Dr. Walter K. Kast und Karl Bleyer...

Staatliche Lehr- und Versuchsanstaltfür Wein- und Obstbau Weinsberg

Dr. Walter K. Kast FDW AK Rebschutz 19.09.2009


OiDiag-System Versionen 2.xDr. Walter K. Kast und Karl Bleyer

Weinsberg




1st tool: date for the first application of fungicides

2nd tool: maximal time lag for last applied fungicide

The two OiDiag tools:



1st tool: theoretical aspects:epidemic may be described by an exponential function

(Vanderpank 1963)

low initial inoculum= 1

0

1 0 0 0 0 0 0 0

2 0 0 0 0 0 0 0

3 0 0 0 0 0 0 0

4 0 0 0 0 0 0 0

5 0 0 0 0 0 0 0

6 0 0 0 0 0 0 0

7 0 0 0 0 0 0 0

8 0 0 0 0 0 0 0

9 0 0 0 0 0 0 0

1 0 0 0 0 0 0 0 0

5 6 7 9 10 11 12

latent phase

Exponentialphase



low initial inoculum= 1

0

1 0 0 0 0 0 0 0

2 0 0 0 0 0 0 0

3 0 0 0 0 0 0 0

4 0 0 0 0 0 0 0

5 0 0 0 0 0 0 0

6 0 0 0 0 0 0 0

7 0 0 0 0 0 0 0

8 0 0 0 0 0 0 0

9 0 0 0 0 0 0 0

1 0 0 0 0 0 0 0 0

5 6 7 9 10 11 12

1st tool: theoretical aspects:epidemic may be described by an exponential function

(Vanderpank 1963)

high initial inoculum= 10

flowering

differences on lowlevels are invisible



1st tool: practical aspects:initial inoculum dictates the the need to start with control

high initial inculum - a lot of grape infetions- high initial inoculum in the next year

low initial inculum - no grape infetions- low initial inoculum in the next year

high initial inculum - a lot of grape infetions- high initial inoculum in the next year

=> start earlier to keep epidemic low

=> start later because epidemic is delayed



Evaluation of the initial inoculum isextremly diffcult

survival as Cleistothecia)

survival in infected buds (flag shoots)



for the initial inoculum no data are available



Powdery mildew symptomes observed at Weinsbergsince 1953 in 6 classes

Note012345

description of symtomes no powdery mildew observed

more than 5% of the vineyards had damage on grapes

late season syptomes in a few vineyards observed

only a few leaves with late season powdery mildew observed

late season syptomes in most of the vineyards on leavees and lateral grapes

a few vineyards had powdery mildew on grapes



Correlations between weather data, the powdery mildew disease indices of the preceeding year

and disease indices of the current years database: 1953 – 2007 (n=54 )

+0,35**disease index of the preceeding year

+0,42**minimum of temperature (mean of the two preceeing years)

correlation todisease notes

source of variation

coefficient of determination: 32%



coefficient of determination: 32%

calculations are possible in January

the complete epidemic of the relevant year is in the offing

=> these two values give an exellent estimation for the initial inoculum



1st tool: delay on base of stage „ 3 leaves unfolded “

input: input:

34,75

mean of the absolute minima of the 2 preceeding winters 0,00 17,50

days after 3 leaves unfolded

disease severity preceeding year

1st spray should start latest :



1st tool: delay on base of stage „ 3 leaves unfolded “

input: input:

disease severity preceeding year

1st spray should start latest : 0,39

mean of the absolute minima of the 2 preceeding winters 5,00 10,30

days after 3 leaves unfolded




1st tool: date for the first application of fungicides

2nd tool: maximal time lag for last applied fungicide

The two OiDiag tools:



maximal time lag for last applied fungicidedepends on:

• active period of the fungicides

• climatical effects on the fungus

• ontogenetics of the vine(relevant: grape)



The idea• classification of fungicides for their

preventive period

• Calculation of an index value integrating ontogenetics and climate

The result:



Stadienspezifische Anfälligkeit

6

26

15

3 20

5

17

7

1 1,60

0

5

10

15

20

25

30

61 68 73 75 77 81

befa

llene

Obe

rflä

che

in %

TrollingerLemberger



6

26

15

3 20

5

17

7

1 1,60

0

5

10

15

20

25

30

61 68 73 75 77 81

befa

llene

Obe

rflä

che

in %

TrollingerLemberger





6

26

15

3 20

5

17

7

1 1,60

0

5

10

15

20

25

30

61 68 73 75 77 81

Bef

alls

tstä

rke

%

TrollingerLemberger



Mehltaufenster: Zeitraum der Besiedlung der Trauben



T1 53 20.5 Vorblüte KumulusT2 57 30.5 letzte Vorblüte TalendoT3 68 9.6 abgehende Blüte VivandoT4 71 19.6 Nachblüte FlintT5 77 1.7 Ende TS VivandoT6 77 14.7 nach TS SysthaneT7 80 29.7. Abschluss SysthaneT1 53 20.5 Vorblüte TalendoT2 57 30.5 letzte Vorblüte VivandoT3 68 9.6 abgehende Blüte Cabrio TopT4 68 21.6 Nachblüte DiscusT5 77 1.7 Ende TS SysthaneT6 77 14.7 nach TS SysthaneT7 80 29.7. Abschluss SysthaneT1 VorblüteT2 57 30.5 letzte Vorblüte TalendoT3 68 9.6 abgehende Blüte Cabrio TopT4 71 19.6 Nachblüte TalendoT5 Ende TST6 nach TST7 Abschluss

3 x Blüte

Oidag

Standard



Mehltauversuch Cabernet Dorsa 2008Blatt 26.6. und Traube 25.7.

05

1015202530354045

15.7. Traubenbefall Stärke%

26.6. Blattbefall Stärke %

Kontrolle BayerDowStandardOiDiag 2.03 x "Fenster"



Mehltauversuch Cabernet Dorsa 20082. Auswertung 19.8.

0

10

20

30

40

50

60

70

Traubenbefall Stärke % Blattbefall Stärke %

Kontrolle BayerDowStandardOiDiag 2.03 x "Fenster"

Mehltauinfektionen erfolgen fast ausschließlich im Mehltaufenstersitzen meist an versteckten Stellen sie werden durch Spritzungen nur unterdrücktwerden allmählich (meist Wochen später) sichtbar

94%99%



42

49

05

1015202530354045

Unbehandelt

7x Discus

3x Discus

% befalleneBeerenoberfläche

Spritzungen während des Mehltaufensters im Vergleich zu 7 Routinespritzungen (Freilandversuche)

1999



65

4

16

0

10

20

30

40

50

60

70

Unbehandelt

7x Vento

3 xVento



2000



54

6 7

0

10

20

30

40

50

60

Unbehandelt

7x Flint

3x Flint



2001



13

7

0

2

4

6

8

10

12

14

16

Unbehandelt

3x Vento



2002

totaler Fehlschlag



13

7 7

0

2

4

6

8

10

12

14

16

Unbehandelt

7x Vento

3x Vento



2002



Ursache der schlechten Wirkung

Ausfall derParzellenspritze

Spritzintervall 18 Tage vor und während der Rebblüte



Calculation of OiDiag-2.X Index Values

Input values needed1. Actual number of leaves developed (stage)2. Precipitation sum/day3. Daily mean of temperature4. Daily Leaf-wetness (hours)5. Humidity: hours with humidity>65< =80 and

hours with humidity>80



Ontogenetical-Index (ONT)

ONT = {(0.0007*N³)+(84*Ln(N)-(9.4*N)-0.67)}/100

N= number of days after “three leaves unfolded”N = IF(N<3;=3,=N2)

IF(N>30;=30,=N)

[set limits:]ONT=IF(ONT<0.2;0.2;ONT)




00,10,20,30,40,50,60,70,80,9

1

1 8 15 22 29 36 43 50 57 64 71 78 850

0,10,20,30,40,50,60,70,80,9

1

1 8 15 22 29 36 43 50 57 64 71 78 85




ONT = {(0.0007*N³)+(84*Ln(N)-(9.4*N)-0.67)}/100

N= number of days after “three leaves unfolded”N = IF(N<3;=3,=N2)

IF(N>30;=30,=N)[set limits:]I2=IF(I1<0.1;0.1;I1)

fixed function with maximum at beginning of flowering period (independent from weather-conditions)

Works well in Weinsberg and Freiburg but transfer is limited in other regionsVitimeteo: Leaves according to the model of Schultz/Geisenheim are going to be used in 2010 Vitimeteo allows to set own values for each number of leaves separately



Index based on climatical conditions (CLI):

Contribution of temperature (TEM)

TEM=(((0.11*T)-(0.0025*T*T))-0.6)*1,63

T = daily mean of temperature

a similar formula was used in OiDiag1.0



Contribution of temperature (TEM)



Contribution for humidity (HUM)

HUM=(H80+(H65*0.7))/24

H65 = hours with humidity>65<|=80H80 = hours with humidity >80

The same function was used in OiDiag1.0

OiDiag1.0 was criticized heavily for the integration of humidity to the index



Contribution of rainfall and leaf wetness (RAI):

R=IF(PREC<2.5; =0; =LWET*1.5)R=IF(PREC>10; =LWET*3.0; =LWET)RAI=R/24

PREC = rainfall/day [mm]LWET = Leaf-wetness [hours/day]



Index based on climatical conditions (CLI):

CLI=(TEM*HUM)*2-(1.1*RAI)

[set limits:]CLI=IF(CLI<0;0;I1)CLI=IF(CLI>1.1;1,1;I1)



Index for the relevant day (IND)

[combine CLI and ONT]

IND=CLI*ONT

[set limits:]IND=IF(IND>1.02;1;I4)



OiDiag2.2-Index (final result)

[calculate sliding means over the last 7 days (%)]

Mean((IND(day-6), IND(day-5)), IND(day-4), IND(day-3), IND(day-2), IND(day-1), IND(actual day))*100)



Exsamples of OiDiag Index-values 2008/09

0

10

20

30

40

50

60

70

80

90

100

13.5 20.5 27.5 3.6 10.6 17.6 24.6 1.7 8.7 15.7 22.7 29.7 5.8 12.8

2008

2009

flowering2009

flowerung2008




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