Persistence of the systemic activity of metalaxyl and fosetyl-Al applied as a soil drench or foliar spray to control Phytophora crown rot of peach

The persistence of the fungicides metalaxyl and fosetyl-Al, when applied by soil drenching or as foliar sprays against crown rot of peach by Phytophthora cactorum or P. citrophthora was examined. Metalaxyl and fosetyl- Al applied by soil drenching inhibited both Phytophthora species for 40 days, but inhibition was reduced after 60 days. Foliar application with fosetyl-Al inhibited both pathogens for at least 20 days, but metalaxyl was ineffective as a foliar spray. The data suggest that when applied as a soil drench both metalaxyl and fosetyl-Al provide effective control of Phytophthora crown rot of peach trees.