US Environmental Protection Agency
Office of Pesticide Programs
Addendum to the 2002 Interim
Reregistration Eligibility Decision (IRED)
for Disulfoton
December 20, 2008
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United States Prevention, Pesticides EPA 738-R-02-010
Environmental Protection and Toxic Substances December 2008
Agency (7508P)
Addendum to the
2002 Interim
Reregistration
Eligibility Decision
(IRED)forDisulfoton
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ADDENDUM TO THE 2002 INTERIM
REREGISTRATION ELIGIBILITY DECISION
(RED)
For
Disulfoton
CASE No. 0102
Approved by:
Steven Bradbury, Ph.D.
Director
Special Review and
Reregistration Division
Date:
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I. Introduction
This document serves as an Addendum to the Disulfoton Interim Reregi strati on
Eligibility Decision (IRED), which was completed in March 2002 and published in July
2002. This addendum addresses public comments received on the IRED and also
discusses the status of several studies required to confirm the Agency's reregi strati on
decision. The IRED served as an interim regulatory decision for disulfoton while the
cumulative risks of the organophosphate pesticides were considered, as required by the
Food Quality Protection Act (FQPA). The Organophosphorus (OP) Cumulative Risk
Assessment, 2006 Update, issued on July 31, 2006, completed the Agency's reassessment
of all disulfoton tolerances, taking into account the cumulative risks of exposure to this
group of OP pesticides with a common mechanism of toxicity. As stated in the Federal
Register notice of August 2, 2006, as a result of the publication of the Organophosphorus
Cumulative Assessment, the IREDs previously issued for a number of organophosphate
pesticides, including disulfoton, are now considered final Reregi strati on Eligibility
Decisions (REDs). The disulfoton RED, in conjunction with the Organophosphorus
Cumulative Risk Assessment and this Addendum, presents the Agency's assessment of
the dietary, occupational, non-occupational, and ecological risks associated with the use
of disulfoton and identifies risk mitigation measures that are necessary to support its
continued use.
A. Background
The disulfoton 2002 IRED concluded that there are no dietary (food and drinking
water) risks of concern associated with the current use of disulfoton. To address potential
risks associated with the residential use of disulfoton, EPA required registrants to
implement a number of mitigation measures, including child resistant packaging and
deletion of indoor and home garden use. Therefore, remaining residential uses do not
exceed the Agency's level of concern. To mitigate ecological risk, the Agency limited
applications of disulfoton to one per calendar year for all crops, except for asparagus,
barley, coffee, and peanuts (North Carolina only), for which no more than two
applications of disulfoton per calendar year are permitted.
The 2002 IRED identified occupational risks of concern [margins of exposure
(MOE) < 100] for handlers who mix, load, and apply disulfoton and for workers who are
exposed to disulfoton residues after application to agricultural crops. As part of its
assessment, the Agency considered the benefits of registered uses and identified measures
necessary to mitigate these occupational risks of concern, such as the cancellation of
certain uses, the requirement of engineering controls for mixing, loading, and application
of products containing disulfoton, and the use of maximum Personal Protective
Equipment (PPE) when engineering controls are not feasible.
To confirm its reregi strati on conclusions, the Agency required the submission of
confirmatory data, which among other requirements included: 1) a worker exposure
monitoring study; and, 2) a drinking water monitoring study for disulfoton and its
degradates to confirm conclusions that drinking water risks are likely to be lower than
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modeled estimates. The Agency issued a generic data call-in (DCI) for these studies in
January 2004.
The Agency received a number of substantive comments concerning the
mitigation measures proposed in the IRED. Some comments addressed the need to add
an additional commodity, Christmas trees, to the list of crops eligible for a second
application of disulfoton. Other comments focused on issues concerning the 2002
IRED's mitigation measures required for use of disulfoton on commercial ornamentals,
asparagus, barley and wheat.
II. Disulfoton Conifer Tree Use
A. Request for Two-Application Exception for Christmas Trees
The Agency received comments from the North Carolina Cooperative Extension
Service on August 16, 2002, requesting that the Agency allow two applications to
Christmas trees as was allowed for asparagus, barley, coffee, peanuts (North Carolina
only), and potatoes. As part of the ecological risk mitigation measures stipulated in the
IRED, Christmas tree growers were to be limited to one application of disulfoton per
calendar year.
The commenter claimed that a second application in the late summer or early fall
during drought conditions is sometimes necessary to control resurgence in spider mite
populations. The Agency has established that at this time there are no viable alternatives
to disulfoton under these pest conditions. Also, usage reports indicate that instances of a
second application are relatively low; one report indicated that fewer than 2% of growers
chose to reapply disulfoton in dry years. Although the maximum number of applications
would increase, the maximum seasonal rate would still be limited to 4.5 Ib a.i./A, the rate
stipulated in the 2002 IRED. Consequently, the Agency has decided to allow a second
application of disulfoton to Christmas trees, if needed.
B. Results of Confirmatory Worker Exposure Monitoring Study
Bayer CropScience (Bayer), the technical registrant of disulfoton, submitted
voluntary cancellation requests for most uses of Di-Syston 15G (EPA Reg. No. 264-723)
(15% active ingredient disulfoton in a granular formulation), rather than develop
confirmatory worker exposure monitoring data required by the generic data requirements
of the IRED. However, Bayer ultimately chose to keep Christmas tree and coffee uses on
the label. The IRED stipulated that the use of the granular formulation on coffee
was eligible for reregi strati on provided that a closed transfer system was implemented by
June 2004; current labels incorporate this requirement. The granular formulation for
Christmas trees was deemed eligible for reregi strati on provided that the application rate
was reduced to 4.5 Ib a.i./A, the use was limited to firs, a closed transfer system was
implemented by June 2004, and confirmatory exposure data for loader/applicators
demonstrated risk within acceptable parameters.
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In support of the continued use of the Di-Syston 15G formulation on Christmas
trees, the Di-Syston Exposure Task Force submitted a study in February 2005, entitled
"Pesticide Exposure Study for a Hand-Operated, Metered, Closed System Applicator for
Di-Syston® (Disulfoton) in Fraser Fir Production in Western North Carolina" (MRID
464780-01). The study sought to determine the dermal and inhalation exposure to
agricultural workers when using a new closed-system applicator (the Select-a-Feed
system) for applying granular insecticide (Di-Syston 15G granules) at the base of Fraser
fir Christmas trees.
In the study, workers wore an inner whole body dosimeter, short sleeved shirts
and short pants, a disposable Tyvek® suit, gloves, hat, and a dust/mist respirator. As use
of the Tyvek® suit exceeds the personal protective equipment (PPE) requirements listed
on the current product label (current PPE requirements for Di-Syston 15G use on
Christmas trees include: long sleeved shirt and long pants, shoes plus socks, and loaders
must wear chemical resistant gloves), the Agency believes this worker exposure study
does not adequately represent the possible exposures that could result from using the
Select-a-Feed applicator system. However, the Agency does believe that the study
provides evidence that a closed system granular dispenser, such as the Select-a-Feed
system, would likely greatly reduce dermal and inhalation exposure to disulfoton during
granular applications to conifer trees. Consequently, the Agency will not require
additional confirmatory worker exposure data to maintain the granular use on Christmas
trees. As stipulated in the IRED, the loading of disulfoton for use on conifer trees must
be made with a closed loading system that meets the requirements listed in the Worker
Protection Standard (WPS) for agricultural pesticides [40 C.F.R. 170.240(d)(4)] and that
is designed by the manufacturer to enclose the pesticide to prevent handler contact.
III. Request for Continued Use of Disulfoton on Easter Lilies
The 2002 disulfoton IRED established that there was not a critical need for
disulfoton use on ornamentals grown for field or nursery stock on a national basis and
concluded that this use is not eligible for reregistration. This decision was based on a
number of factors, including low reported usage of disulfoton on ornamentals, in general,
and the availability of a number of alternatives. However, during the public comment
period for the IRED, the Easter Lily Research Foundation and Crockett United Lily
Growers, Inc. submitted comments on June 18, 2002 and July 9, 2002, respectively,
concerning the use of disulfoton on field-grown lily bulbs. These groups requested
Special Local Need (SLN) FIFRA Section 24(c) registrations to allow the continued use
of disulfoton on Easter lilies in Oregon and California. SLN registrations were issued
based on information provided in public comments and from communication between the
Agency and the commenting parties. A subsequent comment submitted by the Easter
Lily Research Foundation on October 24, 2004 requested the use of Di-Syston 8
Emulsifiable Concentrate (SEC) on Easter lily bulbs rather than the granular formulation.
Although the Agency evaluated ornamental uses for the IRED, the use of
Disulfoton on Easter lily bulbs was not assessed specifically. As described in the
comments, the bulbs are planted in furrows in the fall. After placing the bulbs in the
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furrows, a tractor applies Di-Syston directly over the bulbs before a soil implement
covers the bulbs with anywhere from 2.5 to 6 inches of soil depending on the size of the
planting stock. Workers do not enter the fields again until the following spring.
Commenters also state that use rates are within the range of the Federal label rate of 3.5
to 7.25 ounces of Di-Syston 15G per 100 row feet. The use rates (taking into account
row spacing) in pounds active ingredient per acre are as follows:
• 13,068 row feet per acre with 40 inch spacing equals 4.3 to 8.9 Ib a.i./A;
• 14,520 row feet per acre with 36 inch spacing equals 4.8 to 9.9 Ib a.i./A;
These rates correspond to the rates on the national labels prior to the signing of
the IRED. When the Agency calculated margins of exposure (MOEs) for the use rates
above (assuming 5 to 10 acres treated per day), most short-term risks did not exceed the
Agency's level of concern with the addition of gloves and a dust/mist respirator (as
required on the label) except at the higher acreage (10 acres) and at higher rates (8.9 and
9.9 Ib a.i./A). The maximum single rate of application is revised to not exceed 8.48 Ib
a.i./A.
The Agency is aware that the ornamental industry has little tolerance for insect
damage that can result in aesthetically imperfect plants that consumers will not purchase.
The Agency did evaluate several alternative insecticides but found that none matched the
overall efficacy of disulfoton. Disulfoton use on Easter lily ornamentals in the United
States takes place exclusively in Oregon and California, and existing application methods
should minimize applicator exposure. Based on this information, the Agency believes
there is a strong justification for the continued registration of disulfoton for Baser lily
bulbs and has approved the SLN requests. In 2005 and 2008 respectively, SLN
registrations were granted to allow the use of Di-Syston SEC on Easter lily bulbs in the
states of Oregon and California. Subsequently, the Easter lily use was placed on the
national Di-Syston 8 EC label (EPA Reg. No. 264-734). Please refer to a Memorandum
entitled "BEAD Responses to Comments from Stakeholders on Disulfoton Interim
Reregi strati on Eligibility Decision" dated November 21, 2002, for more information on
the Agency's evaluation of these comments.
IV. Request for Reduced Asparagus REI
The reregi strati on decision for disulfoton use on asparagus stipulated that the
liquid formulation only was eligible for reregistration, and then only in states where
disulfoton was registered as a Section 24(c) SLN for asparagus. The IRED reduced the
maximum number of allowable applications for asparagus from three times per year to
two times per year and the Restricted Entry Interval (REI) was extended to 26 days.
Bayer CropScience subsequently submitted a draft SLN label proposing an REI of 7 days
for disulfoton use on asparagus in the state of Washington. In support of the 7-day REI,
Bayer CropScience submitted two separate studies to EPA assessing postapplication
exposure to disulfoton following application to potatoes:
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• Dingledine, J, et al. (1989) Di-Syston 8: A Residue Monitoring study in Potatoes
to Assess Exposure to Avian Species Following Broadcast Application in
Michigan. Bayer Report No. 99620. MRID No. 41201801
• Willard, T. (1998) Dissipation of Dislodgeable Foliar Disulfoton Residues from
Di-Syston 8 Treated Potatoes. Bayer Report No. 108561. MRID No. 44688001.
A. Study Results and Analysis
EPA deemed neither study adequate to assess postapplication worker exposure
because total toxic residues could not be converted to surface residues in the residue
monitoring study, and possible toxic degradates were not considered in the dislodgeable
foliar residue study. However, Bayer CropScience subsequently combined the studies
and used the specific leaf weight of potato leaves to evaluate dislodgeable foliar residue
dissipation. The pesticide residue amounts derived from leaf weight were used to
estimate postapplication worker exposure to disulfoton after foliar applications to crops.
In evaluating the study data, the Agency found it appropriate to differentiate between arid
and non-arid areas to allow for the decreased dissipation inherent in arid areas and the
innate increased dissipation characteristics of non-arid areas. The Agency has
determined that an 11-day REI is appropriate for arid areas (where average annual
rainfall is less than 25 inches per year) and a 7-day REI is appropriate for non-arid areas.
This distinction results in MOEs > 100 for both arid and non-arid areas. As indicated in
the IRED, use of Di-Syston 8 on asparagus will continue to be limited to states with a
Section 24(c) SLN: California, Michigan, North Carolina, Oregon and Washington.
V. Request for Continued Use of Disulfoton on Barley
In response to the 2002 IRED, the Agency received comments from the Idaho
Barley Commission in August 2002. The Commission submitted economic loss
scenarios resulting from the proposed deletion of disulfoton as a treatment option. Two
economic loss scenarios were mentioned: quality reduction and yield loss. The analysis
concludes that 50% of the affected harvest would be downgraded from the higher-priced
malting barley market to the feed market if disulfoton use was deleted. In addition, the
analysis estimates yield losses of 30% for all states except Montana (2%) and Colorado
(20%). The economic impact was calculated by multiplying the adjusted yield loss
production figures by the price differential between the malting and feed markets for each
state.
The Idaho Barley Commission stated that these economic losses would be due
primarily to damage by the Russian wheat aphid, which they contend would be more
difficult to control if disulfoton was unavailable. These pests hide inside tightly-curled
younger leaves of plants, which protect them from parasitic insects and from insecticides
that act through direct contact. Disulfoton, a systemic pesticide that is absorbed by the
plant, is more effective in controlling this aphid species. The Commission estimated that
the aggregated negative economic impact to U.S. barley producers from a cancellation of
disulfoton use would be approximately $4 million annually.
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After reviewing stakeholder concerns, the Agency concurs that some negative
economic impact is likely to occur for barley growers in the event of disulfoton
cancellation. However, the Agency has determined that viable alternatives are available
to growers including imidacloprid and thiamethoxam as seed treatments, and methyl
parathion in place of disulfoton foliar sprays. Stakeholders asserted that methyl parathion
is not a viable alternative because malting barley buyers will not purchase barley that has
been treated with methyl parathion, apparently for marketing reasons. However, the
Agency was unable to confirm these assertions as the malting barley breweries contacted
would not disclose their pesticide use requirements.
In addition to the availability of alternative treatments, the Agency considered
several other factors in the disulfoton barley reregi strati on decision. The nationwide
proportion of barley acreage treated with disulfoton is low (less than 0.5% based on
USDA/NASS estimates). Thus, negative economic impact on national barley production
is likely also to be low. In addition, modifications of cultural practices can significantly
reduce the risk of aphid infestation. These practices include planting the crop later in the
season to avoid aphid migratory flights and discing or otherwise controlling weeds in or
near fields that could serve as a refuge for aphids, although some aphids (e.g., greenbugs)
are not as effectively managed by this latter method.
In conclusion, based on the most current pest management and economic
information available, the Agency believes that some barley growers may suffer
economic losses without the use of disulfoton as a foliar application. However, these
losses will most likely be due to the deprivation of premium target markets and increased
cost of seed treatment, as opposed to direct yield losses due to insect pest. Furthermore,
based on the current low levels of disulfoton usage, the Agency believes that the majority
of growers will not be significantly affected in this way. The Agency is also confident
that the national production of barley will not be significantly affected, in terms of
economic returns, by the loss of foliar disulfoton. Therefore, the Agency will proceed
with the cancellation of disulfoton use on barley, as specified in the 2002 IRED. Please
refer to the Memorandum entitled "BEAD's Updated Response to Comment from a
Stakeholder on Disulfoton Interim Reregi strati on Eligibility Decision" dated November
4, 2004 for additional information on the Agency's evaluation of this comment.
VI. Comment Concerning Cancellation of Di-Syston 15G on Wheat
A comment dated May 24, 2005 from Dr. David Buntin of the University of
Georgia claimed a lack of viable alternatives for the 15% granular formulation of
disulfoton, Di-Syston 15G, to control the Hessian fly on winter wheat crops in the
Southeastern United States. The 2002 IRED had stipulated that all registered uses of
disulfoton on wheat were to be phased out by June 2005, as part of the mitigation effort
to address drinking water, ecological, and occupational risks.
To evaluate this comment, the Agency investigated the availability of viable
alternatives to control the Hessian fly, as well as the economic significance of winter
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wheat in the Southeastern United States. The primary means of Hessian fly management
is through utilization of resistant cultivars of wheat and by planting later in the fall.
When resistant strains are not available, chemical control becomes the primary means of
pest management. There are a limited number of chemical control options available: two
pyrethroid chemicals, thiamethoxam and lambda-cyhalothrin, are registered for foliar
applications. However, these chemicals target only the adult Hessian fly, leaving a
narrow window of generally only two days for effective application. Imidacloprid is
registered as a seed treatment, but the cost of applying imidacloprid to winter wheat crops
is expected to be substantially more expensive than disulfoton application. In addition,
another organophosphate insecticide, phorate, is no longer registered for use on wheat.
The lack of an effective, economical alternative to Di-Syston 15G affords winter wheat
growers minimal alternatives when resistant varieties are unavailable.
The Agency also investigated the significance of winter wheat for the
Southeastern United States (including Georgia, South Carolina, Alabama and Florida),
where Hessian flies have the potential to damage winter wheat crops. Considering 2004
numbers, total harvested acreage for the region amounted to approximately 360,000
acres, or about 1% of the U.S. total. Economic data for Georgia were used as a case
study to evaluate the economic significance of winter wheat for the region. In Georgia,
the economic significance of winter wheat amounts to less than 1% of the $2.35 billion
agricultural economy.
Winter wheat is not a large portion of Georgia's or the Southeastern United
States' agricultural economies. However, if winter wheat is the only grain crop planted
in the winter in double-crop systems in this region, the Agency recognizes that it could
still constitute an important component of the region's economy despite its small acreage.
For additional details concerning the Agency's evaluation of this comment, please see the
memorandum entitled "Impact of Loss of Disulfoton for Hessian Fly Control in Alabama,
Florida, Georgia, and South Carolina Winter Wheat," dated March 12, 2008.
Although the Agency's evaluation established the economic significance of
winter wheat, the 2002 IRED determined there is substantial occupational risk associated
with the application of disulfoton on wheat. MOEs (margins of exposure) of < 100 are
considered of concern by the Agency and many of the handler scenarios for disulfoton
had MOEs < 100, even with the use of maximum PPE (i.e. double layer clothing, gloves,
and a respirator). Of particular concern are ground applications, which according to
information provided, are the preferred methods of application for controlling the Hessian
fly. Handler exposure while loading the granules into the ground application equipment
is of particular concern. Currently, there is no closed system available for Di-Syston 15G
use on winter wheat to minimize risk during loading and application to mixer-loaders and
applicators. In the absence of application equipment capable of minimizing worker
exposure while handling Di-Syston 15G granules, the Agency will continue to not allow
the use of Di-Syston 15G on winter wheat.
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VII. Waiver Request for a Surface Water Monitoring Study for Disulfoton
The technical registrant for disulfoton, Bayer CropScience, submitted a waiver
request in response to the generic DCI requirement included in the IRED for a surface
water monitoring study for disulfoton and the degradation products, the oxons d.
sulfoxide and d. sulfone. Aquatic metabolism studies submitted to the Agency indicate
that while disulfoton itself is not persistent in water, the total residues including the
parent and the degradates d. sulfoxide and d. sulfone are persistent, with aquatic half-
lives ranging from 46 to 51 days for aerobic aquatic metabolism and 315 to 385 days for
anaerobic aquatic metabolism. The 2002 IRED had assumed a half life of 259 days for
both the anaerobic and aerobic metabolism rates. In the absence of refined toxicity
information on these degradates, the 2006 OP cumulative considered the sulfone oxon at
least lOx as toxic as the parent chemical. This assumption differs from the 2002 IRED,
which considered the oxon degradates and the parent chemical to be of equal toxicity.
In support of the waiver request, the registrant submitted an updated Tier 2
PRZM/EXAMS analysis based on a revised disulfoton label. The registrant indicated in
the waiver request document that the barley, potatoes, and wheat uses were to be
eliminated from the Di-Syston SEC label. Per the 2002 IRED, these crop scenarios were
included in the overall assessment for drinking water exposure from surface water
sources. The registrant indicated that the surface water drinking water assessment should
be based on the remaining crops, rather than the ones that have been eliminated from the
label. The registrant submitted data on the remaining uses in lieu of barley, potatoes, and
wheat, including the following crop scenarios: beans, Brussels sprouts, cabbage, lettuce,
and asparagus. In evaluating the data submitted by the registrant, the Agency used the
current use patterns to recalculate the estimated surface drinking water concentrations
(EDWCs) for disulfoton and the associated degradates.
Using the new model inputs, the Agency was unable to reproduce the EDWC
results from the registrant's modeling. The EDWCs for several crop uses continued to
exceed the drinking water level of comparison (DWLOC) established in the 2002
IRED. Crops with chronic DWLOC exceedances include asparagus, beans, Brussels
sprouts and broccoli, cabbage, cauliflower, lettuce, and Christmas trees. Crops with
acute DWLOC exceedances include Christmas trees, lettuce, cauliflower, cabbage,
Brussels sprouts and broccoli. Based on the number of DWLOC exceedances among the
EDWCs for the different crops, as well as the known persistence and toxicity of the
disulfoton degradates, d. sulfoxide and d. sulfone, the Agency denied the waiver request.
The study is now due on August 15, 2010, consistent with the 22-month timeframe for
completion specified by OPPTS Guideline No. 835.7200. Please refer to Memorandums
entitled "Waiver request for a surface water monitoring study for disulfoton" dated
January 8, 2007 and "Disulfoton Waiver Request Clarification for surface water
monitoring study" dated July 29, 2008 for additional information on the Agency's
evaluation of this waiver request.
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VIII. Label Amendments
The technical registrant has voluntarily deleted the following uses from the Di-
Syston 15 G label: beans, Brussels sprouts, cabbage, cauliflower, cotton, peanuts,
peppers, radish grown for seed, broccoli, and clover grown for seed. Additionally, as a
result of the 2002 IRED, the registrant submitted to the Agency Voluntary Use Deletions
affecting several disulfoton products. Appendix A: Table of Use Patterns Eligible for
Reregistration for Disulfoton has been revised to reflect these use deletions, as well as the
adjustment to the asparagus REI, the increased number of applications allowed for
Christmas trees and the use of disulfoton on Easter lily. The Appendix A included with
this Addendum supersedes the Appendix A included in the 2002 Disulfoton IRED
document. Additionally, this Addendum includes revisions to Table 16 of the RED,
Summary of Revised RED Labeling for Disulfoton. The included sections of the label
table have been updated to reflect the changes introduced by this document. The revised
sections supersede the corresponding sections from the 2002 IRED. The remainder of the
label requirements stipulated in the 2002 IRED remain unchanged.
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Revisions to Table 16. Summmary of Revised RED Labeling for Disulfoton
DESCRIPTION
LABELING
PLACEMENT ON LABEL
Restricted-Entry Interval for
Liquid Formulations
"Use this product only in accordance with its labeling and with the Worker Protection Standard, 40
CFR part 170. This Standard contains requirements for the protection of agricultural workers on farms,
forests, nurseries, and greenhouses, and handlers of agricultural pesticides. It contains requirements for
training, decontamination, notification, and emergency assistance. It also contains specific intructions
and exceptions pertaining to the statements on this label about personal protective equipment (PPE),
notification to workers, and restricted-entry interval. The requirements in this box only apply to uses of
this product that are covered by the Worker Protection Standard."
"Do not enter or allow workers to enter into treated areas during the restricted entry interval (REI). The
REI is 48 hours. In areas where average rainfall is less than 25 inches a year the REI is 72 hours."
"The REI for foliar applications to asparagus is 7 days, but is increased to 11 days in areas where the
average annual rainfall is less than 25 inches per year." Note: information on average annual rainfall
for your area is available from any nearby weather bureau, such as one affiliated with the National
Oceanographic and Atmospheric Administration. Information on average rainfall is also available on-
line through the National Weather Service at http://www.nws.noaa.gov"
"Exception: if the product is soil-injected or soil-incorporated, the WPS, under certain circumstances,
allows workers to enter the treated areas without restriction if there will be no contact with anything that
has been treated."
Directions for Use,
Agricultural Use
Requirements Box
Early Re-Entry Personal
Protective Equipment
established by the RED
"The following PPE is required for early entry to treated areas that is permitted under the WPS and that
involves contact with anything that has been treated, such as plants, soil, or water:
Coveralls worn over long-sleeve shirt and long pants,
Chemical-resistant gloves made of any waterproof material,
Chemical-resistant footwear plus socks,
Protective eyewear, and
Chemical-resistant headgear (if overhead exposure)"
"Notify workers of the application by warning them orally and by posting warning signs at entrances to
treated areas"
Directions for Use,
Agricultural Use
Requirements Box
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DESCRIPTION
LABELING
PLACEMENT ON
LABEL
Other Application
Restrictions (Risk
Mitigation)
Application Restrictions (all crop sites)
Application by hand-held equipment is prohibited for all sites except coffee and Christmas trees.
Crop-Specific Application Restrictions
Asparagus (California, Michigan, North Carolina, Oregon, and Washington 24(c) registrations): Di-Syston
SEC label is to state "Do not apply more than twice per season."
Beans: "Not for use on dry beans, peas, or lentils."
Cabbage: The liquid Di-Syston SEC label must specify, "Do not apply by chemigation."
Cole Crops (broccoli, Brussels sprouts, cauliflower): The Di-Syston SEC label must specify "For use in
California only." "Apply by shank injection only." "Apply only once per year" for broccoli and
cauliflower.
Easter lily: The Di-Syston SEC label must specify that for Easter lilies, only "one in furrow application is
allowed per year." With an application rate of "0.53 to 1.1 fl. oz per 100 row feet."
Lettuce: The liquid Di-Syston SEC label must state "For use in California only."
Cotton: Number of applications must be reduced from 3 to 1 per year, at a rate of 1 Ib ai/A. All labels must
specify "Aerial applications are prohibited." "Apply at plant, in furrow only." "For use only as an herbicide
safener."
Christmas Trees: Maximum application rate on the Section 3 Di-Syston 15G label is 4.5 Ib ai/A. Label
must specify: "For use on firs only." "Product must be either soil incorporated, watered in, or applied to
areas with permanent groundcover." "Do not apply more than twice per season."
Coffee: "For use in Puerto Rico only." "Do not apply more than twice per year."
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REVISED APPENDIX A
Disulfoton (Case 102): Use Patterns Eligible for Reregistration
Site
Application Timing
Application Type
Application Equipment
Formulation
[EPA Reg. no.]
Maximum Single
Application Rate
Maximum
Number of
Applications Per
Season
Maximum Seasonal
Rate Ibs ai/A
Preharvest Interval
Days
Use Limitations
FOOD/FEED CROPS
Asparagus
Postharvest (fern stage)
Foliar application
Ground or aerial
8 Ib/gal EC
[CA840192]
8 Ib/gal EC
[MI060002]
8 Ib/gal EC
[NC860005]
8 Ib/gal EC
[OR040030]
8 Ib/gal EC
[WA040015]
1.0 Ib a.i./A
2
2
180
Use limited to CA, NC,
OR, MI, and WA. No
more than 2
applications per year.
The REI is 7 days, but
is increased to 1 1 days
when average annual
rainfall is less than 25
inches per year.
Beans, Succulent (including snap or green lima)
At-planting
Soil injection
Ground
8 Ib/gal EC
[264-734]
1.0 Ib a.i./A
1
1
60
Not for use on dry
beans, peas, or lentils.
The feeding of treated
vines or hay to
livestock animals is
prohibited.
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Site
Application Timing
Application Type
Application Equipment
Formulation
[EPA Reg. no.]
Maximum Single
Application Rate
Maximum
Number of
Applications Per
Season
Maximum Seasonal
Rate, Ibs ai/A
Preharvest Interval
Days
Use Limitations
Broccoli
At-planting or
Postemergence
Soil injection
Ground
8 Ib/gal EC
[264-734]
1.0 Ib a.i./A
1
1
14
Limited for use in
California only.
Chemigation is not
permitted. Apply by
shank injection only.
Brussels Sprouts
At-planting or
Postemergence
Soil incorporated or soil
injection
Ground
8 Ib/gal EC
[264-734]
1.0 Ib a.i./A
1
1
30
Limited for use in
California only. Do not
apply to plants grown
for seed. Chemigation
is not permitted. Apply
by shank injection
only.
Cabbage (including tight-heading varieties of Chinese cabbage)
Preplant or
Broadcast spray to
transplant seed beds.
At-planting or
postemergence
Soil incorporated or soil
injection
Ground
8 Ib/gal EC
[264-734]
8 Ib/gal EC
[264-734]
1 Ib a.i./A
2 Ib a.i./A
1
1
1
2
NS
42
Chemigation is not
permitted.
Chemigation is not
permitted
Cauliflower
At-planting or
postemergence
Soil incorporated or soil
injection
Ground
8 Ib/gal EC
[264-734]
1.0 Ib a.i./A
1
1
40
Limited for use in
California only. Do not
apply to plants grown
for seed. Chemigation
is not permitted. Apply
by shank injection
only.
15
-------
Site
Application Timing
Application Type
Application
Equipment
Formulation
[EPA Reg. no.]
Maximum Single
Application Rate
Maximum
Number of
Applications Per
Season
Maximum
Seasonal Rate,
Ibs ai/A
Preharvest
Interval Days
Use Limitations
Coffee Beans
Preharvest and
Postharvest
Soil (uniformly under tree
canopy)
Ground
15% G
[264-723]
2-4g/ftoftree
height not to
exceed 8.3 Ib
a.i./A
2
17
90
Disulfoton use on coffee is limited to
Puerto Rico only. Products must be
soil incorporated, watered in, or applied
to areas with permanent ground cover.
No more than one preharvest and one
postharvest application may be made
during the year. Closed
loading/transfer system required.
Cotton
At-planting/replanting
Preplant
Soil injection or in-furrow
soil
Soil spray
Ground
At-planting
Soil injection or in-furrow
soil
Ground
8 Ib/gal EC
[264-734]
6.5% G
[400-408]
l.Olba.i./A
1.0 Ib a.i./A
1
1
1
1
NS
NS
Aerial applications are prohibited.
Apply at-plant, in-furrow only. For use
only as a herbicide safener. Do not
graze treated fields. The feeding of
treated forage to livestock is prohibited.
Lettuce
Chemigation
Side dress injection
Ground
8 Ib/gal EC
[264-734]
8 Ib/gal EC
[CAS 10044]
2.0 Ib a.i./A
2.0 Ib a.i./A
1
1
2
2
60
60
Limited for use in California only.
Application to transplanted lettuce is
prohibited. Low pressure (drip or
trickle) chemigation systems only.
Limited for use in California only.
Application to transplanted lettuce is
prohibited. Low pressure (drip or
trickle) chemigation systems only.
16
-------
Site
Application Timing
Application Type
Application Equipment
Formulation
[EPA Reg.
no 1
Maximum Single
Application Rate
Maximum
Number of
Applications Per
Season
Maximum
Seasonal Rate,
Ibs ai/A
Preharvest
Interval Days
Use Limitations
NON-FOOD/FEED USES
Radish Grown for Seed
At first seed stalk bolting
Soil incorporated
Ground
8 Ib/gal EC
[WA920026]
2.0 Ib a.i./A
1
2
NS
Do not feed or graze radish forage or
fodder. Do not cut radish tops for hay
or forage. No portion of the treated
field, including seed, seed screening,
forage or stubble may be used for
human or animal consumption.
Christmas Trees (Fir Species)
At first bud break
Broadcast
15% G
[264-723]
15% G
[NC8800081]
4.5 Ib a.i./A
2
4.5
NS
For use on firs only. Products must be
soil incorporated, watered in, or applied
to areas with permanent ground cover.
Closed loading/transfer system
required. Not for use on bare ground
plantations.
For use on firs only. Products must be
soil incorporated, watered in, or applied
to areas with permanent ground cover.
Closed loading/transfer system
required. Not for use on bare ground
plantations.
Residential Use on Ornamental Flowers, Roses, Shrubs and Trees
Apply every 6 weeks
throughout growing season.
Broadcast/soil
Incorporated or watered in
Ground
1%G
[72155-49]
0 3 lb/1000 ft2
for flowerbeds
or
0.0 llb/4 ft shrub
or
0.0013 Ib
a.i./bushfor
roses
NS
NS
NS
For residential use only. Not for
commercial use. Product must be soil
incorporated or watered in. Do not
apply with belly grinder. Product
intended for hand application must be
in child resistant packaging with a serf
contained measuring cup/lid, which
clearly measures correct amount to
apply.
Not for use indoors or in greenhouses.
Not for use on home vegetable gardens,
including use on spinach and tomatoes.
17
-------
Site
Application Timing
Application Type
Application Equipment
Formulation
[EPA Reg.
no 1
Maximum Single
Application Rate
Maximum
Number of
Applications Per
Season
Maximum
Seasonal Rate,
Ibs ai/A
Preharvest
Interval Days
Use Limitations
Residential Use on Ornamental Flowers, Roses, Shrubs and Trees
Apply every 6 weeks
throughout growing season.
Broadcast/soil
Incorporated or watered in
Ground
1%G
[432-1286]
0 3 lb/1000 ft2
for flowerbeds
or
001 lb/4 ft shrub
or
0 0013 Ib
a.i./bushfor
roses
NS
NS
NS
For residential use only. Not for
commercial use. Product must be soil
incorporated or watered in. Do not
apply with belly grinder. Product
intended for hand application must be
in child resistant packaging with a serf
contained measuring cup/lid, which
clearly measures correct amount to
apply.
Not for use indoors or in greenhouses.
Not for use on home vegetable gardens,
including use on spinach and tomatoes.
Commercial Use on Easter Lilies
Soil treatment in furrows
before covering bulbs with
soil.
8 Ib/gal EC
[264-734]
8 Ib/gal EC
[CA050010]
8 Ib/gal EC
[OR050024]
8.48 Ib a.i./A
1
8.48 Ib a.i./A
NS
A higher dosage (not to exceed the
maximum single application rate) is
recommended for heavy organic or
muck soils.
18
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