 Now if you go into your field and see a Japanese beetle or two munching on some corn silk, it's not the end of the world and there's nothing really to worry about unless you notice that those silks are starting to get close to that half inch mark and it's also during pollination. Then you might want to look into what your options are to take action. A lot of times we see two things with Japanese beetle feeding on silk. One is that they tend to be limited to the edges of the field. That tends to be where they sort of congregate.