agronomy update - alberta agriculture and forestry peas and lentils • pulse crops grown for feed,...
TRANSCRIPT
Robyne Bowness
Alberta Agriculture and Rural DevelopmentLacombe, AB
Agronomy UpdateJanuary 18th, 2011
Field Peas and Lentils• Pulse crops grown for feed, food, and ingredients• Valuable in crop rotation (N2 fixation)• Important crops globally Demand is increasing every year Canada is second largest exporter
In 2010• Over 895,000 acres of peas harvested
• Over 135, 000 acres of lentils harvested
Source: Alberta Agriculture and Rural Development
Ascochyta Blight of Field Pea• Common disease• Complex of three pathogens Mycosphaerella pinodes ( )
White mould of Lentil• Not so common Sclerotinia sclerotiorum
Caused by fungal pathogens
Can attack the crop at any growth stage
Prefer cool, wet, shadier conditions
Problematic in Alberta during summer 2010
Most serious foliar disease of field pea in Western Canada
Found in all commercial pea fields
Interferes with photosynthesis
Crop lodges
Reduces seed weight, number and quality
Yield losses range from 20-50%• In wet years even higher
Symptoms
• Appear within 2-4 days of infection• Small purple to brown lesions on leaves, stems and pods• Pinpoint lesions on the flowers• Breakdown stem strength – crop lodges• Seeds smaller with dark brown discoloration
Survives in seed, in the soil and on plant debris
Two types of spores - spread by wind or rain splash
Infections early and repeatedly throughout the season
Most critical factor is leaf wetness
Spores
Strategies include• Crop rotation• Disease free seed• Seed treatment• Cultural practices
No cultivars resistant to this pathogen
Most effective strategy is repeated application of fungicides
Fungicide options include:• Bravo 500 ®
• Headline EC ®
• Lance ®
• Quadris ®
Timing is critical
Considerations• Protectants – won’t kill the pathogen• Crop Canopy – dense Before canopy closes
• Level disease• Yield increase is expected
Is yield loss higher than cost of application?
Crop Canopy• Thin, moderate, or thick
Leaf wetness (at noon)• None, low, moderate, or high
Percent of plants showing symptoms• None, low (<20%), moderate (20-50%) or high (50-100%)
5 day weather forecast• Dry, unsettled, showers, wet
Source: Lopetinsky and Hoy, 2008
%
Field inspections should be done twice a week (June)
Add up score for each factor• 1+2+3+4 = ?
Source: Lopetinsky and Hoy, 2008
Estimation Risk Scale Score
Crop CanopyThin
0Moderate
10Mod/ Thick
15Thick
30 30
Leaf wetness/ humidity
None0
Low10
Moderate20
High40 10
Percentage of plants with symptoms
None
0
Low(<20%)
15
Moderate(20-50%)
25
High(50-100%)
4025
5 day weatherforecast
Dry0
Unsettled10
Showers15
Wet20 15
Total --- --- --- --- 1+2+3+4
Source: Lopetinsky and Hoy, 2008
Estimation Risk Scale Score
Crop CanopyThin
0Moderate
10Mod/ Thick
15Thick
30 30
Leaf wetness/ humidity
None0
Low10
Moderate20
High40 10
Percentage of plants with symptoms
None
0
Low(<20%)
15
Moderate(20-50%)
25
High(50-100%)
4025
5 day weatherforecast
Dry0
Unsettled10
Showers15
Wet20 15
Total --- --- --- --- 1+2+3+4
Source: Lopetinsky and Hoy, 2008
Estimation Risk Scale Score
Crop CanopyThin
0Moderate
10Mod/ Thick
15Thick
30 30
Leaf wetness/ humidity
None0
Low10
Moderate20
High40 10
Percentage of plants with symptoms
None
0
Low(<20%)
15
Moderate(20-50%)
25
High(50-100%)
4025
5 day weatherforecast
Dry0
Unsettled10
Showers15
Wet20 15
Total --- --- --- --- 80
Source: Lopetinsky and Hoy, 2008
Field inspections should be done twice a week (June)
Add up score for each factor• 1+2+3+4 = ?
Magic number is 65
Score above 65 points.. • Fungicide application is recommended
Score below 65 points..• Fungicide applications not necessary at this time• Field inspections should continue
Source: Lopetinsky and Hoy, 2008
Prediction system is a tool..
May help making the decision as to whether to spray or not easier
Must be starting with a healthy crop!
No disease, don’t spray!
Caused by Sclerotinia sclerotiorum• Serious foliar disease of many crops• Plant parts - high water content• Losses can be great
On lentil• Usually not of economic importance Lentils better suited to drier areas
• Except in wet years Affects yield and quality
Photos : Faye Dokken – Bouchard and Sabbine Banniza
Symptoms
• Appear late in the season - from flowering to pod set• Stems appear bleached• Leaves and stems turn brown, plants wilt• Plant become covered with white cottony mould• Black sclerotia develop inside and outside of the plant
Photos : Faye Dokken – Bouchard and Sabbine Banniza Photo: Ontario Ministry of Agriculture
Sclerotia survive in the soil
Sclerotia germinate and release spores
Lots of moisture / plants are stressed / conditions are right
Infection occurs• Most critical factor is canopy wetness
Spor
es
Very difficult pathogen to control
Most economic option is cultivar resistance• There are none available
Common strategy is application of fungicides
Not always recommended
Issues:• Not the same as canola• Infects late in the season• Spraying at flowering not effective• Can’t get effective delivery after canopy close
Timing is critical
Only fungicide option available is Lance®
Considerations• Temperature and leaf wetness are favorable• History of Sclerotinia in the field• Before canopy closes
• Spray to protect the crop• Before you see any disease
Is yield loss higher than cost of application?
Strategies include
• Crop rotation with cereal crops• Clean seed – no sclerotia• Wide row spacing / plant densities• Cultural practices• Fields with good drainage
Good news is it only show up once in a while!
Start with a healthy crop
Scout your fields often
Familiarize yourself with the disease
Familiarize yourself with the chemical
Consider the economics of spraying
Good luck!
Faye Dokken-Bouchard, Saskatchewan Agriculture
Sabinne Banniza, University of Saskatchewan
Mark Olson, Alberta Agriculture and Rural Development