Vincent R.Koczurik



Masters Candidate


Research statement -


Purple Loosestrife (Lythrum salicaria) is a perennial herb with annual stems that is of Eurasian origin. It was first introduced into the United States and Canada in the 1800s for ornamental and medicinal uses. Since that time, L. salicaria has become an aggressive competitor in both natural and disturbed wetlands. Much of its success is due to its large seed production; each plant may produce between two and three million seeds a year. Over time, this plant forms dense stands that replace many native plant species, including grasses, sedges, and other flowering plants. When plant diversity in these wetlands is lost, the habitat changes and other organisms, such as animals, are adversely affected. For these reasons, L. salicaria has been declared an invasive species in twenty-seven states. Recently, biologists have begun to experiment with different possibilities for controlling L. salicaria. It has no natural enemies in the United States, but several different types of insects are known to feed on the plant in its native range. Two species of leaf-eating beetles, Galerucella calamariensis and Galerucella pusilla, have since been released at sites within twenty-five states and seven Canadian provinces. The goal is to reduce L. salicaria populations to the point where native species are no longer displaced. However, this process may take many years.



The aim of this research project is to shed more light on how effective these biological control methods are. L salicaria leaves contain phenolic compounds that may reduce herbivory. If the levels of these chemicals increase in response to an attack by Galerucella beetles, long-term control by the introduced insects may not be possible. Galerucella beetles tend to do the most damage in their larval stages, which occur from late spring to early summer. Since adult beetles go dormant by the end of the summer, L. salicaria is often able to flower and produce seed. Little is known about how an induced defense in L. salicaria affects Galerucella or other herbivores, such as deer. Experimental testing done on samples collected from field sites and from plants grown in the greenhouse should lead to a greater understanding about how best to control L. salicaria in the future.


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