Grass grub and porina damage will now be evident in most areas. By now production losses have already occurred but treatment may save the affected pastures. Conventional insecticide is the only control option likely to give control of grass grub in all areas and of porina in the South Island. North Island porina are still susceptible to diflubenzuron until mid-July. Careful consideration needs to be given to control options as spring growth may occur before damage becomes such that plants are lost from pastures.05