RHIZOCTONIA SOLANI IN SUGAR BEET THE EUROPEAN PERSPECTIVE ASSBT 2009 RHIZOCTONIA FORUM ENTOMOLOGY AND PLANT PATHOLOGY Mark Varrelmann Institute for

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1 RHIZOCTONIA SOLANI IN SUGAR BEET THE EUROPEAN PERSPECTIVE ASSBT 009 RHIZOCTONIA FORUM ENTOMOLOGY AND PLANT PATHOLOGY Mark Varrelmann Institute for Sugar Beet Research Department of Phytopathology Göttingen, Germany Moderator: Gary Franc

2 Regions with Rhizoctonia solani occurrence in Germany Dithmarschen Region Nd.bayern Rhein- St.Michaelis- Kiel Rostock Südbaden land donn Total Hamburg Sugar beet-area Endangered area Aachener (ha) ca ha Hannover Bucht, Berlin Niederrhein Pot. endangered Münster (ha) Göttingen Occurrence in Dresden Bonn 003 (ha) Frankfurt am Main Damage > 50 % Nürnberg (ha) Niederbayern 165 Stuttgart Südbaden München

3 Strategies of integrated control Chemical crop protection Application on fungicides is prohibited. Biological control Several bacterial and fungal candidates with promising effects. To date no antagonist t has reached practical field application. AG -IIIB tester I AG -IIIBIIIB tester I (Bilder: IfZ)

4 Strategies of an integrated control Crop rotation Further host plants of R. solani increase disease occurrence and severity in sugar beet (e.g. maize) Cultivation of intercrops before sugar beet is common Percentage of farms with R. solani occurrence Only few information about the 14 impact of further host plants 1 a Sugar beet < 0 % Sugar beet > 0 % Soil tillage Soil compaction possess an influence Soil tillage influences disease occurrence Ws BZ ZE sy [t (t/ha) -1 ] Maize<10% 10-0% >0% <10% 10-0% >0% 10 Data: 1.34 farms of the sugar factory Plattling Kontrolle 41 Zuckerrüben Sugar beet b Inok. X Data b Überr (Buddemeyer (Bürcky & Petersen, & Zellner, (photos: 003) 000) IfZ) c Inok. + Überr.

5 Plant breeding Strategies of an integrated control 18 Resistant cultivars show reduced and delayed occurrence of symptoms under natural infestation. Resistance can be overcome by the pathogen (inoculum conc., T, humidity). Wsy (t/ha) susceptible sugar beet y= - 009x 0,09-034x+113 0,34 11,3 r = 0,97 *** resistant sugar beet not significant Disease severity (1-9)

6 (European?) problems, knowledge gaps, key questions I Performance: yield penalty of resistant cultivars Other hosts of R. solani - proportion of maize in the crop rotation evaluation of rhizoctonia resistance in maize Influence of agronomical measures on disease severity or suppression soil compaction, soil tillage, intercrops

7 Performance of commercial sugar beet varieties under natural infection with Rhizcotonia solani in the field National variety trials 005 (Germany) no disease incidence 50 % disease pressure* WSY (t/ha) a b c d susc. variety a b c d susc. variety a-d: commercial cultivars with resistance against R. solani * 50% diseased surface on taproots of the susc. variety

8 Influence of crop rotation (maize versus wheat/oat) Influence of crop rotation (maize versus wheat/oat) and rhizoctonia resistance in sugar beet on yield in sugar beet and maize

9 Strategies of an integrated control crop rotation experiments Factor 1: sugar beet cultivar (SB) 1. susceptible. resistant Factor : crop rotation 1. maize, maize, sugar beet (M/M). maize, wheat, sugar beet (M/W) 3. wheat, oat, sugar beet (W/O) Factor 3: maize cultivar 1. susceptible. tolerant (Buhre et al., 008, Plant Disease)

10 Influence of crop rotation and sugar beet cultivar on white sugar yield BZE (t/ha) BZE y (t/ha) Wsy Wsy ( t/ha) susceptible resistant M/M sugar beetm/wsugar beet W/O Significant higher wsy after the cultivation of the resistant cultivar. Significant higher wsy after the crop rotation wheat/oat instead of maize/maize.

11 Influence of crop rotation and sugar beet cultivar on white sugar yield y (t/ha) susceptible resistant ab c ab bc a Ws 1 d 11 0 M/M M/W W/O Significant interaction between crop rotation and cultivar. The difference between the cultivars depended on the crop rotation. No significant difference between the rotations following the cultivation of the resistant cultivar.

12 Influence of crop rotation, maize and sugar beet cultivar on maize yield 1 1 Maize yield (t/ha a) a b Maize yield (t t/ha) a ab b susceptible sugar beet resistant sugar beet 0 M/M M/W W/O Significant higher maize yield after the cultivation of a resistant sugar beet cultivar. Maize cultivar influences the disease occurrence, but not yield. Lower disease severity and higher yield after the crop rotation wheat/oat instead of maize/maize. Overall less effects in maize than in sugar beet.

13 Rhizoctonia solani infestation in maize-sugar beet crop rotations Does susceptibility of maize genotypes matter?

14 Field crop rotation experiment Crop rotation: 003 Maize / 004 Sugar beet 005 Maize / 006 Sugar beet Split-plot-design: plot 6 replicates Factors: Main plot: Liquid inoculation (agar plate suspension, y / n) Subplot: Maize genotypes (10) Parameters: Maize: root rot (10 plants per plot) kernel yield ( rows harvested) Sugar beet (one suscept. cultivar): root rot, white sugar yield (3 rows harvested) Inoculation Control 14/11

15 Time course of disease severity 9 8 Diseas se sever rity (1-9) d c b a a a a a a a dd d c bbb b b (b) (a) a b a a a a a a a a b b b Inoculated Not inoculated control 1 a c a a a a a a b a c c c b b b c b 003/Maize 004/Sugar beet 005/Maize 006/Sugar beet (b) (a) Error bar: LSD 5%, Tukey-Kramer 15/11

16 Effect of maize genotypes on Rhizoctonia disease severity (DS) in maize ty (1-9) Disease severi 8 R ² = P< 0.01 d d cd ac ab ab ab ab ab a y= 0.84x Maize genotype in sugar beet Disease se everity (1-9) DS, maize (1-9) DS, maize 003 (1-9) ab ab b ab ab ab ab a a ab Maize genotype et 004 (1-9) DS, sugar be DS, maize 003 (1-9) Error bars: Bar chart: Standard error; Scatter plot: LSD 5%, Tukey-Kramer Consistent susceptibility of maize genotypes over years and with the greenhouse screening. No relation between disease severity in maize and sugar beet in subsequent years. 16/11

17 Susceptibility of maize can be determined in greenhouse resistance tests means Bonitu of urmittel DS field 00 Fe03 eld R² adj = 0, P = 0,004 y = 0,9x + 1, means Boniturmittel of DS greenhouse Gewächshaus /11

18 Summary Susceptibility of maize genotypes was consistent to the greenhouse screening and consistent in different years. Effects of maize genotype and inoculation faded out in the second repetition of crop rotation. Maize genotype influenced inoculum potential measured as disease severity in subsequently grown sugar beet. Maize genotype influenced the yield harvested under diseased conditions both in maize and in sugar beet. However, no relationship was found between susceptibility of maize genotypes and sugar beet performance. 18/11

19 Conclusion If pathogenic R. solani is present, the maize genotype cultivated in crop rotations with sugar beet matters. Resistance of maize genotype is no indicator for its suitability in a maize-sugar beet crop rotation. Some maize genotypes possibly induce soil supressiveness. This makes decisions on the suitability of maize genotypes as a further component of the integrated t control of R. solani highly complex. Results have to be verified under natural conditions. Mechanisms explaining sugar beet and pathogen performance related to maize genotypes are important to study. 19/11

20 Susceptibility of different intercrops to infection with Rhizoctonia solani and their influence on disease severity in subsequently cultivated sugar beets 0/11

21 Greenhouse tests for R. solani susceptibility of different intercrops Baiting test with seedlings of intercrop specs 10 plants per pot (sterilized field soil) Cultivation on 4/18 C and 14 h illumination Inoculation with R. solani infected millet grains in two different densities [0,003 g (K1) and 0,5 g (K)] Weekly rating off R. solani symptoms Last rating after four weeks with the four-class rating scale and determ. of plant weight (Fotos: IfZ) 1/11

22 Testing different intercrop species in greenhouseexperiments for susceptibility against R. solani Disease seve erity (1-4) Control Low inoculation High inoculation Different infestation levels 4 depending on the species B. rapa and R. sativus less 3 susceptible, sceptible P. tanacetifolia, B. juncea and S. alba more susceptible No influence of the cultivar 1 B. juncea 1 B. juncea B. rapa 1 B. rapa P. tanacetifolia 1 P. tanacetifolia Intercrops R. sativus 1 R. sativus S. alba 1 S. alba B. vulgaris /11

23 Field experiments to test different intercrops for susceptibility against R. solani 10 cultivars in 5 different species, susceptible sugar beet cultivar and fallow as controls Inoculation of 50 kg/ha R. solani infected barley grains with a sowing machine before sugar beet sowings Two locations (Göttingen, without natural infestation; Plattling, add. natural infestation). Rating in the growing season (1 = no infestation until 5 = entirely dead d crop), determination i of plant weight before frost Sowing of a susceptible sugar beet cultivar in the following spring (Fotos: IfZ) 3/11

24 Susceptibility of different intercrops in field before winter 5 Control Inoculation rity (1-5) Disease seve 4 3 * n.s. * * * * rassica rapa a B Variable infestation levels depending on the species No influence of different cultivars 1 B. juncea B. rapa P. tanacetifolia R. sativus S. alba B. vulgaris n.s. Phac celia Fallow Control Intercrops Inoculation (photos: 4/11 IfZ)

25 Comparison of greenhouse and field resistance tests eld (1-5) Disease e severity fi 5,0 Brassica juncea 4,5 Brassica rapa Phacelia tanacetifolia Raphanus sativus 4,0 Sinapis alba Beta vulgaris 35 3,5 Regression line r = 0,56 3,0 5,5,0 15 1,5 Confirmation of the results obtained in vitro and greenhouse 1,0 1,0 1,5,0,5 3,0 3,5 4,0 Disease severity greenhouse (1-4) 5/11

26 Effects from intercrop cultivation to infestation of R. solani in sugar beet Effect F P Inoculation *** Species 3.36 ** Location 4.90 * Cultivar (species).7 * Inoculation*species 1.6 n.s. Inoculation*location *** natural infestation vs. artificial inoculation 6/11

27 (European?) problems knowledge gaps, key questions II Plant protection effective fungicides with systemic MOA are not (yet) available Prediction of disease occurrence in the field determination of inoculum potential/concentration in soil parameters of soil suppressiveness Evaluation of resistance in the greenhouse vs. natural infestation differentiation of hybrids 7/11

28 8/11

29 Rhizoctonia solani (Kühn) on sugar beet Root and crown rot on sugar beet can entirely kill the plant. Patchy disease occurrence. (weather, antagonists, soil suppressiveness...?) Yield decline up to 60 %. Heavy infestation can cause complete loss of root yield. 300 Low juice purity (juice 150 extraction, juice purification, juice color, filtration of juice) 100 resulting in worse 50 sugar crystallisation. Yield Ertrag and und Qualität quality y( [relativ] (rel.) BZE RE 50 ZG K Na 00 AmN RZG 0 1,0,8,9 3,0 3,1 3,8 4,3 6, ,6 Increasing zunehmende disease Befallsstärke severity (Büttner et (Bilder: al, 003) IfZ)

30 Strategies of an integrated control Plant breeding Cultivars with (partial-) resistance are available. Quantitative resistance, based on several genes. R. solani possesses necrotrophic colonisation abilities. In resistant cultivars a delayed spread of the fungus is observed. Bildunterschrift (Bilder: IfZ)

31 Design of the crop rotation experiments Susceptible sugar beet Resistant sugar beet Susceptible sugar beet Resistant sugar beet Susceptible sugar beet Resistant sugar beet Maize/maize Maize/wheat Wheat/oat

32 Design of the crop rotation experiments 003 Susceptible Resistant Susceptible Resistant Susceptible Resistant sugar beet sugar beet sugar beet sugar beet sugar beet sugar beet Susceptible maize Tolerant maize Maize/maize Maize/wheat Wheat/oat

33 Influence of cultivar, crop rotation and cultivation method on disease occurrence and white sugar yield Effect Dis. occurrence Wsy F P z F P z Sugar beet cultivar *** *** Crop rotation 3.1 (*) 7.38 ** Environment 3.36 * 61.7 *** Environment * sugar beet cultivar *** 9.78 ** Environment * crop rotation 1.41 n.s n.s. Sugar beet cultivar * crop rotation *** *** Environment * sugar beet cultivar * crop rotation 6.07 *** 4.68 *** Cultivation method (crop rotation) 0.96 n.s..07 (*) Cultivar * cultivation method (crop rotation).1 * 1.71 (*) Environment * cultivation method (crop rotation) 0.74 n.s n.s. Environment * cultivation method * cultivar (crop rotation) 1.1 n.s * Block (Environment) 0.39 n.s. 0.0 n.s. z *** P < 0.001; ** P < 0.01; * P < 0.05; (*) P < 0.1 and n.s.= not significant

34 Influence of the cultivation method in the crop rotation experiment Factor 3: cultivation method 4 variants in each crop rotation (soil tillage and intercrop cultivation, 1-4) Crop rotation Maize/maize Maize/wheat Wheat/oat Cultivation method Autumn 1. year Spring. year Autumn. year 1 Cultivator Plow Cultivator Cultivator Plow Plow 3 Plow - Cultivator 4 Plow - Plow 1 Cultivator - Plow/mustard Cultivator - Plow 3 Plow - Plow/mustard 4 Plow - Cultivator/plow 1 Plow/mustard - Plow/mustard Plow/mustard - Plow 3 Plow - Plow/mustard 4 Plow - Cultivator/plow

35 Influence of cultivar, crop rotation and cultivation method on disease occurrence and white sugar yield Effect Dis. occurrence Wsy F P z F P z Sugar beet cultivar *** *** Crop rotation 3.1 (*) 7.38 ** Environment 3.36 * 61.7 *** Environment * sugar beet cultivar *** 9.78 ** Environment * crop rotation 1.41 n.s n.s. Sugar beet cultivar * crop rotation *** *** Environment * sugar beet cultivar * crop rotation 6.07 *** 4.68 *** Cultivation method (crop rotation) 0.96 n.s..07 (*) Cultivar * cultivation method (crop rotation).1 * 1.71 (*) Environment * cultivation method (crop rotation) 0.74 n.s n.s. Environment * cultivation method * cultivar (crop rotation) 1.1 n.s * Block (Environment) 0.39 n.s. 0.0 n.s. z *** P < 0.001; ** P < 0.01; * P < 0.05; (*) P < 0.1 and n.s.= not significant

36 Influence of cultivation method on disease occurrence and white sugar yield Effect Dis. occurrence Wsy Maize/maize/sugar beet F P z F P z Sugar beet cultivar 66,00 *** 138,5 *** Cultivation method 3,79 * 6,7 ** Maize/wheat/sugar beet Sugar beet cultivar 106,75 ***,11 ** Cultivation method 0,44 n.s. 0,94 n.s. Wheat/oat/sugar beet Sugar beet cultivar 56,85 *** 15, ** Cultivation method 5,31 ** 5,59 ** z *** P < 0.001; ** P < 0.01; * P < 0.05; (*) P < 0.1 and n.s.= not significant

37 Influence of the cultivation method on white sugar yield Maize/maize/sugar beet Cultivation Autumn Spring Autumn method 1. year. year. year 14 1 Cultivator Plow Cultivator Cultivator Plow Plow 13 a a 3 Plow - Cultivator 4 Plow - Plow Wsy (t/ha) b a Significant influence of the cultivation method in the second year Cultivation method plowing before sugar beet is favorable.

38 Influence of the cultivation method on white sugar yield 13 Maize/wheat/sugar beet 14 n.s. Cultivation Autumn Autumn method 1. year. year 1 Cultivator Plow/mustard Cultivator Plow 3 Plow Plow/mustard 4 Plow Cultivator/plow (t/ha) Wsy No influence of the cultivation method in the crop rotation maize/wheat Cultivation method

39 Influence of the cultivation method on white sugar yield 14 ab 13 Wheat/oat/sugar beet a ab b Cultivation Autumn Autumn method 1. year. year 1 Plow/mustard Plow/mustard Plow/mustard Plow 3 Plow Plow/mustard 4 Plow Cultivator/plow Wsy (t/ha) 1 11 Significant influence of the cultivation method from the first year. 10 Influence of the intercrop? Cultivation method

40 Summary Cultivation of a resistant sugar beet cultivar allows sugar beet production under R. solani disease pressure. Increasing proportions of maize in the crop rotation increase the disease occurrence and severity in sugar beet and decrease wsy. The combination of sugar beet cultivar and crop rotation influences the wsy particularly. In addition in subsequently cultivated maize effects of the sugar beet cultivar and crop rotation were observed. BZE (t/ha) The effects in maize are obvious smaller than in sugar beet. 0 M/M M/W W/H (Photos: ARGE Regensburg)

41 Summary Cultivation method had only minor effect on R. solani disease occurrence. In some cases further effects were observed. Plowing before sugar beet was favorable. Influence from intercrop cultivation has to be proven in further experiments. The design of the crop rotation offers the biggest influence on disease occurrence with R. solani in sugar beet, besides the resistant cultivar. (Bilder: ARGE Regensburg, IfZ)

42 Many thanks to the colleagues at the IfZ to the Arbeitsgemeinschaft Regensburg... for your attention

43 Influence of crop rotation and sugar beet cultivar on white sugar yield sus. cultivar res. cultivar Dis. occurrence (1-9) Wsy (t/ha) Wsy (%) 3,48 A 11,86 A 88,0 B 13,46 B 100 M/M 3,03 A 11,94 A 90 M/W,69 AB 1,73 AB 96 W/O 54,54 B 13,3131 B 100 BZE (t/ha a) BZE (t/h /ha) Wsy Wsy (t/ha a) Significant higher wsy after the cultivation of the resistant cultivar. 0 susceptible resistant M/M sugar beetm/wsugar beet W/O Significant higher wsy after the crop rotation wheat/oat instead of maize/maize.

44 Influence of crop rotation and sugar beet cultivar on white sugar yield sus. cultivar res. cultivar Dis. occur- Wsy Wsy rence (1-9) (t/ha) (%) 3,48 A 11,86 A 88,0 B 13,46 B 100 M/M 3,03 A 11,94 A 90 M/W,69 AB 1,73 AB 96 W/O,54 B 13,31 B 100 Wsy (t/ha) d susceptible resistant ab c ab bc a Significant interaction between crop rotation and cultivar. 0 The difference between the cultivars depended on the crop rotation. No significant ifi difference between the crop rotations ti after the cultivation resistant cultivar. 11 M/M M/W W/O