NDVI from June 28 (left) and July 12 (right) showing variation in crop development.
A lag in corn development on the West side of this field was observed in early imagery. Upon ground truthing that area symphylans were observed and documented. The damage was consistent with other infestations found in the region.
Further investigation indicated that while the symphylans likely caused damage, nematodes may also be weakening the plants defenses.
It was known that parts of that field had stunting issues, but the imagery gave a quick concise view of the extent of the area; which was more substantial than initially estimated from the ground. The crop health image is valuable because it makes the differences between good and bad areas of a field stand out. The earlier we can detect the crop stress, the better the chance of protecting the crop and improving yield. In this case an insecticide application at planting is being considered for the following season.
In the second image the canopy is filling in and the result is difference across the field. This is consistent with the weekly observations of the crop consultant.
It’s worth noting that this field had staggered emergence due to spring weather conditions, which probably masked some of the variation across the field. The dark green area on the East side is a different variety.