Task 1: Develop new Cuban bulrush control methodologies.
Operational control methods for nuisance Cuban bulrush populations have been
lacking as the species has been overlooked for decades by more pressing
management concerns. Previous management strategies have only delivered
short-term (4-6 wks.) reduction of Cuban bulrush infestations. The purpose of
this work was to identify potential selective, long-term (>1 yr.) chemical
control methods through small screening and then validating the most effective
control options on field populations of Cuban bulrush to ensure control could
still be attained across a range of environmental scenarios.
This project has identified multiple chemical control
measures that resource managers have tested in MS and FL for the successful
reduction of Cuban bulrush infestations. Research is ongoing to further refine
these protocols prior to determining an operational control strategy.
Task 2: Gain a better understanding of the Cuban bulrush life cycle to
help resource managers improve time management activities
Plants have natural weak points in their life cycles where nutrient stores are
reduced (i.e., after sprouting or flower production). Weak points are an
optimum time to implement control strategies as its unlikely the plant will be
able to recover from the stress induced by control measures without sufficient
nutrient reserves. However, different plant species can have vastly different
life cycles so the optimum control time for species may not work for others. To
determine this weak point for Cuban bulrush, a project was initiated on Lake
Columbus in northeast MS to describe the life history of the species. A follow
up project is being conducted to determine if the life history is similar
across the invaded range of Cuban bulrush in the southeastern U.S.
This project has identified the weak point in the
Cuban bulrush life cycle in MS and is currently determining the same for
populations in FL and LA. Additionally, this project is attempting to determine
which environmental cues (i.e., air or water temperature, photoperiod, etc.)
trigger Cuban bulrush growth each year.
Task 3: Prescribed fire as a mechanism to enhance Cuban bulrush
Cuban bulrush tussock presence decreases light penetration in water, which
inhibits algal and submersed plant photosynthesis, which then reduces dissolved
oxygen concentrations needed for survival of fish and other aquatic fauna.
Herbicide applications can provide an effective control mechanism. However,
effective herbicide treatments can only be applied to Cuban bulrush mid-summer
to late-fall (July through October) as the thatch layer from the previous
year’s growth shields new growth in the spring and early-summer thereby
decreasing herbicide contact with emerging foliage. Late season herbicide
applications can require more herbicide as more plant foliage is present than
earlier months, thus, thatch removal may allow for less herbicide use while
still attaining control of Cuban bulrush.
Prescribed fire is a useful method of thatch reduction in terrestrial systems
but is rarely used in wetland and aquatic settings due to the obvious
over-abundance of water. However, some emergent aquatic plant species maintain
a dense aerial thatch layer that is not hydrated by the underlying water.
Reduction of the thatch layer in winter months via prescribed fire may provide
a cheap mechanism to enhance herbicide contact with new Cuban bulrush foliage
in the spring for greater tussock reduction compared to mid- or late-season
If successful, this integrated control technique can
enhance management across the southeastern U.S. by providing resource managers
a low cost solution to reduce herbicide input while increasing reduction of