A pH-responsive MOF-functionalized hollow mesoporous silica controlled herbicide delivery system exhibits enhanced activity against ACCase-herbicide-resistant weeds.

Abstract

Weeds grow aggressively in agricultural fields, leading to reduced crop yields and an inability to meet the growing demand for food. Herbicides are currently the most effective method for weed control. However, the overuse of herbicides has resulted in the evolution of resistance mutants and has caused environmental pollution. Therefore, new technologies are urgently required to address this global challenge. We report a copper-benzene-1,4-dicarboxylate metal organic framework (Cu-BDC MOF)-functionalized carboxyl hollow mesoporous silica (HMS-COOH) delivery system for the pH-controlled release of the acetyl-CoA carboxylase (ACCase)-inhibiting herbicide quizalofop-p-ethyl (QE). The delivery system (QE@HMS@Cu-BDC) enabled the efficient control of barnyard grasses that are susceptible and resistant to ACCase-inhibiting herbicides, which showed 93.33% and 88.33% fresh weight control efficacy at 67.5 g ha-1 , resepcitviely. With the lowest pH value (3), QE and copper ion were released slowly 70.30% and 78.55% from QE@HMS@Cu-BDC after 89 hours, respectively. QE@HMS@Cu-BDC showed better absorption, conduction, transportation, and ACCase activity inhibition performance than that of QE emulsifiable concentrate (EC) in both susceptible and ACCase-herbicide resistant barnyard grasses. In addition, with the safener effect of carrier HMS@Cu-BDC and the aid of the safener fenchlorazole-ethyl (FE), the application of QE@HMS@Cu-BDC was shown to mitigate the damage caused by QE to rice plant. This work first found this new material (HMS-COOH@Cu-BDC) could be used to mitigate herbicide-induced oxidative stress and improve rice plant safety. Futhermore, the QE@HMS-COOH@Cu-BDC constructed in this research might be used as an efficient nano pesticide formulation for weed controls in paddy rice fields. This article is protected by copyright. All rights reserved.