You’re scouting your crop when you notice the signs of a disease. So you apply a tried-and-true fungicide, confident it’ll kill it off. Except this time, the disease is still there. What happened? You may be dealing with fungicide resistance.
What is Fungicide Resistance?
Fungicide resistance is when too much of a fungal population survives a fungicide.
Most fungal spores die when a fungicide is first used. But there’s the chance a very tiny amount are genetically resistant, so they’ll survive. There are also fungal spores that a fungicide would normally kill that the application may have missed, or weren’t sprayed at a high enough concentration, so they also survive.
If conditions remain favorable for the disease, those surviving spores will reproduce, increasing the overall population of resistant spores. If you use the same fungicide as before, or one with the same chemical class and mode of action—also known as the FRAC code—the cycle will repeat. Eventually, the pathogen will reach a population where the fungicide does not have any effect on the disease.
Figure 2: Fungus resistance to fungicide over time Source: CropLife International
5 Factors that Increase Fungicide Resistance
While part of fungicide resistance is evolutionary and uncontrollable, there are ways growers can help prevent fungicide resistance from advancing. Here are some common errors that lead to fungicide resistance.
Figure 3: How to identify fungus on plant
leaves (Source: lovetoknow)
1. Applying fungicides at the wrong time
One mistake that leads to fungicide resistance is applying a fungicide when there’s a high amount of disease pressure and the fungicide is less likely to be effective. Instead, aim to apply when pathogen populations are still low and more easily controlled, early in an epidemic.2. Improper application
Missing spots or applying off-label rates increase the odds of fungal spores surviving. Make sure your equipment is properly calibrated and you’re following label rates to ensure the crop is getting full coverage.3. Allowing conditions favorable for disease
You can’t control the weather, but you can avoid over-irrigating. You can also implement practices that lower pathogen populations, like rotating crops and minimizing plant stress.4. Not mixing up modes of action
Using a different fungicide with the same mode of action previously applied is equivalent to using the same fungicide again. That’s why it’s important to switch up the FRAC codes you’re applying.5. Using a fungicide susceptible to resistance
Unfortunately, it’s near impossible to find an effective, broad-spectrum, modern fungicide that is not at-risk for resistance.A Solution That Doesn’t Result in Resistance
One way to control diseases without dealing with fungicide resistance is to use alternative, biological solutions, like Terra Vera. Unlike traditional fungicides, Terra Vera’s crop protection products use amino acids to oxidize fungal pathogens. Because there is no active ingredient for diseases to grow resistance to, growers can continue to use Terra Vera’s products over and over again, without concern of losing efficacy. Terra Vera also provides the advantage of biodegrading into nutrients, further strengthening plants’ immune systems. As a result, growers can potentially increase their crop potential by 40%.
Grow Smart from the Start
Using Terra Vera's crop protection and nutrient solutions from start to finish increases your plant's ability to fight off environmental stress so that yield potential and quality are preserved. It can be sprayed on plants even through the late stages of bloom and post-harvest, making it a versatile solution for even the most sensitive genetics. The best part? You can generate Terra Vera solutions onsite with our systems so that you can rest easy knowing your plants are getting fed the freshest ingredients each time.