Preparation of Cu-CS@IN@MIL-100 (Fe) for controlled indoxacarb release and reduced non-target organism risks

Abstract

Control release of pesticides based on target plant characteristics is highly desirable for improving the effective utilization rate and reducing non-target organism risks. Here, the controlled release formulations (Cu-CS@IN@MIL-100 (Fe)) were successfully prepared by employing MIL-100 (Fe) as the carrier material, indoxacarb (IN) as the model pesticide, and chitosan (CS) as a coating to chelate copper ions by chemical crosslinking. The prepared Cu-CS@IN@MIL-100 (Fe) had an acceptable loading content (36.25 %). The introduction of CS and copper ions endowed it with sustained release properties under weak acidity conditions like cotton leaves. The laboratory bioassay experiments showed that Cu-CS@IN@MIL-100 (Fe) had practical good insecticidal activity (LC50 = 4.936 mg/L) in controlling Helicoverpa armigera larvae. For long-term control efficacy experiments, after 14 days of application, the Cu-CS@IN@MIL-100 (Fe) treatment (73 %) mortality of Helicoverpa armigera larvae was significantly higher than the 15 % indoxacarb suspension concentrates (SC) treatment (27 %). Moreover, Cu-CS@IN@MIL-100 (Fe) had no adverse effect on cottonseed germination and the acute toxicity to Chrysopa pallens larvae was significantly lower than IN SC. Therefore, MIL-100 (Fe) could be used as an ecological safety carrier for pesticide delivery to improve IN effective utilization and reduce non-target organism risks.