Watsonville strawberry farmer Miguel Ramos talks about the use chloropicrin in strawberry production at the Ramos Farm. (Photos by Tarmo Hannula/Register-Pajaronian)
WATSONVILLE — As the California Department of Pesticide Regulation (DPR) conducts a roadshow of new control measures designed to protect residents from acute exposures to a soil fumigant predominantly used by the state’s multibillion dollar strawberry industry, the quest for fumigant alternatives continue.
The new rules, which build on U.S. Environmental Protection Agency (EPA) safety measures that took effect last year, are for the chemical chloropicrin, which is either used on its own or mixed with methyl-bromide or 1,3-Dichloropropene, and then injected into the soil 12-16 inches underground or applied through drip irrigation prior to planting.
Applied only by licensed handlers trained to use the restricted-use pesticide, the treated site is then covered with a barrier tarp, trapping the resulting gasses underneath.
It is the potential of gasses escaping and drifting to nearby structures — schools, houses or neighboring fields where farm laborers work — that the new rules hope to mitigate, and why farm worker advocacy groups and anti-pesticide activists packed the room during a recent DPR public forum in Salinas.
Using data gathered from the DPR, Pesticide Watch claims that chloropicrin was responsible for 22 reported drift poisonings affecting at least 704 people from 2003-2012.
The most recent reported exposure in Santa Cruz County occurred in 2005 when two people working at the county landfill were exposed to the materials chloropicrin and methyl-bromide from a nearby fumigated field, according to the county agricultural commissioner’s office.
Short-term health effects include headaches, itchy watery eyes, dizziness and coughing.
“Like most fumigants, they are impossible to control,” said Dana Perls of Pesticide Watch, which held a press conference before the DPR forum on June 10. “Gasses do escape regardless of how diligent you are about trapping.”
But, Perls said, there is a bigger context at play here.
“We want to see fumigants phased out by 2020,” said Perls. “And we need to support farmers and growers to transition off those fumigants.”
The California Strawberry Commission, which also held a press conference before the Salinas forum last week, has pumped more than $13 million to date on research into fumigant alternatives, but they say none are ready to use across a wide-enough scale.
And as the controversial methyl-bromide is phased out, strawberry growers have come to increasingly rely on chloropicrin to control weeds and soil borne diseases, making any talk of increased regulation a nerve-wracking proposal for conventional growers.
As one Watsonville-based organic grower said, “Conventional growers must be freaking out.”
For conventional strawberry growers, who make up 70 percent of the use of chloropicrin, the chemical is an important tool in “cleansing” the soil prior to planting, ridding the growing area of diseases including the devastating Vertissillium.
Strawberries are also one of the few crops with a high enough profit margin that can afford the $3,000 to $3,500 per acre it costs to fumigate.
In Monterey County, where in 2010 1.7 million pounds of chloropicrin was used (30 percent of the total statewide use), many strawberry growers rotate their fields with lettuce growers, who benefit from the prior year’s fumigation and get higher yields than if they had planted in untreated soil.
According to farm advisor Mark Bolda, some soils are more prone to disease — with Castroville, northwest Watsonville and Salinas with a relatively high disease index — making it challenging for farmers in those areas to grow without the use of fumigants.
At the DPR public forum on June 10, farmers stood up to press their case for chloropicrin.
Jesus Alvarado, a strawberry picker for 40 years and now strawberry farmer, said he had been safely using the chemical for years yet asked the community to support them as they worked to explore alternatives.
“We are working on it, but it is hard,” Alvarado said, adding that he grows both conventional and organic strawberries but that organic takes about 30-40 percent more labor than conventional.
The California Strawberry Commission, which represents more than 400 strawberry growers in the state, operates a testing area in Watsonville at the Monterey Bay Academy where fumigant alternatives are explored, including a sterile substrate system that uses coconut coir or peat instead of soil.
The commission and its partners are also looking at anaerobic solutions, which make soil conditions unfavorable for soil diseases and pests.
Techniques include using a combination of rice bran and water or mustard seed cover crop to create anaerobic conditions under tarps, suffocating the pests.
Watsonville-based Farm Fuel has developed an anaerobic soil disinfestation (ASD) soil amendment made from mustard seed and planted about 130 acres last year and are on track to do 1,000 acres this year, according to CEO Stephanie Bourcier.
“It’s been very successful,” said Bourcier. “We are working with lots of growers who want to treat the buffer zone or are interested in trying a process that does not involve fumigation.”
Bourcier said yields during research trials tended to be comparable to those treated with methyl-bromide while plants were more robust.
The state has also contributed to the effort. Earlier this month, the DPR announced that four California research teams at UC institutions and the U.S. Department of Agriculture-Agriculture Research Service will share approximately $1 million in grant funding to develop less toxic methods to deal with soil-born pests.
In particular, the $153,289 grant to UC Davis will fund further research on alternatives to methyl bromide in strawberry nurseries.
The funding was made possible after California legislators authorized DPR’s new Pest Management Research Grants Program in the state’s 2012/13 budget, which is used to fund research in developing practices that reduce the use of high-risk pesticides.
The University of California Cooperative Extension, Santa Cruz County is also undergoing research trials into fumigant alternatives. Headed up by Bolda, the trials look at biological fungicides, and modifying the soil through flooding or by applying steam, which sterilizes the soil and has been used by growers since the early 1900s.
Bolda said as methyl-bromide is phased out and if access to soil fumigants like chloropicrin became more constrained a combination of tactics would be realistically applied, including looking at different varieties of plants that have been bred to withstand disease.
“It will become a more complicated process, which is where education comes in,” said Bolda of the future of strawberry growing in the state.
Bolda said he expects the strawberry industry will become “more knowledge intensive,” where scientists will be called on to work hand in hand with growers, leaving some farmers who can’t adapt, behind.
“It’s the new paradigm we are moving towards,” he said.
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