MAF 1 Drift fraction / Vegetation factor 2
8.2 Harmful effects .1 Phytotoxicity
Also a total of fourteen trials are used to evaluate the phytotoxicity of Proman in potatoes in the Netherlands. All trials were carried out in the Maritime climatic zone. An overview of the distribution of the trials by country and year is given in table 8.2.1a
Table 8.2.1a. Overview of the selectivity trials.
Number of trials
Crop(s) Country Years Type of trial
Maritime zone
GEP, non-GEP, official
2010 S + Y 1 GEP
France
2011 S + P 1 GEP
2010 S + Y 1 GEP
Germany
2011 S + P 1 GEP
2009 S + Y 2 GEP
Belgium
2010 S + Y 2 GEP
2010 S + Y 1 GEP
Netherlands
2011 S + P 2 GEP
United Kingdom 2010 S + Y 1 GEP
2011 S + Y 1 GEP
Potatoes
Czech Republic
2012 S + Y 1 GEP
TOTAL - - - 14 -
S = selectivity trial, Y = trial with yield assessment, P = trial with assessment of impact on propagation.
A total of fourteen phytotoxicity trials were carried out in the Maritime climatic zone to evaluate the phytotoxicity of Proman in potato. See table 3-6 and 3-7 for an overview and the methodology of the trials. Phytotoxicity is also assessed in the effectiveness trials and in a extra variety trial. These effectiveness trials and the variety trial are used supplementary to evaluate the phytotoxicity of Proman.
In twelve phytotoxicity trials no phytotoxic symptoms were found after an application with the proposed dose rate of 3-4 L/ha Proman. Even after an application with the double dose rate no phytotoxic symptom was found in these trials on any assessment.
In two phytotoxicity trials a very low level (<1% chlorosis) was found after an application with 4 L/ha Proman. After an application with the double dose rate (6-8 L/ha) this phytotoxicity was higher, but also at a low acceptable level (<3% chlorosis). These phytotoxic symptoms had disappeared at later
assessments.
In most supplementary trials no phytotoxic symptoms were found after an application with the proposed dose rate of 3-4 L/ha Proman.
In some supplementary trials a very low level of phytotoxicity (<3% chlorosis) was found after an application with 3-4 L/ha Proman. These phytotoxic symptoms had completely disappeared at the following assessments.
In the trials where phytotoxic symptoms were found after an application with Proman, these phytotoxic symptoms were also found after an application with the reference products. For this reason the observed phytotoxicity is considered to be acceptable.
8.2.2 Yield
8.2.2.1 Effect on yield
In ten phytotoxicity trials also the yield was assessed. See table 8.2.1a for an overview of the trials.
In these trials, the proposed use of Proman and the 2N dose rate of Proman had no significant effects on the crop yield compared to the untreated control and the reference products based on metribuzine or the reference product based on clomazone.
Moreover no significant phytotoxic effects have been reported during the other phytotoxicity trials and the supplementary efficacy trials which could have consequences on the yield.
Conclusion
The proposed use of Proman has no adverse effects on the yield quantity on potato.
8.2.2.2 Effects on the quality of plants or plant products
Two trials carried out in 2010 in Germany and United Kingdom were used to evaluate the effects of Proman (2 L/ha and 4 L/ha), on the quality of potato for processing and taint.
Tubers from these trials were harvested and used for processing and taint testing. Taint testing was performed in accordance to EPPO standard PP 1/242.
No differences were found in these tests between samples from potatoes treated with 2 L/ha Proman, 4 L/ha Proman and the untreated control and the reference products based on clomazone or metribuzine in taint and quality parameters of potato after processing.
Conclusion
No negative effect on the quality of potato is expected after an application of the proposed use of Proman.
8.2.2.3 Effects on transformation processes
No trials were carried out to assess the effects of Proman on the transformation processes of potatoes.
Products based on metobromuron have been applied in Europe for many years and effects of these products are not mentioned. For this reason it is not expected that Proman has an effect on the transformation processes of potatoes.
Conclusion
It is not expected that Proman has an effect on the transformation processes of potatoes.
8.2.3 Effects on succeeding crops or substitution crops
Two trials were carried out in 2009 in Belgium and France to evaluate the crop safety of Proman on the emergence and development of succeeding crops.
These trials were conducted to evaluate the effect of Proman (2 L/ha and 4 L/ha) on six succeeding crops. In these trials, the crop was drilled about one month after the application of Proman on bare soil
of the same trial site. As succeeding crops were used field bean, field pea, garden carrot, garden turnip, maize and sugar beet.
The crops were assessed from first emergence in the untreated control, for crop emergence and/or crop density, for phytotoxicity, for any differences in crop vigour. Turnip and sugar beet expressed significant sensitivity to the treatments (emergence and phytotoxicity). Turnip is a representative crop for all Brassicas.
Carrots, maize, field beans and field peas were not affected, or sometimes not significantly affected by the high rate.
Conclusion
It is not recommended to sown Brassicas and sugar beet after an application of 4 L/ha Proman.
The applicant proposed a restriction on the label for Brassicas and sugar beet, that soil cultivation with ploughing is necessary before sowing/planting as succeeding crop after an application of Proman in potato is recommended.
The following restriction sentence has been included on the label:
Mocht de behandelde teelt in het voorjaar mislukken dan wordt afgeraden om koolgewassen, koolzaad of suikerbieten als vervanggewas te gebruiken. Voor het zaaien of planten van allerlei volgteelten wordt een kerende grondbewerking d.m.v. ploegen aangeraden.
8.2.4 Effects on plants or plant products to be used for propagation
Four trials carried out in 2011 and 2012 in Germany, the Netherlands and France are used to evaluate the crop safety of Proman (2, 4 and 8 L/ha) in seed potatoes. In these trials observations were made on germination parameters in the following season.
After harvest 100 tubers of size 35-45mm were taken per plot and stored in a cool room during winter.
In spring they were moved into a warmer room to force germination. From samples of 50 tubers the number and the height of sprouts were assessed after storage.
Also 50 tubers are planted in the field, and one month after planting the crop emergence and phototoxic symptoms were assessed.
In all trials no differences in germination parameters or emergence or phytotoxicity were seen at any of the tested dose rates compared to the untreated control
Conclusion
The proposed use of Proman does not give any adverse effects on parts of plants used for propagation.
8.2.5 Effects on adjacent crops
In the trials, no adverse effects of Proman on adjacent crops were reported. Adverse effects are also not expected by normal use of Proman due to good agricultural practice.
Conclusion
It is not expected that Proman has an effect on adjacent crops of potatoes.
Conclusion harmfull effects:
The available information is sufficient for the evaluation of the phytotoxicity of Proman in potato for the Maritime climatic zone. In some trials 4 L/ha Proman showed some acceptable phytotoxicity
(chlorosis) in early assessments, but this negative effect normally disappeared in the later assessments.
It can be concluded that the proposed uses of Proman is safe in potato.
In most trials the proposed use of Proman showed no phytotoxicity.
The product complies with the Uniform Principles because it does not, in accordance with article 2.2., induce any unacceptable side effects on plants or plant products, when used and applied in
accordance with the proposed label.
8.3 Resistance
Proman is based on the active substance metobromuron. Metobromuron belongs to the chemical group of the Ureas, and is an inhibitor of photosynthetis as its mode of action involves inhibiting photosynthetic electron transfer at photosystem two (PS II). Herbicides based on metobromuron were applied in Europe for many years, and there have been no recorded cases of resistance to the active substance metobromuron.
Metobromuron is classified in HRAC Group C2, and resistance against these group of herbicides is already found in Europe in many weeds (e.g. in biotypes of ALOMY, AMARE, APSPV, CHEAL, CONCA, ECHCG, ECHCR, LOLMU, LOLRI, and SENVU). The first case was recorded in Germany in 1980. For this reason Proman has a risk of resistance for the control of weeds in potato, and it is recommended to have a resistance management strategy.
Possibilities to reduce the risk of developing resistance are:
- Pre-emergence applications of herbicides in potatoes followed by post-emergence or post-planting applications of herbicides to control later emerged weeds. The use of Proman in sequence with other herbicides, with different modes of action;
- mechanical weed control (e.g. tillage);
- potatoes grown in a crop rotation.
The proposed use of Proman is with a maximum of one pre-emergence application of Proman per season. Furthermore, it is advised to alternate with active substances of other chemical groups and potatoes are normally grown in a good crop rotation. Therefore no further resistance management is necessary.
It is expected that the selection pressure of Proman on weeds is low, when it is used with a maximum of one application per season, and when it is alternated with active substances of other chemical groups in an alternating crop rotation, since there is a resistance risk associated with the product a restriction management sentence needs to be included:
Resistentiemanagement
Dit middel bevat de werkzame stof metobromuron. Metobromuron behoort tot de Ureum verbindingen.
De Hrac code is C2.
Bij dit product bestaat er kans op resistentieontwikkeling. In het kader van resistentiemanagement dient u de adviezen die gegeven worden in de voorlichtingsboodschappen, op te volgen.
Conclusion
The product complies with the Uniform Principles, article 2.1.3 as the level of control on the long term is not influenced by the use of this product because of the possible build up of resistance.