This is a work product of the National Organic Standards Board (NOSB). It does not represent official 

National Organic Program (NOP) positions or policy.

National Organic Standards Board

Crops Subcommittee

Petitioned Material Proposal

Polyoxin D Zinc Salt

January 29, 2013

Polyoxin D Zinc Salt was petitioned in 2012 as a Synthetic Substance to be Allowed for 

Use in Organic Crop Production (7CFR 205.601).

Polyoxin D Zinc Salt (EPA Reg. No. 68173-1) is a fungicide derived from Streptomyces 

cacaoi var.asoensis, a soil-borne microorganism, through an aerobic fermentation 

process. While it appears that the polyoxin D may be a naturally derived material, the

added zinc salt may or may not be synthetic. The manufacturer of Polyoxin D Zinc Salt 

could not confirm the source of the Zinc Salt, as to whether it was “virgin” zinc from a 

mine or from a recycled zinc source. Thus, it would have to be considered a synthetic 

material. The zinc salt is added to give the polyoxin D a longer residual time on the plant 

surface. The manufacturer has chosen to withhold disclosure of its manufacturing 

process, citing it as proprietary and confidential business information. As stated in the 

2012 technical review (TR), which was based on the un-redacted version of the petition, 

the Zinc Salt appears to be a reaction product and not a naturally occurring form.

The petitioner has submitted several petition amendments that include an expanded 

tolerance exemption for polyoxin D zinc salt from EPA for use on all food commodities 

and expanded use allowances for all food and feed crops. This includes both preharvest and post-harvest uses. Some examples of plant diseases and pathogens for 

which its use is intended to control are: Alternaria, Anthracnose, Botrytis, Brown Patch, 

Downy Mildew, Powdery Mildew, and Rhizoctonia.

Polyoxin D zinc salt is a fungicide labeled for use on an expanded list of crops. It works 

as a fungistatic material, rather than with fungicidal activity. This means that rather than 

killing the bacteria or fungi, it inhibits the growth of the fungi colony by inhibiting the 

chitin growth in the cell walls. Polyoxin D zinc salt is used exclusively on plants. It is not 

registered for use as an antibiotic in human or veterinary medicine. However, the TR 

indicates that polyoxin D zinc is a broad spectrum fungicide, raising concerns about its 

impact on beneficial soil organisms, citing its residual life in soil. While it has impact on 

non-target beneficial fungi and bacteria in the soil, proponents of this material maintain 

that it should not have a long lasting effect due to its mode of action and short half-life in 

water. While there are concerns raised about the effect on beneficial fungi and insects, 

supplemental data submitted by the petitioner attempts to address the majority of these 

concerns on an individual basis. 

The EPA lists polyoxin D zinc salt (EPA Reg. No. 68173-1) as a Fungicide Resistance 

Action Committee (FRAC) Code of 19 i.e., the target site of action is a chitin 

synthestase. This means that it has a unique mode of action, which proponents of its 

use cite as extremely useful in a rotational fungicide program in organic farming 

operations as a resistance management tool. The TR listed a number of alternative 

materials and practices. The majority of the Subcommittee members found this to be 

incompatible with organic practices. 
Revised March 2012

Evaluation Criteria 

(Applicability noted for each category; Documentation attached) Criteria 

Satisfied? 

1. Impact on Humans and Environment ☒ Yes ☐ No 

☐ N/A 

a. Essential & Availability Criteria ☐ Yes ☒ No 

☐ N/A

2. Compatibility & Consistency ☐ Yes ☒ No 

☐ N/A

3. Commercial Supply is Fragile or Potentially Unavailable ☐ Yes ☐ No 

☒ N/A

as Organic (only for § 205.606)

Substance Fails Criteria Category: [2, 3 ] Comments:

Proposed Annotation (if any):

Basis for annotation: ☐ To meet criteria above ☐ Other regulatory criteria ☐

Citation 

Notes: 

Recommended Committee Action & Vote, including classification recommendation 

(state actual motion):

Classification Motion: Motion to classify Polyoxin D Zinc as petitioned as synthetic.

Motion by: Harold Austin Seconded by: Colehour Bondera

Yes: 8 No: 0 Absent: 0 Abstain: 0 Recuse: 0

Listing Motion: To add Polyoxin D Zinc Salt to the National List at § 205.601 as a 

Synthetic Substance Allowed for Use in Organic Crop Production.

Motion by: Harold Austin Seconded by: Colehour Bondera

Yes: 3 No: 4 Absent: 0 Abstain: 1 Recuse: 0

Crops ☒ Agricultural ☐ Allowed1 ☐

Livestock ☐ Non-synthetic ☐ Prohibited2 ☐

Handling ☐ Synthetic ☒ Rejected3 ☒

No restriction ☐ Commercial 

unavailable as organic

☐ Deferred4 ☐

1

Substance voted to be added as “allowed” on National List to § 205. with 

Annotation (if any): 

2

Substance to be added as “prohibited” on National List to § 205. with Annotation (if 

any): 

Describe why a prohibited substance: 
Revised March 2012

3

Substance was rejected by vote for amending National List to § 205. . Describe 

why material was rejected: 

4

Substance was recommended to be deferred because 

If follow-up needed, who will follow up: 

Approved by Subcommittee Chair to Transmit to NOSB

Jay Feldman, Subcommittee Chair January 29, 2013

NOSB Evaluation Criteria for Substances Added To the National List

Category 1. Adverse impacts on humans or the environment? Substance: 

Question Yes No N/A1 Documentation (TAP; petition; 

regulatory agency; other)

1. Are there adverse 

effects on environment 

from manufacture, use, 

or disposal?

[§205.600 b.2]

X

2. Is there environmental 

contamination during 

manufacture, use, 

misuse, or disposal? 

[§6518 m.3]

X The TR (lines 190-195) states that the EPA 

considers polyoxin D zinc salt a low 

environmental risk, listing several reasons 

for this rationale. Also, included in the 

supplemental information submitted by the 

petitioner on October 2, 2012 as part of an 

EPA posting to the Federal Register on 

September 12, 2012. The TR does mention 

(line 194) that failure to follow the product 

label could result in death of fish and 

aquatic organisms. In the TR (lines 197-

204) states that biopesticides generally 

pose lower risks than chemically produced 

pesticides. The manufacturing process is 

CBI, but the TR states the process would 

be similar to other antibiotics produced 

from Streptomyces. (TR July 11, 2102) The 

TR states (lines 190-204) that polyoxin D

could get into water if misused by not 

following the label. Waste may be disposed 

of on site or at an approved waste facility, 

but not disposed of in waste water. (TR 

July 11, 2012)

3. Is the substance harmful 

to the environment and 

biodiversity?

[§6517c(1)(A)(i);6517(c)(

2)(A)i] 

X X Polyoxin D zinc salt is moderately toxic to 

fish and aquatic invertebrates and should 

not be discharged into water. (TR lines 

279-280). If label instructions followed, 

those concerns would be mitigated (EPA, 
Revised March 2012

2001)(TR lines 290-291). Should be 

considered toxic to various soil fungi and 

bacteria (TR lines 234-235). However, the 

TR (lines241-251) does state that 

alternative fungicides, such as copper or 

sulfur, may have similar or more severe 

effects. No documented studies to verify 

the effects by comparison to other 

fungicides. In the TR it mentions (TR line 

54) Action of Substance: Inhibits cell wall 

chitin synthesis (Misato, 1977, O’Neill, 

2006). It further states (TR lines 257-262) it 

has been shown to inhibit chitin synthetase 

in cockroaches, and may therefore affect 

beneficial insects. EPA: Toxic to Honey 

Bees. 11

Kaken cites EPA 2”Polyoxin D and 

its zinc salt do not inhibit the synthesis of 

chitin in animals that contain chitin, such as 

for insects and crustaceans that contain 

chitin in their exoskeletons.

4. Does the substance 

contain List 1, 2 or 3 

inerts? [§6517 c 

(1)(B)(ii); 205.601(m)2]

? The TR states that Polyoxin D Zinc Salt is 

formulated with undisclosed inert 

ingredients. TR line 58 (TR July 11, 2012)

The TR further states that the preferred 

surfactants used in the dry flowable form 

are formalin sodium naphthalenesulfonate

(inert list 4B) or non-ionic polyoxyethylene 

alkyl ethers (inert list 4B) (Tokumura, et al.,, 

2001). Formulation process is CBI

5. Is there potential for 

detrimental chemical 

interaction with other 

materials used?

[§6518 m.1]

X X Because of its activity as a fungicide, it may 

have a negative impact on beneficial fungi.

Polyoxin D inhibits the germination of 

Trichoderma viride (Benitez, et al., 1976). 

T. viride is closely related to T.harzianum, 

which is used in organic farming under the 

brand name Root Shield (OMRI, 2012). 

There are a couple of other fungi used as 

biological controls in organic farming. (TR 

lines216-222). However, it has also been 

shown to promote the biocontrol of Bacillus 

subtilis, with a strong synergistic effect on 

Alternaria mali suppression. (TR lines 225-

226) (TR July 11, 2012) Also, in the TR (TR 

lines 220-224) it lists Gliocladium 

virens,Paecilomyces fumosoroseus, and 

Streptomyces griseoviridis as other fungi 

used as biological control agents in organic 

 1 EPA, May 11 ,2012, Science Review of Product Chemistry, Residue Chemistry, Non-Target Organism, and Toxicity Data in Support of Label 

Amendment for Polyoxin D Zinc Salt. (Included with supplemental petition)

2 EPA, May 11 ,2012, Science Review of Product Chemistry, Residue Chemistry, Non-Target Organism, and Toxicity Data in Support of Label 

Amendment for Polyoxin D Zinc Salt. (Included with supplemental petition).
Revised March 2012

agriculture. G virens is marketed as 

SoilGard, P. fumosoroseus is the active 

ingredient in PFR-97 and S.griseoviridis is 

sold as Mycostop (OMRI, 2012). (TR line 

223) states that polyoxin D zinc salt was 

found to reduce the efficacy of the virus 

used to control the black cutwork 

(sic)(Agrotis ipsilon) (Bixby-Brosi and 

Potter, 2012 In the soil tests, the half-lives 

were 15.9 days for aerobic soils and 59.2 

days for anaerobic soils. (EPA science 

review, p12). However, in the document 

provided by the petitioner (January 18,2013 

section 5.2) it states that in the presence of 

sunlight polyoxin D zinc salt degrades by 

50% within 0.4 days (9.6 hours) “in sterile 

natural water, pH 5.0, pH 7.0, and pH 9.0 

buffers, respectively.” The petitioner says 

that it inhibits fungi growth but does not kill 

it, maintain that it would not be a detriment 

to organic products such as Root Shield, 

currently used in organic farming (same 

doc. Pg 24 section 5.5).

6. Are there adverse 

biological and chemical 

interactions in agro-

ecosystem? [§6518 m.5]

XX TR 233-237: “As a broad-spectrum 

antibiotic and fungicide, polyoxin D Zinc 

Salt is toxic to soil fungi. Polyoxins and 

other antibiotics were found to increase 

melanins in Alternaria kikuchiana (Kohno, 

et al., 1983; Butler and Day, 1998). The 

ecological functions of melanins are still 

unknown, but they are believed to enhance 

the phytotoxic and pathogenic properties of 

plant pathogens (Butler and Day, 1998). 

Earthworms were shown to have a 

preference for melanized fungi (Marfenina 

and Ischenko, 1997; Butler and Day, 

1998).” There is some concern that 

polyoxin D used on turf to have a moderate 

risk of resistance. (Vincelli and Williams 

2012)(TR lines 253-261) Again alternative 

materials may have similar or worse 

effects.(TR lines 246-248) (TR July 11, 

2012) In the Jan. 18, 2013 (pages 20 -26)

document provided by the petitioner it does 

not actually kill fungi, just inhibits growth. 

Also is not harmful to beneficial insects. 

Same report (pages 27-28) also that 

polyoxin D zinc salt is a FRAC 19 class 

(Kaken 2008) (EPA Reg. No. 68173-1) of 

fungicide. It has a unique mode of action 

that would aid in resistance management 
Revised March 2012

as part of an IPM disease control program. 

Only class 19 fungicide currently listed.

7. Are there detrimental 

physiological effects on 

soil organisms, crops, or 

livestock? [§6518 m.5]

X The TR states that there may be adverse 

effects to beneficial soil organisms when 

exposed to polyoxin D. TR lines 241-242.

It goes on to state that alternative 

fungicides may have similar or even greater 

effects on soil ecology, but that no studies 

could be found that compare the impacts 

between polyoxin D and other fungicides in 

organic production, specifically. TR lines 

246-251. (TR July 11, 2012) Is not labeled 

for use on livestock or pastures.

8. Is there a toxic or other 

adverse action of the 

material or its 

breakdown products?

[§6518 m.2]

X The following refers to polyoxin D zinc’s 

use as an antibiotic: Polyoxin D has been 

shown to be effective as a drug to treat 

human and animal pathogens Candida 

albicans and Cryptococcus neoformans 

(Becker, et al., 1983: Hilenski, et al., 1986). 

Polyoxin D also shows some efficacy in the 

reduction of the protozoan parasite 

Encephalitiozoon cuniculi infecting 

immune-compromised AIDS patients 

(Sobottka, et al., 2002). All three of the 

above mentioned studies were in vitro

experiments and not substantiated by any 

in vivo claims or studies. Polyoxin D zinc 

salt in currently not listed for use in human 

or veterinary medicine.

Moderate acute dermal toxicity; moderate 

toxicity primary eye irritation. (TR Table 2.)

9. Is there undesirable 

persistence or 

concentration of the 

material or breakdown 

products in 

environment? [§6518 

m.2]

X The EPA’s risk assessment of polyoxin D 

Zinc Salt to carry a low environmental risk 

due to its specific mode of action, low 

toxicity, rapid degradation and low

application rate (EPA 2008) TR lines 190-

191.“The EPA waived environmental fate 

and ground water data due to the use 

pattern, application methods, and mitigation 

of non-target aquatic organism toxicity with 

appropriate precautionary label statements 

under “Environmental Hazards. Failure to 

follow the label instructions may result in 

the death of fish and 194 aquatic 

organisms (EPA, 2001, 2008).” (TR 191-

195) Soil half-life from aerobic microbial 

metabolism is reported to be 15.9 days. 

Degradation in water and sunlight is 

reported to be approximately 2.3 days 

(Smith, 2012). (TR line 153)(July 11, 2012)

10.Is there any harmful XX All polyoxins have shown to have low 
Revised March 2012

effect on human health? 

[§6517 c (1)(A)(i); 6517 

c(2)(A)i; §6518 m.4]

mammalian toxicity.(Copping and Duke, 

2007)(TR lines 305-309)). Could case slight 

skin irritation. Positive benefits for human 

and animal pathogens Candida albicans 

and Cryptococcus neoformans (Becker,et 

al. 1983: Hilenski, et al., 1986) (TR lines 

311-314) Polyoxin D Zinc Salt is currently 

not listed for use for human or veterinary 

medicinal uses. Also has be shown to have 

an effect on the protozoan parasite 

Encephalitozoon cuniculi infecting the 

immune system in AIDS patients (Sobottka,

et al., 2002) (TR lines 311-314) This was 

the result of one in vitro experiment. (TR 

July 11,2012) EPA: results of the 

mutagenicity studies indicated Polyoxin D 

Zinc Salt Technical was weakly mutagenic 

in an Ames Assay (MRID# 433230-01) and 

not mutagenic in a host mediated assay 

(MRID # 432618-36). If a food/feed use is 

ever sought, the test results will require a 

review of the mutagenicity data base to 

determine the need for additional 

studies.2Mammalian chromosome 

aberration studies with hamster cells 

showed highly significant increases in

chromosomal aberrations over solvent 

control.3 However, in view of other studies 

submitted by the petitioner, EPA decided 

that the studies indicate that polyoxin D 

zinc salt is not mutagenic or clastogenic.

11.Is there an adverse 

effect on human health 

as defined by applicable 

Federal regulations? 

[205.600 b.3]

X

12.Is the substance GRAS 

when used according to 

FDA’s good 

manufacturing 

practices? [§205.600 

b.5]

X

13.Does the substance 

contain residues of 

heavy metals or other 

contaminants in excess 

of FDA tolerances? 

[§205.600 b.5]

X

1

If the substance under review is for crops or livestock production, all of the questions 

from 205.600 (b) are N/A—not applicable.
Revised March 2012

2 EPA. Consideration of Eligibility for Registration of the New Pesticide Active Ingredient 

Polyoxin D Zinc Salt – DECISION MEMORANDUM,p 15.

3 EPA, May 11, 2012. Science Review of Product Chemistry, Residue Chemistry, NonTarget Organism, and Toxicity Data in Support of Label Amendment for Polyoxin D Zinc 

Salt. (Included with supplemental petition.)

NOSB Evaluation Criteria for Substances Added To the National List

Category 2. Is the Substance Essential for Organic Production? Substance: 

Question Yes No N/A1 Documentation (TAP; petition; 

regulatory agency; other)

1. Is the substance formulated or 

manufactured by a chemical 

process? [6502 (21)]

X X Included in a new document received 

on January 18, 2013 from the 

petitioner it states on page 5 section 

1.1, that, polyoxin D is made from an 

aerobic fermentation process, thus a 

natural process. However, they do 

state that they do not know whether

the zinc salt is from a mined or from a 

recycled zinc source. The TR states 

that the manufacturing process has at 

least one step that would be similar to 

other Streptomyces products that are 

classified as synthetic on section 

205.601 of the National List: 

streptomycin and tetracycline 

(terramycin). Similarly, polyoxin D 

Zinc Salt may also be classified as a 

synthetic.TR lines 146-148. It would 

appear that polyoxin D may be nonsynthetic, but it would be assumed 

that the zinc salt would be synthetic, 

due to the lack of being able to 

properly verify its source.

2. Is the substance formulated or 

manufactured by a process that 

chemically changes a substance 

extracted from naturally occurring 

plant, animal, or mineral, sources? 

[6502 (21)]

X X Refer to the above answer in 

Category 2, Question 1.

3. Is the substance created by naturally 

occurring biological processes? 

[6502 (21)]

X It is produced from a natural occurring 

soil microorganism Streptomyces 

cacaoi by a controlled fermentation 

process, according to the TR lines 

119 – 120. (TR July 11, 21012) The 

petition states that polyoxin D Zinc 

Salt is isolated from a broth 

(extraction media) and then dried. 
Revised March 2012

Actual process is part of their CBI 

information. One part of the TR states 

that a review of all the structural forms 

of polyoxin does not include the Zinc 

Salt as a natural product 

(Worthington, 1988). TR lines 141-

142. Also, refer to the answers as 

stated in Category 2, Question 1 & 2.

4. Is there a natural source of the 

substance? [§205.600 b.1]

X X

5. Is there an organic substitute? 

[§205.600 b.1]

X

6. Is the substance essential for 

handling of organically produced 

agricultural products? [§205.600 b.6]

X

7. Is there a wholly natural substitute 

product?

[§6517 c (1)(A)(ii)]

X X There is a natural occurring quinone 

plumbagin, isolated as a botanical 

that is comparable to polyoxin D 

(Dekeyser and Downer 1994), but it is 

not commercially available in the US 

at this time. There are coppers and 

sulfur materials currently allowed for 

use. TR 321-328. (TR July 11, 2012)

8. Is the substance used in handling, not 

synthetic, but not organically 

produced?

[§6517 c (1)(B)(iii)]

X

9. Are there any alternative substances? 

[§6518 m.6]

X There are other alternative 

substances available. The TR lists 

several that are currently allowed: 

JMS Stylet Oil, Dow’s M-Pede, 

Regalia, Sonata, and Kaligreen to 

name just a few. See TR July 12, 

2012 table: Comparison of the 

Endorse WDG label with Alternative 

Pesticides., located between lines 

355-356. The efficacy of each of 

these materials is not listed.

10.Is there another practice that would 

make the substance unnecessary? 

[§6518 m.6]

X X (TR lines 376-391) The TR lists 

several possible practices that could 

be used possibly in place of polyoxin 

D Zinc Salt. Antibiosis – using the live 

organisms rather than their extracts. 

This seems to be more consistent 

with organic farming 

principles.(Milner, et al. 1997) Also 

beneficial antagonistic Streptomyces 

spp – but commercial development is 

slow in coming.(Liu, et al., 1997) (TR 

July 11, 2012) Also, crop rotation, 

crop nutrient management practices, 
Revised March 2012

sanitation to remove disease vectors, 

selection of resistant species and 

varieties ( where applicable) beneficial 

antagonistic bacteria, monitoring. TR 

367-382

1

If the substance under review is for crops or livestock production, all of the questions 

from 205.600 (b) are N/A—not applicable.

NOSB Evaluation Criteria for Substances Added To the National List

Category 3. Is the substance compatible with organic production practices? 

Substance: 

Question Yes No N/A1 Documentation (TAP; petition; 

regulatory agency; other)

1. Is the substance compatible with 

organic handling? [§205.600 b.2]

X

2. Is the substance consistent with 

organic farming and handling? [§6517 

c (1)(A)(iii); 6517 c (2)(A)(ii)]

X X There are concerns with the possible 

impact on beneficial soil organisms. 

Toxic to bees. (TR lines 305-309) 

EPA exempts it from tolerance (40 

CFR 180.1285) Also in a petition 

Addendum dated October 2,2012 the 

EPA has granted the petitioner an 

expanded exemption of tolerance to 

“all food commodities” and given 

expanded uses for all food and feed 

crops pre-harvest and post- harvest. 

3. Is the substance compatible with a 

system of sustainable agriculture? 

[§6518 m.7]

X X No, because it is not a unnecessary 

synthetic input. Also, because it does 

show toxicity to fungi and bees.

However, some felt it was a useful 

tool as part of a rotational disease 

control program. 

4. Is the nutritional quality of the food 

maintained with the substance? 

[§205.600 b.3]

X

5. Is the primary use as a preservative? 

[§205.600 b.4]

X

6. Is the primary use to recreate or 

improve flavors, colors, textures, or 

nutritive values lost in processing 

(except when required by law, e.g., 

vitamin D in milk)? [205.600 b.4]

X

7. Is the substance used in production, 

and does it contain an active 

synthetic ingredient in the following 

X
Revised March 2012

categories:

a. copper and sulfur compounds;

b. toxins derived from bacteria; X According to the TR (TR line 110) 

polyoxin D is a toxin derived from a 

bacteria (Streptomyces cacaoi 

var.asoensis) (TR July 11, 2012)

c. pheromones, soaps, horticultural 

oils, fish emulsions, treated seed, 

vitamins and minerals?

X

d. livestock parasiticides and 

medicines?

X

e. production aids including netting, 

tree wraps and seals, insect traps, 

sticky barriers, row covers, and 

equipment cleaners?

X

1

If the substance under review is for crops or livestock production, all of the questions 

from 205.600 (b) are N/A—not applicable.

NOSB Evaluation Criteria for Substances Added To the National List

Category 4. Is the commercial supply of an agricultural substance as organic, 

fragile or potentially unavailable? [§6610, 6518, 6519, 205.2, 205.105 (d), 205.600 

(c) 205.2, 205.105 (d), 205.600 (c)] Substance: Name

Question Yes No N/A1 Documentation (TAP; petition; 

regulatory agency; other)

1. Is the comparative description 

provided as to why the non-organic 

form of the material /substance is 

necessary for use in organic 

handling? 

X

2. Does the current and historical 

industry information, research, or 

evidence provided explain how or 

why the material /substance cannot 

be obtained organically in the 

appropriate form to fulfill an essential 

function in a system of organic 

handling? 

X

3. Does the current and historical 

industry information, research, or 

evidence provided explain how or 

why the material /substance cannot 

be obtained organically in the 

appropriate quality to fulfill an 

essential function in a system of 

organic handling? 

X
Revised March 2012

4. Does the current and historical 

industry information, research, or 

evidence provided explain how or 

why the material /substance cannot 

be obtained organically in the 

appropriate quantity to fulfill an 

essential function in a system of 

organic handling?

X

5. Does the industry information 

provided on material / substance 

non-availability as organic, include ( 

but not limited to) the following:

a. Regions of production (including 

factors such as climate and 

number of regions);

X

b. Number of suppliers and amount 

produced;

X

c. Current and historical supplies 

related to weather events such as 

hurricanes, floods, and droughts 

that may temporarily halt 

production or destroy crops or 

supplies; 

X

d. Trade-related issues such as 

evidence of hoarding, war, trade 

barriers, or civil unrest that may 

temporarily restrict supplies; or

X

e. Are there other issues which may 

present a challenge to a 

consistent supply?

X

1

If the substance under review is for crops or livestock production, all of the questions 

from 205.600 (b) are N/A—not applicable.