Semester of Graduation
Spring 2026
Degree
Master of Science (MS)
Department
Entomology
Document Type
Thesis
Abstract
Plant health is one of the important aspect of pest management. Strengthening plant health through balanced nutrition can improve plant vigor and enhance defensive responses. Copper and sulfur are among the essential nutrients required for plant growth and development, and they are essential for various plant physiological functions. Additionally, copper and sulfur are also involved in plant biochemical pathways that impact plant structural integrity and plant chemical defenses like secondary metabolite synthesis. Applying copper and sulfur-based nutrition to plants may enhance their ability to defend against pests and pathogens. Although copper and sulfur are supplied by commercial fertilizers, a substantial amount can be lost after application through leaching, runoff, and volatilization. To overcome these challenges, this study utilizes a lignin and poly(lactic‑co‑glycolic acid) (PLGA) based polymeric nanocarrier to deliver copper and sulfur precisely to plants. Thus, this research study aims to evaluate the efficacy of lignin-grafted-PLGA copper sulfide nanoparticles (CuS LNPs) in enhancing soybean, Glycine max (L.) Merrill (Fabales: Fabaceae) growth and health as a nanofertilizer, while simultaneously testing their impact in improving plant defenses against insect pests under open field and greenhouse conditions through feeding bioassays using treated foliage.
Across field and greenhouse experiments, lignin-grafted-PLGA copper sulfide nanoparticles (CuS LNPs) showed limited effects on soybean growth and its insect management. In the field, seed treatment with nanoparticle treatments resulted in extremely poor germination; however, no effects on yield quantity or quality were observed. Foliar applications at various growth stages of soybean did not differ in plant heights, chlorophyll, yield, pest population dynamics, and plant tissue copper and sulfur concentrations among the three treatments, CuS LNPs (nanocarrier with active ingredient), Empty LNPs (only the nanocarrier without any active ingredient), and untreated control (UTC). In no-choice feeding bioassays using foliar treated foliage and soybean looper, Chrysodeixis includens (Walker) (Lepidoptera: Noctuidae) larvae, CuS LNPs affected larval mortality, larval weight, and area of defoliation at 14 days after treatment (14 DAT) but had minimal or no effects at other sampling times. In greenhouse experiments, foliar applications showed no significant difference among treatments in plant heights and chlorophyll. However, in the no-choice feeding bioassays conducted at 14 DAT, larval weights were significantly reduced with CuS LNPs. Overall, CuS LNPs did not improve soybean growth under the tested conditions, indicating their limited effects as nanofertilizer, although their sublethal effects on insect feeding suggest further evaluation. Our results also found no toxic or adverse impacts of these nanoparticles on soybean plants.
Date
3-27-2026
Recommended Citation
MUNAGALA, POORNA KALYANI, "Evaluating the Impacts of Lignin grafted PLGA Copper Sulfide Nanoparticles on Plant Health and Insect Management" (2026). LSU Master's Theses. 6379.
https://repository.lsu.edu/gradschool_theses/6379
Committee Chair
Davis, Jeffrey A.
LSU Acknowledgement
1
LSU Accessibility Acknowledgment
1