Goldenrod plants are getting tall now, getting flowers ready to bloom, and becoming food for a variety of insects. One of the herbivores is conspicuous, if you take a little time to notice. Some stem tips look vigorous with leaves facing upward and outward and flower buds developing, like the picture above, but other stem tips are closed up and bent over, with the leaves facing inward and down. The outer surfaces are still green and, at a tissue level, seem healthy. But something is wrong.
Many plants show deformities, so these clusters of leaves might be some kind of developmental problem or pathogen infection. But no. If you pull the leaves apart carefully, there is white material holding the leaves together, and at the very center, there is a tiny moth larva. The white material is silk, spun by the caterpillar – yes, even one so small – tying the leaves together, holding them close to the caterpillar for protection and for food.
When I looked up “leaf tier” for goldenrods (pronounced “tie-er,” not “teer”), several species came up, representing multiple families, such as Tortricidae and Gelechiidae. I don’t have access to a microscope, so I can’t be sure which species I’m finding (and even with a microscope, species identification would be quite difficult), but they are doing well, whatever they are.
Most of the stem tips are undamaged, soldiering onward and upward. But they are beginning to show their age as insects find places on them and in them to live and to eat. The food web and growing season are marching forward together.