Beetle-Mania: They’re Back (Japanese Beetles, that is)
It’s that time of year again—Japanese beetles (Popillia japonica) are back and ready to wreak havoc on virtually anything with leaves. First introduced to this region through rose bushes, anything in the rose family, as well as fruit trees like apples and peaches, are particularly attractive to these pests. While neither corn nor soybeans are a primary target, Japanese beetles will eat just about everything and can pose a serious threat to crops if the population is high.
The main threat beetles pose to soybeans is skeletonizing the leaves of the plants—eating all of the leaf structure except the veins, rendering the leaf unable to photosynthesize.
In soybeans, early beetle damage usually shows up in anomalies on the edges of fields as the population begins to move in. Look for a sudden but sharp decline in NDVI using AgMRI’s Change algorithm to scan for areas of possible beetle pressure where defoliation is already occurring.
In corn, beetles pose the biggest yield risk to the silks once they emerge. These little critters love cutting corn-silks, which has a direct impact on yield as the damaged silks prevent successful pollination.
In corn, fields with replanted areas are at a higher risk of insect feeding, so keep an eye out for replant areas that are progressing at un-uniform rates. Again, the Change algorithm is particularly useful in alerting to these, and any other insect or disease pressure taking hold in fields at this point in the season.