A Mature fruit with corky scars on the surface show the effects of a brief sawfly larva attack. More severe attacks result in the fruits dropping early and, if the apple is cut open, will often reveal a cream-coloured grub about 15mm long. The grubs pupate in the ground during July. This pest bores into fruit, causing it to fall early, though it rarely affects a significant proportion of the crop. It’s not usually a serious problem