To avoid many disease and insect problems in the coming spring, summer, it is important to practise good garden sanitation always. But winter clean up is one of the most important since debris lying about makes a habitat for overwintering spores, seeds, diseases, and eggs of insects. If you clear out all the places where things cannot overwinter, you have helped yourself for the coming year! Throw all this debris away, It is better not to compost this now, or if you do, compost it in a very far location from where you will be planting and bury it deeply.
Pruning dead and diseased wood off your shrubs and trees is important, especially on fruit trees. Dispose of the cuttings or burn them since they may harbor disease and insect eggs.