Which invasive plant has pesticide-resistant reproductive structures that can lie dormant in the substrate?

Curly-leaf pondweed is the correct choice because it is known for its ability to produce reproductive structures, such as turions, which are capable of surviving adverse environmental conditions. These turions allow the plant to remain dormant in the substrate for extended periods, even in the presence of herbicides. This resilience poses significant challenges in managing its populations, as traditional pesticide treatments may not be effective in eliminating these dormant structures.

In contrast, while other choices like watermilfoil, naiad, and bladderwort are also aquatic plants, they do not have the same level of resistance or the specific reproductive strategies that allow curly-leaf pondweed to persist through herbicide applications and re-establish populations efficiently after treatment. Understanding the characteristics of these invasive species is vital for developing effective management practices.