Weed control other methods

Allelopathic compounds act as repellents for herbivorous pests, so the same strategy used in weed control could be effective against pests and pathogens. Only allelopathy is not possible to use the complete control of weeds, pests or diseases it is necessary to combine it with other methods of plant protection. 

On farms practicing no-till com production, herbicides are the main tool for weed control. Without herbicides, notill farmers would have to switch to some other form of tillage operation. They could no longer use no-tillage methods, resulting in much more soil erosion. Triazine and other herbicides in com will continue to represent the main weed control technology for the vast majority of com acreage. 

Weed control has to depend to a greater extent on cultivation methods and a greater understanding of weed species is needed than in circumstances where they can simply be sprayed out of existence. Pests and diseases may also be affected by cultivation methods but interactions with other organisms are of enormous importance. 

One of the most important characteristics contributing to the value of herbicides has been plant selectivity. The fact that some plants (weeds) are killed by herbicides while others (crops) are naturally resistant has been very important to selective weed control in crop production. A few herbicides that have been useful without natural or biological resistance, such as glyphosate and paraquat, have found great success in crop production due to the use of other methods of selective weed control (e.g., directed applications, applying prior to crop emergence or applying to dormant perennials). 

In 1982, American Cyanamid began commercial development of the imidazolinone class of herbicides. These herbicides control a broad spectrum of economically important weeds in corn and soybeans. Although differences in tolerance of corn hybrids for imidazolinone herbicides exist (5), no hybrids with sufficient tolerance to allow application of current imidazolinone herbicides to corn fields have yet been identified. Other methods to supplement the inadequate levels of natural tolerance have likewise been ineffective. 

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