8.1 Efficacy evaluation Dose justification
During the period 1991 – 2010 a total of 20 field trials were carried out, as part of the effectiveness trials in which different dose rates of Symphonie were laid out. These trials were carried out in the Netherlands, the United Kingdom and France.
The effectiveness of Symphonie was assessed by determining the control of Rhizoctonia solani in potato tubers in relation to the untreated objects and is compared to the control achieved by treatment with a reference product with active ingredient pencycuron at its recommended label rate. Symphonie was applied to potato tubers by dusting at a dose rate of 84.4, 90, 120 and 156 g ai/tonne. Information on the design of these trials is supplied in section 6.1.3 of this report.
The Netherlands
In the ten trials conducted in the Netherlands in 1991 and 1992, Symphonie was applied to potato tubers at dose rates of 90 and 120 g ai/tonne. Application of Symphonie resulted in highly varying levels of disease control over the trials.
Application of Symphonie at the dose rate of 120 g ai/tonne resulted in an average of 46%
control in relation to the untreated objects, with control levels ranging from 0 to 99%. Similar levels of control were achieved by application of the dose rate of 90 g ai/tonne (an average of 46%). Control levels at the lower dose rate ranged from 0 to 100%. In general, these data were confirmed by statistical analysis.
The United Kingdom
In three of the five trials conducted in the United Kingdom in the spring of 1995, 1999 and 2003, Symphonie was applied to potato tubers at dose rates of 90 and 120 g ai/tonne.
Application of Symphonie resulted in highly varying levels of disease control over the trials.
Two of these three trials showed minimal levels of control for both dose rates (0 – 8%).
Application of Symphonie at the dose rate of 120 g ai/tonne resulted in 100% control in a single trial in relation to the untreated objects. A slightly lower control level of 93% was achieved in this trial by the dose rate of 90 g ai/tonne. Yet these differences were within the statistic range.
France
In the seven trials conducted in France in the spring of 2009 and 2010, Symphonie was applied to potato tubers at dose rates of 84.4, 120 and 156 g ai/tonne. Application of Symphonie resulted in varying levels of disease control over the trials.
Application of Symphonie at the dose rate of 120 g ai/tonne resulted in an average of 76%
control in relation to the untreated objects. A lower dose rate of 84.4 g ai/tonne of Symphonie gave rise to an average of 71% control. The highest dose rate of 156 g ai/tonne of
Symphonie resulted in the lowest level of control with an average of 66%.
In four of the seven trials control levels were high (>84%), in these trials no significant dose-related effect was observed. Only in the three trials with lower levels of disease control (3 – 75%) the dose rate of 120 g ai/tonne resulted in significantly higher levels of control in comparison to the dose rates of 84.4 and 156 g ai/tonne.
Conclusion minimum effective dose
The claim for use of Symphonie as a fungicide to control Rhizoctonia diseases in potatoes is a dose rate of 90 g ai/tonne. In the 20 field trials conducted between 1991 and 2010,
control achieved with 120 g ai/tonne, was statistically comparable to the control achieved with 90 g ai/tonne.
In the seven trials conducted in France, the individual results were generally considerably less variable than those of the trials conducted in the Netherlands and the United Kingdom.
In four of the seven trials levels of control were high (>84%), in these trials no significant dose-related effect was observed for Symphonie. Only in the three trials with lower levels of disease control (3 – 75%) the dose rate of 120 g ai/tonne resulted in significantly higher levels of control in comparison to the dose rates of 84.4 and 156 g ai/tonne.
Due to the highly varying levels of control in the conducted trials and the lack of a significant dose related difference in disease control, the dose rate of 120 g ai/tonne cannot be justified in deliberation of these results. It is recommended that the currently registered dose of 90 g ai/tonne is maintained.
Effectiveness
The effectiveness of Symphonie was assessed by determining the control of Rhizoctonia solani in potato tubers in relation to the untreated objects and was compared to the control achieved by treatment with a reference product with active ingredient pencycuron at its recommended label rate.
The Netherlands
In the ten trials conducted in the Netherlands in the spring of 1991 and 1992, Symphonie was applied to potato tubers at growth stage BBCH 0. In these trials the fields were of the following soil types; sand, loam and clay. Tubers were assessed at 135 – 199 days after application. The presence of R. solani was variable, with incidence indexes in the untreated objects ranging from 0.44 to 8.8.
Application of Symphonie resulted in highly varying levels of disease control over the trials.
Application of Symphonie at the dose rate of 120 g ai/tonne and at the currently authorized rate of 90 ai/tonne both resulted in an average of 46% control in relation to the untreated objects. Control levels ranged from 0 to 99%, with very low levels of control (<1%) in three trials, low to moderate control in three trials (18 – 45%), and high control in four trials (76 – 100%). Application of the reference product at its labelled rate resulted in an average of 41 % control. Control levels for the reference product ranged from 0 to 97%. Within the individual trials, control levels were generally comparable to or slightly lower than those levels seen after application of Symphonie.
Overall higher levels of control were achieved at higher levels of infection. In general these results were confirmed by statistical analysis.
The high variance in control levels were contributed to the attack from Rhizoctonia from the soil, which cannot be controlled by tuber application. No relation was observed between the level of control and soil type.
The United Kingdom
In the five trials conducted in the United Kingdom in the spring of 1995, 1999 and 2003, Symphonie was applied to potato tubers at growth stage BBCH 0. In these trials the fields were of the following soil types; sand, sandy loam and alluvium. Tubers were assessed at 111 – 303 days after application. The presence of R. solani was variable with incidence levels in the untreated objects of 0.5 – 22.5%.
Application of Symphonie resulted in highly varying levels of disease control over the trials.
Two trials showed very low levels of control (<1%) for all applications, including the reference product. For the remaining three trials Symphonie was applied at the dose rate of 120 g ai/tonne in three trials resulting in an average of 97% control, in relation to the untreated objects. In a single trial Symphonie was applied at the currently authorized dose rate of 90 g ai/ha resulting in 93% control, in relation to the untreated objects. Application of the reference
product at its labelled rate in two trials resulted with an average of 96% control, in relation to the untreated objects, in a comparable level of control.
In the trials were both dose rates of Symphonie, and the reference product were applied control levels between treatments were within the statistic range.
No relation was observed between the level of control and soil type.
France
In the seven trials conducted in France in the spring of 2009 and 2010, Symphonie was applied to potato tubers at growth stage BBCH 0. In these trials soil type was not specified.
Tubers were assessed at 82 – 229 days after application.
The presence of R. solani was variable with incidence levels in the untreated objects of 1.3 – 90.8%.
Application of Symphonie and the reference product resulted in varying levels of disease control over the trials, with one trial showing low levels of control (<11%), two trials with low to moderate levels of control (23 – 75%) and four trials with high levels of control (81 – 100%). Application of Symphonie at the dose rate of 120 g ai/tonne resulted in an average of 76% control in relation to the untreated objects. Control levels ranged from 2.7 – 100%. A comparable level of control was seen after application of Symphonie at a dose rate of 84.4 g ai/tonne, just below the currently registered dose (an average of 71% control in relation to the untreated objects). Control levels ranged from 4.7 – 100%.
Application of the reference product at its labelled rate resulted with an average of 65% in a slightly lower level of control. Control levels for the reference product ranged from 10.3 – 100%.
Generally these results were confirmed by statistical analysis.
Conclusion efficacy tests
In a total of 22 trials conducted in the spring of period 1991 – 2010, Symphonie was applied to potato tubers at a dose rate of 90 g ai/tonne. Incidence of infection with Rhizoctonia solani in the potato tubers was variable. Over all trials conducted, the level of control achieved with Symphonie at its proposed dose rate was comparable to the control achieved with
Symphonie at the higher dose. Control levels achieved by the reference product were comparable or slightly lower. However levels of control were highly variable (0 – 100%) due to the inherent variability of the soil-based fungal disease.
Though the level of control achieved by Symphonie was not very high, its control was comparable or superior to the control achieved with the reference product. Therefore it is concluded that Symphonie is sufficiently effective for control of Rhizoctonia solani in potato tubers.
Conclusion
The product complies with the Uniform Principles because it does in accordance with article 2.1 control Rhizoctonia solani in potatoes at a dose rate of 150 g product/100kg potatoes.
8.2 Harmful effects 8.2.1 Phytotoxicity
A total of 18 selectivity trials were conducted during 1995, 1999, 2005, 2009 and 2010 in the United Kingdom and France. Trials were free of disease, or disease was not regarded as significant.
All trials were conducted to the principles of Good Experimental Practice (GEP) although the 1995 trials were conducted before the introduction of the Official Recognition scheme.
Trials are conducted according to the following EPPO guidelines:
PP 1/135 Phytotoxicity assessment
All trials took place in fields, next to commercial crops. Trials received a single application of treatment at BBCH 0.
Potato tubers were treated with Symphonie at the dose rates of 84.4, 90, 120, 156 and 240 g ai/tonne and the reference product at its labelled rate of 250 g ai/tonne and at 500 g ai/tonne.
Application was made by dusting.
Trial plot size varied from a plot of 2m x 5m, one row of 10m and two rows of 3 m. In all trials, plots were replicated four times and were arranged in a randomized block design.
Visual assessments were made on phytotoxicity (at 55 and 80 days after application) and crop vigour (at 24-84 days after application) . The scale used for the assessment of crop vigour was 0%: dead crop, 100%: untreated control. Additionally plant emergence was assessed.
The United Kingdom
12 selectivity trials were conducted in the spring of 1995,1999 and 2005. Assessments were made on crop vigour and plant emergence.
Plant emergence was generally assessed at 32 and 48 days after application. A detrimental effect on plant emergence was observed in only two trials, of which the effect in one trial was transient. Application of Symphonie at the dose rate of 120 g ai/tonne resulted in an average of > 100% plant emergence in relation to the untreated objects. High plant emergence ,an average of >100% in relation to the untreated objects, was also seen after application of Symphonie at 240 g ai/tonne and the reference product at 250 and 500 g ai/tonne. Plant emergence after application of Symphonie at a dose rate of 90 g ai/tonne was only assessed in four trials, of which two had low plant emergence.
Plant vigour was assessed in four trials at 24 to 84 days after application. These trials generally showed a slightly lower crop vigour in relation to the untreated objects at 24 – 38 days after application, after which crop vigour increased to 100%. At approximately 57 days after application crop vigour declined to reach 100% crop vigour again after 71 days. No dose-related effects were seen.
Phytotoxicity was only assessed in a single trial. No symptoms of phytotoxicity were observed.
France
Six selectivity trials were conducted in the spring of 2009 and 2010 in France. Assessments were made on plant emergence, crop vigour and phytotoxicity.
Plant emergence was assessed in five trials at approximately 40 days after application.
A detrimental effect on plant emergence after application of Symphonie, in relation to the untreated objects, was seen in a single trial but these effects were transient. No dose related effects of Symphonie were seen. Plant emergence after application of the reference product at 240 g ai/tonne was lower in two trials. Overall application of Symphonie at the dose rate of 120 g ai/tonne resulted in an average of 97% plant emergence in relation to the untreated objects.
Plant vigour was assessed in a single trial at 36, 43 and 50 days after application in relation to the untreated objects. Application of Symphonie at a dose rate of 156 g ai/tonne resulted in lower plant vigour (85%) compared to application of Symphonie at dose rates 84.4 and 120 g ai/tonne and application of the reference product (95-100% plant vigour). Nonetheless, statistical analysis showed these differences to be negligible.
Phytotoxicity was only assessed in a single trial, at 89 and 126 days after application. No significant phytotoxicity was observed. Additionally plant height was assessed in two trials at respectively 72 and 77 days after application. No significant differences in plant height in relation to the untreated control were observed.
Conclusion on phytotoxicity
In a total of 18 selectivity trials conducted during 1995, 1999, 2005, 2009 and 2010 in the United Kingdom and France, assessments were made on plant emergence, crop vigour and phytotoxicity. Overall, plant emergence and crop vigour were not significantly affected after application of Symphonie at the dose rate of 120 g ai/tonne. Some slight delays in plant emergence were observed, but effects were transient and also present after treatment with the reference product.
No phytotoxicity symptoms were recorded after application of Symphonie at the dose rate of 120 g ai/tonne or at dose rates of 84.4, 90 and 156 g ai/tonne. Likewise, no phytotoxicity symptoms were observed after application of the reference product.
It is concluded that application of Symphonie at the dose rate of 90 g active ingredient per tonne potato tubers, is selective in potato tubers and does not have detrimental effects on plant emergence, crop vigour, or yield.
8.2.2 Yield
In a total of 21 efficacy trials conducted between 1991 and 2010 in the Netherlands, the United Kingdom and France, the effect of Symphonie on yield was determined. Application of Symphonie at the dose rate of 120 g ai/tonne, resulted in an overall average of 105% yield in relation to the untreated objects. This was similar to the yield after application with the
reference product at its labelled rate.
With exception of the seven efficacy trials conducted in France, application of Symphonie did not have detrimental effects on yield. On the contrary, the average yield of potatoes treated with Symphonie in the trials conducted in the Netherlands and the United Kingdom suggest a positive effect of application. Negative effects on yield were seen in the trials conducted in France. Application of Symphonie at the proposed dose rate resulted in an average of 93%
yield in relation to the untreated control. However it must be noted that in these trials, application of the reference product at its labelled rate resulted in similar detrimental effects on yield.
In general, application of Symphonie to potato tubers infected with Rhizoctonia solani at the dose rate of 90 g active ingredient per tonne does not have a negative effect on yield.
In a total of 14 selectivity trials, conducted in 1995, 1999 and 2009 in the United Kingdom and France, the effect of Symphonie on the yield of disease-free potatoes was determined, and compared to that of the reference product.
Overall, yield was positively affected after treatment with Symphonie at the dose rate of 120 g ai/tonne (an average of 109% in relation to the untreated objects) and at the dose rate of 240 g ai/tonne (an average of 112% in relation to the untreated objects). Similar results were achieved by application of the reference product at its labelled and double its labelled rate.
In general, application of Symphonie to uninfected potato tubers at the dose rate of 90 g active ingredient per tonne or at double this rate, does not have a negative effect on yield.
Potatoes of different varieties were used in these trials. The effect of treatment with Symphonie and the reference product resulted in similar effects on yield throughout the different varieties.
Generally, no significant negative effect on the total yield of the potato crop after treatment with Symphonie at the proposed dose rate was observed. Effects on yield were similar to those after treatment with the reference product. Although double dose rates of Symphonie were only tested in trials free of disease, no dose-related negative effects are expected in potatoes infected with R. solani.
8.2.3 Effects on succeeding crops or substitution crops
As Symphonie is a fungicide, no herbicidal activity is expected. It is unlikely that there would be any herbicidal effect on any succeeding crop planted after harvest of potato crop treated with Symphonie. Further information on the fate and behaviour of the active substances of Symphonie in the soil can be found in the relevant section in the fate and behaviour dossiers submitted for this product. It is submitted that there will be no unacceptable effects to
succeeding crops from applications of Symphonie.
Additionally products based on flutolanil have already been authorized for usage as a fungicide for several years over Europe in potato. Based on practical experience, adverse effects on succeeding crops are not to be expected.
8.2.4 Effects on plants or plant products to be used for propagation
As Symphonie is a fungicide, no herbicidal activity is expected. It is intended for use on tubers planted as seed. No significant phytotoxicity, nor a detrimental effect on yield has been observed in the conducted trials. Phytotoxic effects on daughter tubers subsequently used for seed are therefore unlikely.
Additionally products based on flutolanil have already been authorized for usage as a fungicide for several years over Europe in potato. Based on practical experience, adverse effects on plants used for propagating purposes are not to be expected.
8.2.5 Effects on adjacent crops
As Symphonie is a fungicide, no herbicidal activity is expected. Symphonie is applied directly to seed tubers. It is therefore unlikely that there would be any negative effect on adjacent crops. Additionally products based on flutolanil have already been authorized for usage as a fungicide for several years over Europe in potato. Based on practical experience, adverse effects on adjacent crops are not to be expected.
Conclusion
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
Symphonie contains the active ingredient flutolanil. Flutolanil belongs to a group of fungicides known as the carboxamides, also referred to as the carboxanilides. The FRAC code is 7. Its mode of action is to inhibit electron transfer reactions through the succinate-ubiquinone oxidoreductase complex (Complex II) of the mitochondrial respiratory chain. Otherwise described as inhibition of cell respiration by inhibiting succinate oxidation.
Symphonie contains the active ingredient flutolanil. Flutolanil belongs to a group of fungicides known as the carboxamides, also referred to as the carboxanilides. The FRAC code is 7. Its mode of action is to inhibit electron transfer reactions through the succinate-ubiquinone oxidoreductase complex (Complex II) of the mitochondrial respiratory chain. Otherwise described as inhibition of cell respiration by inhibiting succinate oxidation.