USE A FORECAST SYSTEM TO DEVELOP INTEGRATED PEST
MANAGEMENT STRATEGIES FOR LATE BLIGHT IN SOUTHERN CHILE
I.Acuña, R. Bravo, B. Sagredo, M. Gutierrez, I. Maldonado, N. Gaete, J. Inostroza, G. Secor and J. Kalazich
Finance by FIA-PI-C-2003-1-A-17.
CHILE
70.000 ha25 t/ha90.000 growers60% in thesouthern
Situation of Late Blight in Chile
•First Report: 1950’s in tubers coming from Argentina•Incidence andseverity is variable year to year in thesouth, common in the north•Last years: Changes in potatoproduction system
2006-07Low potato pricesOverwintering potatoesManagement problemUnefficient Chemical control
Epiphitotic disease
Integrated Pest Management Considerations
HostPotato
WeatherTª, RH, Pp
PathogenP. infestans
Grower
¿?
P.infestans collection250 isolates were collectedfrom the southern Chile: Los Lagos and Araucanía regions.
Season N°2003/04 2004/05
99151
Studies on Characteristic of P. infestansPopulation in Chile
200pb
150pb
200pb
150pb
Pi02
1 2 4 5 6 7 8 9 101112131415 1617181920212223242526272829303132333435363738394041424344454647484950
Mating type
Metalaxyl resistance
SSR DNA polymorphism: primers Pi02, Pi04, Pi56, Pi66, Pi33, Pi70, Pi16 and Pi26, plus DNA controls.
Virulence
Isoenzimas GPI Monomórficos
PEP Tres genotipos 24 50 66 67 68 69 70 71 72 73 74 75 76 77 79 80 81 82 83 84 85 86 87 88 89 24 50 66 67 68 69 70 71 72 73 74 75 76 77 79 80 81 82 83 84 85 86 87 88 89
1 2 4 5 6 7 8 9 10 13 14- 15 16 17 18 19 20 21 23 24 25 26 27 28 291 2 4 5 6 7 8 9 10 13 14- 15 16 17 18 19 20 21 23 24 25 26 27 28 29
M50 M67
Alelo
Alelo
Homocigotos
Heterocigoto
Mating type determination at North Dakota StateUniversity, Fargo, ND,USA. Dr. Gary Secor.
A1
X
X
A2150 isolates fromcolecction 2003-04 and 2004-05: A1 Mating type
Allozymes GPI and PEPGPI Monomorphic
1 2 4 5 6 7 8 9 10 13 14- 15 16 17 18 19 20 21 23 24 25 26 27 28 29
Allele aDiallelicAllele b
PEP Three genotypes24 50 66 67 68 69 70 71 72 73 74 75 76 77 79 80 81 82 83 84 85 86 87 88 89
Simple Sequence Repeat (SSR) DNA
Monomorphic primers: Pi04,Pi33,Pi66 Pi70
200pb
150pb
505152 53 5455 5657 58 59 60 6162 63 6465 66 67 68 69 7071727374 75 76 77 78 79 80 8182 83 84 8586 8788 89 90Pi04
200pb
150pb
Pi02
1 2 4 5 6 7 8 9 101112131415 1617181920212223242526272829303132333435363738394041424344454647484950
Marcadores polimórficos: Pi02,Pi16
DENDOGRAM
0.75 0.81 0.88 0.94 1.00SM Coefficient
Group with 72 isolates
Group with 12 isolates
Group with 6 isolates
• Three groups with same genotypes
• 100% of the isolates
SM = 1
SM = 0.84
Metalaxil Resistance in vitro Test
Season 2003-04 (n=98)
Season 2004-05 (n=152)
0-10 23.4 43.4 Sensitive10 to 60 76.5 55.9 Intermediate
>60 0 0.7 Resistante
Growth on 10 ug/l media relative to
unamended media
Metalaxil resistance
Isolates (%)
0102030405060708090
100
Isol
ates
(%)
0 .01 0.06 0.07 0.08 0.09 0.1 0.2 0.23 0.26 0.4 0.6 0.8 3 28 100
EC50 Metalaxil (ppm)
Low resistanceto Metalaxil,Less than 1%.
EC50 < 3 ppm.Only 2 isolateshow 27.7 and100 ppm(0,0.1,1,10,100ppm)
2003-04 colecction2004-05 collection
0
2
4
6
8
10
12
14
16
18
20Fr
ecue
ncia
(%)
• 0= No symptoms.(-)• 1= Hypersensitivity.(-)• 2= Lesion < 1 cm, no sporulation.(+)• 3= Lesión > 1 cm, with sporulation.(+)
PATHOTYPE FREQUENCY
11 Differentials of the SCRI send from NDSU
VIRULENCE FREQUENCY
0
10
20
30
40
50
60
70
80
90
100
R1n=175
R2n=175
R3n=175
R4n=175
R5n=175
R6n=175
R7n=175
R8n=175
R9n=175
R10n=175
R11n=175
Freq
uenc
y (%
)
Host: Potato Cultivars
0
2 0 0
4 0 0
6 0 0
8 0 0
10 0 0
12 0 0
14 0 0
16 0 0
18 0 0
2 0 0 0
2 2 0 0A
mad
eus
R 8
9063
-84
Pehu
ench
eR
890
63-5
9R
A44
8-1
Des
irée
Gra
nola
Rx
9002
0-9
Car
dina
lO
naK
aru
RA
362
-35
Puka
ráR
910
34-6
RA
110
-5R
900
29-2
41R
910
15-2
0R
ed S
carle
tYa
gana
Rod
eoA
ster
ixR
910
11-1
R 8
7009
-28
Mon
alis
aR
911
93-1
Atla
ntic
Bin
tjeR
osar
aR
.Rus
set
R 9
0213
-55
Shep
ody
AU
DPC
POTATO CULTIVARS RELATIVE RESISTANCE TO LATE BLIGHT INIA-REMEHUE
Evaluation replicated at 3 locations during 3 years
Forecasting Late Blight
Weather Network at the Araucaniaand Los Lagos regions
Araucania regionCarahuePuerto SaavedraTeodoro SchmidtPillanlelbunVilcún
Los Lagos regionRapacoOsornoPurranqueLos MuermosCastro
WeatherWeather Data Record Data Record andand ProcessingProcessing
ComputerComputer Data Data processingprocessing
Late Blight
Forecast
PotatoCrop
Tª, RH, Pp.
Forecast Models: During the seasons 2004-07, Threemodels were evaluated, calibrated and validated withfarmers:
NEGFRY (Hansen et al., 1995): Based in two models: - Phytoprog (Schrodter y Ulrich,1966): Negative prognosis, used Ta, RH and Pp. - Simcast (Fry et al., 1983; Grunwald et al., 2000): Simulation onweather, fungicide and cultivar resistance.
DACOM Plant Plus Online: - Wheather data (in the future).- Uses infection periods, fungicide wear off, unprotected canopy, and sporulation:
BLITECAST (Krause et al., 1975): - Combines severity values model of Wallin (1962) and the favorable day model of Hyre (1954)- Uses RH and temp to calculate severity values (when 18 severity values are accumulated, late blight is predicted to occur in 7-14 days and the first protectant fungicide is recommended)
Folla
je d
añad
o (%
)
0
10
20
30
40
50
60
70
80
90
100
14-Dic 24-Dic 3-Ene 13-Ene 23-Ene 2-Feb 12-Feb 22-Feb
Testigo
Calendario Fijo
Blitecast
Negfry
DacomAlarma
Aplicación
Los MuermosFo
llaje
dañ
ado
(%)
0
10
20
30
40
50
60
70
80
90
100
14-Dic 24-Dic 3-Ene 13-Ene 23-Ene 2-Feb 12-Feb 22-Feb
Testigo
Calendario Fijo
Blitecast
Negfry
DacomAlarma
Aplicación
Los Muermos
0
10
20
30
40
50
60
70
80
90
100
14-Dic 24-Dic 3-Ene 13-Ene 23-Ene 2-Feb 12-Feb 22-Feb
Testigo
Calendario Fijo
Blitecast
Negfry
DacomAlarma
Aplicación
Alarma
Aplicación
Alarma
Aplicación
Los Muermos
1 Testigo 8.6 d 90.0 d 982.9 a2 Calendario Fijo 0.2 a 16.2 a 177.8 d3 Pronosticador Blitecast 4.4 c 32.5 c 358.2 b4 Pronosticador Negfry 1.3 b 27.5 bc 302.4 bc5 Pronosticador Dacom 0.1 a 20.0 ab 220.9 cd
CvPrueba de FProbabilidad 0.0001 0.0001
127.70.0001
72.00 130.951.94 6.49 14.24
TratamientoFollaje Dañado (%)Fecha de Evaluación AUDPC07-Feb-06 21-Feb-06
Late blight damage, forecast and fungicideapplication. Los Muermos, Los Lagos region. 2005-06
Porcentage of foliar damageand AUDPC in potato cvDesireé.
(Mancozeb-clorotalonil)
Late blight damage, forecast and fungicide application. INIA-La Pampa, Los Lagos region. 2005-06
0
10
20
30
40
50
60
70
80
90
100
6-Dic 16-Dic 26-Dic 5-Ene 15-Ene 25-Ene 4-Feb
Folla
je D
añad
o (%
)
Testigo
Calendario Fijo
Blitecast
NegfryDacom
La Pampa
Aplicación
Alarma
1 Testigo 22.4 b 33.0 b 87.2 c 100.0 c 1642.8 a2 Calendario Fijo 1.5 a 7.1 a 9.1 a 84.0 a 530.0 c3 Pronosticador Blitecast 16.0 b 22.3 b 35.9 b 100.0 c 1028.2 b4 Pronosticador Negfry 0.6 a 5.2 a 6.5 a 80.4 a 470.6 c5 Pronosticador Dacom 2.7 a 9.8 a 13.1 a 91.7 b 629.2 c
CvPrueba de FProbabilidad
TratamientoFollaje Dañado (%)Fecha de Evaluación
AUDPC23-Mar-06 28-Mar-06 08-Abr-06 17-Abr-06
6.44 7.23 13.67 48.82 18.5418.23 13.55 34.6 16.17 36.310.0001 0.0002 0.0001 0.0001 0.0001
0
10
20
30
40
50
60
70
80
90
100
6-Feb 16-Feb 26-Feb 8-Mar 18-Mar 28-Mar 7-Abr 17-Abr
Folla
je D
añad
o (%
)Testigo
Calendario Fijo
Blitecast
Negfry
Dacom
Alarma
Aplicación
Pto. Saavedra
0
10
20
30
40
50
60
70
80
90
100
6-Feb 16-Feb 26-Feb 8-Mar 18-Mar 28-Mar 7-Abr 17-Abr
Folla
je D
añad
o (%
)Testigo
Calendario Fijo
Blitecast
Negfry
Dacom
Alarma
Aplicación
Pto. Saavedra
Late blight damage, forecast andfungicide application. Pto. Saavedra, Araucania región. 2005-06
Percentageof foliar damage andAUDPC in potato cvKaru.
0
1
2
3
4
5
1-D ic
6 -D ic
11-D ic
16 -D ic
2 1-D ic
2 6 -D ic
3 1-D ic
5-Ene
10 -Ene
15-Ene
2 0 -Ene
2 5-Ene
3 0 -Ene
4 -Feb
9 -Feb
14 -Feb
19 -Feb
2 4 -Feb
0
1
2
3
4
5
1-D ic
6 -D ic
11-D ic
16 -D ic
2 1-D ic
2 6 -D ic
3 1-D ic
5-Ene
10 -Ene
15-Ene
2 0 -Ene
2 5-Ene
3 0 -Ene
4 -F eb
9 -F eb
14 -F eb
19 -Feb
2 4 -F eb
2005-06
2006-07
Late blightforecast atCastro, Chiloé
Green: No sprayYellow: WarningOrange: 7 day sprayRed: 5 day spray
2006-07BliteCast Model:18 severity valuesand 80% RH
0
1
2
3
4
5
1-D ic
6 -D ic
11-D ic
16 -D ic
2 1-D ic
2 6 -D ic
3 1-D ic
5-Ene
10 -Ene
15-Ene
2 0 -Ene
2 5-Ene
3 0 -Ene
4 -Feb
9 -Feb
14 -Feb
19 -Feb
2 4 -Feb
0
1
2
3
4
5
1-D ic
6 -D ic
11-D ic
16 -D ic
2 1-D ic
2 6 -D ic
3 1-D ic
5-Ene
10 -Ene
15-Ene
2 0 -Ene
2 5-Ene
3 0 -Ene
4 -Feb
9 -F eb
14 -Feb
19 -Feb
2 4 -Feb
2005-06
2006-07
Late blightforecast at Los Muermos
Green: No sprayYellow: WarningOrange: 7 day sprayRed: 5 day spray
2006-07BliteCast Model:18 severity valuesand 80% RH
0
10
20
30
40
50
60
70
80
90
100
15-N ov
2 5-N ov
5-D ic
15-D ic
2 5-D ic
4 -Ene
14 -Ene
2 4 -Ene
3 -Feb
13 -Feb
2 3 -Feb
5-M ar
15-M ar
Scheduled : M ancozeb
Scheduled : Pro pamocarb - C lo ro t alonil-Propamocarb - C lo ro t alonil
A larm 1 : M ancozeb
A larm 1 : Propamocarb - C lo ro t alonil-Propamocarb - C lo ro t alonil A larm 2 : M ancozeb
A larm 2 : Prop amocarb - C lo ro t alonil-Propamocarb - C lo ro t aloni
C ont ro l
0
1
2
3
4
5
15-N ov
2 5-N ov
5-D ic
15-D ic
2 5-D ic
4 -Ene
14 -Ene
2 4 -Ene
3 -Feb
13 -F eb
2 3 -Feb
5-M ar
15-M ar
0
1
2
3
4
5
15-N ov
2 5-N ov
5-D ic
15-D ic
2 5-D ic
4 -Ene
14 -Ene
2 4 -Ene
3 -Feb
13 -F eb
2 3 -Feb
5-M ar
15-M ar
Late blight damage andchemical treatmentsaccording to forecast onpotato cv Yagana(susceptible), under irrigation. 2006-07
Alarm 2:BliteCast Model:15 severity values and80% RH and modificationsfor Hyre model.
Alarm 1:BliteCast Model:18 severity values and80% RH
Spray ScheduledSpray on alarm 2Spray on alarm 1
0
500
1000
1500
2000
2500
Yagana sin riego Desiree sin riego Yagana con riego Desireé con riego
AU
DPC
T 1 T 2 1 2 3 4 5 6 7 8 9 10 1112 13 14 15 16 17 18 19 20 21
CF
CFCF CFA1
A2
A1
A1
A1
A2
Flecha: Testigo, CF: Calendario Fijo: 7 aplicaciones, A1: 4 aplicaciones, A2: 6 aplicaciones
Severidad de daño por tizón tardío en plantas de papa cvYagana y Desireé, bajo diferentes estrategias de manejo con
uso de pronosticadores
¡Muchas Gracias!
