Here are some on-line sources for many crop
This is a new section that I have just started, which I will be adding to weekly. It is sources that I have found while looking for myself, or that I have come across while searching on-line. Some times it takes ages to find the best advice, so if you have good links please add then in the comments, or email me.
Guide to major grape diseases (pdf) Agriculture and Agri-food Canada -The purpose of this guide is to help growers and advisers properly recognize diseases of grapes in Eastern Canada. However, I am sure it will be useful to most grape growers, large or small.