Mitigation Proposal: Control of Resident and Bystander Acute Exposure from Soil 2013a.
Planting beds were prepared with a 6-foot center wheel spacing tractor (2-wheel drive Model 6615, John Deere, Moline, IL) and were fumigated with methyl bromide 80/20 formulation (80% methyl bromide, 20% chloropicrin
) at the rate of 283.5 kg/ ha.
The researchers anticipate that growers will likely end up using an assortment of biological control and chemical options--instead of relying on a few magic-bullet chemicals like methyl bromide paired with chloropicrin
Many began to rely more heavily on other, still allowable fumigants: they increased the percentage of chloropicrin
they used in combination with methyl bromide, or they switched to chloropicrin
alone or in combination with 1,3-D (Telone).
* Fumigants (37 entries, including chloropicrin
, methyl bromide, 1,3-dichloropropene, metam-sodium, metam-potassium, and sulfuryl fluoride)
As a result of this phaseout, which began in 2001, the use of alternative fumigants such as 1,3-dichloropropene (1,3-D) and chloropicrin
(trichloronitromethane) has increased (CDPR 2009).
The pesticides evaluated include chloropicrin
, chlorothalonil, chlorpyrifos, S,S,S-tributyl phosphorotrithioate, diazinon, 1,3-dichloropropene, dichlorvos (naled breakdown product), endosulfan, eptam, methidathion, methyl bromide, methyl isothiocyanate (MITC; metam sodium breakdown product), molinate, propargite, and simazine.
Fumigants other than methyl bromide, such as chloropicrin
, remain widely used in California strawberry production.
Standard Test Method TMS-003: Chlorination Disinfection By-products (Heloacetonitriles, Chloroketones, Chloropicrin
, Chloral Hydrate) in Water.
Recognition of the fungicidal properties of chloropicrin
and the enhanced efficacy achieved by addition of methyl bromide lifted this limitation and allowed for a dramatic expansion in the production of fresh strawberries in California.
Eleven pesticides with more than 1 million pounds per year of use in California had insufficient toxicologic and environmental data for hazard weighting (sulfur, petroleum oil, sodium chlorate, copper hydroxide, mineral oil, copper sulfate, chloropicrin
, petroleum distillates, sulfuryl fluoride, calcium hydroxide, and diuron).
Many perennial crop growers have adopted methyl bromide alternatives such as 1,3-dichloropropene (1,3-D) and chloropicrin
. These alternatives, however, are also highly regulated because of their toxicity and the emission of volatile organic compounds (VOCs), which degrade air quality by forming ground-level ozone.