Robyne Bowness. Alberta Agriculture and Rural Development Lacombe, AB. Agronomy Update January 18 th, 2011

Transcription

1 Robyne Bowness Alberta Agriculture and Rural Development Lacombe, AB Agronomy Update January 18 th, 2011

2 Field Peas and Lentils Pulse crops grown for feed, food, and ingredients Valuable in crop rotation (N 2 fixation) Important crops globally In 2010 Demand is increasing every year Canada is second largest exporter Over 895,000 acres of peas harvested Over 135, 000 acres of lentils harvested Source: Alberta Agriculture and Rural Development

3 Ascochyta Blight of Field Pea Common disease Complex of three pathogens Mycosphaerella pinodes ( ) White mould of Lentil Not so common Sclerotinia sclerotiorum

4 Caused by fungal pathogens Can attack the crop at any growth stage Prefer cool, wet, shadier conditions Problematic in Alberta during summer 2010

5 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

6 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

7 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

8 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

9 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?

10 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

11 Field inspections should be done twice a week (June) Add up score for each factor =? Source: Lopetinsky and Hoy, 2008

12 Estimation Risk Scale Score Crop Canopy Thin 0 Moderate 10 Mod/ Thick 15 Thick Leaf wetness / humidity None 0 Low 10 Moderate 20 High Percentage of plants with symptoms None 0 Low (<20%) 15 Moderate (20-50%) 25 High (50-100%) day weather forecast Dry 0 Unsettled 10 Showers 15 Wet Total Source: Lopetinsky and Hoy, 2008

13 Estimation Risk Scale Score Crop Canopy Thin 0 Moderate 10 Mod/ Thick 15 Thick Leaf wetness / humidity None 0 Low 10 Moderate 20 High Percentage of plants with symptoms None 0 Low (<20%) 15 Moderate (20-50%) 25 High (50-100%) day weather forecast Dry 0 Unsettled 10 Showers 15 Wet Total Source: Lopetinsky and Hoy, 2008

14 Estimation Risk Scale Score Crop Canopy Thin 0 Moderate 10 Mod/ Thick 15 Thick Leaf wetness / humidity None 0 Low 10 Moderate 20 High Percentage of plants with symptoms 5 day weather forecast None 0 Dry 0 Low (<20%) 15 Unsettled 10 Moderate (20-50%) 25 Showers 15 High (50-100%) Wet Total Source: Lopetinsky and Hoy, 2008

15 Field inspections should be done twice a week (June) Add up score for each factor =? 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

16 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!

17 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

18 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

19 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 Spores

20 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

21 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?

22 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!

23 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!

24 Faye Dokken-Bouchard, Saskatchewan Agriculture Sabinne Banniza, University of Saskatchewan Mark Olson, Alberta Agriculture and Rural Development