What are the Biological Factors influencing the Resistance ?
Some of the characteristics of the weeds have great impact and actually delay the development of herbicide resistance. As mentioned before, even though the herbicide resistance problem has become worse in recent years, it is certainly not as serious as resistance to fungicides and insecticides. Weeds usually exhibit a great reproductive ability, which is maintained even when environmental conditions are not ideal for plant development. When weed populations decrease in the field as a result of some control strategy, the few individuals that escape herbicidal treatment are capable of producing enough seed to ensure the permanence of a seed bank in the soil allowing the perpetuation of the species. This plasticity of the populations greatly influences the “dilution” of resistant weeds that have become selected by the continuous use of a particular herbicide. Seed’ longevity and dormancy in the soil also delay the selection of biotypes resistant to herbicides.
