1-[(4-chlorophenyl)methyl]-1-cyclopentyl-3-phenylurea

Toxicity to terrestrial plants

Link to relevant study record(s)

Reference

Endpoint:

toxicity to terrestrial plants: long-term

Type of information:

experimental study

Adequacy of study:

key study

Study period:

August 2000 to 2001-01-09

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Qualifier:

no guideline available

Principles of method if other than guideline:

- Principle of test: Screening data are used to show whether the product causes phytotoxic effects on non-target plants under procedures as recommended by OECD for non - herbicidal CPPs. Pencycuron tech. (NTN 19701) is a fungicide with a proposed maximum seasonal spray application rate of about 2500 g a.s./ha
- Short description of test conditions: Pencycuron tech. was applied at rates from 250 to 7500 g a.s./ha: 1) to the soil surface in which plants were subsequently grown and 2) to the foliage of emerged plants.
- Parameters analysed / observed: In the pre-emergence test no phytotoxic effects occurred up to 7500 g a.s./ha. When applied to foliage (post-emergence) also no phytotoxic effects were observed up to 7500 g a.s./ha.

GLP compliance:

no

Remarks:

This is a screening study and thus GLP is not required.

Analytical monitoring:

no

Vehicle:

yes

Remarks:

DMF (N,N-Dimethylformamide)

Details on preparation and application of test substrate:

The test material was applied as active ingredient with a water application rate of 1000 litres/ha (post-emergence with 0.1% Renex 36) from a stock solution of NTN 19701 in DMF (N,N-Dimethylformamide).
Spray treatments were applied in an automatic spray chamber for primary screening tests. The spray chamber was adjusted as follows: pressure 3 bar; height of spray boom 45 cm; nozzle type: 8003E; water application rate to the target area 1000 litres/ha; the material was applied in single applications of 250; 500; 1000; 1250; 2000; 2500; 5000 and 7500 g a.s./ha. For spray treatments the test solutions were briefly shaken and then directly applied through a spraying nozzle. Each application was automatically performed by touching a button. Prior to each application of new test material, the spray nozzle was cleaned at the rinsing station. The adjustments of the spray chamber were recalibrated every six months. Applications were made separately to the soil surface (pre-emergence) or on plants (foliar).

Species:

other: Abutilon theophrasti

Plant group:

Dicotyledonae (dicots)

Species:

other: Amaranthus retroflexus

Plant group:

Dicotyledonae (dicots)

Species:

Beta vulgaris

Plant group:

Dicotyledonae (dicots)

Species:

other: Galium aparine

Plant group:

Dicotyledonae (dicots)

Species:

other: Ipomoea hederacea

Plant group:

Dicotyledonae (dicots)

Species:

other: Sinapis alba

Plant group:

Dicotyledonae (dicots)

Species:

other: Alopecurus myosuroides

Plant group:

Monocotyledonae (monocots)

Species:

other: Avena fatua

Plant group:

Monocotyledonae (monocots)

Species:

other: Echinochloa crus-galli

Plant group:

Monocotyledonae (monocots)

Species:

other: Setaria viridis

Plant group:

Monocotyledonae (monocots)

Species:

Zea mays

Plant group:

Monocotyledonae (monocots)

Test type:

seedling emergence toxicity test

Study type:

laboratory study

Substrate type:

other: sandy loam

Limit test:

no

Total exposure duration:

21 d

Test temperature:

The plants were kept at a day/night cycle of 22°C/15°C, respectively.

Moisture:

50%

Details on test conditions:

Horticultural Conditions
Pre-emergence
Seeds of all mentioned plant species were planted together into soil (sandy loam, organic matter of 2.5%-3%) in greenhouse pots of 420 cm2 surface (pot T59). Typically 10 seeds of each of the 11 species were sown 24 hours prior to application of the test substance. The soil allowed good germination. Growing plants were watered as needed.

Post-emergence
Seeds of all mentioned plant species were planted together into soil (sandy loam, organic matter of 2.5%-3%) in greenhouse pots of 420 cm2 surface (pot T59). Typically 10 seeds of each of the 11 species were placed. Plants were grown in the greenhouse for about 14 days prior to application of the test material. Growing plants were watered as needed.

Growing Conditions
The plants were kept at a day/night cycle of 22°C/15°C, respectively. The relative humidity in the test chamber was set at 50% and the duration of illumination (8000 lux) was 14 hours to 10 hours in a day/night rhythm. Plants used for the foliar treatments (post-emergence) were grown for approximately 2 weeks prior to the application. The final evaluation was done 17 days after treatment. Plants used for pre-emergence treatments were sown, sprayed with the test material and directly placed under the specified growing conditions. The final evaluation was done 21 days after treatment initiation.

Rating Scale for Visual Observations and Data Evaluation
Evaluation of phytotoxicity was done by visual observations using a rating scale of 0 to 100%, where 100% represented complete destruction of above ground parts and 0% represented no visual damage (normal growth) as compared to untreated plants. The test results were recorded by electronic data processing and printed subsequently. These print outs were checked by the evaluators, the laboratory supervisor and an outside person and signed with the date of entry.

Nominal and measured concentrations:

Nominal concentrations: 250, 500, 1000, 1250, 2000, 2500, 5000 and 7500 g a.s./ha.

Species:

other: Abutilon theophrasti, Amaranthus retroflexus, Beta vulgaris, Galium aparine, Ipomoea hederacea, Sinapis alba, Alopecurus myosuroides, Avena fatua, Echinochloa crus-galli, Setaria viridis, and Zea mays.

Duration:

21 d

Dose descriptor:

other: NOER

Effect conc.:

>= 7 500 g/ha

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

seedling emergence

Key result

Species:

other: Abutilon theophrasti, Amaranthus retroflexus, Beta vulgaris, Galium aparine, Ipomoea hederacea, Sinapis alba, Alopecurus myosuroides, Avena fatua, Echinochloa crus-galli, Setaria viridis, and Zea mays.

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

>= 2.5 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

seedling emergence

Details on results:

Visual Observations
The results from the pre-emergence (soil applied) test are summarised in Table I and the results from the foliar application are given in Table II. NTN 19701 was applied at rates from 250 to 7500 g a.s./ha: 1) to the soil surface in which plants were subsequently grown and 2) to the foliage of emerged plants. The effects were calculated as mean between two replicates. In the pre-emergence test no phytotoxic effects occurred up to 7500 g a.s./ha. When applied to foliage (post-emergence) also no phytotoxic effects were observed up to 7500 g a.s./ha.

See "Attachments" in "Overall remarks, attachments" for the tables.

Validity criteria fulfilled:

yes

Conclusions:

When applied to soil (pre-emergence) or to foliage (post-emergence) none of the 5 monocotyledoneous and 6 dicotyledoneous plant species out of 7 plant families showed phytotoxic effects up to the proposed maximum seasonal spray application rate of 7500 g a.s./ha.

Executive summary:

When applied to soil (pre-emergence) or to foliage (post-emergence) none of the 5 monocotyledoneous and 6 dicotyledoneous plant species out of 7 plant families showed phytotoxic effects up to the proposed maximum seasonal spray application rate of 7500 g a.s./ha. The NOEC was determined to be 7500 g a.s./ha (corresponding to 2.5 mg a.s./kg soil dw).

Description of key information

Seedling emergence study: Following a soil surface (pre-emergence) and foliage (post-emergence) application of Pencycuron at 250 to 7500 g a.s./ha to 11 terrestrial plant species. None of the 11 plant species showed phytotoxic effects up to the proposed maximum seasonal spray application rate of 7500 g a.s./ha. The NOER was determined to be ≥7500 g/ha (corresponding to a NOEC of ≥2.5 mg/kg soil dw).

 

Test species	Result	Assessment	Reference
Abutilon theophrasti, Amaranthus retroflexus, Beta vulgaris, Galium aparine, Ipomoea hederacea, Sinapis alba, Alopecurus myosuroides, Avena fatua, Echinochloa crus-galli, Setaria viridis, and Zea mays.	21-d NOER ≥7500 g a.s./ha  21-d NOEC ≥2.5 mg a.s./kg soil dw	Key study	Meisner (2001)

Key value for chemical safety assessment

Long-term EC10, LC10 or NOEC for terrestrial plants:

2.5 mg/kg soil dw