Researchers and growers test methyl bromide replacement
By Vicky Boyd
Stuart, Fla., tomato grower Jock Ivy says he's confident he can cut his usage of methyl bromide fumigant in half by using metalized silver mulch that retains more of the gas in the soil.
The 2005 season was the first time he tried the reflective bed covering in cooperative trials with U.S. Department of Agriculture plant pathologist Dan Chellemi.
The results were so good that Ivy con-verted his several hundred acres of tomatoes to metalized mulch for the fall 2006 season. Not only does the reflective bed covering hold in the fumigant longerallowing it to do a better job of killing soilborne pestsbut it also repels virus-carrying whiteflies.
"The reflective does seem to help with insects, and it tends to hold the moisture better," Ivy says. "It's stronger, which means you can stretch it over the beds, and it's easier to work with."
The mulch also saves Ivy money by allowing him to use lower fumigant rates and lengthen his insecticide spray intervals.
Chellemi, who'se based in Fort Pierce, Fla., is experimenting with that same mulch technology and methyl iodide, a soil fumigant from Arysta LifeSciences Corp. of Cary, N.C.The fumigant, trade named Midas, is not yet registered.
But the Environmental Protection Agency issued an experimental-use permit in September 2006 that allows 1,000 acres in Florida, Georgia, Michigan, North Carolina, South Carolina, Tennessee and and Virginia to be treated and the crops sold without restrictions.
The company hopes for a similar program in the Southwest this summer, says Mike Allan, Arysta’s global fumigant product manager.
The Midas formulation being tested is a blend of 50 percent methyl iodide and 50 percent chloropicrin.
A race to find replacements
Part of the impetus behind Chellemi’s work is the fact that methyl bromide will be available only for another three to five years.
Under the Montreal Protocol of 1987, developed nations agreed to phase out the use of ozone-depleting chemicals, including methyl bromide. The countries were supposed to halt all production and use of the products by Jan. 1, 2005.
But a handful of countries, including the United States, said they had no methyl bromide alternatives and successfully sought critical-use exemptions.
For the 2007 season, U.S. growers expect to receive an allocation of 18 percent of 1991 baseline levels, which were 56.3 million pounds.