There is also a humming line that can be wound around canes criss-crossed over your vegetables to prevent bird attacks. Netting can also prevent cabbage white butterflies from laying there eggs on your brassicas. Barriers can also be used to prevents diseases. For example, peach leaf curl is a devastating fungus that can simply be prevented by placing a barrier of polythene sheeting over a trained peach tree in the winter. This simple barrier prevents the spores splashing up onto the plant.
Slugs are most peoples worst enemy.
There are all sorts of weird and wonderful things available for slug control on the organic market now. One that springs to mind is a band of copper that gives the slugs electric shocks. If using a barrier method with slugs remember that success depends on you being extremely generous with the chosen deterrent and not skimping. For more information on the control of slugs please see our slug leaflet. Another popular method of protecting your plants is to use traps.