With this information, hopefully new plant cultivars could be developed that are more stress resistant. For instance, greater investment by a plant in roots, rather than shoots, can make the plant more resistant to herbivory since reserves stored in roots can be mobilized to produce new leaves. The ability of the cottonwood to induce or increase levels of defense chemicals was studied. The results demonstrate that different types of damage produce different chemical changes in the plants, which shifts the palatability of the plants to insects. These induced chemicals are flavonoids.
Flavonoids are nontoxic and are responsible for some flower colors in plants.
This shows that plants aren't the simple creatures that we often think. They can clearly change their chemical defense based on the type of damage. Upcoming research with Cottonwood will investigate the effects of drought, and root damage as plant stresses, on plant chemistry and insect resistance. Another project on controlling insects on woody ornamentals is with the Como Conservatory evaluating the use of oils and soaps on controlling 5 species of scale insects. We began an IPM program with the Minnesota Zoo for their insect problems.