Semester of Graduation

Fall 2021

Degree

Master of Science (MS)

Department

Entomology

Document Type

Thesis

Abstract

The integration of monitoring and chemical control is an efficient strategy for managing invasive apple snails, Pomacea maculata, in the rice (Oryza sativa L.) and crawfish systems of southwest Louisiana. However, their current distribution, expansion rates, and susceptibility to chemical control methods in this area are not well known. This study evaluated the expansion of P. maculata in southwest Louisiana and assessed potential chemical control for P. maculata among toxicity assays using various application rates. The effects of potential chemical control were also assessed on a non-target species, the red swamp crawfish (Procambarus clarkii). P. maculata was recorded to have area expansion occur at approximately 880 km2 per year and a northward expansion at a rate of 6 km per year with the majority of presence recorded in southern areas. P. maculata had a lower probability of being found in aquatic habitats with decreasing levels of dissolved oxygen. The treatment of 8 ppm using a liquid form of copper sulfate and the treatment of 12 ppm using a crystal form of copper sulfate each caused nearly 50% average P. maculata mortality and were the lowest effective treatments. No treatment of either form of copper sulfate had a significant effect on P. clarkii mortality. P. maculata egg mass hatching success and hatchlings were highly affected by a low treatment (5%) and a high treatment (10%) of crop oil adjuvant with no significant difference between the two treatments. The results suggest continuous P. maculata expansion in southwest Louisiana as well as copper sulfate treatments that are effective to P. maculata mortality and not effective to P. clarkii mortality. P. maculata egg masses can also be potentially controlled with crop oil. Future studies should attempt to find new factors associated with P. maculata occurrence in southwest Louisiana. More research should be conducted on the levels of copper sulfate that are actually ingested by P. maculata after initial exposure as well as new methods for crop oil applications on P. maculata egg masses.

Committee Chair

Wilson, Blake E.

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