How to Prevent Corn and Soy Diseases

According to market data, corn and soy yields decreased from 2018 – 2019. While the yields weren’t particularly bad–in fact, they were very impressive for the soy industry–plant diseases may have caused this drop in number. In 2018, the U.S. average corn yield was 176.4 bushels per acre. In 2019, this number dropped to 168 bushels per acre. Similarly, in 2018, the U.S. average soy yield was 51.6 bushels per acre. This number dropped in 2019 to 47.4 bushels per acre. So what exactly happened to cause this shift in numbers?   

Corn and Soy Diseases

Many corn and soy farmers did well in 2018 and 2019. But weather and plant diseases did hurt others, especially those whose fields were exposed to excessive rainfall during the harvest season. For example, in 2018, crop yields fell by more than 10% in some portions of the Southeast. 

And experts warn that those whose crops suffered from plant diseases in 2019 could experience a similar situation if preventative measures are not taken.

Humidity and wet weather are two variables that affect corn and soy crop diseases. If you grow in an area that sees this sort of weather, you should properly prepare your crops to ensure you don’t suffer a huge yield loss. And if your crops suffered during the last two growing seasons, use precautions before planting your next crop. Many diseases can overwinter. 

Before we discuss preventive measures, let us first outline some common corn and soy diseases. 

Common Corn Diseases

Many corn diseases thrive in wet and humid weather. Here are the most common corn diseases and their characteristics: 

  • Gray Leaf Spot:
    • Thrives in high humidity and warm, wet weather 
    • Characterized by gray/brown spots that eventually elongate 
    • Reduced yields by up to 40 bushels per acre 
  • Northern Corn Leaf Blight: 
    • Thrives in wet and humid weather 
    • Characterized by gray, green, or tan lesions on lower level of leaves that spread up to the husks 
    • Reduces yields by 50%
  • Tar Spot: 
    • Thrives in cool temperatures, high humidity, and frequent rainfall
    • Characterized by black spots on corn leaves 
    • Reduces yields by up to 40 bushels per acre  
  • Southern Rust: 
    • Thrives in high humidity and temperatures (above 80 F) 
    • Characterized by small, orange pustules that appear densely clustered on leaves 
    • Reduces yields by 45% 
  • Anthracnose Leaf Blight: 
    • Thrives in wet, warm, cloudy weather 
    • Characterized by tan spots on leaves that are framed by yellow, red, or brown borders 
    • Results in stalk and stem rot, lodging, and plant death 

Common Soy Diseases 

As with corn diseases, soy diseases thrive in wet and humid weather. Here are the most common soy diseases and their characteristics: 

  • Frogeye Leaf Spot: 
    • Thrives in high humidity 
    • Characterized by small, dark spots with purple borders on leaves, stems, and pods that grow larger and turn gray or brown 
    • Reduces yields by 30% 
  • Brown Spot: 
    • Thrives in warm and wet weather between planting and canopy 
    • Characterized by purple lesions that turn brown 
    • Results in yellow, drooping leaves, stunted pod fill, and reduced yields 
  • White Mold: 
    • Thrives in cool temperatures and frequent rainfall 
    • Characterized by cotton-like growth on stems 
    • Reduces yields by two to five bushels per acre fr every 10% increase in fungus 
  • Aerial Blight: 
    • Thrives in high humidity and warm temperatures 
    • Characterized by reddish/brown lesions on petioles, stems, and pods that evolve into web-like fungus
    • Reduces yields by 50% 

As you can see, wet and humid conditions can cultivate diseases that cause significant yield loss for corn and soy crops. With preventative measures, however, you can protect your crops from such diseases–even after a bout of illness in last year’s crop.

Preventing Crop Diseases

The best way to prevent corn and soy diseases is to study your field’s history. Determine whether your crops have been hit by such diseases before; analyze weather patterns during those time(s); and plan to manage the diseases in upcoming seasons. 

Before planting next season’s crop, ensure the soil is healthy. Many diseases can overwinter in the soil, so it’s important to ensure there are no traces of last season’s disease in your field. If your crops suffered last season, the most important thing to do after harvest is to till the soil. (We usually advise against tilling, but in some cases, it is absolutely necessary.) By tilling, you will bury any diseases deep down in the soil so they won’t be able to survive the winter.     

Once you have prepared the soil for next season’s crops, you should develop a plan to mitigate any future crop losses. Planting crop rotations is an effective and proactive way to protect your crops from disease. Always plant non-host crops so disease pathogens have time to die off before you beginning planting your corn and soy crops. 

When it is time to plant you corn and soy crops for next season, ensure you have the best tools. Disease-resistant corn and soy hybrids will help mitigate crop losses due to diseases; they won’t effectively eliminate diseases, but they will certainly help. In addition, select a fungicide that will protect your crops from diseases during humid and wet weather. 

In addition to preventing yield losses, it is also important to invest in innovative ways to increase yields. At xVirity, we have just the solution. 

xVital for Yield Gains

xVital is an all-natural, liquid fertilizer that is both ecofriendly and effective. Made with only two ingredients–nitrate and ionized water–xVital is the perfect solution for farmers seeking to reduce nutrient pollution; support soil health; and increase crop yields. 

Our plasma technology uses an electromagnetic field, so unlike conventional fertilizers, xVital is not bound or attached to salt. High salt contents can make your soil acidic and prevent your plants from absorbing essential nutrients and water. If your field possess acidic soil, using xVital can help reduce its salt content, effectively supporting your soil and plants’ health. Comparatively, xVital is not only more ecofriendly than conventional fertilizers, but it is also better for crops overall!


You can learn more about our product here.



Prevent the Return of Last Year’s Yield-Robbing Diseases