Rotate Crops & Controls
Prevent Resistance Buildup in Pests & Pathogens
If crops are replanted year after year in the same location, pests and diseases will tend to build up resistance to the controls used to keep them at bay. Crop rotation is a great way to prevent buildup of pathogens in the soil that are specific to that type of crop. It is also a good way to minimize populations of overwintering crop-specific pests.
Another effective way to minimize resistance buildup is by alternating the control. Certain controls can also be combined for better efficacy. These methods involve spraying different controls in alternating intervals or combining different controls in the same tank mixture.
Rotating Controls for Early and Late Blight
At our Albion research farm, when treating tomatoes for early and late blight prevention, we typically alternate controls by spraying with Oxidate® OG (a peroxide-based fungicide/bactericide) to first sanitize the crop and then follow up with Champ® WG OG (a copper fungicide). The next time we spray, we might again treat with Oxidate® OG, but then follow up with a different fungicide, such as Actinovate® OG.
Combining Controls for European Corn Borer or Cucumber Beetles
Combining control products with different modes of action will slow the buildup of resistance by targeting specific functions. For example, in European corn borer control, spinosad, the active ingredient of Entrust® OG, targets the insect's nerves and muscles; while Bacillus thuringiensis, the active ingredient of Dipel® OG, targets the insect's mid gut. Using a tank mix (combination) of materials such as these will have a synergistic control that will be more effective than independent applications.
Similarly, for control of cucumber beetles, Pyganic® OG (a pyrethrin-based insecticide) might be tank mixed with Surround® OG (a kaolin clay-based repellent) to provide both initial knockdown and subsequent repulsion of these cucurbit-loving pests.
There are other alternative controls to which arthropods and other pests cannot build up resistance. Safer® Brand Diatomaceous Earth (OG) kills by ingestion or by contact with the powder, which contains the fossilized remains of diatoms that cut the exoskeleton, causing dehydration within 48 hours. SuffOil-X® (OG) is a high-paraffinic, low-aromatic oil that suffocates eggs, larvae, nymphs, and adults of soft-bodied insects and mites. Other paraffinic or mineral oils and insecticidal soaps are also effective means of control without the possibility of resistance buildup.
Sluggo® OG is a unique granular product that contains the naturally occurring mineral iron phosphate, which breaks down into soil fertilizer, combined with a mollusk bait that lures the slugs to their demise. It is safe to use around children, pets, and wildlife, yet resistance-proof and lethal to slugs and snails.
Take Notes, Mix It Up, and Keep It Safe
These are just a few examples of methods available for providing the control you need, while minimizing the risk of resistance buildup in pests and pathogens. From the commercial grower on down to the home gardener, keeping detailed records of which insect or disease issues are prevalent, the controls that were used, and how they worked is crucial to success. Always remember to read and carefully follow all label instructions when applying any pest or disease controls. When applied with a bit of commonsense, the fundamentals of crop rotation, control rotation, control combination, and resistance-proof choices are safe, effective, and environmentally sustainable.
- Read our Tips for Effective, Sustainable Pest and Disease Control.
- View All Johnny's Pest & Disease Controls.
- Integrated Pest Management (IPM) Principles, a fact sheet from the US Environmental Protection Agency.