Methyl bromide alternatives

10 Pages·1997·2.7 MB·English

Historic, Archive Document
Do not assume content reflects current
scientific knowledge, policies, or practices.
a
bromide alternatives
USDA
April 199
INS FEB-9 A 2: 28
ae Consideration of Benefits
The New Food Quality;2A h e a Seftitig pesticide tolerances
using Wenefits considerations, builds in
Protection Act Sid
a safety factor for “nonthreshold”
health risks.. Strictly limits exemp-
Cal/EPA Reactions
tions from the established standards to
ensure a stable food supply and
A complex piece of legislation, the mandates that the public be informed
new Food Quality Protection Act when crop emergencies require that
(FQPA) reforms the nation’s food the standard be relaxed.
safety laws. Signed into law by
President Clinton on August 3, 1996, Provides Protection for Infants and
the act amends the two major laws Children
involving pesticides: the Federal Requires explicitly that pesticide
Insecticide, Fungicide, and Rodenti- residues be safe for infants and
cide Act (FIFRA) and the Federal children and includes an additional
Food, Drug, and Cosmetic Act safety factor of 10-fold, if necessary,
(FFDCA). FQPA revises the FFDCA to allow for uncertainty in data
so that the 1958 Delaney Clause no collected on children’s diets. Also
longer affects pesticides. The Delaney takes into account children’s special
Clause established a zero cancer risk sensitivity to pesticides.
This issue and all back issues of the
Methyl Bromide Alternatives newsletter standard for pesticide residues on
are now available on the Internet at some processed foods as compared to Sets National Uniformity
<http://www.ars.usda.gov/is/np/mba/ a negligible risk standard for raw Prohibits state and local governments
mebrhp.htm>. Visit the ARS methyl commodities. from setting pesticide tolerances more
bromide research homepage at <http:// rigid than those established by the
www.ars.usda.gov/is/mb/
FQPA is important to the methyl U.S. Environmental Protection
mebrweb.htm>.
bromide issue because many of the Agency, unless states petition EPA for
potential alternatives to be considered exception.
will fall under its provisions.
Gives Consumers Right To Know
Highlights of the new law include the Requires EPA to prepare for produce
Inside This Issue following: retailers a brochure discussing the
risks and benefits of pesticides, how to
Amends the Federal Food, Drug, avoid risks including recommending
and Cosmetic Act and Creates substitute foods, and identifying foods
Single Safety Standard that have tolerances for pesticide
Replaces the Delaney Clause—thereby residues that were granted under the
abolishing the zero cancer risk benefits provisions of FQPA. Recog-
standard for pesticide residues in some nizes states’ rights to require warning
processed foods—with a single “safe” or labels on food treated with pesti-
standard of a reasonable certainty of cides, such as California’s Proposition
no harm to consumers for pesticide 65.
residues in raw and processed foods.
This newsletter provides information on research for methyl bromide alternatives from
USDA, universities, and industry.
Address technical questions to Kenneth W. Vick, USDA, ARS, National Program Staff,
Bldg. 005, Room 237, BARC-West, 10300 Baltimore Ave. Beltsville, MD 20705.
Phone [phone], Fax [phone].
Address suggestions and requests to be added to the mailing list to Doris Stanley,
USDA, ARS, Information Staff, 6303 Ivy Lane, Room 444, Greenbelt, MD 20770.
Phone [phone], Fax [phone].
U.S. Department of Aor’
Vol. 3, No. 2 Methyl bromide alternatives, April 1997
Regulation, Cal/EPA. Methyl bromide The Section 18 exemption process is
Requires Reevaluation of Tolerances
and its alternatives may be affected by intended to be an expedited process.
Requires all existing pesticide residue
how some of the act’s provisions are Exemptions are short-lived and must
tolerances to be reviewed within 10
years to ensure they meet the new implemented. be reapproved annually. Tolerances
health-based standard. and, therefore, exposures to Section 18
Wells cautions that the tolerance chemicals are time-limited until the
reassessment timeframes are exceed- chemical is registered. Using the
Changes the Federal Insecticide,
Fungicide and Rodenticide Act ingly short, given the complexity of same process to establish tolerances
the new safety standard. Depending for exemptions and full registrations
¢ Pesticide Reregistration Program:
Reauthorizes and increases user on how EPA uses default assumptions seems to contradict the emergency
fees from $14 million to $16 in implementing the new safe standard nature of the process.
million each year; the fees cover for tolerances under the new act,
review of older pesticides to growers could be left with fewer “The way EPA implements this
ensure they meet current stan- products to address pest problems, provision is critical for growers of
dards. Makes reassessment of which could increase the chances of minor crops to continue to respond to
tolerances part of reregistration. pests’ developing resistance to the emergency situations that arise in
remaining compounds. California,” Wells says. “We know
¢ Pesticide Registration Renewal: that EPA is working hard to comply
Requires EPA periodic review of “There could also be a loss of materi- with the new act in a timely fashion,
pesticide registrations to establish als critical to IPM systems, resulting and we’re working closely with
a 15-year cycle to ensure that all in a return to older, more chemically them.”
pesticides meet new safety intensive pest control strategies. Loss
standards. of key pesticides could also result in FQPA is expected to have some
increased usage of remaining com- positive impacts on California
¢ Registration of Reduced-Risk pounds with potentially harmful agriculture. “There are incentives for
Pesticides: Provides for quick environmental and health minor crop uses,” says Wells. “Since
review of reduced-risk pesticides consequences,” he notes. most crops grown in California are
to enable them to reach the market fruits, vegetables and nuts, we're a
sooner to replace older, potentially An example of this would be that loss ‘minor crop’ state. We produce more
more risky chemicals. of insecticides effective at low rates of than 250 raw agricultural commodi-
application may lead to more frequent ties. But they don’t represent major
¢ Minor-Use Pesticides: Establishes use of other insecticides or use at markets for pesticides which were
minor-use programs in EPA and higher rates, causing the potential for developed primarily for use on corn,
USDA to coordinate use issues greater worker exposure and adverse soybeans, wheat, rice, and cotton,
and policy and provides a revolv- environmental consequences such as which are the nation’s major crops.”
ing grant fund to develop data runoff into surface waters or air
necessary to register minor-use pollution. Wells says that California Wells says that in the past, pesticide
pesticides. would like to see EPA move cau- registrants have sometimes made the
tiously and consider the potential economic decision not to produce
Also encourages minotr-use registra- impacts of the use of default assump- costly data to enter or remain in the
tions through extensions for submit- tions on pest management systems. minor crop marketplace. “The
ting pesticide residue data and incentives and program direction
exclusive use of data, flexibility to Under the new act, the requirement for provided by FQPA should begin to
waive certain data requirements, and tolerances for emergency exemptions address the needs of minor crop
requiring EPA to expedite review of under Section 18 of FIFRA could also growers for viable pest management
minor use applications. be significant for California. Section tools, especially if Congress appropri-
18 allows EPA to exempt certain uses ates the authorized funds for the
Cal/EPA Reactions to FQPA of a pesticide from the requirements of revolving grants program to be
the act. These emergency exemptions administered by USDA,” he explains.
While provisions of the new Food address pest emergencies that arise
Quality Protection Act addressing when no suitable pesticides are According to Wells, the reduced-risk
minor crops will have some positive registered for use on that pest. Since provisions of the Act will give EPA the
impacts on California agriculture, the California is unique in its diversity, impetus to further promote develop-
act contains problematic features that pest pressures, climatic conditions, ment of reduced-risk pesticides.
may reduce the availability of impor- and lack of sufficient pest manage- These provisions will allow EPA to
tant pest control tools, according to ment techniques for all minor uses, focus registration priorities on
James W. Wells, director of these Section 18 emergency exemp- implementing integrated pest manage-
California’s Department of Pesticide tions are vital to the health of the ment (IPM) nationwide.
state’s agriculture.
2
U.S. Department of Agriculture
Vol. 3, No. 2 Methy! bromide alternatives, April 1997
“California farmers are well posi- “Although we haven’t found anything power and, thus, a larger tractor than
tioned to expand IPM practices and as effective as methyl bromide, we got that needed for a typical bedder.
adopt reduced-risk pest management good results when we used Tillam to Gilreath says that readily available
practices when new products become control the nutsedge and chloropicrin cultivation equipment typically
available,” he says. for soilborne diseases,” Gilreath consists of a disk and a field cultiva-
reports. “We found that Tillam tor, or an S-tine harrow. This harrow
controls nutsedge in both mulched and has small sweeps and rolling cages on
Using Tillam on nonmulched tomatoes. However, the rear for breaking up soil crusts and
applying a herbicide can require trash. Numerous field ditches for
Florida Tomatoes additional equipment and more time in irrigation and drainage make right
field and bed preparation.” angle disking virtually impossible.
As time ticks away, steadily decreas-
Also, how the Tillam is applied is Given time constraints, especially
ing the number of crop seasons left
vitally important. “The herbicide between the fall and spring seasons in
before 2001, the search for alterna-
must be thoroughly incorporated in the west central Florida, land preparation
tives to methyl bromide intensifies.
soil within minutes after it is applied. must be done quickly with a minimum
Each year, Florida growers produce
Using bedding disks does not provide amount of equipment, according to
fresh-market tomatoes worth about
adequate mixing of the herbicide with Gilreath. “Viability of any alternative
$450 million on 50,000 acres, relying
the soil and could result in crop fumigant would depend on an easy, or
almost exclusively on methyl bromide
injury,” he states. minimal, change in growers’
to rid their soil of pests and diseases.
equipment and operations,” he says.
Researchers at the University of
Although the Tillam label specifies
Florida have stepped up their efforts to
double incorporation by disking at Therefore, in the spring of 1996, he
find pest control strategies that are as
right angles, research has determined and colleagues selected a test site in
effective as methyl bromide, yet
that unidirectional incorporation by Bradenton that was heavily infested
environmentally sound and
disk, field cultivator, or rototiller with purple nutsedge and incorpo-
economically feasible for growers.
followed by preparation of a raised rated Tillam into the soil with one pass
bed gives comparable results. Gilreath of a disk or field cultivator in one
“Controlling weeds, especially purple
says that thoroughly mixing Tillam direction and prepared the beds with a
nutsedge, is one of the most important
into the soil will improve its effective- typical bedder. They compared this
limitations of fumigant alternatives for
ness and reduce its phytotoxicity. plot to one where they used a tractor-
Florida growers who now plant
Also, the soil should be moist and free powered rototiller prior to bed
tomatoes on raised, polyethylene
of clods and large pieces of plant preparation and added applications of
mulched beds of methyl bromide-
debris. A fumigant should then be Telone C-17.
treated soil,” explains James P.
applied as soon as possible after
Gilreath. A weed scientist with the
incorporating Tillam. In fine, sandy soil with 0.78 percent
University of Florida’s Gulf Coast
organic matter and 7.1 pH, they
Research & Education Center in
It is generally recommended that applied Tillam at 4 pounds of active
Bradenton, Gilreath and colleagues
power-driven cultivation equipment or ingredient per acre, and incorporated
have been experimenting with the
a tandem disk be used to apply Tillam the herbicide 6 inches deep with a 5-ft
herbicide Tillam (or pebulate).
preplant, followed by a spike-tooth disk, a 6-ft field cultivator and a
Although Tillam is an old product,
harrow, with disking performed twice tractor-powered rototiller immediately
commercial tomato growers in Florida
at right angles. “In experiments with after application to the soil surface.
have little experience with it because
mulched tomatoes, we got good Telone C-17 was applied at 35 gallons
methyl bromide gives such good weed
nutsedge control by using a rototiller per acre.
control.
to incorporate Tillam, then injecting
Telone C-17 (1,3-dichloropropene plus ‘We found no difference in nutsedge
Aided by University of Florida
17 percent chloropicrin). In fact, this control in plots that were tilled with a
researchers John P. Jones and Joseph
treatment worked as well as methyl] rototiller, disk or field cultivator.
W. Noling, Gilreath has been working
bromide applied alone in many of our When we added a fumigant, nutsedge
with Tillam since 1994. Research
experiments,” Gilreath reports. control was better initially, but by late
collaborators include USDA’s Agricul-
season there was no difference in the
tural Research Service, the Florida
But most tomato growers don’t have amount of nutsedge growing in
Fruit and Vegetable Association, the
rototillers to incorporate Tillam into fumigated and nonfumigated plots,”
Florida Tomato Committee and the
the soil. Although bed preparation Gilreath says. “Plant vigor and fruit
U.S. Environmental Protection
equipment that includes a rototiller in production were greater in fumigated
Agency.
the mouth of the bedder is available, plots, but about the same in plots
the rototiller requires more horse-
3
U.S. Department of Ac’
Vol. 3, No, 2 Methyl! bromide alternatives, April 1997
where Tillam had been incorporated will do to control nutsedge and other a predetermined amount of methyl
by rototiller, disk or field cultivator.” troublesome weeds,” says Gilreath. bromide in a designated space for a
specific residency period. Approxi-
Trials on commercial tomato farms One thing is clear, the future of soil- mately 50 percent of the initial amount
have demonstrated good weed control borne pest control without methyl of methyl bromide is absorbed and the
when Tillam was applied and incorpo- bromide will be one of a more rest is vented to the atmosphere at the
rated with a S-tine harrow, followed prescriptive nature. The grower will end of this period.
by bed formation with bedding disks have to know and target pests in order
or disk hillers and a bed press. to select what is best for individual “Our tests on cherries and grapes in
However, nutsedge was not a problem situations. chamber fumigation have shown
weed on these farms. Gilreath says approximately 20 percent of the
that the acid test is under way this Says Gilreath, “We are entering the methyl bromide is either consumed or
spring on a commercial tomato farm age of integrated pest management in absorbed by the fruit or its containers,
that has a history of nutsedge prob- soil fumigation. It will be a challenge, with the balance vented to the atmo-
lems. “We hope results there will but farmers face those every day. sphere. The amount of methyl
reflect our research findings,” he says. Hopefully, research will lead the way.’ 9 bromide absorbed varies, depending
on the commodity and how it is
Growers are concerned with a number fumigated,” says Willis.
of factors related to fumigant alterna- A New Patented
tives to methyl bromide. Besides As part of a joint collaboration to help
Process Contains,
efficacy, the ease with which a new the Chilean horticultural industry meet
procedure can be adapted is signifi- environmental obligations to reduce
Recaptures, and
cantly important, as is the cost of the emissions of ozone-depleting
equipment replacement and any Recycles Methyl substances, Environment Canada is
inherent changes. Different fumigants helping build a methyl bromide
have different price tags, but all of the Bromide recovery plant. The plant has been
currently available alternatives require installed on the premises of David del
the use of a herbicide like Tillam. At Curto SA in Kalinka, Chile, where
As the new millennium approaches, so
approximately $31.25 per acre, the grapes are fumigated.
cost for Tillam isn’t restrictive. does the proposed methyl bromide
Although proper application increases phaseout. The scientific community is As part of the project, Knowzone
delving deep to find possible alterna-
the cost factor due to equipment and Solutions developed and supervised a
tives to methyl bromide. But a single
manpower requirements, the cost is testing program to ensure the plant
still nominal. solution may not exist. met its intended performance specifi-
cations. Don Smith, a leading expert
A Canadian company, Knowzone
Gilreath says that the package treat- on recycling technology, observed the
ment of Telone C-17 and Tillam costs Solutions, Inc., Etobicoke, Ontario, testing and provided a report for the
about the same as methyl bromide on believes containing, recapturing and Executive Committee of the Multilat-
an equivalent rate basis, but it costs recycling methyl bromide offers the eral Fund. (Copies of the report are
more to apply these materials, and potential to maintain its beneficial available from Errick Willis, Ph: 416-
none of the alternatives are as fool- uses, yet dramatically reduce ozone- 622-7920 or fax: [phone].)
proof as methyl bromide. damaging emissions into the atmo-
sphere. Praxair Canada, Inc., granted The stainless steel methyl bromide
Research has shown that Tillam works Knowzone Solutions, Inc., the recovery plant is a self-contained unit
worldwide right to the patented
as well with chloropicrin and other that sits on a concrete base adjacent to
fumigants as it does with Telone C-17. Bromosorb™ process that contains, the fumigation chamber. It is con-
However, Telone C-17 provides more recaptures and recycles methyl nected by PVC ducts to one of the
bromide.
broad-spectrum pest control than the fumigation chambers. The solid-wall
other alternatives. fumigation chamber is equipped with
“The Bromosorb™ process provides a
internal fans to ensure good fumigant
unique opportunity to capture approxi-
“Whatever alternative we choose most mixing throughout the chamber.
likely will have to be combined with a mately 95 percent of the methyl
herbicide, though few herbicides are bromide currently being released to Gas comes into the recovery plant
the atmosphere,” says Errick Willis,
approved for use on other vegetables. from a low position on the back wall
We really don’t know what growers of president of Knowzone Solutions. of the chamber, and the return line
cucumbers, watermelons, peppers, enters in the back near the top of the
eggplants and a host of other crops In chamber or space fumigation, most chamber, feeding into the internal
of the methyl bromide is vented into circulation duct. Electrical controls
the atmosphere. Soil fumigation uses
4
U.S. Department of Agriculture
Vol. 3, No. 2
Methyl bromide alternatives, April 1997
and instruments are contained in a bromide can be added. The zeolite is The runs were performed at different
cabinet. Since the fumigation cham- then cooled and fumigation continues. times during the day and evening with
ber was designed to operate automati- a range of ambient temperatures.
cally, an operator is only needed to Recaptured methyl bromide is stored However, there was only a small
start the various phases of the opera- on the Halozite® adsorbent until it is difference in the rate of cooling. If the
tion and to monitor the gas concentra- needed again. If the Bromosorb™ recovery plant is going to be used
tion from time to time. unit is permanently attached to a when ambient temperatures are much
fumigation chamber, methyl bromide higher, attention should be given to the
To initiate the fumigation process, the can be regenerated while the fumiga- cooling rates and subsequent adsorp-
chamber is filled with fruit and methyl tion chamber is emptied of the treated tion process to ensure the recycle
bromide is introduced into the commodity and refilled. Regeneration process occurs within a 2-hour time
chamber in accordance with label occurs in a closed loop with air heated limit. The performance specification
instructions. Once the commodity, to 285 °F, which releases the captured called for a reduction in methyl]
soil, or space has been successfully methyl bromide from the Halozite® bromide concentration in the chamber
fumigated, the methyl bromide- adsorbent. to 500 ppm within 45 minutes.
containing air is circulated through the
Bromosorb™ unit where methyl] While in the closed loop, the recycled “There was a loss of approximately
bromide is adsorbed on Halozite®, a methyl! bromide is tested to ensure its 1.6 Kg of methyl bromide in each
type of zeolite, and the exhaust is chemical composition meets the run,” notes Willis. “The most prob-
recycled through the fumigation area. profile of virgin methyl bromide. The able cause is leaks in the connection
This cooled-loop circulation continues gas chromatograph also measures the between the chamber and the recy-
until the concentration of methyl concentration of methyl bromide so a cling unit, because there was no
bromide at the inlet and outlet of the precise calculation can be made of the pressure change during the heating
Bromosorb™ unit are equalized. At additional amounts that must be added and cooling stream. Circulating gases
this point, the exhaust stream contain- and to ensure that fumigation is undergo a temperature change from
ing less than 50 parts per million consistent with the label instructions. approximately 100 °F during cooling
(ppm) of methyl bromide is released Once the fumigation chamber has to hotter than 300 °F during heating.
into the atmosphere to make the area been reloaded with the commodity, the A pressure increase of 0.35 bars (5.25
safe for personnel. recycled methyl bromide is reintro- pounds per square inch) would have
duced to the chamber along with the been expected from a closed system
“For the second cycle, we load the specified amount of virgin methyl] without zeolite.
fumigation chamber while the bromide, and the process repeats itself.
adsorbent is heating,” Willis explains. “Another potential cause of the methyl
“We put the Chilean plant through bromide loss is a breakdown of the
Zeolite holds more methyl bromide seven complete cycles before the methyl bromide on the zeolite. There
when it is cold and much less when performance tests,” says Willis. “In was no indication on the gas chro-
warm. This different adsorptive all, the plant underwent 12 cycles ina matograph of any other compound
capacity is used to release methyl week. The testing program included being formed and there were no odors
bromide from the zeolite so it can be five runs. We conducted four empty- detected that would be present with
returned to the fumigation chamber. chamber fumigation runs and we did acids,” says Willis.
The adsorbent material rejects water, one fumigation on a pallet of fruit to
so its efficiency is unaffected in high see if there were any gross changes in These tests were carried out to achieve
humidity. It also has greater adsorp- plant performance or methyl bromide a minimal fumigant concentration of
tive capacity than carbon at low inlet purity. The fumigation chamber was 48 g/m’, which is equivalent to a 95.5-
concentrations, so it can operate left sealed until the end of run 3, then percent reduction. The adsorption
efficiently in concentrations of less vented in preparation for run 4, where time was extended to 60 minutes for
than 500 ppm. we used fruit. The chamber was also all runs. In the fifth run, a concentra-
vented after runs 4 and 5. tion of 616 ppm (94 percent) was
The heating cycle continues until the achieved. Adsorption performance
temperature of the internally circulat- ‘We concluded that one pallet of fruit results are very repeatable.
ing gas that leaves the zeolite reaches in a 283m? chamber would not
285 °F (140.6 °C). Next, the internal generate sufficient water vapor or Further tests with the fumigation
circulation fan is started and methyl] volatile compounds to carry out chamber loaded with fruit will be
bromide is introduced from the definitive purity tests. We realized necessary. These tests are required to
recovery plant into the chamber. The that testing methyl bromide residues see if the fruit and its packaging
desorption of methyl bromide into the on the fruit from only one pallet would significantly affect the adsorption and
chamber from the hot zeolite begins. not be realistic,” says Willis. desorption process and the amount of
At this point, additional methyl time needed. They will also show
U.S. Department of Agr
Vol. 3, No. 2 Methy! bromide alternatives, April 1997
whether the recycled methyl bromide Basamid (dazomet), Telone C-17 and responses, low pest control and higher
contains unacceptable impurities. methyl bromide in different costs due to double-drip line delivery.
concentrations.
A portable unit, the Bromosorb™ is The Florida experiments also con-
ideal for space or soil fumigation. The “After we compared initial results firmed dazomet to be inferior in
Halozite® adsorbent is maintained at obtained in 1994 from the four controlling nematodes, compared with
ambient pressure and the methyl experimental sites, we knew that a other alternative chemicals like Telone
bromide remains stable indefinitely. separate, but complementary, herbi- C-17. “Under dazomet and metam
This allows the portable Bromosorb™ cide treatment would have to be added sodium treatments, root gall ratings in
unit to be moved to the next fumiga- to all of the fumigants we were most cases were no different from the
tion location where the adsorbent is evaluating if we wanted to control untreated control. We applied
regenerated and the methyl bromide weeds and maintain tomato yields,” dazomet at a 400-pound broadcast
can be used. Noling explains. “For all succeeding rate, which is considerably less than
trials, we included 4 pounds of active the maximum rate labeled for other
“If broadly applied, the Bromosorb™ ingredient per acre of the herbicide crops. Because of its high cost and
technology can dramatically reduce Tillam (Pebulate).” poor performance, we didn’t think it
the amount of damaging methyl prudent or economically viable to
bromide being released to the atmo- According to Noling, the results of the consider increasing application rates
sphere, while preserving its use as an 14 studies indicate that none of the any further,’ Noling says. “Also, there
important fumigant,” says Willis. alternatives came up to the overall were other treatments to explore that
performance of methyl bromide. had higher efficacy at a lower cost.”
Telone C-17, combined with Tillam, Dazomet is not currently registered for
Summary of Florida came closest to methyl bromide in use on food crops in the United States.
maintaining yields and controlling
Studies: Possible nematodes and weeds. None of the Results from the 14 experiments
alternative fumigants, when applied identified Telone C-17 as the next best
Chemical Alternatives
without Tillam, controlled yellow or alternative to methyl bromide. With
purple nutsedge, one of the most high pest pressures, all of the chemical
for Tomatoes
troublesome weeds for Florida tomato alternatives tested—except Telone C-
growers. 17 and chloropicrin combined with
Since the spring of 1994, scientists at Tillam—tresulted in considerably
the University of Florida have “We need to be careful not to apply lower yields than those of the methyl
completed 14 studies on potential these results to any other crop produc- bromide standard.
chemical alternatives to methyl tion system where we now use methyl
bromide fumigation for tomato bromide. For example, using Tillam Telone C-17 also demonstrated
production in Florida. USDA’s on Florida pepper has in some cases excellent control of nematodes.
Agricultural Research Service and the caused severe phytotoxicity,” Noling Compared to chloropicrin, Telone C-
Florida Fruit & Vegetable Association cautions. “Additional research is 17 (with Tillam) controlled nutsedge
collaborated on the research venture. needed to find a suitable alternative better and produced yields closer to
herbicide for crops that can’t tolerate those with methyl bromide, over a
The studies were done at University of Tillam.” broad range of soilborne pest pres-
Florida research facilities in Quincy, sures.
Bradenton, Gainesville and Since most of the studies did not
Immokolee. reflect situations of high disease But Telone C-17 is not without its
severity, Noling says, some may need problems. Noling comments that
“These sites were chosen to reflect to be reexamined. “Also, since all of California cancelled its use in 1990
regional variation in tomato produc- the tested alternative chemicals because of potential human health and
tion practices and were known to be require a longer period to break down safety concerns. Traces of Telone
infested with a number of economi- in the soil, delays will occur in have been found in groundwater.
cally important soilborne pests such as planting crops. Growers will need to However, after considerable field
nematodes, fungi, bacteria and be aware of the possibility of crop research, in 1994, California restored
common weeds,” says Joseph W. phytotoxicity and subsequent yield registration and use of Telone under
Noling. He is a nematologist at the losses; limited acreage and strict enforcement
Citrus Research and Education Center of new application procedures.
in Lake Alfred. After only one trial, Enzone was
dropped from the experiment because “We recognize that Telone C-17, like
Alternative fumigant treatments of poor yields, phytotoxic plant methyl bromide, is not immune from
evaluated included Enzone, Vapam environmental problems and future
(metam sodium), chloropicrin,
U.S. Department of Agriculture
Vol. 3, No. 2
Methyl! bromide alternatives, April 1997
regulatory action which may affect its laboratory, greenhouse and field keep the tube from melting. (2) While
use in agriculture,” Noling says. experiments. The experimens were painting the plastic white to terminate
“Recent action by the U.S. Environ- validated in large-scale demonstration the solarization period, growers must
mental Protection Agency ensures that plots on six commodities at nine make certain that coverage is uniform
the manufacturer of Telone will likely different commercial farms. and complete to prevent any additional
have to reduce maximum application solar radiation from penetrating the
rates on the label, limit geographical Due to differences in fertilizer plastic and heating the soil to levels
areas of use, and significantly increase applications, inadequate coverage of detrimental to the health of
requirements for personal protective paint during termination of the transplants.
safety equipment for field workers.” solarization period, or failure to
collect complete yield data, a direct In a followup survey of participants
In addition to concerns like planting yield comparison between soil evaluating the performance of soil
delays, potential phytotoxicity, cost, solarization and methyl bromide solarization, growers indicated that
and possible corrosion of storage treated plots was made on three of soil solarization has a future role in
containers, there is the issue of seven farms with fresh market tomato. their production system. When asked
commercial availability. DowElanco, On one farm, solarization out-yielded what extent of their total acreage
the manufacturer of Telone, does not methyl bromide-treated plots by 122 could utilize soil solarization, the
have the facilities to produce enough boxes per acre. On the other two response varied from undecided to 50
of the chemical to supply the potential farms, methyl bromide out-yielded percent.
demand of the agricultural community soil solarization plots, but by less than
should the chemical be broadly 100 boxes per acre. In the location In conclusion, soil solarization appears
adopted for use on an extensive scale. where pepper was evaluated, grower to be a viable alternative to preplant
“The development of any new packout data indicated that methyl fumigation with methyl bromide for
chemical alternative to methyl] bromide out-yielded soil solarization fall-cropped fresh market vegetables
bromide, especially one that will be plots by 78 boxes per acre. in Florida. However, soil solarization
extensively used, is likely to raise has specific application requirements
new and unexpected questions and Weed suppression in soil solarization and limitations which will restrict its
problems that must be addressed plots was comparable to plots treated widespread application. Fields must
before the alternative can be imple- with methyl bromide in all locations be prepared and plastic applied seven
mented,” Noling comments. except when purslane (Portulaca or eight weeks before planting. Soil
oleracea L) and Texas panicum moisture requirements are more
(Panicum texanum Buckl.) were stringent than those required for
TECHNICAL present. In these cases, soil solariza- fumigation with methyl bromide. Soil
tion failed to provide adequate control. solarization alone does not provide
REPORTS
At low levels of disease, soil solariza- effective control of plant parasitic
tion provided better control of nematodes and when used in a
southern blight (Sclerotium rolfsii) nematode-infested field, should be
than methyl bromide (Maxwell/ combined with an effective nemati-
Suber). Root gall ratings of root cide. Suppression of weeds to the
systems indicated that soil solarization point of eliminating their effect on
did not provide adequate control of yield is adequate in most situations,
Principal Investigator: D.O.
root-knot nematodes (Meloidogyne but it should be pointed out that weed
Chellemi, University of Florida, North
spp.). Combining solarization with growth beneath the plastic mulch is
Florida Research and Education
reduced rates of Telone C-17 provided not eliminated.
Center, Quincy, FL 32351, now with
reductions in root galling similar to
the ARS-U.S. Horticultural Research
those achieved with methyl bromide. Finally, we highly recommend that
Laboratory, Orlando, FL 32803.
In general, it appeared that the longer soil solarization be used within the
Cooperators: S.M. Olson, R.
the solarization period, the more context of an IPM program for
McSorley, J.R. Rich, K.D. Shuler, L.E.
effective the suppression of soilborne soilborne pests which includes the
Datnoff, and K.L. Pernezny
pests. Soil moisture at or near field coordinated use of multiple pest
capacity was also essential for management tactics based on scouting
Florida fresh-market tomato producers
effective suppression of soilborne reports of prior pest levels.
account for 17 percent of all methyl
pests.
bromide use in the United States. In
Adoption of this approach will require
an effort to develop an integrated pest
Two technical problems which became additional management of information
management program (IPM) for
evident during the large-scale applica- and decisionmaking by the grower.
soilborne pests of fresh-market
tions were: (1) If drip irrigation tubing
tomato, we investigated the potential
is used, it must be covered with soil to
contribution of soil solarization in
U
U.S. Department of Agr:
Methyl bromide alternatives, April 1997
Windsor, Ontario, Canada —May 19-26, 1997
Ontario is hosting the International Scientific Conference, Greenhouse Grower Conven-
tion and Trade Show, May 19-26, at the Cleary International Center and Windsor Hilton
Hotel in Windsor. Called “Growing Media and Hydroponics,” this year’s meeting will
feature Cees Sonneveld from the Netherlands, Merle Jensen, USA, and Peter Adams, UK,
along with 44 more invited speakers from 18 countries.
For more information, contact Tom Papadopoulos, Greenhouse and Processing
Crops Research Center, Agriculture and Agri-Food Canada, Harrow, Ontario, NOR
1GO; phone: [phone], ext. 423; fax: [phone]; e-mail,
papadopoulost @em.agr.ca; website, <http://res.agr.ca/harrow/circ09.htm>.
Monterey, California —June 10-12, 1997
The Methyl Bromide Global Coalition is sponsoring the 1997 Methyl Bromide State of
the Science Workshop, June 10-12, at the Double Tree Hotel, Two Portola Plaza in
Monterey, CA.
Purpose is to update scientific knowledge on the role of bromine and methyl bromide in
stratospheric ozone loss, identify remaining uncertainties, and discuss possible future
research. The workshop will be presented in five sessions: Atmospheric Measurements,
Sources and Sinks, Laboratory Kinetics, Modeling, and Open Discussion.
For additional information, contact Bobbie McCallum, Methyl Bromide Global
Coalition, P.O. Box 57, Hollister, CA 95024; Overnight delivery address, 8770
Highway 25, Hollister, CA 95023; phone: [phone]; fax: [phone].
San Diego, California —November 3-5, 1997
Mark your calendar for the 1997 Annual International Research Conference on Methyl
Bromide Alternatives and Emissions Reduction, to be held November 3-5 in San Diego.
Scientists from around the world will present new research information and updates on
promising alternatives to methyl bromide. More information will be available soon from
Methyl Bromide Alternatives Outreach (MBAO). A call for papers will be issued shortly.
For additional information call MBAO at 209-244-4710.
Mention of trade names or commercial products in this publication is solely for the purpose of
providing specific information and does not imply recommendation or endorsement by the
U.S. Department of Agriculture.
This publication reports research involving pesticides. It does not contain recommendations
for their use nor does it imply that uses discussed here have been registered. All uses of
pesticides must be registered by appropriate State and/or Federal agencies before they can be
recommended.
The United States Department of Agriculture (USDA) prohibits discrimination in its programs
on the basis of race, color, national origin, sex, religion, age, disability, political beliefs, and
marital or familial status. (Not all prohibited bases apply to all programs.) Persons with
disabilities who require alternative means for communication of program information (Braille,
large print, audiotape, etc.) should contact the USDA Office of Communications at (202)
720-2791.
| To file a complaint, write the Secretary of Agriculture, U.S. Department of Agriculture,
Washington, DC, 20250, or call 1-800-245-6340 (voice) or [phone] (TDD). USDA is
an equal employment opportunity employer.
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