fungicide evaluation to rate the efficacy to control tuber ... · max (y)= m_tuber_blight of the...

Fungicide evaluation to rate the efficacy to control tuber blight.

EuroBlight: Results 2009-2018

A. Evenhuis1, R. Bain2, B.J. Nielsen3, W. van den Berg1 & H.T.A.M. Schepers1

1 Wageningen University and Research, Field Crops, The Netherlands 2 SRUC, Crop and Soil Systems, United Kingdom 3 University of Aarhus, Faculty of Agricultural Sciences, Denmark Wageningen Plant Research is the collaboration of Wageningen University and the foundation Stichting

Wageningen, May 2019

CONFIDENTIAL

Report 37503709000

A. Evenhuis1, R. Bain2, B.J. Nielsen3, W. van den Berg1 & H.T.A.M. Schepers1, 2019. Fungicide evaluation to rate the efficacy to control tuber blight. EuroBlight: Results 2009-2018. Wageningen Plant Research, Confidential Report 3750370900.

© 2019 Wageningen, Stichting Wageningen Research, Wageningen Plant Research, P.O. Box 16, 6700 AA Wageningen, The Netherlands; T +31 (0)317 48 07 00; www.wur.nl/plant-research Chamber of Commerce no. 09098104 te Arnhem VAT NL no. 8065.11.618.B01 Stichting Wageningen Research. All rights reserved. No part of this publication may be reproduced, stored in an automated database, or transmitted, in any form or by any means, whether electronically, mechanically, through photocopying, recording or otherwise, without the prior written consent of the DLO Foundation. Wageningen Research is not liable for any adverse consequences resulting from the use of data from this publication. Confidential Wageningen Plant Research Report 3750370900

Contents

Table of Contents

Contents 3

Summary 5

1 Introduction 7

2 Materials and methods 8

2.1 Trial set up 8 2.2 Fungicides 9 2.3 Experimental conditions 10 2.4 Disease observations 17 2.5 Statistical analyses 18

3 Results and discussion 20

3.1 Late blight epidemic 20 3.1.1 Foliar blight 2009 20 3.1.2 Foliar blight 2010 22 3.1.3 Foliar blight 2011 24 3.1.4 Foliar blight 2012 26 3.1.5 Foliar blight 2014 28 3.1.6 Foliar blight 2015 30 3.1.7 Foliar blight 2016 32 3.1.8 Foliar blight 2017 34 3.1.9 Foliar blight 2018 36

3.2 Effectiveness of the fungicides 38 3.2.1 StAUDPC 38 3.2.2 Tuber blight 40

3.3 Decimal rating for control tuber blight 42 3.4 Conclusions 44

Confidential Wageningen Plant Research Report 3750370900 | 5

Summary

Late blight caused by Phytophthora infestans is the most important foliar disease in the cultivation of potatoes. The crop needs to be protected from P. infestans by spraying fungicides regularly during the growing season. It is important to use fungicides that effectively protect both leaves and tubers against this disease. Each fungicide has its own mode of action and efficacies and therefore has specific characteristics. To evaluate each characteristic an EuroBlight-Table is set up to get an overview of the value of each characteristic. Until 2011 the ratings for the control of tuber blight were based upon expert judgement, from both Agrochemical companies and independent researchers. To evaluate the effectiveness of fungicides harmonised protocols were discussed at Hamar. It was proposed that ratings of fungicides for the EU-table are possible when field experiments are carried out over 2 years in 3 European countries. Field experiments were carried out in Denmark, United Kingdom and the Netherlands from in 2009 onwards to 2018. In 2011 the first decimal rating for tuber blight control of active ingredients was published on the EuroBlight website and in the Cyprus proceedings. In 2013 no tuber blight experiments were carried out, however in 2014 new experiments were started and were continued until 2018. Thus 27 experiments were carried out to compare the effectiveness against tuber blight by measuring the protection of leaves and tubers against infection by late blight caused by application of a fungicide in a standard 7-day spray schedule (this standard spray schedule is not necessarily related to the label recommendations). Dose rates were the highest preventative doses registered in Europe. The results of the trials were used to re-evaluate the effectiveness of fungicides to control potato tuber blight. This report describes the analysis of the efficacy of fungicides to control potato tuber blight during the second part of the season. The method to establish efficacy ratings is described and discussed. During the growing season the percentage foliar infection was assessed at least weekly. To evaluate the epidemic, the Area under the Disease Progress Curve (AUDPC) was determined. Not all fungicides were tested at every location in each year. REML analysis was conducted to analyse the data, using GENSTAT 18th ed. Based on the average tuber blight incidence (Table 0), ratings for the effectiveness of the fungicides to control tuber blight were calculated, according to formula 0.

)MAX(

)MAX(5ERy

yy kk

−= , (0)

ERk = efficacy rating of the fungicide k to control tuber blight y = m_tuber_blight MAX (y) = m_tuber_blight of the fungicide with the highest tuber blight incidence determined in the series of experiments. In 2011 a tuber blight rating was established for the first five fungicides, and published on the EuroBlight website. Mancozeb was used as a reference and is considered not effective to control tuber blight.

6 | EuroBlight report confidential 3750370900

Table 0. Effectiveness of fungicides to control tuber blight. Fungicide Active ingredient Dose rate

kg or l /ha StAUDPC1 Tuber

Blight2 Ratings3

(%) EU Table4

mancozeb mancozeb 2.0 9.9 6.8 0.0 Ranman cyazofamid 0.5 -5 - 3.8 Ranman + Proxanil

cyazofamid + (cymoxanil + propamocarb)

0.5 + 2.0 - -

4.6

Canvas + mancozeb

amisulbrom + mancozeb 0.5 + 2.0 - - 3.7

Banjo Forte dimethomorph + fluazinam 1.0 - - 3.3 Infinito fluopicolide + propamocarb 1.6 - - 3.9

Zorvec Encantia oxathiapiprolin +

famoxadone 0.5

3.8 1.2 4.1 1 : Value established by REML Analysis; back transformed after log10(x+1) transformation. 2 : Value established by REML Analysis; back transformed after logit transformation. 3 : Ratings after angular transformation of tuber blight incidence, from 2014 onwards logit transformation was used. 4 : http://www.euroblight.net/upload/euroblight/document/Euroblight_tuber_blight_efficacy_2009_2011.pdf 5 : No new data available In Hamar a more dynamic ratings system for fungicide efficacy in controlling leaf blight was presented. A similar ranking system for tuber blight was proposed. The main advantage is that ratings are determined using a system that is more objective than that used to produce table ratings up until the Hamar meeting in 2008. Another advantage is that there is scope for future, more effective fungicides to be rated higher than 3, the maximum before this system was adopted. Furthermore ratings once given are not fixed, thus relative changes in the effectiveness of fungicides can be made apparent. These data can and should be used to discuss the procedures in order to establish a final protocol.

EuroBlight report Confidential 3750370900 | 7

1 Introduction

Late blight caused by Phytophthora infestans is the most important foliar disease in the cultivation of potatoes. The crop needs to be protected from P. infestans by spraying fungicides regularly during the growing season. It is important to use fungicides that effectively protect both leaves and tubers against this disease. Each fungicide has its own mode of action and efficacies and therefore has specific characteristics. To evaluate each characteristic an EuroBlight-Table is set up to get an overview of the value of each characteristic. Until now the ratings for the control of tuber blight were based upon expert judgement, both from Agrochemical companies and independent researchers. To evaluate the effectiveness of fungicides harmonised protocols were discussed at Hamar. It was proposed that ratings of fungicides for the EU-table are possible when field experiments are carried out over 2 years in 3 European countries. Three experiments were carried out in 2009 in 3 European countries, and a further three trials in 2010, 2011, 2012, 2014, 2015, 2016, 2017 and 2018, to compare the effectiveness against tuber blight by measuring the protection of leaves and tubers against infection by late blight. This protection originates from the protectant, curative and antisporulant properties of the active ingredients for leaf blight control in addition to specific protection of tubers. Dose rates were the highest preventative doses registered in Europe. The results of the trials were used to re-evaluate the effectiveness of fungicides to control potato tuber blight. Based on the experiments carried out in the period 2009-2012, 5 fungicides were rated for their efficacy to control tuber blight: http://www.euroblight.net/FungicideComparison.asp?language=UK. In 2019 one fungicide was added to the table. This report describes the analysis of the efficacy of fungicides to control potato tuber blight during the second part of the season, based on the experiments from 2009 to 2018. The method to establish efficacy ratings is described and discussed.

http://www.euroblight.net/FungicideComparison.asp?language=UK


2 Materials and methods

2.1 Trial set up Experiments were conducted in Denmark, the Netherlands and United Kingdom. Full details are contained in the individual trial reports. Experiments were carried out from 2009 to 2012 and 2014 to 2018. The experiments were carried out according to the harmonised protocol as discussed during the Workshops of the “European network on Potato Late Blight in Hamar (2008). The protocol can be found on the EuroBlight website (http://www.euroblight.net/EuroBlight.asp) and is presented in Appendix 1. In general the trials conformed to local good agricultural practice, except the fungicide sprayings against P. infestans were carried out as mentioned in Table 1. The trials had a minimum of four replicates. The experiments were carried out in accordance with GEP.


2.2 Fungicides In Denmark the fungicide sprays were carried out with a Hardi flat fan (ISO) LD 025 sprayer. The fungicides were sprayed with pressure of 3.0 bar, at 4.0 km/h and with 300 l water / ha. In the Netherlands fungicide applications were carried out using a SOSEF-sprayer or a CDH sprayer with Teejet XR110.04 nozzles approximately 50 cm above the foliage. Sprayings were carried out with 250 l/ha. In the UK fungicides were applied using a tractor-mounted AZO compressed air sprayer with Lurmark F03-110 nozzles. Fungicides were applied in 200 litres of water per hectare at a pressure of 3.5 bar. Potato plants were sprayed for the first time at 100 % emergence or when the foliage was meeting along the rows in each experiment. Fungicides were sprayed in a weekly spray schedule, according to protocol. In the first part of the season the experiment was sprayed with mancozeb to control potato late blight in the foliage. The applied dose rate varied between 1.0 kg/ha to 2.25 kg /ha depending on the trial manager. Details are given in the report of each experiment separately. In the UK in 2010 the experiment was sprayed with Curzate M at a dose rate of 2.0 kg/ha. In the UK in 2014 to cope with the combination of exceptionally early and severe natural infection (EU-13-A2) together with a variety very susceptible to leaf blight three of the blanket pre-test fungicide applications were Dithane 945 + C50 + Revus (see Table 6). The three-way tank mix was an emergency treatment to prevent the plots being destroyed by blight before tubers were produced. In the second part of the season specific sprayings to control tuber blight were carried out. The first specific spray application was carried out when foliar blight levels were between 0.5% to 5%. Fungicides evaluated are listed in Table 1. If necessary the crop was sprayed full field with Signum, Amistar or Narita to control early blight. If needed an extra spray application of mancozeb during the second part of the season was carried out to dampen the foliar blight epidemic. Table 1. Fungicides to control tuber blight sprayed in the experiments in the second part of the season. Fungicide Active ingredient Dose rate #

Exp.1 Company

mancozeb mancozeb 2.0 kg /ha 262 - Ranman cyazofamid 0.5 7 Belchim Crop Protection

Ranman + Proxanil cyazofamid + cymoxanil +

propamocarb 0.5 + 2.0 6 Belchim Crop Protection

Canvas + mancozeb amisulbrom + mancozeb 0.5 + 2.0 6 Nufarm Banjo Forte dimethomorph + fluazinam 1.0 6 Adama Infinito fluopicolide + propamocarb 1.6 9 Bayer Crop Science


famoxadone 0.5 6 Corteva

1 : Gives the number of experiments in which these fungicides were included in 2009 to 2018. 2 : In NL 2009 mancozeb was not included in the experiment.


2.3 Experimental conditions

The experimental conditions are presented in Tables 2 to 10. Artificial inoculation was not necessary in 2007 in the Netherlands and the UK. One plant in the spreader rows adjacent to each plot was artificially inoculated with a mixture of P. infestans isolates in 2006. The artificial inoculation was carried out 1 or 2 times. One plant in the spreader rows adjacent to each plot was artificially inoculated with a mixture of P. infestans isolates in NL and DK. In the UK one isolate of the 13_A2 genotype was used in most years, sometimes more than one. In 2015 the trial field was inoculated with a 6_A1 isolate. In the UK 13_A2 was dominant at the end of the growing season in all years. Artificial inoculation was carried out 1 or 2 times depending on the onset of the late blight epidemic. Table 2. Experimental conditions at the different locations in 2009. Denmark 2009 Netherlands 2009 UK 2009 Location Jyndevad Lelystad Auchincruive Estate,

Ayr Soil Clay Sandy Loam Variety Kardal Bintje King Edward Replicates 4 4 5

Planting 6 May 5 May 1 June Emergence 27 May - Rotary tillage 12 May - Inoculation 15 July 22 July & 7 August Natural infection from

other trials in the same field

Haulm killing spreader rows

- - -

Irrigation 25 June (27 mm) 10 August (27 mm)

18 August (10 mm) None

General sprayings Dithane 18 & 27 June; 1, 8, 15, 22, 29 July; 5 & 12

August

12, 18, 25 June; 2,9 & 16 July

8, 15, 25 July; 2 August

Specific sprayings July - 30 - Specific sprayings August 21 & 27 10, 17 6, 13, 21, 27 Specific sprayings September

2 & 9 - 4

Haulm killing 17 September 20 & 27 August 2 & 11 September Harvest 19 October 9 September 5, 6 & 7 October Tuber blight assessment 22 October 11 September 13, 14, 16 & 17

November Tuber blight assessment - 7 October 1 to 5 & 8 February


Table 3. Experimental conditions at the different locations in 2010. Denmark 2010 Netherlands 2010 UK 2010 Location Nørregård Flakkebjerg Lelystad Auchincruive Estate,

Ayr Soil Clay Silty Sandy Loam

Variety Karnico Bintje King Edward Replicates 4 4 5 Planting 27 April 18 May 24 May Emergence 1 June 7 June 14 June (herbicide) Inoculation 7 July 22 July 13_A2 from

neighbouring trials Haulm killing spreader rows

- - -

Irrigation 5, 12, 19, 26 July (30 mm)

- 6 x between 27/8 and 15/9

General sprayings Dithane 30 June, 7, 14, 23, 26 July, 5 August

10, 17, 24 June, 2, 8, 15, 23, 30 July, 6

August

25 August & 1 September

General spraying Curzate M

- - 8, 15, 23 July, 1 & 9 August

Specific sprayings July - - - Specific sprayings August 16, 23 & 30 August 18 & 24 August 16, 24 & 31 August Specific sprayings September

6 & 14 September - 8, 17 & 24 September

Haulm killing 23 September 31 August 25 & 30 September Harvest 18 October 21 September 27 October Tuber blight assessment - 22 September 14 December Tuber blight assessment 15 December 21 October 9 March


Table 4. Experimental conditions at the different locations in 2011. Denmark 2011 Netherlands 2011 UK 2011 Location Nørregård Flakkebjerg Lelystad Auchincruive Estate,

Ayr Soil JB 5-6 Clay Silty Sandy Loam

Variety Daniella Bintje Maris Piper Replicates 4 4 4 Planting 29 April 12 May 19 May Emergence 1 June ~27 May Herbicide applied 17

June Inoculation 6 July 14 July From neighbouring

trials on unknown dates

Irrigation 29 July (5 mm), 19, 25 August (10 m)

None

General sprayings Dithane 29 June, 5, 12 & 18 July

9, 17, 23, 30 June; 7, 15 & 221 July

6, 13, 20, 27 July, 3, 12, 19, 261 August

Specific sprayings July 25 July 29 - Specific sprayings August 1, 7, 15, 21, 27 5, 12, 18, 24 - Specific sprayings September

5 - 1, 8, 15, 23, 30

Haulm killing 20 September 25 August 7 October Harvest 25 October 12 September 31 Oct. – 2 November Tuber blight assessment 28 October 13 September 2 to 13 Dec. 2011 Tuber blight assessment 12 December 18 October 20 – 28 February 2012

1 Dithane sprayed at a dose rate of 1 kg / ha.


Table 5. Experimental conditions at the different locations in 2012. Denmark 2012 Netherlands 2012 UK 2012 Location Grønmajsegård Lelystad Auchincruive Estate,

Ayr Soil JB 5-6 Clay Silty Sandy Loam

Variety Karnico Bintje Maris Piper Replicates 4 4 5 Planting 23 April 7 May 25 May Emergence 25 May Inoculation 4 July 14 July Natural infection Irrigation 27 May, 21 & 29

August, 6 September (25 mm)

16 August (15 m)

General sprayings Dithane 28 June, 4, 12, 18 & 27 July

8, 14, 21, 29 June; 4, 11, 181 & 251 July; 11

August

62, 132, 202, 27 July

Specific sprayings July - - 31 July Specific sprayings August 3, 13, 18, 24 4, 10, 15 7, 14, 21, 28 August Specific sprayings September

1, 9, 16 - 4 September

Haulm killing 13 & 20 September 17 August 8 September Harvest 22 October 5 September 24 & 25 October Tuber blight assessment 30 October 6 September Start 16 Nov 12 Tuber blight assessment 10 December 12 October Start 21 February 13

1 Dithane sprayed at a dose rate of 1 kg / ha. 2 Quell Flo applied in place of Dithane for three applications


Table 6. Experimental conditions at the different locations in 2014. Denmark 2014 Netherlands 2014 UK 2014 Location Flakkebjerg Lelystad Auchincruive Estate,

Ayr Soil Danish JB No. 6 Clay Silty Sandy Loam Variety Dianella Bintje Shepody Replicates 4 4 4 Planting 1 May 2 May 30 May Emergence 1 June Inoculation 1 July 16 July Natural infection

(13_A2) Irrigation 14 & 27 June , 9, 18 &

25 July, 7 August (25 mm)

12, 16, 22 & 28 August (15 mm)

-

General sprayings Dithane 17 26 June, 3, 10, 17 & 25 July

3, 10, 17, 24 June; 1, 8, 15 & 22 July

27 June, 24 & 31 July

General spraying Dithane + C50 + Revus

- - 3, 10 & 17 July

Specific sprayings July - - - Specific sprayings August 14 , 21, 28 11, 15, 21 7, 15, 22, 28 Specific sprayings September

4, 9

-

4

Haulm killing 25 & 28 August 11 September Harvest 27 October 15 September 7, 8 & 11 October Tuber blight assessment 7 November 16 September 2-9 December Tuber blight assessment 4 December 15 October 26-30 January 2015

Table 7. Experimental conditions at the different locations in 2015. Denmark 2015 Netherlands 2015 UK 2015 Location Flakkebjerg Lelystad Auchincruive Estate,

Ayr Soil Danish JB No. 6 Clay Silty Sandy Loam Variety Eurogrande Bintje Shepody Replicates 4 4 4 Planting 21 April 1 May 10 June Emergence 1 June 25 June - Inoculation 10 July 25 June None (natural from

other trials) Irrigation 13, 20 July, 7, 22

August 12, 19 & 25 August 7-10 Oct (total 32

mm) General sprayings mancozeb

26 June, 2, 13 & 22 July

15, 22, 29, June; 6, 13, 20, 29 July; 7

August

29 July, 19 & 26 August, 2 September

General spraying mancozeb + cymoxanil

- - 9, 16, 22 July, 6, 12 August

Specific sprayings July - - - Specific sprayings August 11, 19, 26 11, 18, 24 - Specific sprayings September

2, 9 - 9, 16, 23,

Specific sprayings October 1 Haulm killing 28 August 13 October Harvest 20 October 24 September 25 November Tuber blight assessment 21 October 25 September 22 December Tuber blight assessment 8 December 19 October 18 February


Table 8. Experimental conditions at the different locations in 2016 Denmark 2016 Netherlands 2016 UK 2016 Location Flakkebjerg Lelystad Auchincruive Estate,

Ayr Soil Fine clay loam Clay Silty Sandy Loam Variety Eurogrande Bintje Shepody Replicates 4 4 4 Planting 9 May 2 May 18 June Emergence 1 June 1 June - Inoculation 9 July 29 June None (natural from

other trials) Irrigation 6 June, 26 July, 10

August, 7 & 28 September (total 95

mm)

12, 19 & 25 August -

General sprayings mancozeb

1, 7, 14 & 21 July 13, 16, 24, June; 1, 7, & 14 July

21 & 28 July


- - 4, 9 & 14 August

Specific sprayings July - 20, 27 Specific sprayings August 9, 16, 24 & 30 3, 9 18, 25, 31 Specific sprayings September

6, 13 - 07, 14, 22

Specific sprayings October Haulm killing 12 August 20 September + 08

October Harvest 14 October 9 September 24 + 25 October Tuber blight assessment 21 October 12 September 22 December Tuber blight assessment 25 November 20 October 18 February



Ayr Soil Fine clay loam Clay Silty Sandy Loam Variety Kuras Bintje Shepody Replicates 4 4 4 Planting 3 May 2 May 20 June Emergence 5 June 25 May - Inoculation 5 July 13 July None (natural from

other trials (13_A2)) Irrigation 26 June, 18 July, 29

August (total 75 mm) 27 July, 3, 8 & 12

August -


4 & 11 July 14, 21, 27, June; 4, 11, & 20 July

- -


- 8 June 17, 24 & 31 July 6, 13 & 21 August

Specific sprayings July 18, 25 & 31 26 - Specific sprayings August 7, 14, 23 & 29 2, 7, 11 28 Specific sprayings September

5, 11 & 18 - 5, 12, 19

Specific sprayings October - - - Haulm killing - 16 August 28 September Harvest 18 October 7 September 26 to 28 October Tuber blight assessment 19 October 11 September 6 December 17 Tuber blight assessment 7 December 5 October 5 February 18



Ayr Soil Fine clay loam Clay Silty Sandy Loam Variety Signum Bintje Shepody Replicates 4 4 4 Planting 22 April 7 May 22 June Emergence 28 May 25 May - Inoculation 27 June 12 July (EU-13-A2) None (natural from

other trials (13_A2)) Irrigation 14, 24 June, 6 July, 1,

9 & 15 August (total 210 mm)

17, 23 & 27 July 8, 15 & 22 August (total 90

mm)

-


20 & 27 June, 3 July 7, 14 & 20 June; 5, 12, & 19 July

26 July, 2 & 9 August -

Specific sprayings July - - - Specific sprayings August 29 7, 14 & 21 15, 21, 28 Specific sprayings September

5, 10, 18 & 25 - 4, 11, 17

Specific sprayings October - - - Haulm killing - 27 & 31 August 28 September Harvest 8 November 18 September 29 to 31 October Tuber blight assessment 9 November 19 September 4 to 12 December 18 Tuber blight assessment 13 December 23 October 11 to 21 February 19

2.4 Disease observations During the growing season the percentage foliar infection was assessed at weekly intervals. To evaluate the epidemic, the Area under the Disease Progress Curve (AUDPC) was determined. StAUDPC values were calculated by dividing the AUDPC value by the number of days between the first and last disease observation. The number of days from the first to last disease observation varied for each experiment and ranged between 27 and 54 days. The StAUDPC provides an indicator for the efficacy of the fungicides during the whole growing season. Appendix 2 lists StAUDPC values for fungicides tested in each experiment, for each replicate separately. Tuber blight assessments were made shortly after harvest and after incubation in a non-refrigerated storage. Both number and weight of the potatoes were assessed. Infected tubers were removed at the first assessment. These tubers were counted and weighed. At the end of the incubation period tubers were washed and a second tuber blight assessment was made. In the UK tubers were washed, and dried quickly under ventilation, prior to the first assessment. The number and weight data from both assessments were combined and the percentage tuber blight was calculated.


2.5 Statistical analyses 27 experiments were carried out. Each experiment was laid out as randomised complete block design with one treatment factor, being the fungicides to be tested, and four to five replicates. Because not all fungicides were in all experiments the use of directive ANOVA was not possible. Therefore a mixed model analysis (REML) was performed on log10 StAUDPC and a generalized linear mixed model analyses (GLMM) was performed from 2014, on tuber blight incidence based on numbers and weight, measured per experimental plot. Because the measurement period was not equal in all trials StAUDPC was analysed instead of AUDPC. StAUDPC equals the AUDPC divided by the number of days between first and final measurement of disease incidence. The code of the Genstat 18th ed. program (Payne et al., 2009) used for the statistical analysis is in Appendix 3. A mixed model consists of fixed treatment terms (here fungicide) and random block terms (here experiment, block and plot): ijpkijiijkp PBEblighttuber ++++=− βµ , (1) where μ = overall mean Ei = effect of experiment i ~ N(0, σE2) Bij = effect of block j within experiment i ~N(0, σB2) Pijp = effect of plot p within block Bij ~N(0, σP2) βk = effect of fungicide k

Units with high residuals were determined to establish non – consistent performance of fungicides. The stability of the effectiveness of the fungicides between experiments was evaluated. The mean StAUDPC and tuber blight incidence per fungicide is reported in Appendix 2. Based on the angular transformed tuber blight incidence (Angn_%_tuber_blight), ratings for the effectiveness of the fungicides to control late blight were calculated, according to formula (2) until 2012. From 2014 onward, back transformed means from the GLMM analysis with a logistic transformation were used.

)MAX(

)MAX(5ERy

yy kk

−= , (2)

ERk = efficacy rating of the fungicide k to control tuber blight during. y = mn_tuber_blight MAX (y) = mn_tuber_blight of the fungicide with the highest tuber blight incidence determined in the series of experiments.


REML and GLMM analyses were used while not each fungicide was present in all experiments. The experiments were conducted in three countries in 2009, 2010, 2011, 2012, 2014, 2015, 2016, 2017 and in 2018. Tuber blight incidence levels varied with each experiment. The REML directive takes the specific conditions of the experiment into account. Assume that fungicide A was tested in experiments with a relatively high disease level and fungicide B in experiments with a relatively low disease level. Then the arithmetic mean of m_tuber_blight of fungicide A would be adjusted with a decrease and fungicide B would be adjusted with a rise of m_tuber_blight. By doing so the tuber blight incidence level for all the fungicides is adjusted to the same level, making a fair comparison between fungicides possible. The use of StAUDPC as a co-variate to determine the efficacy of the fungicides to control tuber blight was rejected. The use of a co-variate is only allowed when differences between plots existed prior to the applied treatments. A variable measured afterwards, which may be influenced by the treatments, is not suitable as a co-variate. In fact in that case it is considered a response variate (Oude Voshaar, 1994 [page 54]). In case of StAUDPC it is obvious that it is influenced by the fungicide treatments itself. Literature Montgomery, D.C. and Peck, E.A., 1982. Introduction to Linear Regression Analysis. John Wiley & Sons. New York. Oude Voshaar, J.H., 1994. Statistiek voor onderzoekers. Wageningen Press, Wageningen, 253 p. Payne, R.W., Harding, S.A., Murray, D.A., Soutar, D.M., Baird, D.B., Glaser, A.I., Channing, I.C., Welham, S.J., Gilmour, A.R., Thompson, R., Webster, R., 2009. The Guide to GenStat Release 12, Part 2: Statistics. VSN International, Hemel Hempstead.


3 Results and discussion

3.1 Late blight epidemic

Table 11 shows the start of the potato late bight epidemic in the various field experiments. Table 11 First observation of P. infestans infected foliage in the infector plants and in treated plots, during the experiments. Infector plants Treated plots Year DK NL UK DK NL UK 2009 27-7 - - 21-8 18-7 24-7 2010 - 13-6 - 12-8 10-8 13-8 2011 - - - 18-7 20-7 22-8 2012 - 10-7 - 24-7 4-7 <25-7 2014 - 16-7 - 23-7 6-8 < 25-7 2015 - 21-7 - < 3-8 28-7 11-8 2016 11-07 < 6-7 - 19-7 < 6-7 < 3-8 2017 13-7 <17-7 - 13-7 <17-7 <11-8 2018 29-8 18-7 - 29-8 18-7 8-8

-: not observed

3.1.1 Foliar blight 2009

Late blight occurred at the end of July in the Netherlands and United Kingdom, in 2009. In Denmark the first lesions were found in the second half of August. In the Netherlands and United Kingdom the late blight epidemic developed substantially in August (Figures 1-3).

Figure 1. The development of foliar blight during the growing season in Denmark, 2009. The first specific spraying was carried out on 21 August.


Figure 2. The development of foliar blight during the growing season in the Netherlands 2009. The first specific spraying was carried out on 30 July.

Figure 3. The development of foliar blight during the growing season in the United Kingdom 2009. The first specific spraying was carried out on 6 August.



In 2010 the late blight epidemic started in August (Figures 4-6) and developed rapidly.


Figure 5. The development of foliar blight during the growing season in the Netherlands 2010. The first specific spraying was carried out on 18 August.



Foliar blight developed progressively from mid-August onwards in the field experiment in Denmark (Figure 7) and the Netherlands (Figure 8). In the UK Phytophthora epidemic started from mid-September (Figure 9).




Figure 9. The development of foliar blight during the growing season in the United Kingdom 2011. The first specific spraying was carried out on 1 September.



Several fungicides were testerd in the 2012 experiments, however none of them required a rating by the companies. Data were thus removed from the report, showing only mancozeb as thereference. Late blight occurred at in the beginning of July in the Netherlands and United Kingdom, in 2012. In Denmark the first lesions were found at the end of July. In the Netherlands the late blight epidemic developed substantially in August. In Denmark and the UK the late blight epidemic lingered over a period of 6 weeks or more (Figures 10-12).




Figure 12. The development of foliar blight during the growing season in the United Kingdom 2012 The first specific spraying was carried out on 31 July.



Several fungicides were testerd in the 2014 experiments, however none of them required a rating by the companies. Data were thus removed from the report, showing only mancozeb as thereference. In Denmark, July 2014 was hot and dry and the development of late blight was very slow. All plots were cover sprayed with mancozeb until 25 July. To enhance development of late blight the plots were left unsprayed for two weeks. At 10 August the level of attack in the plots were 0.01-0.1% and at 14 August the first test spray was performed. There was a severe development of late blight in the untreated plots starting mid-August (Figure 13). In the Netherlands the first few leaf lesions were found on 16 July, however until the beginning of August no increase of potato late blight was found. From mid-August onwards a severe development of late blight was observed (Figure 14). The first spray application was carried out on 11 August, three days later than planned due to rain fall. Although disease severity was low at the time maybe disease pressure for tuber infection was high. In the UK early, severe and unexpected natural infection occurred at the trial site. The protocol stated that mancozeb or mancozeb + cymoxanil could be applied to manage the foliar blight epidemic to a severity of 0.5%. In practice the treatment programmes began with one spray of Dithane 945 followed by three applications of Dithane 945 + C50 + Revus and then two sprays of Mancozeb. The three-way tank mix was used as an emergency treatment to prevent the plots being destroyed by blight too early in the growing season (Figure 15).




In Denmark the potato late blight epidemic developed slowly from the beginning of August (Figure 16). Only the mancozeb treatment developed quite strong at the end of the experiment in the second part of September.

Figure 16. The development of foliar blight during the growing season in Denmark, 2015. The first specific spraying was carried out on 11 August. In the Netherlands the potato late blight epidemic developed strong in the second half of August (Figure 17), caused by a combination of natural precipitation and irrigation. In the UK the potato late blight development was slow (Figure 18). Weather circumstances were not conducive for blight development in the foliage. Irrigation (Seephose) was used for a prolonged period later in the growing season to maintain reasonable soil moisture contents. Overhead irrigation was used shortly before desiccation to provide a substantial “rain” event for tuber infection.



Figure 18. The development of foliar blight during the growing season in the United Kingdom 2015. The first specific spraying was carried out on 9 September.



In Denmark the potato late blight epidemic developed gradually from the end of July (Figure 19). Only the mancozeb treatment developed quite strong at the end of the experiment in the second part of September.

Figure 19. The development of foliar blight during the growing season in Denmark, 2016. The first specific spraying was carried out on 9 August. In the Netherlands the potato late blight epidemic developed strong in the first half of August (Figure 20). Therefore the experiment was stopped after the fourth spray application according to schedule. Potato late blight was found in all treatments, however differences between treatments were found.


Figure 20. The development of foliar blight during the growing season in the Netherlands 2016. The first specific spraying was carried out on 20 July. In the UK the potato late blight development was slow at first (Figure 21), but increased substantially in September.




Several fungicides were testerd in the 2017 experiments, however none of them required a rating by the companies or the number of eperiments was not yet sufficient. Data were thus removed from the report, showing only mancozeb as thereference. In Denmark late blight developed late in the season, from the last week of August (Figure 22).

Figure 22. The development of foliar blight during the growing season in Denmark, 2017. The first specific spraying was carried out on 18 July 2017. In the Netherlands potato late blight developed gradually in July. In the beginning of August the late blight severity increased (Figure 23).


Figure 23. The development of foliar blight during the growing season in the Netherlands 2017. The first specific spraying was carried out on 26 July. In the UK potato late blight increased significantly in the second half of September (Figure 24). It was a very wet season (precipitation in August, September and October was 110.4, 111.2 and 109.6 ml respectively) therefore no irrigation was required.




Several fungicides were testerd in the 2018 experiments, however none of them required a rating by the companies or the number of eperiments was not yet sufficient. Data were thus removed from the report, showing only mancozeb as thereference. In Denmark late blight developed very late in the season, from mid September (Figure 25). This was due to the exceptionally dry and warm conditions during the summer of 2018.

Figure 25. The development of foliar blight during the growing season in Denmark, 2018. The first specific spraying was carried out on 29 August. Also in the Netherlands weather conditions were dry and warm. After the change of weather on 9 August 2018 the potato late blight epidemic started to develop (Figure 26).


Figure 26. The development of foliar blight during the growing season in the Netherlands 2018. The first specific spraying was carried out on 7 August. Also in the United Kingdom the late blight epidemic started late due to a dry summer (Figure 27).



3.2 Effectiveness of the fungicides

3.2.1 StAUDPC The AUDPC or the StAUDPC can be used as a measure of the severity of the late blight epidemic. Control of late blight by fungicides will decrease the rate of the epidemic, and therefore reduce the AUDPC and StAUDPC values. Foliar blight levels (Tables 12 to 16) were significantly different between treatments. Details are given in the individual reports per experiment. On average foliar blight was much more severe in 2010 than in 2009. Late blight severity in 2011 and 2012 varied with the location. In 2014 potato late blight occurred early in the season. Especially in the UK disease pressure was high resulting in a high StAUDPC. In the Netherlands disease pressure was high during crop emergence. However in July the weather was not conducive for potato late blight leading to a moderately low StAUDPC. In Denmark the potato late blight epidemic was not heavy resulting in a low StAUDPC. The severity of the late blight epidemic partly determines the infection risk of tubers. The infection risk is further determined by precipitation rates and foremost the efficacy of fungicides to control tuber blight. In fact a low disease severity, as low as a few procent, may give rise to high tuber blight incidence if the circumstances are conduceive. Table 12. Effectiveness of the fungicides to control potato late blight as represented by the StAUDPC.

Fungicide StAUDPC 2009 StAUDPC 2010 DK NL UK DK NL UK

mancozeb 10.2 -1 6.6 35.8 20.5 21.6 Ranman 11.2 2.4 4.0 35.4 17.7 19.0 Ranman + Proxanil 11.0 0.4 1.6 15.6 11.4 - Canvas + mancozeb 9.4 1.1 4.4 33.3 18.7 9.3 Banjo Forte - - - 31.7 15.6 5.9 Infinito 11.5 1.5 2.2 30.3 16.4 8.2

1: Not included in trial Table 13. Effectiveness of the fungicides to control potato late blight as represented by the StAUDPC.


mancozeb 8.7 8.6 9.7 1.6 7.4 2.8 Ranman -1 1.1 - - - - Ranman + Proxanil - 0.2 - - - - Canvas + mancozeb - - - - - - Banjo Forte 4.7 0.8 2.4 - - - Infinito 3.0 0.7 1.5 - - -

1: Not included in trial


Table 14. Effectiveness of the fungicides to control potato late blight as represented by the StAUDPC.


mancozeb 3.8 6.5 19.0 10.0 21.7 0.5 Zorvec Encantia -1 - - 4.4 15.4 0.4 EXP15-09 - - - 3.0 13.0 0.4



mancozeb 8.0 7.2 23.7 32.8 25.9 12.4 Zorvec Encantia 4.2 1.6 2.5 -1 - -


Fungicide StAUDPC 2018 DK NL UK

mancozeb 23.0 25.7 15.7


3.2.2 Tuber blight Tuber blight levels were low in all three experiments in 2009 ranging from almost 0 to 1.6% (Table 17), nevertheless significant differences between treatments were found within experiments. In Denmark in 2009 the second tuber blight assessment could not be carried out due to frost damage. In 2010 tuber blight levels varied. In 2010 tuber blight incidence was high in the Netherlands, and moderately high in Denmark. Despite abundant foliar blight, tuber blight levels in the UK were low in 2010. Details of the experiments are given in the individual trial reports. In 2011 tuber blight levels were moderately high, whereas in 2012 tuber blight levels were low (Table 18). Table 17. Effectiveness of the fungicides to control potato late blight as represented by tuber blight incidence (%).

Fungicide % tuber blight 2009 % tuber blight 2010 DK NL UK DK NL UK

mancozeb 0.1 -1 0.6 8.5 30.4 0.0 Ranman 1.0 0.3 0.2 2.3 8.6 0.0 Ranman + Proxanil 0.1 0.5 0.1 2.0 3.0 - Canvas + mancozeb 0.6 0.3 0.3 1.3 10.4 0.1 Banjo Forte - - - 2.3 20.8 0.2 Infinito 0.2 0.5 0.1 1.4 15.3 0.1

1: Not included in trial Table 18. Effectiveness of the fungicides to control potato late blight as represented by tuber blight incidence (%).


mancozeb 10.3 19.9 2.6 2.0 6.1 1.0 Ranman -1 2.3 - - - - Ranman + Proxanil - 0.6 - - - - Canvas + mancozeb - - - - - - Banjo Forte 3.3 2.8 0.3 - - - Infinito 0.4 2.1 0.9 - - -

1: Not included in trial


In 2014 and 2015 tuber blight incidence was extremely high in the Netherlands and moderately high in Denmark and the UK. In 2016 tuber bligth incidence was generally moderate. In 2017 and 2018 tuber blight incidence in the Netherlands was moderate to high and in Denmark low. Tuber blight incidence in the UK was moderate in both years. Table 19. Effectiveness of the fungicides to control potato late blight as represented by tuber blight incidence (%).


mancozeb 25.5 52.1 4.6 11.7 53.0 16.0 Zorvec Encantia -1 - - 2.0 11.4 3.8



mancozeb 7.9 11.2 15.8 0.3 24.5 7.7 Zorvec Encantia 1.0 1.7 8.1 -1 - -


Fungicide % tuber blight 2018 DK NL UK

mancozeb 1.4 32.7 12.0


3.3 Decimal rating for control tuber blight A new rating system for foliage blight was introduced. A rating system for the control of tuber blight based on the same principles would offer the same benefits. A draft protocol for rating the efficacy of fungicides to control tuber blight season was agreed upon and is presented in Appendix 1. The efficacies of the fungicides were established (Table 22). Introduction of StAUDPC as a co-variate to determine the efficacy of the fungicides to control tuber blight is statistically not correct. Also biologically it does not make much sense, since the tuber blight levels in the untreated control are often lower than in treated plots where fungicides are used with poor tuber blight protection abilities. The reason for that is that the potato late blight epidemic in the untreated control is very fast in comparison to sprayed plots. The risk of zoosporangia washing from the canopy into the ridges and to the tubers is therefore lower. Analysis of efficacy of fungicides to control tuber blight of the first four years was carried out after angular transformation. However when the data of 2014 were included in the calculation negative tuber blight incidence was calculated for some treatments, which obviously made no sense. This was caused by high tuber blight incidence in 2014. Using REML analysis in combination with angular transformation led to very low estimates for missing values in years before 2014 and subsequently negative tuber blight incidence. A good alternative was provided by a logit transformation of the tuber blight data with the GenStat procedure GLMM (Appendix 3).


Fungicides can be rated according to formula 2 in which tuber blight incidence was transformed into a decimal rating. Table 22. Effectiveness of fungicides to control tuber blight. Fungicide Active ingredient Dose rate

kg or l /ha

StAUDPC1

Tuber Blight2

Ratings3

(%) EU Table4

mancozeb mancozeb 2.0 9.9 6.8 0.0 Ranman cyazofamid 0.5 -5 -5 3.8 Ranman + Proxanil

cyazofamid + (cymoxanil + propamocarb)

0.5 + 2.0 - -

4.6

Canvas + mancozeb

amisulbrom + mancozeb 0.5 + 2.0 - - 3.7

Banjo Forte dimethomorph + fluazinam 1.0 - - 3.3

Infinito fluopicolide + propamocarb

1.6 - - 3.9


famoxadone 0.5

3.8 1.2 4.1 1 : Value established by REML Analysis; back transformed after log10(x+1) transformation. 2 : Value established by REML Analysis; back transformed after logit transformation. 3 : Ratings after angular transformation of tuber blight incidence, from 2014 onwards logit transformation was used. 4 : http://www.euroblight.net/upload/euroblight/document/Euroblight_tuber_blight_efficacy_2009_2011.pdf 5 : No new data available Using formula 2 the minimum rating will be 0, and is given to the fungicide with the highest tuber blight value over all the experiments. A disadvantage of this method is that the fungicide with the highest tuber blight figure might change during the years and thus rated 0. The highest possible rating is 5. A fungicide can only be rated 5.0 exactly when no late blight occurs in the tubers in any of the experiments. Obviously a rating of 5 is almost impossible to achieve. Even in the 2009 experiments no fungicide was able to prevent tuber blight completely. The ratings of the fungicides are negatively correlated with the average tuber blight incidence established in the trials. An advantage of the method proposed is that fungicides with a better performance than the fungicides with the highest performance so far can be rated better. Another advantage of the method is that ratings once given are not fixed. With new data, a rating could be adjusted to the current performance of the fungicide. However when the database expands changes in the ratings will become rare.


3.4 Conclusions In Hamar a more dynamic ratings system for fungicide efficacy in controlling foliar blight was presented. A similar ranking system for tuber blight was implemented in 2012. The main advantage is that ratings are determined using a system that is more objective than that used to produce table ratings up until the Hamar meeting in 2008. Another advantage is that there is scope for future, more effective fungicides to be rated higher than 3, the maximum before this system was adopted. Furthermore ratings once given are not fixed, thus relative changes in the effectiveness of fungicides can be made apparent. However in the current situation this is not done. .


Appendix 1. Protocol for testing “Effectiveness: tuber blight” (Phytophthora infestans).

Ruairidh Bain [email protected] EUROBLIGHT protocol Version 1.1 Draft 9 January 2009 Purpose/aim of trials To compare the efficacy of fungicides in minimizing the incidence of tuber blight through a direct effect, i.e. “activity against tuber infection as a result of fungicide application after infection of the haulm, during mid- to late-season when there is a direct effect on the tuber infection process”. EPPO guideline PP 1/2 (3) (revised in 1996) describes the standard requirements of the field trial. Specific requirements • The trial should use a local potato variety that is susceptible to tuber blight (but not too

susceptible to foliar blight) grown as a ware or starch crop. The growth habit of the cultivar should be recorded i.e. determinate or indeterminate growth.

• The trial should have a minimum of four but preferably six replicate plots per treatment. This is to allow for the generally greater variability in tuber blight incidence compared with foliar blight severity. The total plot area per treatment should be 180 m2, i.e. four plots of 45 m2 or six plots of 30 m2, with a minimum of four rows per plot.

• Each treatment consists of a simple fungicide program, starting with blanket sprays of a fungicide with no, or limited, activity against zoospores, e.g. Dithane or Curzate M, applied until there is foliar blight in the fungicide-treated plots. The purpose of the blanket sprays is to allow a slow foliar epidemic with the same amount of foliar blight in each plot. Application of these cover sprays should start according to local conditions and applied at intervals judged to be appropriate for a slow epidemic. Application must be before the first infection is seen in the plots.

• Once foliar blight has established in the trial plots, the test fungicides should be applied for the remainder of the growing season until desiccation, regardless of the limited number of applications on the label. A spray interval of 7 (+/-) 1 day is anticipated. The short spray interval should ensure that differences in foliar blight control for the test treatments are as small as possible. It may be necessary to shorten or lengthen the spray intervals to match blight risk. This will be at the discretion of the trial manager. The test fungicides should be applied before foliar blight severity exceeds 0.5% foliar blight. It is anticipated that there will be between three and six applications of the test fungicides.

• It is preferable not to include untreated plots in the trial as these would result in uneven foliar blight gradients.

• Standard treatments can be included in later trials once there is sufficient data to choose the most appropriate standards.

• In order to obtain a long-lasting infection pressure, one or more measures can be used according to local preferences.

• Two untreated spreader rows planted between replicates along the complete length of the trial. These should consist of a susceptible (e.g. Bintje) and an intermediate resistant variety.

• spreader rows with one variety and selective fungicide use on the spreader row • surrounding the trial with maize to increase and maintain a humid microclimate • Selected individual plants in the spreader rows should be inoculated with P. infestans isolates

representative of the local population using recently isolated strains. Record the provenance and genotype characteristics of the strain(s) if known.

• The timing of inoculation should ensure that the test fungicides are not applied until ground cover is close to 100% and progeny tubers are present.

• Misting is permissible when conditions are exceptionally dry and disease is not progressing. • Irrigation is also permissible if there is insufficient rainfall (at the correct time) to transfer

inoculum onto the tubers. • Record crop cover. Crop cover provides information on how much of the fungicide spray was

intercepted by the crop. Crop cover is defined as the percentage of the soil surface obscured by


foliage when viewed from above. A grid divided into 20 equal squares allows cover to be assessed to the nearest 5%. Assess by holding the grid at a fixed height above the crop and estimate what percentage of the grid area is filled by leaf material. Assessments should be made at each fungicide application until crop cover reaches 100%. They should also be made if cover declines from 100% towards the end of the growing season.

• Crop growth stage should be recorded at each spray date using the BBCH key. • The dose rate of each test fungicide should be the highest preventative dose registered in Europe. • Assess foliar blight every week (or more frequently when necessary) in spreader rows and plots

by rating the % infected leaf area. Assess foliar blight using the assessment key in the EPPO-guideline PP 1/2 (3) combined with the key published in Trans. Brit. Mycol. Soc. 31 (1947): 140-141 or the Dutch PD scale guideline. If foliar blight is not uniformly distributed across the plots then its distribution should be recorded.

• Rainfall, air temperature, soil temperature and soil moisture should be recorded. • Desiccation: The optimum time to desiccate the haulm can be identified if tuber samples are

harvested weekly from extra plots of one standard treatment, starting when foliar blight appears in the plots. The tuber samples must be assessed within 24 hours of harvest. These weekly samples will allow changes in the incidence of tuber blight to be monitored.

• A herbicide desiccant should be used. Mechanical destruction of the haulm and sulphuric acid are not permitted.

• The harvest of tubers for the assessment of tuber blight should not take place until the haulm has been dead for a minimum of 3 weeks. However, harvest should not be delayed beyond 5 weeks after complete death of the haulm. Random samples should be taken from the centre rows of each plot for assessment. As a guide, 1600 tubers should be assessed per treatment. The tubers (all > 35 mm) should be thoroughly washed and assessed non-destructively for blight (pre-storage assessment). Any greened tubers should not be assessed. Blighted tubers should be discarded and the rest stored for a minimum of 8 weeks in a non-refrigerated store, after which the tubers are re-assessed (post-storage assessment). At both assessments weights and tuber numbers for blighted tubers and non-blighted tubers should be recorded.

• The tuber blight data should be analyzed using analysis of variance with the foliar blight results included as a covariate.

• Tuber blight ratings will be calculated once there are data from six good trials, over 2 years.


Appendix 2. Raw data

Plot data of late blight StAUDPC and tuber blight from Denmark 2009:

Fungicides Rep. Country AUDPC StAUDPC n % tuber

blight w % tuber

blight

mancozeb 1 DK 242 9.0 0.00 0.00 mancozeb 2 DK 235 8.7 0.00 0.00 mancozeb 3 DK 269 10.0 0.00 0.00 mancozeb 4 DK 359 13.3 0.25 0.27 Ranman 1 DK 269 10.0 3.00 0.67 Ranman 2 DK 228 8.5 0.25 2.14 Ranman 3 DK 373 13.8 0.75 1.20 Ranman 4 DK 344 12.8 0.00 0.00

Ranman + Proxanil 1 DK 339 12.6 0.00 0.00 Ranman + Proxanil 2 DK 242 9.0 0.00 0.00 Ranman + Proxanil 3 DK 299 11.1 0.25 0.16 Ranman + Proxanil 4 DK 312 11.5 0.00 0.00 Canvas + mancozeb 1 DK 181 6.7 0.75 0.44 Canvas + mancozeb 2 DK 190 7.0 0.00 0.00 Canvas + mancozeb 3 DK 365 13.5 1.50 1.28 Canvas + mancozeb 4 DK 283 10.5 0.00 0.00

Infinito 1 DK 228 8.5 0.00 0.00 Infinito 2 DK 275 10.2 0.00 0.00 Infinito 3 DK 381 14.1 0.75 0.65 Infinito 4 DK 354 13.1 0.00 0.00


Plot data of late blight StAUDPC and tuber blight from The Netherlands, 2009:


blight w % tuber

blight Ranman 1 NL 32 1.0 0.23 0.12 Ranman 2 NL 50 1.5 0.53 0.23 Ranman 3 NL 109 3.3 0.00 0.00 Ranman 4 NL 122 3.7 0.44 0.56

Canvas + mancozeb 1 NL 23 0.7 0.11 0.06 Canvas + mancozeb 2 NL 34 1.0 0.51 0.62 Canvas + mancozeb 3 NL 55 1.7 0.52 0.60 Canvas + mancozeb 4 NL 37 1.1 0.23 0.38

Infinito 1 NL 29 0.9 0.59 0.62 Infinito 2 NL 75 2.3 0.41 0.27 Infinito 3 NL 56 1.7 0.29 0.60 Infinito 4 NL 43 1.3 0.69 0.82

Ranman + Proxanil 1 NL 7 0.2 0.12 0.04 Ranman + Proxanil 2 NL 19 0.6 0.85 0.67 Ranman + Proxanil 3 NL 14 0.4 1.02 0.52 Ranman + Proxanil 4 NL 13 0.4 0.21 0.30

Plot data of late blight StAUDPC and tuber blight from the United Kingdom, 2009:


blight w % tuber

blight Laminator Flo 4 UK 91 2.6 0.31 0.19 Laminator Flo 3 UK 191 5.5 2.19 2.06 Laminator Flo 1 UK 489 14.0 0.00 0.00 Laminator Flo 2 UK 275 7.9 0.00 0.00 Laminator Flo 5 UK 115 3.3 0.63 0.41

Ranman 2 UK 97 2.8 0.00 0.00 Ranman 4 UK 74 2.1 0.31 0.32 Ranman 1 UK 169 4.8 0.00 0.00 Ranman 3 UK 223 6.4 0.62 0.39 Ranman 5 UK 132 3.8 0.00 0.00

Ranman + Proxanil 4 UK 30 0.9 0.00 0.00 Ranman + Proxanil 5 UK 23 0.6 0.00 0.00 Ranman + Proxanil 3 UK 77 2.2 0.31 0.23 Ranman + Proxanil 1 UK 72 2.1 0.00 0.00 Ranman + Proxanil 2 UK 77 2.2 0.00 0.00 Ranman + Proxanil 4 UK 30 0.9 0.00 0.00 Canvas + mancozeb 1 UK 174 5.0 0.00 0.00 Canvas + mancozeb 2 UK 114 3.3 0.00 0.00 Canvas + mancozeb 3 UK 139 4.0 1.25 1.22 Canvas + mancozeb 4 UK 126 3.6 0.00 0.00 Canvas + mancozeb 5 UK 212 6.1 0.00 0.00

Infinito 3 UK 65 1.9 0.00 0.00 Infinito 1 UK 71 2.0 0.31 0.54 Infinito 2 UK 149 4.3 0.00 0.00 Infinito 5 UK 42 1.2 0.31 0.14 Infinito 4 UK 52 1.5 0.00 0.00


Plot data of late blight StAUDPC and tuber blight from Denmark, 2010:


blight w % tuber

blight Canvas + mancozeb 1 DK 2307 32.0 0.00 0.00 Canvas + mancozeb 2 DK 2249 31.2 1.02 0.93 Canvas + mancozeb 3 DK 2465 34.2 1.63 1.12 Canvas + mancozeb 4 DK 2570 35.7 2.62 2.43

Ranman 1 DK 2221 30.8 0.80 1.24 Ranman 2 DK 2367 32.9 1.32 1.36 Ranman 3 DK 2612 36.3 3.50 3.15 Ranman 4 DK 2982 41.4 3.41 4.45 Infinito 1 DK 1803 25.0 0.24 0.30 Infinito 2 DK 2041 28.3 1.42 1.75 Infinito 3 DK 2318 32.2 2.44 2.47 Infinito 4 DK 2569 35.7 1.61 2.07

mancozeb 1 DK 2493 34.6 5.65 5.05 mancozeb 2 DK 2770 38.5 3.21 3.20 mancozeb 3 DK 2511 34.9 14.77 5.81 mancozeb 4 DK 2538 35.3 10.36 10.20

Banjo Forte 1 DK 1882 26.1 1.33 0.93 Banjo Forte 2 DK 2567 35.7 1.79 1.59 Banjo Forte 3 DK 2692 37.4 3.40 3.30 Banjo Forte 4 DK 1995 27.7 2.49 2.63

Ranman + Proxanil 1 DK 1116 15.5 2.52 2.20 Ranman + Proxanil 2 DK 983 13.6 1.45 0.70 Ranman + Proxanil 3 DK 1217 16.9 2.34 2.50 Ranman + Proxanil 4 DK 1174 16.3 1.51 1.11




blight w % tuber

blight Banjo Forte 1 NL 470 18.1 28.55 25.47 Banjo Forte 2 NL 367 14.1 16.41 16.85 Banjo Forte 3 NL 419 16.1 15.67 15.68 Banjo Forte 4 NL 370 14.2 22.43 24.66

Canvas + mancozeb 1 NL 508 19.5 18.76 15.81 Canvas + mancozeb 2 NL 498 19.1 6.54 6.77 Canvas + mancozeb 3 NL 498 19.1 8.96 9.11 Canvas + mancozeb 4 NL 445 17.1 7.44 8.49

Ranman 1 NL 593 22.8 14.60 12.49 Ranman 2 NL 352 13.5 4.67 5.20 Ranman 3 NL 396 15.2 6.02 5.29 Ranman 4 NL 498 19.1 8.92 7.88

Ranman + Proxanil 1 NL 443 17.0 4.70 4.49 Ranman + Proxanil 2 NL 220 8.5 1.96 2.11 Ranman + Proxanil 3 NL 288 11.1 2.29 1.72 Ranman + Proxanil 4 NL 239 9.2 3.24 2.98


mancozeb 1 NL 715 27.5 34.23 31.97 mancozeb 2 NL 366 14.1 27.82 28.30 mancozeb 3 NL 576 22.2 34.04 35.76 mancozeb 4 NL 475 18.3 25.66 26.97




blight w % tuber

blight mancozeb 1 UK 1642 33.5 0.00 0.00 mancozeb 3 UK 1196 24.4 0.00 0.00 mancozeb 2 UK 1787 36.5 0.00 0.00 mancozeb 4 UK 402 8.2 0.00 0.00 mancozeb 5 UK 260 5.3 0.21 0.12 Ranman 4 UK 903 18.4 0.00 0.00 Ranman 2 UK 1465 29.9 0.23 0.30 Ranman 3 UK 1348 27.5 0.00 0.00 Ranman 5 UK 73 1.5 0.00 0.00 Ranman 1 UK 868 17.7 0.00 0.00

Canvas + mancozeb 2 UK 903 18.4 0.41 0.35 Canvas + mancozeb 3 UK 659 13.4 0.00 0.00 Canvas + mancozeb 4 UK 308 6.3 0.00 0.00 Canvas + mancozeb 5 UK 137 2.8 0.00 0.00 Canvas + mancozeb 1 UK 266 5.4 0.00 0.00

Infinito 4 UK 343 7.0 0.21 0.09 Infinito 1 UK 684 14.0 0.00 0.00 Infinito 2 UK 483 9.9 0.00 0.00 Infinito 3 UK 350 7.1 0.21 0.26 Infinito 5 UK 151 3.1 0.00 0.00

Ranman + Proxanil 4 UK 30 0.9 0.00 0.00 Ranman + Proxanil 5 UK 23 0.6 0.00 0.00 Ranman + Proxanil 3 UK 77 2.2 0.31 0.23 Ranman + Proxanil 1 UK 72 2.1 0.00 0.00 Ranman + Proxanil 2 UK 77 2.2 0.00 0.00


Plot data of late blight StAUDPC and tuber blight from Denmark, 2011: Fungicides Rep. Country AUDPC StAUDPC n % tuber blight w % tuber blight mancozeb 1 DK 446 9.5 9.12 9.12 mancozeb 2 DK 226 4.8 8.89 8.89 mancozeb 3 DK 484 10.3 11.87 11.87 mancozeb 4 DK 480 10.2 11.36 11.36

Banjo Forte 1 DK 334 7.1 4.63 4.63 Banjo Forte 2 DK 162 3.4 3.63 3.63 Banjo Forte 3 DK 225 4.8 3.45 3.45 Banjo Forte 4 DK 166 3.5 1.32 1.32

Infinito 1 DK 147 3.1 0.32 0.32 Infinito 2 DK 118 2.5 0.76 0.76 Infinito 3 DK 154 3.3 0.36 0.36 Infinito 4 DK 147 3.1 0.15 0.15



blight w % tuber

blight mancozeb 1 NL 440 12.2 16.46 18.54 mancozeb 2 NL 253 7.0 12.44 13.39 mancozeb 3 NL 360 10.0 21.04 23.50

mancozeb 4 NL 179 5.0 29.68 30.22 Banjo Forte 1 NL 14 0.4 2.38 3.41 Banjo Forte 2 NL - - - - Banjo Forte 3 NL 37 1.0 2.02 2.92 Banjo Forte 4 NL 34 1.0 4.07 4.02


Ranman 1 NL 86 2.4 3.78 3.22

Ranman 2 NL - - - -

Ranman 3 NL 23 0.7 2.50 2.52

Ranman 4 NL 14 0.4 0.60 0.36

Ranman + Proxanil 1 NL - - - - Ranman + Proxanil 2 NL 4 0.1 0.68 1.89 Ranman + Proxanil 3 NL 14 0.4 0.36 0.52 Ranman + Proxanil 4 NL 8 0.2 0.89 1.98




blight w % tuber

blight Infinito 1 UK 109 2.6 0.21 0.02

Banjo Forte 2 UK 68 1.6 0.63 0.31 Mancozeb 1 UK 428 10.2 0.83 0.61

Banjo Forte 1 UK 69 1.6 0.00 0.00 Mancozeb 2 UK 293 7.0 3.80 3.23 Infinito 2 UK 34 0.8 0.64 0.59

Banjo Forte 3 UK 182 4.3 0.21 0.15 Banjo Forte 4 UK 79 1.9 0.42 0.46 mancozeb 4 UK 418 10.0 3.16 2.89 mancozeb 3 UK 493 11.7 2.53 1.67

Infinito 3 UK 48 1.1 0.63 0.16 Infinito 4 UK - - 2.11 1.96


Plot data of late blight StAUDPC and tuber blight from Denmark, 2012: Fungicide Rep. Country AUDPC StAUDPC n % tuber blight w % tuber blight mancozeb 1 DK 144 3.0 1.36 0.70 mancozeb 2 DK 39 0.8 3.25 3.17 mancozeb 3 DK 92 1.9 1.55 1.40 mancozeb 4 DK 34 0.7 2.00 1.99


Fungicide Rep. Country AUDPC StAUDPC n % tuber blight w % tuber blight mancozeb 1 NL 214 6.9 4.99 5.92 mancozeb 2 NL 259 8.4 8.21 9.07 mancozeb 3 NL 223 7.2 5.93 6.23

mancozeb 4 NL 217 7.0 5.26 6.25 Plot data of late blight StAUDPC and tuber blight from the United Kingdom, 2012:

Fungicide Rep. Country AUDPC StAUDPC n % tuber blight w % tuber blight mancozeb 1 UK 122 3.0 0.00 0.00 mancozeb 5 UK 81 2.0 1.24 0.83 mancozeb 2 UK 132 3.2 1.27 0.86 mancozeb 3 UK 149 3.6 0.35 0.26 mancozeb 4 UK 93 2.3 2.31 2.45

Plot data of late blight StAUDPC and tuber blight from Denmark, 2014:

Fungicide Rep. Country AUDPC StAUDPC n % tuber blight w % tuber blight mancozeb 1 DK 89.1 1.6 27.0 27.4 mancozeb 2 DK 248.4 4.6 40.1 54.3 mancozeb 3 DK 300.5 5.6 22.0 22.4 mancozeb 4 DK 173.1 3.2 12.9 17.1

UTC 1 DK 89.1 1.6 27.0 27.4 UTC 2 DK 248.4 4.6 40.1 54.3 UTC 3 DK 300.5 5.6 22.0 22.4 UTC 4 DK 173.1 3.2 12.9 17.1


Fungicide Rep. Country AUDPC StAUDPC n % tuber blight w % tuber blight mancozeb 1 NL 263 7.1 59.8 59.3 mancozeb 2 NL 274 7.4 51.6 49.7 mancozeb 3 NL 205 5.6 46.1 42.8

mancozeb 4 NL 224 6.1 50.9 57.7 Plot data of late blight StAUDPC and tuber blight from the United Kingdom, 2014:

Fungicide Rep. Country AUDPC StAUDPC n % tuber blight w % tuber blight mancozeb 1 UK 272.1 6.8 7.0 5.8 mancozeb 2 UK 1424.5 35.6 2.8 2.3 mancozeb 3 UK 573.3 14.3 7.1 7.3 mancozeb 4 UK 776.5 19.4 1.5 0.6



Zorvec Encantia 1 DK 121 2.5 2.2 2.3 Zorvec Encantia 2 DK 122 2.5 2.2 4.0 Zorvec Encantia 3 DK 298 6.1 3.0 2.5 Zorvec Encantia 4 DK 315 6.4 0.5 0.5


Fungicides Rep. Country AUDPC StAUDPC n % tuber blight w % tuber blight mancozeb 1 NL 585 18.9 52.9 53.4 mancozeb 2 NL 579 18.7 56.1 58.1 mancozeb 3 NL 798 25.7 50.8 52.6 mancozeb 4 NL 724 23.4 52.1 54.5

Zorvec Encantia 1 NL 363 11.7 9.4 8.8





Fungicides Rep. Country AUDPC StAUDPC n % tuber blight w % tuber blight mancozeb 1 UK 20.8 0.37 14.1 12.3 mancozeb 2 UK 28.1 0.50 8.5 8.2 mancozeb 3 UK 33.4 0.60 20.4 18.2 mancozeb 4 UK 29.3 0.52 21.0 22.8

Zorvec Encantia 2 UK 16.3 0.29 11.7 14.2 Zorvec Encantia 1 UK 21.7 0.39 1.5 1.8 Zorvec Encantia 3 UK 20.9 0.37 0.4 0.2 Zorvec Encantia 4 UK 30.4 0.54 1.7 1.9



Zorvec Encantia 1 DK 99 1.5 1.3 0.5 Zorvec Encantia 2 DK 230 3.4 1.0 0.8 Zorvec Encantia 3 DK 324 4.8 0.0 0.0 Zorvec Encantia 4 DK 480 7.2 1.7 1.2


Fungicides Rep. Country AUDPC StAUDPC n % tuber blight w % tuber blight Dithane NT 1 NL 319 8.9 13.0 12.6 Dithane NT 2 NL 210 5.8 10.9 10.8 Dithane NT 3 NL 101 2.8 8.5 8.7

Dithane NT 4 NL 399 11.1 12.3 13.7




Zorvec Encantia 4 NL 119 3.3 3.4 2.9 Plot data of late blight StAUDPC and tuber blight from the United Kingdom, 2016:

Fungicides Rep. Country AUDPC StAUDPC n % tuber blight w % tuber blight Dithane NT 1 UK 869 18.1 22.8 21.4 Dithane NT 2 UK 962 20.0 15.2 16.9 Dithane NT 3 UK 1470 30.6 13.3 15.8 Dithane NT 4 UK 1244 25.9 11.7 13.4

Zorvec Encantia 1 UK 94 2.0 16.1 18.4 Zorvec Encantia 2 UK 118 2.5 6.0 5.3 Zorvec Encantia 3 UK 100 2.1 5.3 6.4 Zorvec Encantia 4 UK 167 3.5 4.8 5.2


Plot data of late blight StAUDPC and tuber blight from Denmark, 2017: Fungicide Rep. Country AUDPC stAUDPC n % tuber blight w % tuber blight Dithane NT 1 DK 2378 35.5 0.0 0.0 Dithane NT 2 DK 2292 34.2 0.6 0.8 Dithane NT 3 DK 2178 32.5 0.0 0.0 Dithane NT 4 DK 1933 28.8 0.7 0.6

Plot data of late blight StAUDPC and tuber blight from the Netherlands, 2017:

Fungicide Rep. Country AUDPC stAUDPC n % tuber blight w % tuber blight Dithane NT 1 NL 643 22.2 15.2 16.3 Dithane NT 2 NL 636 21.9 19.3 16.2 Dithane NT 3 NL 583 20.1 15.4 16.4 Dithane NT 4 NL 1143 39.4 48.0 55.5


Fungicide Rep. Country AUDPC stAUDPC n % tuber blight w % tuber blight Dithane NT 1 UK 480 9.2 11.0 12.6 Dithane NT 2 UK 655 12.6 4.0 2.9 Dithane NT 4 UK 795 15.3 3.3 2.6 Dithane NT 3 UK 654 12.6 12.5 12.9

Plot data of late blight StAUDPC and tuber blight from Denmark, 2018: Fungicide Rep. Country stAUDPC n % tuber blight w % tuber blight Dithane NT 1 DK 21.2 1.5 1.3 Dithane NT 2 DK 19.1 1.6 0.9 Dithane NT 3 DK 29.5 1.9 1.2 Dithane NT 4 DK 22.1 0.7 0.6

Plot data of late blight StAUDPC and tuber blight from the Netherlands, 2018: Fungicide Rep. Country stAUDPC n % tuber blight w % tuber blight Dithane NT 1 NL 20.5 27.1 29.5 Dithane NT 2 NL 26.3 28.3 28.6 Dithane NT 3 NL 26.9 25.2 25.5 Dithane NT 4 NL 28.9 50.1 51.5

Plot data of late blight StAUDPC and tuber blight from the United Kingdom, 2018: Fungicide Rep. Country stAUDPC n % tuber blight w % tuber blight Dithane NT 1 UK 16.7 11.1 15.8 Dithane NT 2 UK 16.6 11.4 14.2 Dithane NT 3 UK 16.4 12.0 15.9 Dithane NT 4 UK 13.2 13.5 17.6


Appendix 3. REML and fungicide rating

IMPORT 'W:/PSG/PPO-AGV/Projecten/EU Tabel Tuber/2018/Tabel/Tuber blight data 2009-

2018.xlsx'; SHEET = 'data genstat'; ISAVE = isave

TABU [ CLASS = fungicide; PRIN = mean ] weight

SUBSET [ weight .GT. 0; yes ] isave[]

TABU [ CLASS = fungicide; PRIN = mean ] weight

TREL [ GROU = fungicide; PENG = Exp; YT = 'n_%_tuber_blight'; XT = 'AUDPC' ]

n_%_tuber_blight; AUDPC

TREL [ GROU = Exp; YT = 'n_%_tuber_blight'; XT = 'AUDPC' ] n_%_tuber_blight; AUDPC

STORE [ LIST = all ]

TABU [ CLASS = Exp, fungicide ] n_%_tuber_blight, AUDPC; MEAN = M[1,2]

VTAB CLASS = !P(Exp, fungicide); TABLE = M[1,2]; VARI = n_%_tuber_blight, AUDPC

PEN 1; LABEL = fungicide

TREL [ GROU = Exp; YT = 'n_%_tuber_blight'; XT = 'AUDPC'; YMA = .075; \

USEPENS = yes ] n_%_tuber_blight; AUDPC

DELE [ REDE = yes; LIST = all ]

RETR [ LIST = all ]

DHIST AUDPC

CALC nrmax = NVAL ( AUDPC )

VARI [ VAL = 1 ... #nrmax ] nr

REST nr, AUDPC; AUDPC .EQ. MAX ( AUDPC )

PRIN nr, AUDPC

REST nr, AUDPC

TABU [ CLASS = jaar; COUNTS = counts1 ]

TABU [ CLASS = plot, Exp; COUNTS = counts2 ]

PRIN counts1; F = 5

DELE [ REDE = yes ] counts2

TABU [ CLASS = jaar, Exp; PRIN = c ]

TABU [ CLASS = jaar, country; PRIN = c ]

TABU [ CLASS = Exp, herhaling; PRIN = c ]

GETA [ ATTR = label ] fungicide; SAVE = save

TEXT [ VAL = #save[] ] label

VCOM [ FIXED = fungicide ] Exp / herhaling

TABU [ CLASS = jaar; PRIN = mean; IP = as ] AUDPC, stAUDPC, n_%_tuber_blight,

w_%_tuber_blight

DESCRIBE AUDPC, stAUDPC, n_%_tuber_blight, w_%_tuber_blight

FOR [ INDEX = i ] \

y = AUDPC, stAUDPC, n_%_tuber_blight, _%_tuber_blight; \

m = mAUDPC, mstAUDPC, mn_%_tuber_blight, w_%_tuber_blight

IF i .IN. !(1, 2)

REML [ PRIN = #, mean ] LOG10(y+1); RESI = resi; FITT = fitt

VKEE fungicide; MEAN = MEAN


VARI [ VAL = #MEAN ] m

CALC m = ( 10 ** m ) - 1

GRAP [ NR = 21; NC = 51 ] resi; fitt

ENDIF

IF i .IN. !(3, 4)

GLMM [ FIXED = fungicide; RANDOM = Exp / herhaling; PRIN = #, mean; \

DISTRIBUTION = binomial; LINK = logit; DISP = * ] y; FITT = fitt; NBIN = 100

VKEE [ RESI = resi ] fungicide; MEAN = MEAN

VARI [ VAL = #MEAN ] m

CALC m = ILOGIT ( m )

GRAP [ NR = 21; NC = 51 ] resi; fitt

ENDIF

ENDFOR

TABU [ CLASS = Exp, fungicide ; PRINT = mean; MARG = yes ] n_%_tuber_blight

DSCA mAUDPC, mstAUDPC, mn_%_tuber_blight, mw_%_tuber_blight

GETA [ ATTR = label ] fungicide; SAVE = save

PEN 1; LABEL = save[]

DSCA mAUDPC, mn_%_tuber_blight

DSCA mstAUDPC, mn_%_tuber_blight

DSCA mn_%_tuber_blight, mw_%_tuber_blight

CORR [ PRIN = corr ] mn_%_tuber_blight, mw_%_tuber_blight

PRIN label, mAUDPC, mstAUDPC, mn_%_tuber_blight, mw_%_tuber_blight

FOR [ INDEX = i ] y = mAUDPC, mstAUDPC, mn_%_tuber_blight, mw_%_tuber_blight

CALC y = 5 * ( MAX ( y ) - y ) / MAX ( y )

ENDFOR

CAPTION '0 - 5'; META

PRIN label, mAUDPC, mstAUDPC; F = 10

PRIN label, mn_%_tuber_blight, mw_%_tuber_blight; F = 10

Corresponding address for this report: P.O. Box 16 6700 AA Wageningen The Netherlands T +31 (0)317 48 07 00 www.wur.nl/plant-research Confidential Wageningen Plant Research Report 3750330500

The mission of Wageningen University and Research is “To explore the potential of nature to improve the quality of life”. Under the banner Wageningen University & Research, Wageningen University and the specialised research institutes of the Wageningen Research Foundation have joined forces in contributing to finding solutions to important questions in the domain of healthy food and living environment. With its roughly 30 branches, 5,000 employees and 10,000 students, Wageningen University & Research is one of the leading organisations in its domain. The unique Wageningen approach lies in its integrated approach to issues and the collaboration between different disciplines.

http://www.wur.nl/plant-research

fungicide evaluation to rate the efficacy to control tuber ... · max (y)= m_tuber_blight of the...

Documents