One cold, dreary winter day during reading period, we pondered plant life on campus. After learning about herbivory in lecture, we thought it would be interesting to use the Foldscope as an opportunity to see some up close. We had also just finished a project on beech leaf litter and were searching for ways to apply what we had learned to other species. Because of its abundance on campus, we decided to take a look at signs of herbivory on ivy plants using the Foldscope we received from our lab instructor.

We began by using the Foldscope on a healthy leaf to get a feel for the proper coloring and structure of the leaf under such magnification.

A healthy ivy leaf under the Foldscope.                                      Stem of healthy ivy leaf under the Foldscope.

Then, we observed a small yellow spot surrounded by a red ring on one of the ivy leaves that we collected and decided to do a bit of research.  According to the Missouri Botanical Garden Ivy, which is of the genus Hedera , can develop what they refer to as a “bacterial leaf spot,” which is what we believe that we saw on the leaf. According to the Missouri Botanical Garden, these spots appear as a result of excess water pooled on the leaves of the ivy.

A macroscopic (left) and close-up (right) of the border between the spot of bacterial infection and the rest of the leaf.

We also noticed an interesting web-like pattern on some of the ivy we saw growing on the ground outside of Frist Campus Center. We thought that this was due to herbivory, however after some research, we could not find any herbivores that create such a pattern on ivy leaves.

In some places, the leaf was intact but had begun to thin.

At the center of the web-like patch, the majority of the leaf disappeared.

One possible explanation that we came up with that might be the cause of this pattern of decay found on some of the ivy, is a progressed state of bacterial or fungal infection. Some questions that we are still left with after this investigation are:

If the observed pattern is a result of infection, what pathogen causes such an infection?

Is there a possibility that this pattern is a result of both herbivory and infection-Is there an insect that, similar to bark beetles and pines, introduces bacteria or fungus to the plant after feeding on it?

Dyonishia and I conducted this project as a part of Professor Pringle’s EEB321 class at Princeton University.

We cited information from these links:

http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=r450

http://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/diseases/fungal-spots/leaf-spots-of-english-ivy.aspx