Rhizoctonia-Mapping in European Corn – Initial Results

Prof. Dr. Joseph-Alexander VerreetChristian-Albrechts-Universität zu Kiel, Germany

“Rhizoctonia-Mapping in European Corn –

Initial Results from France and Germany”

Preliminary results

“Rhizoctonia - Mapping in European Corn – Initial Results from France and Germany”

Basics

• Rhizoctonia referred to a large complex group of organisms with many subspecies

• The pathogen causes serve symptoms and yield losses on more than 500 various plant

species • Damages include seedling damping-off and root rots as well as leaf-blights

• Isolates differ in pathogenicity, morphology, cultural and physiological characteristics• Rhizoctonia spp. are soil-borne, ubiquitous, necrotrophic pathogens with a wide host range

and saprophytic behavior

- Rhizoctonia spp. -

Soil borne = wide host range;

saprophytic behavior and the localization in soil creates a further barrier for disease control

The pathogen cannot be eliminated but can be suppressed to a level that doesn’t cause economic losses !!!

Preliminary results


Environmental Requirements

• Optimal temperature (T) R. solani = 21-32 °C; R. cerealis = 10-18°C

• Soil structure = Main factor influencing the spatial distribution :

• Soil composition high contents of sand favored a high spread of the mycelium• Soil compaction high levels of mycelium in a low volume of soil

• Soil compaction inoculum density high disease severity

High impact of physical properties in soil: • Pore size distribution, quantity of air- and water filled pores

• Influence of nutrient contents in different soils on disease severity is not clarified yet

Serve symptoms under reduced tillage practice

Preliminary results

“Rhizoctonia - Mapping in European Corn – Initial Results from France and Germany”Taxonomic Classification

Teleomorph

Anamorph

Rhizoctonia spp.

Thanatephorus cucumeris

(multinuclear)

Rhizoctonia solani

Ceratobasidiumcereale

(binuclear)

Rhizoctonia cerealis

Waitea circinata

(multinuclear)

- Rhizoctonia zeae

- Rhizoctonia oryzae

Preliminary results


Anastomosis Groups and their Hosts

AG / Host Wheat Barley Corn Sugar beet Potato Rice Soy Cotton OrchidaceaeAG 1 IA X X X X X

AG 1 IB X X X X

AG 2-2 IIIB X X X X

AG 2-2 IV X

AG 3 X

AG 4 X X

AG 5 X X X X X

AG 6 X

AG 7 X X X

AG 8 X X

AG 9 X X X

AG 10 X X

AG 11 X X X X

AG 12 X

AG 13 X

Teleomorph: Thanatephorus cucumerisAnamorph: Rhizoctonia solani

Preliminary results


Anastomosis groups and their Hosts

Teleomorph: Ceratobasidium cereale = sexual stageAnamorph: Rhizoctonia cerealis and others = asexual stage

• Nomenclature according to the North American anastomosis system blue

• Nomenclature according to the Japanese anastomosis system green

CAG/Host CerealsBunch

grasses(Agrostis)

Peanut

(Arachis)

Pea

(Glycine)

Fleabane

(Erigeron)

‚Cheesewood‘

(Pittosporum)

Cucumber

(Cucumis)

CAG 1 (AG–D)

R. cerealis

Xsharp

eyespot

X

CAG 2 (AG–A) X

CAG 3 (AG–E) X

CAG 4 (AG–F) X

CAG 5 (AG-R) X

CAG 6 (AG–E) X

CAG 7 (AG-S) X

Preliminary results

“Rhizoctonia - Mapping in European Corn – Initial Results from France and Germany”Tested Anastomosis Groups – European Rhizoctonia-Mapping

Rhizoctonia spp.

Thanatephorus cucumeris

AG 1

AG 1-1 A

AG 1-1 B

AG 2 AG 2-2 III B

Ceratobasidiumcereale R. cerealis

Waitea circinata

R. zeae

R. oryzae

not analyzed

Preliminary results


Experimental Design - European Rhizoctonia-Mapping

Experimental design:

• GS 31-35 roots for example Meißen I• GS 61-65 roots for example Meißen II

• GS 31-35 soil pg/g soilLocations:

25 locations in Germany 30 locations in France

2 locations in Switzerland

Traffic lights like systemfor classifikation of the disease severity ‰:

Verification – 20 ‰20 - 400 ‰

400 - 1000 ‰1000 - > 1000 ‰

PLANT: Rhizoctonia spp.- DNA - Disease severity ‰

SOIL: Rhizoctonia spp. - DNA pg/g

Rhizoctonia-MappingFrance,Germany,

Switzerland

Preliminary results


Rhizoctonia-Mapping Corn – Results from Europe

Pathogen D (25) F (30) CH (2)

AG 1-1 A(Plant and

soil)

8 10 0

Plant GS 35 6 2 0

Plant GS 65 5 8 0

Plant GS 35 and 65

3 0 0

Soil GS 35 0 0 0

Soil GS 65 0 0 0

Soil GS 35 and 65

0 0 0

No detection in soil

Verification – 20 ‰

20 - 400 ‰

400 - 1000 ‰

1000 - > 1000 ‰Previous Crop Corn

R. solaniAG 1-1 A

Plant samplesNo detection in soil !!

Preliminary results


Rhizoctonia-Mapping Corn –Results from Europe


20 - 400 ‰

400 - 1000 ‰

1000 - > 1000 ‰Previous Crop Corn


AG 1-1 B(Plant and

soil)

13 10 0

Plant GS 35 9 1 0

Plant GS 65 11 9 0

Plant GS 35 and 65

7 1 0

Soil GS 35 3 1 0

Soil GS 65 1 4 0

Soil GS 35 and 65

0 0 0

R. solaniAG 1-1 B

Plant and soil samples

Preliminary results




AG 2-2 III B(Plant and

soil)

10 14 0

Plant GS 35 6 4 0

Plant GS 65 6 9 0

Plant GS 35 and 65

4 1 0

Soil GS 35 1 2 0

Soil GS 65 1 6 0

Soil GS 35 and 65

0 0 0

Previous Crop Corn

R. solaniAG 2-2 III B Plant and soil

samples


20 - 400 ‰

400 - 1000 ‰

1000 - > 1000 ‰

Preliminary results




R. cerealis(Plant and

soil)

16 13 1

Plant GS 35 5 0 0

Plant GS 65 16 13 1

Plant GS 35 and 65

4 0 0

Soil GS 35 0 0 0

Soil GS 65 0 1 0

Soil GS 35 and 65

0 0 0

Previous Crop Corn and Wheat

R. cerealisPlant and soil

samples


20 - 400 ‰

400 - 1000 ‰

1000 - > 1000 ‰

Preliminary results

“Rhizoctonia - Mapping in European Corn – Initial Results from France and Germany”Rhizoctonia-Mapping Corn – Results from Schleswig-Holstein

Futterkamp (C/W)

Kastorf

Leezen

Kummerfeld

ElskopBarlt

Krumstedt

Barkhorn Hohenschulen

Bovenau

Loit

Scholderup

Schafflund

NordstrandDörpstedt

Sönke-Nissen-Koog

• 17 locations in Schleswig-Holstein

• 7 locations wheat

• 10 locations corn• soil samples from 5, 15 and 30 cm

soil depth• testing for AG 1-1 A, AG 1-1 B,

AG 2-2 IIIB and R. cerealis• sampling date: early August

locations wheat

locations corn

Quantitative Detection of Rhizoctonia spp. - locations

C = corn; W = wheat Preliminary results


Frequency of the evidence of individual pathogens

AG 1-1 B AG 1-1 A AG 2-2 IIIB R. cerealis

5,8 %17,6 %

47 %

88,2 %

•100 % of the locations with evidence of Rhizoctonia spp.

•58,8 % of the locations with 2 Rhizoctonia spp.

•41,2 % of the locations with 1 Rhizoctonia spp.

R. cerealis and R. solani AG 2-2 IIIBare of the greatest

importance !!

Preliminary results


Futterkamp (M)

Leezen

Kummerfeld

Krumstedt

Hohenschulen

Schafflund

Dörpstedt

0 2000 4000 6000 8000 10000

Elskop

Schafflund

Hohenschulen

Futterkamp (M)

Kummerfeld

Leezen

Dörpstedt

Krumstedt

Rhizoctonia-DNA in relation to plant-DNA (‰)

Elskop

53871 ‰

Quantitative Rhizoctonia solani - DNA detection of AG 2-2 IIIBin plant

No detection in soil


20 - 400 ‰

400 - 1000 ‰

1000 - > 1000 ‰

Preliminary results

“Rhizoctonia - Mapping in European Corn – Initial Results from Schleswig-Holstein”Rhizoctonia-Mapping Corn – Results from Schleswig-Holstein

12958 ‰ 53871 ‰

0

2000

4000

6000

8000

Scho

lder

up

Nor

dstr

and

Scha

fflun

d

Bar

khor

n

Hoh

ensc

hule

n

Futte

rkam

p

Kum

mer

feld

Leez

en

Dör

pste

dt

Kru

mst

edt

Monokultur > 2 Jahre

AG 2-2 IIIB R. cerealis

0 0 0 0

corn monoculture > 2 yearsprevious crop cereals

Quantitative Rhizoctonia solani - DNA detection of AG 2-2 IIIBin plant

Rhi

zoct

onia

-DNA

in re

latio

n to

pla

nt-D

NA (‰

)

Preliminary results


0 150 300 450

30 cm

15 cm

5 cm

Pflanze

Kummerfeld

0 150 300 450

30 cm

15 cm

5 cm

Pflanze

Dörpstedt

0 150 300 450

30 cm

15 cm

5 cm

Pflanze

Krumstedt

2354 ‰

7292 ‰ 53871 ‰

0 150 300 450

30 cm

15 cm

5 cm

Pflanze

Leezen

4034 ‰

- Disease severity of AG 2-2 IIIB- Detection in plant and soil samples

Quantitative Rhizoctonia solani - DNA detection of AG 2-2 IIIBin plant and soil

Quantitative Rhizoctonia solani-DNA in soil (pg/g) and plant (‰)

plant

plant

plant

plant

Preliminary results


0 2000 4000 6000 8000 10000

Elskop

Schafflund

Hohenschulen

Futterkamp (M)

Kummerfeld

Leezen

Dörpstedt

Krumstedt 53871 ‰

Quantitative Rhizoctonia cerealis - DNA detection in plant

Quantitative Rhizoctonia cerealis-DNA in relation to plant DNA (‰)

Futterkamp

Kastorf

LeezenBarlt

Krumstedt

Hohenschulen

Bovenau

Loit

Scholderup

Schafflund

NordstrandDörpstedt

Barkhorn

Elskop

Preliminary results


0

5000

10000

15000

20000

S.-N

.-Koo

g

Loit

Elsk

op

Bar

lt

Futte

rkam

p

Bov

enau

Kas

torf

Vorfrucht Raps

Erre

ger-

DN

A zu

Pfla

nzen

-DN

A (‰

)

AG 2-2 IIIB R. cerealis

0 0 0 0 0 0 028 ‰ 27 ‰

239954 ‰ 1352673 ‰881256 ‰

previous crop = oil seed rape

Rhi

zoct

onia

cer

ealis

-DN

A in

rela

tion

to p

lant

-DN

A (‰

)

Quantitative Rhizoctonia cerealis - DNA detection in plant

Preliminary results


0 150 300 450

30 cm

15 cm

5 cm

Pflanze

Elskop

5386 ‰

0 150 300 450

30 cm

15 cm

5 cm

Pflanze

Futterkamp (W)

239954 ‰

Quantitative Rhizoctonia cerealis - DNA detection in plant and soil

Quantitative Rhizoctonia cerealis - DNA in soil (pg/g) and plant (‰)

plant

plant

Preliminary results

“Rhizoctonia - Mapping in European Corn – Initial Results from France and Germany”SUMMARY

In 2014 corn and soil samples of 25 locations in Germany, 30 locations in France and two locations in Switzerland were examined regarding to the disease pressure of the anastomosis groups AG 1-1 A, AG 1-1 B, AG 2-2 IIIB and R. cerealis.

Disease severity was measured with specific developed primers through qPCR.

84,2 % of the locations are charged with at least one of the above-mentioned pathogens. At 15,8 % of the sampled sites no pathogen was detected.

AG 2-2 IIIB and R. cerealis showed both in terms of detection frequency and disease severity the highest relevance.

Additionally, 17 sites in Schleswig-Holstein (Germany) were examined, 10 sites with corn plants and 7 sites with wheat plants.

The soil samples were subdivided in three soil depths (5, 15 and 30 cm).

AG 2-2 IIIB and R. cerealis showed the highest relevance in view of disease severity.

AG 2-2 IIIB was dominant at sites with >2 years corn monoculture.

The disease severity of R. cerealis increased at sites were wheat plants were examined.

AG 1-1 A and AG 1-1 B could not be detected in soil samples.

The highest levels of DNA residues of AG 2-2 IIIB and R. cerealis in soil were detected in the soil depth of 15 cm. For interpretation the previous tillage systems need to be considered.

The results of the European survey documents a high degree of Rhizoctonia spp. inoculum.Preliminary results

Documents

Rhizoctonia-Mapping in European Corn – Initial Results