VATIS UPDATE Article

Researchers at University of Florida, the United States, conducted experiments at the Gulf Coast Research Education Center in Florida, to evaluate nutsedge and broadleaf weed control with combinations of dimethyl disulfide, chloropicrin, 1,3-dichloropropene, and metam potassium in tomato. No fumigant, 131 kg ha-1 1,3-dichloropropene + 200 kg ha-1 chloropicrin (1,3-D+Pic), 392 kg ha-1 of dimethyl disulfide (DMDS), or 340 kg ha-1 of DMDS + 90 kg ha-1 of chloropicrin (DMDS+Pic) were applied with three shanks at 20 cm in a raised bed.

Within each fumigation treatment no metam potassium, or metam potassium at 195 kg/ha was applied at 30 cm using a Yetter rig prior to the initial bed shape, at 10 cm at the top of the bed with six shanks, or at both depths. All beds were covered with TIF plastic immediately after fumigation. The experiment was set up as a factorial with four blocks and conducted in the spring 2014, fall 2014, and spring 2015 crop.

In two of the three seasons, metam potassium applied at 10 cm significantly reduced nutsedge density compared to the nontreated control. Applications at 30 cm appeared to provide no added benefit. Though not always significant, metam potassium alone tended not to provide the level of control achieved when combined with other fumigants at 20 cm. In two of the three seasons, DMDS alone reduced nutsedge density compared to the nontreated control and in all three seasons DMDS combined with metam potassium at 10 cm enhanced the level of control achieved.