Burgeoning Resistance Requires New Strategies

Abstract

In years gone by mixed farming was practiced, and weeds were kept at bay with a modicum of success by crop rotation with lots of cultivation. Crop varieties then available were far more competitive with the weeds than those presently grown. Yields were low because the crop competitiveness has a high cost in yield (cf. Herms and Mattson, 1992). Energy costs either as fuel for tractors, fodder for animals, or food for laborers were high. The advent of high yield-index crops and their greater relative responsiveness to fertilizer and water than their grandparents brought weeds, with a vengeance. A lower, noncompetitive stature is a direct outcome of high yield indices. Herbicides were and are a necessity to keep the crop yields up and the weeds down in the new, wimpy crops. Such herbicide use is wholly justified when one considers the alternative: famine. We don’t eat the straw, just the grain, so why grow straw? The herbicides made it too easy. The fields were clean, so why not grow just the high value cash crops; no need to rotate, and with no-till and herbicides, why ever cultivate and cause compaction and erosion? All this followed a scientific “razor” (principle), widely found in text books, by the 14th century English cleric Richard of Occam. As often stated Occam’s Razor is: “The simplest solution to a problem is most likely to be the best one”. Monoculture of major cash crops using a single herbicide over wide areas was the simplest solution to weed problems in crop food production. Industry, extension, and academia used Occam’s Razor and exhorted farmers to KISS, where KISS stood for “keep it simple, stupid”. My high school agronomy instructor 40 years ago ranted against monoculture, always stating that in the long run, rotation always pays. To him KISS meant: “keep it sophisticated, smarty” and time and again this has been proven right.