Organic and specialty crop growers are trying to make a living off the rising consumer interest in locally grown and organic foods.  But the smaller farms are often islands surrounded by a sea of conventionally grown crops that get sprayed with herbicides, insecticides and fungicides.  Pesticide drift is a serious concern for them, and they’ve come up with a variety of defenses.  Many plant buffer strips.  Twelve states participate in a registry of organic and other farms to tip aerial and ground sprayers off to areas they need to avoid.  And in Iowa, a group has produced a pamphlet that instructs farmers how to protect vulnerable crops.  The aerial spraying industry and pesticide manufacturers, meanwhile, say they’ve made big strides in controlling drift through education and new technologies.