Transcript MSU key messages

Pulse Disease Concerns
in Montana
Dr. Mary Burrows
Montana State University, Bozeman, MT
[email protected]
406-994-7766
Top 4 tips for a healthy pulse crop
1. Start with high-germ, good quality seed of an
adapted variety
–
Ascochyta blight, bacterial blight, Anthracnose, and viruses
can come in on seed
2. Use a fungicide seed treatment
– Damping off, root rots
3. Good crop rotation practices
– Root rots and foliar diseases
4. Scout crop on a regular basis
- Foliar diseases and abiotic issues
Ascochyta blight
• Three different species on Pea
• Ascochyta pisi, A. pinoides (Mycosphaerella
pinoides), Phoma medicaginis var. pinodella
(formerly A. pinodella)
• Different species on Lentils and
Chickpeas
• Lentil = Ascochyta lentis
• Chickpea = Ascochyta rabiei
• Spread by water splashing and wind
• 60 – 75 F, humidity and rain
Montana Ascochyta seed testing
2009
2010
# of seed lots
above
threshold
2011 (since Sept 2010)
n
Average
%
# of seed lots
above
threshold
n
Average
%
# of seed lots
above
threshold
Crop
n
Average
%
Chickpea
2
0.00
0
4
0.75
1
7
0.17
2
Lentil
25
0.12
1
53
0.25
2
50
1.78
4
Pea
57
0.18
3
83
1.71
39
23
2.33
14
•Action threshold = 0% chickpea, 0.7% pea, 2% lentil
•Where ‘action’ means seed treatment for ascochyta or not planting that seed
•Action threshold is based on relative resistance of the crop to the disease
Ascochyta blight symptoms: chickpea
Leaf symptoms
Pycnidia (fungal spore structures)
Fungicide
No fungicide
Photo: Chengci Chen, Karnes Neill, MSU
Ascochyta blight symptoms: Pea, Lentil
Photo: S. Markell, NDSU
Photo: S. Markell, NDSU
Bacterial blight of Pea
• Psedomonas syringae pv. pisi
• Seedborne inoculum (persists 3 years)
– Also residue- and soil-borne
• Local splash dispersal is the most
important for spread
• Yield loss strongly correlated with leaf
area loss
• No adapted cultivars with resistance
Bacterial blight of pea
Angular lesions
Watersoaking and ooze
Use a fungicide seed treatment
• Help manage root rots
– For a few weeks
• Aid emergence and stand establishment
• Why is this important?
– Disease likely occurs early, shows up later
• Protect against seed-borne diseases
– Use Mertect/LSP against Ascochyta in chickpea; Dynasty
(azoxystrobin) good for pea, lentil Ascochyta
Photo: S. Markell, NDSU
Seed treatment trials
•
•
•
•
Uniform pea seed treatment trials (ND, MT, WA)
6 locations, 2008; 2 locations, 2010
Low disease severity in general
Agronomics were dependent on site and year
– In Montana:
• Cruiser increased yield if there was pea weevil pressure
• No one seed treatment stood out as better than the rest
• Chickpea seed treatments, 2007
– Very wet site at Sidney, mefanoxam (metalaxyl) increased
stands and yield in kabuli chickpeas - Pythium
Seed Treatment
• Will seed treatments always pay? NO
• Questions to ask:
– How long have you been planting pulse
crops?
– What’s you’re rotation?
– Do you have stand establishment problems?
– Have you seen problems in your fields?
Seed Treatments
• Make sure your product has Fusarium and Rhizoc
control (True Fungi) in addition to Pythium
(metalaxyl/mefanoxam)
• Examples: ApronMaxx, Trilex AL, Acquire + Acronis
• 2009 ND field crop fungicide guide
• Product labels
• Use Mertect/LSP if you have Ascochyta in the seed;
Dynasty will also work but only for pea and lentil
(chickpea Ascochyta is resistant to strobilurins)
Good crop rotation practices
• 3-4 year rotation between legume crops
is recommended for disease
management
• Should reduce root pathogen
population: particularly the Fusarium
species that attack pea
• Will also reduce inoculum for foliar
pathogens
Fusarium




Can be stress related
Common in drought
years
Dry rot with indistinct
brown lesionsoccasional general
browning
Few secondary roots
Rhizoctonia
• Warm moist soil
• Distinct chocolate brown to
dark red lesions
• Often seen in association
with Fusarium
Lentil with root rot
Photo: S. Mills, MSU
Healthy lentil
Fusarium wilt of pea
Fusarium oxysporum f.sp. pisi
• Resistant varieties
• Seed treatment
• Rotation
Scout crop on a regular basis
• Foliar diseases
– Ascochyta blight
– Powdery mildew
• Abiotic issues
Foliar Fungicides
• Serious disease = serious yield reductions
– Fungicides can help prevent loss
• Fungicides will not always pay: beware the
development of fungicide resistance!
• Scout for diseases
• Consider climate
– Humid with rain in the forecast
• Early bloom is optimum time to spray
• Late-season fungicides will not penetrate thick
powdery mildew (peas) – neither will dessicants
Fungicide Resistance in
Chickpeas
• Fungicides Available before 2005
– Chlorothalonil – Protectant (Bravo)
– 2002: Azoxystrobin – QoI class (Quadris)
– 2003: Pyraclostrobin – QoI class (Headline)
• Initially, QoI’s very effective, so effective that…
• Growers were spraying multiple applications
• Resistance to Headline/Quadris identified in
2005
• Widespread resistance in 2006
Percent of Isolates
Ascochyta resistance to
Headline/Quadris (strobilurins)
From K. Wise
Yield lb/A
2007 Chickpea Fungicide TrialMinot
From K. McKay
Ascochyta Blight in Chickpeas
• Ascochyta in chickpeas does not cause
disease in lentils or peas
• Ascochyta population in chickpeas is
resistant to strobilurin fungicides
– Headline and Quadris ineffective
• Still the case
• Rotate chemicals
– Bravo, Proline, Endura, Proline
Preventing/Managing
Fungicide Resistance
• Rotate FRAC groups! Not product
• Follow the label
– Use appropriate timing
• Don’t wait until epidemic is full force
– Use appropriate rate
– Use appropriate technique (nozzles, water,
etc.)
• Tank mixes
Thank you
• Sam Markell, Rubella Goswami, NDSU
• Chengci Chen, Karnes Neill, Joyce
Eckoff, Rachel Leisso, Ken Baker, MSU
• Northern Pulse Growers Association
• USDA-Cool Season Food Legume
Program
Moccasin, MT, 2008
ID#
1
2
3
4
5
6
7
8
9
10
Treatment Name
Untreated
Tops 30
Trilex Concentrate
Trilex Concentrate +
Tops 30
Trilex Concentrate +
Gaucho 600
Apron MAXX
Cruiser MAXX
Mertec
Acquire + Acronis
Tachigaren
LSD(P=0.05)
CV
Stand
Count
(30 DAP, Root Rot
2
plants/ft ) Incidence
30 ab
5.5
35 a
6.0
35 a
4.2
Root Rot
severity
9 ab
7 ab
3b
Yield
(bu/A)
12.9 a
12.8 a
14.3 ab
6.0
30 ab
5b
13.7 ab
5.5
4.6
4.7
5.4
6.1
5.3
NS
23.1
13 b
28 ab
23 ab
18 ab
15 ab
20 ab
22
70
5b
5b
5b
4b
9 ab
7 ab
8
91
15.1 b
12.5 a
15.7 b
13.9 ab
12.4 a
12.7 a
2.1
10.6
Sidney, MT, 2008
Stand
Count
ID#
1
2
3
4
5
6
7
8
9
10
Treatment Name
Untreated
Tops 30
Trilex Concentrate
Trilex Concentrate +
Tops 30
Trilex Concentrate +
Gaucho 600
Apron MAXX
Cruiser MAXX
Mertect
Acquire + Acronis
Tachigaren
LSD(P=0.05)
CV
(30 DAP,
2
plants/ft )
6.0
6.2
6.8
Root Rot Root Rot
Incidence Severity
Yield
(%)
(% root) (bu/A)
30 ab
9 ab
12.3 ab
35 a
7 ab
10.4 a
35 a
3b
11.1 ab
7.0
30 ab
5b
13.9 bcd
6.7
6.5
6.8
7.0
7.0
6.4
NS
15.2
13 b
28 ab
23 ab
18 ab
15 ab
20 ab
22
71
5b
5b
5b
4b
9 ab
7 ab
8
91
12.7 ab
15.9 cde
14.1 bcd
16.6 de
18.1 e
13.2 abc
3.0
12.8
Moccassin, 2010
Yield (lbs/a)
Treatment
1. Control
2. Trilex 2000
3. Apron Maxx RTA
4. Apron Maxx RTA + Mertec
5. Nodulator granular
6. Nitragen-C (peat)
7. Trilex2000 + Nodulator granular
8. Trilex2000 + Nitragen-C (peat)
9. Apron Maxx + Nodulator granular
10. Apron Maxx + Nitragen-C (peat)
11. Apron Maxx + Mertect + Nodulator granular
12. Apron Maxx + Mertect + Nitragen-C (peat)
13. Stamina + Acquire + Nodulator Granular
14. Stamina + Apron Maxx RTA + Nodulator Granular
15. Rancona Summit + nodulator
16. Vitaflo 280 + nodulator
n
4
4
4
4
4
4
4
4
3
4
4
4
4
4
3
4
Yield
stderr
2036.6
2143.3
1999.5
2271.6
2344.2
2082.4
2327.3
2173.1
2236.0
2168.5
2331.4
2220.2
2145.0
2316.2
2471.1
2235.9
Mean
2214.6
R sq
CV
0.6
8.4
p-value rep
p-value treatment
<.0001
0.1324
80.9
110.6
67.9
196.1
118.1
63.8
189.8
135.7
70.1
195.7
65.7
66.2
56.2
133.7
133.6
131.2
What is causing our root rots?
• Over 80% isolates from ND Survey were
Fusarium species
• In MT, small chickpea survey in 2007:
Fusarium, Pythium causing damping off of seed
• Rhizoctonia can also be important
• Do all the Fusarium species cause disease,
equally?
Distribution of fungal isolates in field peas in 2008
1% 2%
18%
Rhizoctonia solani
19%
Fusarium avenaceum
Fusarium oxysporum
Fusarium redolens
15%
25%
Fusarium graminearum
Fusarium acuminatum
Fusarium solani
20%