Semester of Graduation

Spring 2026

Degree

Master of Science (MS)

Department

Entomology

Document Type

Thesis

Abstract

Botanical insecticides are derived from natural sources and widely used in agriculture.  However, their effectiveness is often limited by the rapid degradation under UV light.  One example is azadirachtin (Azadirachta indica), a natural compound that comes from the neem tree, and is widely known for its antifeedant properties as well as for being an insect growth regulator which impacts insect normal development.  Although azadirachtin has good properties as an insecticide, it is highly susceptible to ultraviolet light which reduces its persistence and efficacy.  Nanoparticles represent a promising innovation in insect pest management as a delivery system, enhancing insecticide efficacy through the improvement of chemical stability and controlled release of the active ingredient.  Therefore, this study evaluated the use of a lignin based nanodelivery system to improve azadirachtin efficacy to control insects.  Laboratory experiments were performed using adult Myzus persicae (Sulzer) to assess insect mortality, settling behavior, and probing behavior after exposure to nanoentrapped azadirachtin.  Field experiments were also conducted in soybean to evaluate insecticidal performance by measuring soybean pest populations, seed damage, and 100-seed weight.  Laboratory results showed that nanoformulations increased aphid mortality over time, but a limited effect was shown in probing and settling behaviors.  Field results showed AzaMax (formulated product) caused early mortality, weight reduction, and reduced feeding by Chrysodeixis includens (Walker) when larvae were exposed to soybean leaves treated with AzaMax.  However, field sampling revealed that none of the treatments were found to have significant differences in the numbers of stink bugs [Piezodorus guildinii (Westwood), Nezara viridula (L.), and Euschistus quadrator Rolston], and Spissistilus festinus (Say) over time (0, 2,7, 14 days after treatment).  Because of the lack of consistent suppression of stink bugs, no significant improvements were detected in seed damage and 100-seed weight. Therefore, it was concluded that lignin-based nanoparticles entrapped with azadirachtin did not consistently enhance efficacy.

Date

3-26-2026

Committee Chair

Davis, Jeffrey A.

LSU Acknowledgement

1

LSU Accessibility Acknowledgment

1

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Available for download on Friday, March 26, 2027

Included in

Entomology Commons

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