Published online by Cambridge University Press: 12 June 2017
Field experiments conducted in 1992 and 1993 evaluated transplanted watermelon tolerance to ethalfluralin applied PPI, PRE (before transplanting), and POST (immediately after transplanting) at 1.2 or 2.4 kg ai/ha. Other treatments for comparison included the registered herbicides ethalfluralin POST-directed spray (PDS), ethalfluralin PDS followed by (fb) naptalam POST, bensulide plus naptalam PPI, and a nontreated check. All treatments controlled common lambsquarters and goosegrass 83 to 100% 2 and 6 weeks after treatment (WAT). Watermelon was injured 30 to 77% in 1992 and 14 to 83% in 1993 by ethalfluralin PPI or PRE at 1.2 or 2.4 kg/ha. Ethalfluralin POST was not injurious to watermelon. In 1992, watermelon treated with ethalfluralin POST at 1.2 and 2.4 kg/ha yielded 52 to 62% more fruit than watermelon from the nontreated check. In 1993, yield of transplanted watermelon treated with ethalfluralin POST was similar to that in the nontreated check.