Other Resistances
Fungicide and insecticide resistance were discovered long before herbicide resistance. This is because fungi and insects have large populations and reproduce rapidly, compared to weeds that only reproduce once a year. Insects can reproduce several times a year, and some fungi and bacteria can reproduce as much as several times an hour. Large populations lead to a lot of genetic diversity. In large populations, small groups of pest become tolerant of the control measure. Because weed populations evolve over several years, selection pressure from using the same herbicide for multiple years in a row allows resistant biotypes to increase within a population.
One example of helping to control the development of resistant populations is the regulation of refuge areas planted in association with Bt hybrids. Because insect resistance can develop so quickly, to keep populations balanced and the technology effective, a certain portion of the field is designated to keep the population of European corn borer from developing resistance.
As with herbicides, to alleviate insecticide or fungicide resistance, scout fields, rotate modes of action and apply fungicide/insecticide at the recommended use rate. Other management strategies include:
- Integrating non-chemical methods of control, like disease-resistant crop varieties and crop rotation.
- Time insecticide applications correctly and apply at locally recommended thresholds
- Monitor pest populations for shifts
- Protect beneficial insects which may play an integral role in pest management
- Consider crop residue options