Imidacloprid Crystal Polymorphs for Disease Vector Control and Pollinator Protection

Xiaolong Zhu, Chunhua T. Hu, Bryan Erriah, Leslie Vogt-Maranto, Jingxiang Yang, Yongfan Yang, Mengdi Qiu, Noalle Fellah, Mark E. Tuckerman, Michael D. Ward, Bart Kahr

Research output: Contribution to journalArticlepeer-review


Imidacloprid, the world’s leading insecticide, has been approved recently for controlling infectious disease vectors; yet, in agricultural settings, it has been implicated in the frightening decline of pollinators. This argues for strategies that sharply reduce the environmental impact of imidacloprid. When used as a contact insecticide, the effectiveness of imidacloprid relies on physical contact between its crystal surfaces and insect tarsi. Herein, seven new imidacloprid crystal polymorphs are reported, adding to two known forms. Anticipating that insect uptake of imidacloprid molecules would depend on the respective free energies of crystal polymorph surfaces, measurements of insect knockdown times for the metastable crystal forms were as much as nine times faster acting than the commercial form againstAedes, Anopheles, andCulexmosquitoes as well asDrosophila(fruit flies). These results suggest that replacement of commercially available imidacloprid crystals (a.k.a. Form I) in space-spraying with any one of three new polymorphs, Forms IV, VI, IX, would suppress vector-borne disease transmission while reducing environmental exposure and harm to nontarget organisms.

Original languageEnglish (US)
Pages (from-to)17144-17152
Number of pages9
JournalJournal of the American Chemical Society
Issue number41
StatePublished - Oct 20 2021

ASJC Scopus subject areas

  • Catalysis
  • General Chemistry
  • Biochemistry
  • Colloid and Surface Chemistry


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