How to use your TerrAvion imagery to manage a soybean cyst nematode presence
Soybean Cyst Nematode (SCN) affects soybean production worldwide. Growers in the United States have battled SCN since the early 1950s and the pest is believed to cost growers over $500 million annually as yields can be reduced up to 75%. TerrAvion imagery can assist you in spotting above-ground symptoms of SCN in your fields and also help with targeted soil sampling for the pest if needed.
Above-ground symptoms of SCN in soybeans appear as stunted, yellowed areas of low vigor. These infested areas will vary in size, often showing a sharp dividing line at the edges between stunted and healthy plants. Symptoms of Soybean cyst nematodes damage are often mistaken for stress from compaction, iron deficiency chlorosis, other nutrient deficiencies, as well as drought stress, herbicide injury, or other plant diseases. You can differentiate the symptoms depending on the time of the season. Symptoms from the previously mentioned issues tend to occur earlier in the season, typically by June, whereas above-ground symptoms due to SCN will more likely occur later, in July and August.
This is an image of a soybean field taken on June 1st. You can see the growth looks mostly uniform in the natural color image, and when we look at the NDVI image, you can see that the field is indeed growing evenly.
If this field were infested with SCN, the parasite would be feeding on the crop below ground, undetectable in the imagery at this time.
However, if we look at the imagery 5 weeks later, during the first week of August, we can see that suspicious spots of low vigor have emerged in the field.
If you notice a suspicious low vigor zone such as this later in the growing season, you should do an in-field inspection of the area. Soybean cyst nematodes are microscopic, but they can be spotted by a trained eye. However, the best way to determine if your crop has been infested is to take soil samples in the areas that you have identified through your imagery. If nematode density is consistently correlated with a field characteristic, you can target areas to sample soil in a cost-effective manner. Consult with your agronomist on how to proceed with soil sampling.
If your soil samples show an SCN infestation, you should talk with your agronomist about offseason treatments, as there currently are no viable in-season treatment options. Off-season treatment options include nematicide applications, planting SCN resistant seeds, seed treatments, and rotation to a Soybean cyst nematodes resistant crop such as corn. Studies have shown that rotating a crop resistant to SCN can reduce the number of nematodes by up to 50% in the first year. Other preventative measures include maintaining adequate plant health by managing soil fertility and pH and employing proper sanitation methods for any tools/equipment or people that could lead to contamination.
This is how you can use TerrAvion to combat SCN infestations.