While the phase-out of methyl bromide has been challenging for many vegetable producers, researchers have been working diligently to come up with effective alternatives, and there is success to report.

Although these alternatives are effective, they do require a more intense management program utilizing fumigants, mulches and herbicide programs, says Stanley Culpepper, University of Georgia Extension weed scientist.

Culpepper presented his findings at the recent Southeast Regional Fruit & Vegetable Conference held in Savannah, Ga.

Three systems, he says, have performed consistently well in Georgia. They include 1) the UGA 3-WAY, using LDPE mulch; 2) Paladin Pic plus herbicides with a high-barrier mulch; and 3) the WSP plus herbicides with a high-barrier mulch.

For successful fumigation, says Culpepper, each of these systems requires proper bed formation, mulch installation, soil moisture, bed compaction and blow-out-value (to prevent end-of-field dripping).

The UGA 3-WAY, he explains, includes a systems approach using Telone II, chloropicrin and metam (Vapam, others).

“This system has proven its effectiveness when applied accurately. Ideally, this would include Vapam applied 4 inches deep and apart, chloropicrin 8 inches deep and Telone II 12 inches deep,” he says.

This system is more effective and far more consistent with spring application when compared to fall applications, says Culpepper. “Greater than 90 percent nutsedge control has been achieved in 21 of 22 spring experiments.”

Telone II at 12 gallons per acre, chloropicrin at 150 pounds per acre and Vapam at 75 gallons per acre are recommended.

Rates are provided as broadcast, he says, and application should be only in the bed. “When replacing Telone II and chloropicrin, Pic Chlor 60 at 21 gallons per acre is in order, but growers may experience slightly less nutsedge control. In this case, a herbicide program is suggested.

The Paladin Pic program includes a 79:21 mixture of dimethyl disulfide to chloropicrin and is extremely effective in controlling nutsedge as well as nematodes, says Culpepper.