of water) should be applied upto one meter from the base of the tree, which prevent the adult from laying eggs.