Just a few clarifications on the hydrilla IPM research and demonstration project that is ongoing in Florida and Mississippi.
As you know, a team of researchers at the University of Florida, Florida A&M University, and the U.S. ACE Engineer Research and Development Center is investigating an integrated approach to hydrilla control. The goal is to combine different biological and chemical control tactics to improve control of hydrilla populations in Florida.
Depending entirely on the application of the same herbicides year after year increases the risk of resistance development, which has been documented with fluridone. Likewise, simply augmenting natural populations of an insect herbivore or fungal pathogen will not provide effective hydrilla control. However, integrating several control agents (e.g., chemical with biological) should make hydrilla more vulnerable to the effects of each agent.
What is going to be combined and how is this expected to work?
* The ALS inhibiting herbicide imazamox induces branching of hydrilla and the growth of new shoot tips.
* The naturalized insect herbivore Cricotopus lebetis, whose larvae mine, feed and develop within shoot tips of hydrilla, changes the architecture of the plant, and its population should increase in response to the imazamox.
* The native fungal pathogen Mycoleptodiscus terrestris can, under certain environmental conditions, reduce hydrilla biomass significantly. Feeding damage by mining larvae should increase vulnerability of hydrilla to fungal infection.
What are the expected consequences?
According to the above described working hypothesis, hydrilla will be prevented from reaching the water surface. This should reduce negative impacts such as obstructed navigation and the shading out of more desirable native plant species.
We acknowledge the funding provided by the U.S. Department of Agriculture, National Institute of Food and Agriculture, Risk Avoidance and Mitigation Program (grant 2010-02825).
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