Notes: (R)-(−)-Metalaxyl-d6 is intended for use as an internal standard for the quantification of (R)-(−)-metalaxyl by GC- or LC-MS. (R)-(−)-Metalaxyl is a fungicide and an active enantiomer of metalaxyl (Item No. 25817).{68502,68503} It is active against several isolates of the plant pathogenic fungus P. nicotianae (EC50s = H. annus) from infection by P. helianthi.{68503} It is toxic to D. magna and D. rerio (LC50s = 176.4 and 237.67 mg/L, respectively).{42435} Formulations containing (R)-(−)-metalaxyl have been used in the control of fungi in agriculture.