Document ID: EPA-HQ-OPP-2007-0158-0008
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2011-04-20T04:00Z

Request for Exemption from the Requirements of a Tolerance

AF36 on Pistachios

EPA BIOPESTICIDES AND POLLUTION PREVENTION DIVISION COMPANY NOTICE OF
FILING FOR PESTICIDE PETITIONS PUBLISHED IN THE FEDERAL REGISTER  

EPA has received a pesticide petition  from [Interregional Research
Project Number 4 (IR-4), Rutgers University, 500 College Road East,
Suite 201W, Princeton, NJ 08540 on behalf of the Arizona Cotton Research
and Protection Council], [3721 East Wier Avenue Phoenix, Arizona
85040-2933]  proposing pursuant to section 408(d) of the Federal  Food,
Drug, and Cosmetic Act (FFDCA),  21 U.S.C. 346a(d), to amend 40 CFR part
180.1206 to establish a tolerance exemption for the microbial pesticide
[Aspergillus flavus AF36] in or on Pistachios.



Pursuant to section 408(d)(2)(A)(i) of the FFDCA, as amended,
[Interregional Research Project Number 4 (IR-4), Rutgers University, 500
College Road East, Suite 201W, Princeton, NJ 08540 on behalf of the
Arizona Cotton Research and Protection Council] has submitted the
following summary of information, data, and arguments in support of the
pesticide petition.  This summary was prepared by [Interregional
Research Project Number 4 (IR-4) Rutgers University, 500 College Road
East, Suite 201W, Princeton, NJ 08540 on behalf of the Arizona Cotton
Research and Protection Council 3721 East Wier Avenue Phoenix, Arizona
85040-2933] and EPA has not fully evaluated the merits of the pesticide
petition.  The summary may have been edited by EPA if the terminology
used was unclear, the summary contained extraneous material, or the
summary unintentionally made the reader conclude that the findings
reflected EPA’s position and not the position of the petitioner. 

I.   [Interregional Research Project Number 4 (IR-4), Rutgers
University, 500 College Road East, Suite 201W, Princeton, NJ 08540 on
behalf of the Arizona Cotton Research and Protection Council 3721 East
Wier Avenue Phoenix, Arizona 85040-2933]  Petition Summary

    

A.  Product name and Proposed Use Practices 

	Aspergillus flavus AF36, a non-aflatoxin-producing strain of A. flavus,
 is proposed for application to pistachios to reduce the incidence of
aflatoxin producing strains of A. flavus and thereby reduce aflatoxin
contamination of pistachios.  Aspergillus flavus AF36 which does not
produce aflatoxin, competitively excludes aflatoxin producing A. flavus
strains without increasing A. flavus in the environment in the long
term.  Sterile wheat seed colonized with Aspergillus flavus AF36 is
applied at 10 pounds of end-use product (total amount of active
ingredient less than 0.01 lb/acre) per acre.  The pesticide is currently
being used in certain counties in California and the States of Arizona
and Texas in cotton. The current submission proposes to establish a
temporary exemption from tolerance for residues of A. flavus AF36 on
pistachios.

B.  Product Identity/Chemistry 

	1. Identity of the pesticide and corresponding residues.    [The
pesticide and corresponding residues are identified as Aspergillus
flavus AF36. ] 

	2. Magnitude of residue at the time of harvest and method used to
determine the residue.   [Aspergillus flavus AF36 is a naturally
occurring fungus that was originally isolated from cottonseed produced
in the Yuma Valley of Arizona.  Aspergillus flavus AF36 has been shown
to be naturally and consistently associated with pistachios grown in
California.  A. flavus is a widespread fungus.  It is particularly well
adapted to the hot regions of California where it is widespread in the
environment.  The communities of A. flavus in the desert and in
agricultural fields are naturally composed of both aflatoxin producing
(toxigenic) and aflatoxin non-producing (atoxigenic) strains.  Both
atoxigenic and toxigenic strains have been found on essentially all
plant material and soils in California.  The goal of applications is to
increase the percent of the Aspergillus flavus community composed of the
strain AF36 and to decrease the percent of A. flavus that produces
aflatoxins on the crop and the field.

	3. A statement of why an analytical method for detecting and measuring
the levels of the pesticide residue are not needed.   An exemption from
the requirement of a

tolerance for residues of the microbial pesticide A. flavus AF36 in/on
pistachios is being proposed for pistachios in California.   All lots of
the active ingredient (A. flavus isolate AF36) and the formulated
product are monitored as part of a rigorous quality control program.
Starter cultures of A. flavus isolate AF36 used in the production of the
end-use product are always screened for aflatoxin production using TLC
and appropriate standards. Quality control standards are zero tolerance
in the starter cultures and in the formulated product for aflatoxin
production, and for A. flavus not identified as A. flavus isolate AF36. 
A. flavus AF36 has never been found to produce aflatoxin. Starter
cultures of A. flavus AF36 as well as end-use products containing this
active ingredient are also identified to isolate by vegetative
compatibility analysis.] 

C.  Mammalian Toxicological Profile 

An acute oral toxicity test was performed whereby a single oral dose of
5,000 milligrams/kilogram (mg/kg) per animal of Aspergillus flavus AF36
colonized wheat seed was administered by gavage to five male and five
female Sprague Dawley rats.  The oral LD50 of Aspergillus flavus AF36
was determined to be greater than 5,000 mg/kg rat body weight.  No
clinical signs were observed during the 14 day study and no
abnormalities or adverse effects were observed in any of the rats upon
necropsy.

               An initial pulmonary rat study which  resulted in
lethality in a significant number of animals treated with either the
live Aspergillus flavus AF36 in Tween 80 or heat killed Aspergillus
flavus AF36 in Tween 80.  Onset of symptoms was rapid after dosing with
all deaths occurring by day four of the study.  All rats surviving to
day four of the study recovered and all rats sacrificed (as scheduled)
on day 8 or day 15 of the study had totally eliminated viable
Aspergillus flavus AF36 from the lungs, caecal contents, and faeces. 
There was no evidence of infectivity.  The aetiology of deaths was
unclear.  It appeared that Aspergillus flavus AF36 prepared using Tween
80 caused a severe acute inflammatory response.  Retrospective
literature review and consultation with a toxicologist supported the
theory that the responses were a result of a synergism with Tween 80
and/or of Tween 80 breakdown products formed during preparation of the
spore suspension.

              A second rat study was therefore undertaken.  In the
second study the conidia were both washed from the wheat and suspended
in sterile physiological saline instead of Tween 80.  Animals (2 male
and 2 female for each treatment level) were dosed at 0, 105, 106, 107,
and 108 colony forming units per rat.  There were no clinical signs in
any of the treatment groups considered to be associated with the test
substance.  Rats were sacrificed at day 8 without treatment associated
mortality.  No abnormalities were observed in any of the animals at the
macroscopic examination at termination. 

Based on these two mammalian studies, it was concluded that Aspergillus
flavus AF36 does not present either a toxicological or an infectious
risk to mammals.  

Data waivers were requested for the toxicology studies listed below on
the following basis:(1) researchers and other workers have worked with
Aspergillus flavus AF36 at the Southern Regional Research Center for
over 10 years and in commercial fields (1996 to 1998) and in hand picked
field plots (1989 to 1994) without report of any adverse health effects;
(2) Aspergillus flavus AF36 is widely distributed in the environment and
its occurrence is natural; and 3) the label will require applicators and
other handlers to wear Personal Protective Equipment (PPE) such as
waterproof gloves, a dust/mist filtering respirator with the appropriate
NIOSH approval prefix N-95, P-95, or R-95, coveralls, long sleeved shirt
and long pants, and shoes plus socks, and goggles, so exposure should be
limited.  Applications will involve aerial application by
mixers/handlers who are licensed and trained to even handle restricted
materials. At the 10 lb/acre application rate of the formulated
material, the total amount of active ingredient is less than 0.01
lb/acre. Applications of AF36 do not significantly impact the total
amount of Aspergillus flavus in the soil or crop, but only change the
proportion of the AF36 strain in relation to the overall soil or crop
population. Since the product is applied as a granular formulation on
wheat, exposure from drift is minimal.

1. Acute dermal toxicity. This study was waived based upon the lack of
toxicity in animals dosed orally. While Aspergillus flavus has been
reported to be a dermal sensitizer, this testing is not warranted, since
the PPE required on the label will provide adequate protection from
dermal exposure to workers and pesticide handlers.

               

 2. Primary dermal irritation. This study was waived based upon the lack
of toxicity in animals dosed orally.  Aerial applications will be made
by mixers/handlers and applicators, who are required to wear appropriate
PPE, and are licensed and trained to even handle restricted materials.
At the 10 lb/acre application rate of the formulated material, the total
amount of active ingredient is less than 0.01 lb/acre. Applications of
AF-36 do not significantly impact the total amount of Aspergillus flavus
in the soil or crop, but only change the proportion of the AF-36 strain
in relation to the overall population. Since the product is applied as a
granular formulation on wheat,  exposure from drift is minimal.

3 Primary eye irritation.  This study was waived based upon the use of
appropriate PPE, including goggles, and other factors listed above. 
Since the product is applied aerially as a granular formulation on
wheat, exposure from drift is expected to be minimal.

4. Acute  Intraperitoneal.  This study was waived based upon the lack of
toxicity in animals dosed orally and by intratracheal instillation.  In
addition, the factors listed above will mitigate exposure, which is
expected to be minimal.

5.  Genotoxicity, reproductive and developmental toxicity, subchronic
toxicity and chronic toxicity testing were not performed, since no
adverse effects were observed in the acute toxicology study Tier 1
studies.   Tier II (885.3550) , subchronic toxicology study (USEPA OPPTS
885.3600) and chronic feeding studies (guideline 152-50) are only
required if triggered by adverse effects observed in Tier I studies. 

D.  Aggregate Exposure

	1. Dietary exposure. 

	i. Food.   Aspergillus flavus AF36 is a naturally occurring organism,
which does not produce aflatoxin and is thus safer than the
aflatoxin-producing A. flavus isolates that produce aflatoxin.  Proposed
uses and application rates will not result in increases in the total
population of A. flavus on the mature crop beyond naturally occurring
background levels.

Aspergillus flavus AF36, when applied to the soil just prior to bloom,
has been shown to significantly reduce the levels of aflatoxin in
pistachios at harvest without changing the quantity of A. flavus on the
crop.  Furthermore, the proposed use and application rate will not
increase exposure of humans to A. flavus by dietary means.  
Applications of Aspergillus flavus AF36 do not increase the indigenous
populations of A. flavus associated with the harvested crop.  The
applications merely alter the composition of the fungal community
associated with the mature crop so that aflatoxin producing strains are
far less frequent.  The result is a much lower incidence of aflatoxins
in the crop and in the environment associated with the developing and
mature crop. 

	ii. Drinking water Aspergillus flavus AF36 is a naturally occurring
organism that is already widespread in the environment and is not
considered to be a risk to drinking water.  Both percolation through
soil and municipal treatment of drinking water would reduce the
possibility of exposure of A. flavus through the drinking water. 
Applications of Aspergillus flavus AF36 do not increase the long-term
populations of A. flavus in the environment, and thus are not expected
to influence the relationship of A. flavus to water sources. 
Applications merely change the composition of the A. flavus community so
that aflatoxins are less common in the environment.  

	2. Non-dietary exposure.   The potential for non-occupational,
non-dietary exposure to the general population is not expected to be
significant and is not expected to present any risk of adverse health
effects.]

E.  Cumulative Exposure  

	There are no other registered products containing Aspergillus flavus
AF36 or any other isolates (strains) of the microbial active ingredient.
 Data submitted show that the fungal metabolite of concern which is
aflatoxin is not produced by Aspergillus flavus AF36 in the crop or in
artificial media in the lab.   Aspergillus flavus AF36 has been shown to
exclude aflatoxin producing fungi competitively from the developing crop
and to reduce aflatoxin contamination of pistachio.  Data show that the
proposed use will not result in appreciable increases in the long-term
population of A. flavus on the crop beyond naturally occurring levels. 
Furthermore, there is no expectation of cumulative effects with other
pesticides.

F.  Safety Determination 

	1. U.S. population. Aspergillus flavus AF36 is a naturally occurring
organism. This isolate has low toxicity as demonstrated by the acute
oral toxicity study in rats.  A. flavus is ubiquitous throughout the hot
desert valleys in Arizona.  Studies have shown that treatment of cotton
fields just prior to flowering with sterile wheat seed colonized by
Aspergillus flavus AF36 at 10 lbs. per acre does not increase the
long-term populations of A. flavus either on the crop at maturity or in
the soil 1 year after application.  Based on this information, IR-4 is
of the opinion that the aggregate exposure to A. flavus over a lifetime
should not change with application of Aspergillus flavus AF36, and
exposure to both aflatoxin producing A. flavus strains and aflatoxin
should decrease.  This should be beneficial to human health.  Thus,
there is a reasonable certainty that no harm will result from aggregate
exposure to Aspergillus flavus AF36. 

	2. Infants and children.   Based on the lack of toxicity and natural
occurrence, there is reasonable certainty that no harm to infants,
children, or adults will result from aggregate exposure to Aspergillus
flavus AF36.  Exempting Aspergillus flavus AF36 from the requirement of
a tolerance should pose no significant risk to humans or the
environment. 

G.  Effects on the Immune and Endocrine Systems

	Aspergillus flavus AF36 is a naturally occurring organism, which does
not produce aflatoxin, and is thus safer than the A. flavus isolates
that produce aflatoxin.  To date there is no evidence to suggest that
Aspergillus flavus AF36 functions in a manner similar to any known
hormone, or that it acts as an endocrine disrupter. 

H.  Existing Tolerances

	The registrant is not aware of any existing tolerances or tolerance
exemptions for Aspergillus flavus AF36, other than the tolerance
exemption on cotton (40 CFR 180.1206). There is a current temporary
exemption from tolerance on pistachio and corn

I. Efficacy Data

The atoxigenic Aspergillus flavus strain AF36 (the same product that is
widely used in Arizona cotton fields to substantially reduce aflatoxin
contamination of cottonseed) was applied as a biocontrol agent in
commercial pistachio orchards in California in 2008 and 2009. The AF36
strain was applied as a wheat-AF36 product (the same product and same
application rate as used in commercial cotton fields) as a single annual
application to the soil surface of the orchards in late June or early
July. The level of the atoxigenic strain AF36 in the soil increased
substantially in the treated orchards after applying the wheat-AF36
product. Prior to applying the AF36 product, only 2% of the A. flavus
isolates from the soil of these orchards belonged to the AF36 strain.
But three months after the single application, 43% of the A. flavus
isolates in the soil belonged to the AF36 strain. In 2009 an additional
application of the AF36 product was made in these orchards, and three
months after this application 89% of the isolates were AF36. This
demonstrates that the application of the wheat-AF36 product was
successful in substantially increasing the level of AF36 in the
orchards. Nonetheless, application of the wheat-AF36 product did not
result in increased levels of kernel decay, and no cyclopiazonic acid
was detected in nuts from treated orchards. Furthermore, nuts from the
orchards treated with the AF36 product were less likely to be
contaminated with aflatoxin than those from nearby untreated orchards in
2008 and in 2009. 

Nut samples from the orchards treated with the AF36 product were less
likely to be contaminated with aflatoxin than those from untreated
orchards for both 2008 and 2009 harvests . Although sometimes pistachio
orchards will have only a single harvest, in some cases there will be a
second harvest or reshake. In 2009 the reshakes from the treated
orchards had less aflatoxin contamination than those from untreated
orchards . Although about 30% more samples collected from untreated
orchards in 2009 were analyzed for aflatoxins, these samples had twice
as high an incidence as those collected from AF36 treated orchards ,
suggesting that the AF36 treatment contributed to this reduction of
aflatoxin contamination of pistachios. It is expected that with a
further increase of AF36 in the orchards there will be a further
decrease in aflatoxin contamination as has been shown in other crops
(i.e. cottonseed, corn, etc.).

	Application of the AF36 product did not increase the amount of
cyclopiazonic acid (CPA) in the nuts. No CPA was detected in any of the
nut samples from the treated orchards or from untreated orchards.
Because application of AF36 did not increase CPA in the nuts nor
increase nut decay, it is expected that treatment with AF36 will
decrease aflatoxin contamination without any adverse effects to the
nuts.

J.  International Tolerances

There are no Codex maximum residue levels established for residues of
Aspergillus flavus AF36.  Aspergillus flavus AF36 containing products
are presently not registered for pest control outside of the United
States.  

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