I too, echo some of the statements of the above captioned individuals. I think some combination of chemical and non-chemical control of pests is the most promising. I assumed that natural control methods were very well known, but perhaps there are regional success stories that some haven't heard. In the Pacific Northwest we have had excellent success using the cinnabar moth to control tansy.
Mediterranean mantises work well for a variety of insect pests.
They will reproduce at least once during a 3-month summer and are voracious. In a mild winter they will winter over. They are really death on grasshoppers and locusts. Ladybugs for aphids. Pasture rotation and mowing to control parasites and weeds.