picoxystrobin (ISO); methyl (2E)-3-methoxy-2-[2-({[6-(trifluoromethyl)pyridin-2-yl]oxy}methyl)phenyl]acrylate

Toxicity to terrestrial plants

Administrative data

Endpoint:

toxicity to terrestrial plants: long-term

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Report date:

2009

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 208 (Terrestrial Plants Test: Seedling Emergence and Seedling Growth Test)

Deviations:

yes

Remarks:

Total accumulated light intensity to be maintained between 10 and 27 Einsteins/m2/day. During the study, total accumulated light intensity dropped below 10 Einsteins/m2/day from May 25 to 29, and on July 21 and 29. There was no impact on study

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.4100 (Terrestrial Plant Toxicity Tier I (seedling emergence))

Deviations:

yes

Remarks:

Total accumulated light intensity to be maintained between 10 and 27 Einsteins/m2/day. During the study, total accumulated light intensity dropped below 10 Einsteins/m2/day from May 25 to 29, and on July 21 and 29. There was no impact on study.

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPP 122-1 (Terrestrial Plant Toxicity Tier I (seedling emergence))

Deviations:

yes

Remarks:

Total accumulated light intensity to be maintained between 10 and 27 Einsteins/m2/day. During the study, total accumulated light intensity dropped below 10 Einsteins/m2/day from May 25 to 29, and on July 21 and 29. There was no impact on study.

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

methyl (E)-3-methoxy-2-{2-[6-(trifluoromethyl)pyridin-2-yloxymethyl]phenyl}acrylate

EC Number:

601-478-9

Cas Number:

117428-22-5

Molecular formula:

C18H16F3NO4

IUPAC Name:

methyl (E)-3-methoxy-2-{2-[6-(trifluoromethyl)pyridin-2-yloxymethyl]phenyl}acrylate

Test material form:

solid

Details on test material:

Purity: not specified

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Samples collected from the test concentration spray mixture following test solution preparation were analyzed to confirm the test substance concentration. The rate applied was 500 g a.s./ha.

Calibration standards of the test substance, ranging in concentration from 3.00 to 30.0 mg a.s./L, were prepared in acetonitrile and analyzed with the samples.

Test substrate

Vehicle:

yes

Remarks:

domestic well water purified by reverse osmosis

Details on preparation and application of test substrate:

The test substance spray mixture was prepared in the carrier solution, domestic well water purified by reverse osmosis containing 0.125% (v/v) non-ionic surfactant (Tween 80).

All applications were made using an automated research track sprayer equipped with a Teejet 8002 E nozzle. The sprayer was calibrated to apply approximately 400 L water/ha at approximately 2.8 bar (40 psi). High spray volumes were used to maximize coverage of the soil surface. The test solution was applied to the surface of the soil in test pots after the seeds were planted beginning with the water control, followed by the test item concentration.

Test organisms

1

Species:

Zea mays

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

- Common name: Corn
- Plant family: Poaceae
- Variety: 33J56
- Source of seed: Pioneer Hi-Bred International, Inc., Johnston, Iowa, USA
- Historical germination of seed: 94% (lot: 043004)

2

Species:

Avena sativa

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

- Common name: Oat
- Plant family: Poaceae
- Variety: Armor
- Source of seed: Wilken Seed Grains, Inc., Pontiac, Illinois USA
- Historical germination of seed: 84% (lot: 05-23-07)

3

Species:

Allium cepa

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

- Common name: Onion
- Plant family: Liliaceae
- Variety: WI-3115
- Source of seed: Wannamaker Seeds, St. Matthews, South Carolina, USA
- Historical germination of seed: >85% (lot: WS08-13)

4

Species:

Lolium perenne

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

- Common name: Ryegrass
- Plant family: Poaceae
- Variety: Gator 3
- Source of seed: Meyer Seed Co., Baltimore, Maryland, USA
- Historical germination of seed: 90% (lot: 846-7-05175)

5

Species:

Cucumis sativus

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: Cucumber
- Plant family: Cucurbitaceae
- Variety: Straight Eight
- Source of seed: Meyer Seed Co., Baltimore, Maryland, USA
- Historical germination of seed: 85% (lot: H-353)

6

Species:

Brassica napus

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: Oilseed rape
- Plant family: Brassicaceae
- Variety: 46A65
- Source of seed: Pioneer Hi-Bred Production, Ltd., Caledon, Ontario, Canada
- Historical germination of seed: 82% (lot: B-891021)

7

Species:

Pisum sativum

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: Pea
- Plant family: Fabaceae
- Variety: Laxton Progress #9
- Source of seed: Meyer Seed Co., Baltimore, Maryland, USA
- Historical germination of seed: 80% (lot: G-92)

8

Species:

Glycine max (G. soja)

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: Soybean
- Plant family: Fabaceae
- Variety: Williams 82
- Source of seed: Missouri Foundation Seeds, Columbia, Missouri, USA
- Historical germination of seed: 98% (lot: 65-15-04)

9

Species:

Beta vulgaris

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: Sugar beet
- Plant family: Chenopodiaceae
- Variety: Beta 4609R
- Source of seed: Betaseed, Inc., Shakopee, Minnesota, USA
- Historical germination of seed: 97% (lot: 129024-085-1CD-1)

10

Species:

Lycopersicon esculentum

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: Tomato
- Plant family: Solanaceae
- Variety: Rutgers
- Source of seed: Meyer Seed Co., Baltimore, Maryland, USA
- Historical germination of seed: 80% (lot: C-609)

Study design

Test type:

seedling emergence and seedling growth test

Study type:

other: Greenhouse study

Substrate type:

artificial soil

Remarks:

greenhouse soil mixture used in this study consisted of an industrial quartz sand, kaolin clay, peat, fertilizer, and pulverized limestone, which was added to buffer the soil.

Limit test:

yes

Total exposure duration:

21 d

Post exposure observation period:

Number of emerged seedlings at 7, 14, and 21 days after treatment
Number of survival of test plants at 7, 14, and 21 days after treatment
The shoot height of live test plants at 21 days after treatment
Shoot dry weights of plants at 21 days after treatment
The condition (visual response) of test plants at 7, 14, and 21 days after treatment.

Test conditions

Test temperature:

All species except for ryegrass, tomato, and oilseed rape: 18.3-34.0 °C
Ryegrass: 19.8-35.3 °C
Oilseed rape and tomato: 19.7-35.4°C

Details on test conditions:

TEST SYSTEM
- Test container: Standard plastic pots (16 cm diameter, 12 cm deep)
- Seed planting: Soil was added to the test pots, and a template was used to prepare 10 holes of similar size and depth. Seeds were visually examined for malformations and variations in size. Seeds used in the test were of similar size, otherwise, one indiscriminately selected seed was placed in each of ten holes, for a total of ten planted seeds in each pot. Holes were then closed by slightly depressing the soil surface.
- No. of seeds per container: 10
- No. of replicates per treatment group: 4
- No. of replicates per negative control: 4

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
- Sampling depth (cm): 12
- Texture: Sandy loam
- pH: 6.0 (water), 5.7 (CaCl2)
- % sand: 67
- % silt: 13
- % clay: 20
- Bulk density: 1.23 g/cm3
- Moisture at 1/3 Bar: 16%
- Organic matter: 1.5% (0.9% organic carbon)
- CEC: 7.5 meq/100 g
- Potassium: 53 ppm
- Magnesium: 95 ppm
- Calcium: 835 ppm
- Sodium: 10 ppm

GROWTH CONDITIONS
- Photoperiod: 16 hours with natural light augmented with high-pressure sodium lamps
- Light intensity and quality: All species except for ryegrass, tomato, and oilseed rape: Photosynthetically active radiation between 7.0 and 14.4 moles per square meter per day (Einsteins). Ryegrass: between 10.0 and 15.6 moles per square meter per day (Einsteins). Oilseed rape and tomato: between 8.3 and 12.7 moles per square meter per day (Einsteins).
- Relative humidity: All species except for ryegrass, tomato, and oilseed rape: ranging from 28 to 93%; Ryegrass: ranging from 40 to 93%; Oilseed rape and tomato: ranging from 41 to 94%
- Watering regime and schedules: After treatment, an initial watering was made from the top to ensure movement of the test substance into the soil profile. Subsequently, the test containers were watered by sub-irrigation with domestic well water as needed for seedling growth.

Nominal and measured concentrations:

Carrier control, surfactant control (0.125% non-ionic surfactant), 500 g a.s./ha.

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Species:

Zea mays

Duration:

21 d

Effect conc.:

500 g/ha

Basis for effect:

seedling emergence

Remarks on result:

other: 11% reduction from control

Effect concentrations 2

Species:

Avena sativa

Duration:

21 d

Effect conc.:

500 g/ha

Basis for effect:

other: shoot dry weight

Remarks on result:

other: 9% reduction from control

Effect concentrations 3

Species:

Allium cepa

Duration:

21 d

Effect conc.:

500 g/ha

Basis for effect:

growth

Remarks:

shoot height

Remarks on result:

other: 13% reduction from control

Effect concentrations 4

Species:

Lolium perenne

Duration:

21 d

Effect conc.:

500 g/ha

Basis for effect:

other: shoot dry weight

Remarks on result:

other: 15% reduction from control

Effect concentrations 5

Species:

Cucumis sativus

Duration:

21 d

Effect conc.:

500 g/ha

Basis for effect:

other: visual response

Remarks on result:

other: 9% reduction from control

Effect concentrations 6

Species:

Brassica napus

Duration:

21 d

Effect conc.:

500 g/ha

Basis for effect:

other: visual response

Remarks on result:

other: 15% reduction from control

Effect concentrations 7

Species:

Pisum sativum

Duration:

21 d

Effect conc.:

500 g/ha

Basis for effect:

other: visual response

Remarks on result:

other: 10% reduction from control

Effect concentrations 8

Species:

Glycine max (G. soja)

Duration:

21 d

Effect conc.:

500 g/ha

Basis for effect:

other: visual response

Remarks on result:

other: 15% reduction from control

Effect concentrations 9

Species:

Beta vulgaris

Duration:

21 d

Effect conc.:

500 g/ha

Basis for effect:

other: visual resopnse

Remarks on result:

other: 9% reduction from control

Effect concentrations 10

Species:

other: tomato (Solanum lycopersicum)

Duration:

21 d

Effect conc.:

500 g/ha

Basis for effect:

other: visual response

Remarks on result:

other: 11% reduction from control

Details on results:

The results for the most sensitive parameter for the available species at 21 days after soil exposure to the test substance are summerized in the table above.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Inhibition of all measured parameters for all species tested at a single limit test rate was less than 25% relative to the untreated control plants.

Executive summary:

Non-target terrestrial plant response to a single application rate of the test substance was evaluated on ten common plant species according to OECD guideline 208. Effects on seedling emergence and early growth following soil surface application to planted seeds prior to emergence were assessed. The single test rate was 500 grams of active substance per hectare (g a.s./ha). All tests were conducted in an artificial green house soil mixture (pH: 6.0, O.M.: 1.5%, T.O.C.: 0.9%) under greenhouse conditions. The test system was comprised of four replicates with ten planted seeds for the test rate(s) and control. Applications were made with a track sprayer calibrated to apply approximately 400 L water/ha. Test duration was 21 days. The number of plants emerged, visual rating of plant condition, and the number of plants surviving was recorded on days 7, 14, and 21. In addition, plant shoot height was recorded on day 21. Dry weight was determined from plant shoots collected at test termination on day 21.

Inhibition of all measured parameters for all species tested at a single limit test rate was less than 25% relative to the untreated control plants.