Adjuvant effects on spray deposition and efficacy of diquat and glufosinate against Euphorbia heterophylla and Digitaria insularis
摘要
Agricultural adjuvants are among the most critical factors influencing spray deposition and herbicide efficacy. This study evaluated spray deposition parameters by applying non-ionic adjuvants on Euphorbia heterophylla and Digitaria insularis, and assessing their effects on the efficacy of diquat against E. heterophylla and glufosinate against D. insularis. Spray deposition treatments involved mixing the herbicides with five adjuvant classes (alkylphenol ethoxylated—AE, nonylphenol polyethanol—NP, trisiloxane ethoxylate—TE, mineral oil—MO, and alkyl ester phosphoric acid—AEPA). Two separate greenhouse dose–response experiments were conducted to identify effective adjuvants for enhancing the efficacy of diquat and glufosinate against E. heterophylla and D. insularis. Spray deposition on E. heterophylla and D. insularis generally improved, with varying results depending on the adjuvant class. All tested adjuvants enhanced diquat efficacy against E. heterophylla, except for TE in the second experiment. Among the adjuvants, AE exhibited the highest performance. However, adding AE, NP, TE, or MO to the glufosinate spray solution did not enhance its effectiveness against D. insularis. Additionally, AEPA exhibited an antagonistic effect on glufosinate performance.