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Updated: Feb 28, 2026
Topical Application Bioassay to Quantify Insecticide Toxicity for Mosquitoes and Fruit Flies
Published on: January 19, 2022
DDT Polymorphism and the Lethality of Crystal Forms
Jingxiang Yang1,2, C T Hu1, Xiaolong Zhu1
1Department of Chemistry and Molecular Design Institute, New York University, 100 Washington Square East, Room 1001, New York City, NY, 10009, USA.
Abstract:
DDT (1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane), a contact insecticide with a rich and controversial history since its activity was discovered in 1939, has long been thought to be monomorphic. Herein we report the discovery and characterization of a second polymorph, designated Form II, which can be isolated as single crystals, but converts very slowly at room temperature to the form reported previously, now designated as Form I. Computations based on an evolutionary algorithm for crystal structure prediction revealed that Forms I and II are among the four lowest energy crystal structures of fifty calculated. A preliminary study of the contact insecticidal activity toward fruit flies (Drosophila melanogaster) indicates that Form II is more active, suggesting opportunities for more effective solid-state formulations that would allow reduced amounts of DDT, thereby minimizing environmental impact.
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