Ashley B.C. Goode
Philip W. Tipping
Melissa C. Smith
Lyn A. Gettys
Brittany K. Knowles
Eileen Pokorny
Luz Salinas
Don DeAngelis
Linhao Xu
2023
<div id="abstracts" class="Abstracts u-font-serif text-s"><div id="abs0002" class="abstract author"><div id="abss0002"><p id="spara012">An experiment along with simulation modeling was applied to study the combinations of herbicide treatment and biological control that best limit invasive water hyacinth (<i>Pontederia crassipes</i>, formerly<span> </span><i>Eichhornia crassipes</i>) in freshwater aquatic systems. The experiment consisted of 14 different treatments of<span> </span><i>P. crassipes</i><span> </span>in 1.67 m<sup>2</sup><span> </span>outdoor tank mesocosms. Seven treatments were with and seven were without insect biological control agents,<span> </span><i>Neochetina eichhorniae</i>. In both of the sets of seven treatments, there was one no-herbicide treatment, a one-time full-strength herbicide treatment with 40 %, 80 % and 100 % coverage of the<span> </span><i>P. crassipes</i>, and a one-time half-strength herbicide treatment with 40 %, 80 %, and 100 % surface area coverage. An overarching hypothesis was that leaving part of a tank unsprayed, providing habitat for the maintenance of biological control agents, would optimize control. Data from the experiment, measured on five days over the 167-day period, were used to calibrate a difference equation model of<span> </span><i>P. crassipes</i><span> </span>with and without the biological control agent. The model was then used to project longer term dynamics of the system. The model predicted that an initial one-time herbicide treatment, combined with application of the biocontrol agent at 80 % areal coverage, could maintain<span> </span><i>P. crassipes</i><span> </span>at levels lower than the carrying capacity of the plant's biomass over the long term, though not enough that<span> </span><i>N. eichhorniae</i><span> </span>would be considered, by itself, a highly effective control. However, the results suggest that a combination of biocontrol with 80 % spraying coverage every 600 days or so would be an effective integrated biocontrol strategy for maintaining decreased<span> </span><i>P. crassipes</i><span> </span>biomass at low levels over the long term.</p></div></div></div>
application/pdf
10.1016/j.ecolmodel.2023.110566
en
Elsevier
Less is more: Less herbicide does more when biological control is present in Pontederia crassipes
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