grubs in fruit

can anyone tell me how to protect my apple trees from grubs this year has been very bad?

There are a couple of things you could try.  The most likely source are wingless female moths that climb up the tree in spring and they lay eggs in the developing fruit.  First, remove any fruit that drops near the tree as they are likely to contain the next generation ready for the following year, and secondly put a grease band round the tree trunk in the winter months - these should trap insects that climb up (see http://apps.rhs.org.uk/advicesearch/Profile.aspx?pid=518)