Canola Watch

2007 Canola Watch Reports

#4 Western Canada – May 24, 2007

In this issue:
(click the bookmark links below to move to specific sections of this report)

Seeding progress variable
Soil moisture conditions still good to excessive
Frost damage light so far
Delayed seeding tips
Reassess variety suitability
Broadcast seeding not generally recommended
Consider fertilizer and herbicide post-seeding options
Check for soil crusting
Good control of early weed growth is key
Canola is emerging; start scouting fields 7-10 days after seeding
Flea beetles reported
Remember to work safely!

The Alberta Canola Producers Commission (ACPC) has developed an Alberta focused version of this report. Visit the ACPC website at: http://www.canola.ab.ca

Canola seeding progress remains variable across the prairies. Seeding is wrapping up across southwest, central and eastern areas of Manitoba and many southern parts of Saskatchewan and Alberta. Seeding progress was delayed by rains and snow in all provinces. Areas furthest delayed include northeastern Saskatchewan between Prince Albert and Nipawin, central Alberta from Red Deer to Barrhead and many parts of the Peace region including Grande Prairie, Rycroft and Falher. There have been reports of some growers returning their canola seed for earlier varieties and switching to alternate crops, principally barley.

Soil moisture conditions continue to range from good to excessive across most of western Canada. Variable precipitation (from trace to 125 mm) was received across many parts of the west. Areas including northern and northeastern Saskatchewan, central Alberta north of Calgary, and much of the Peace region continue to remain wet with lots of areas of standing water.

For current maps of moisture conditions from PFRA for western Canada, check the following links for precipitation since September 1 and April 1 respectively:
http://www.agr.gc.ca/pfra/drought/prpay07_e.htm
http://www.agr.gc.ca/pfra/drought/prpgs07_e.htm

The latest crop report from Manitoba Agriculture, Food & Rural Initiatives is available at: http://web2.gov.mb.ca/agriculture/mwcr/index.php

The latest crop report from Saskatchewan Agriculture, Food & Rural Revitalization is available at:
http://www.agr.gov.sk.ca/docs/reports/crop_report/crprpt070519.asp

Additional moisture information for Alberta is available from Alberta Environment at:
http://www3.gov.ab.ca/env/water/WS/data/precipmaps/weekly.pdf

More frost was reported in many areas across the west this past week, with some areas reporting lows as cold as -6 degrees C. Damage to emerging canola is reported to be light so far, due to the fact that most crops had not yet emerged. The amount of frost injury will depend on moisture conditions, duration of the frost and coldest temperature reached, rate at which thawing occurs, the growth stage of the plants, and the amount of cold temperature hardening the plants have experienced. Canola seedlings will usually recover from a light spring frost that does not damage the plant’s growing point. A light frost that wilts the leaves, but does not cause any browning, will not severely damage the plants. Some discolouration of the leaves may occur, usually a yellowing or whitening especially under drought conditions.

To evaluate a frost-damaged field, walk a diagonal path across the field and evaluate all plants in a 1/4 m2 (3 ft2) area every 20 paces. This should result in 50 to 100 samples. Record your observation from each sample. Calculate the percentage of the field that has adequate plant recovery. For example, let’s take a field where 80% of the field has a minimum of 20 to 40 recovering healthy plants per m2 (2 to 4 per ft2) and a light weed population, and the remainder of the field has fewer plants (may even be none to spotty). This field likely still has a higher yield potential than one that is reseeded, especially if it's the end of May or first week of June. The surviving plants will take advantage of the reduced competition for light, moisture and nutrients and grow larger, producing more branches, pods and seeds per pod, compensating for the lost plants. With a moderate weed population that cannot be controlled effectively, the canola plant density should be higher (perhaps 60 to 70 recovered plants/m2  or 6 to 7 per ft2), because weed competition will limit the ability of the canola to compensate. In either situation the surviving plants will require longer to mature (as much as five to eight days), but a re-seeded crop will require an even longer frost free period and have a greater risk of fall frost damage.
Wait several days following the frost to determine the extent of the damage and whether or not the growing point has been killed. If there is any green colour at the growing point in the centre of the frozen leaf rosette, the plant should recover. Under good growing conditions, green re-growth from the growing point should occur in four to five days. Under poor growing conditions--cold and/or dry—re-growth may take up to 10 days. Refer to the following Canol@Fact “Tips for assessing spring frost damage in canola” for more information:  http://www.canola-council.org/PDF/may5_Canola_AssessingSpring.pdf#zoom=100
Remember, that a proper assessment of frost damage cannot be made for several days--until it can be determined whether new growth is appearing from damaged plants.

Although seeding remains delayed in many areas of Saskatchewan and Alberta compared to the last few years, growers can still take steps to speed maturity and offset some of these delays. The combination of good to excellent soil moisture combined with favourable soil temperatures is ideal for rapid and even emergence as long as the proper seeding techniques are used. Seed shallow to facilitate rapid emergence, ideally at a depth of ½ to ¾ of an inch. Keep any pre-seeding tillage shallow to help maintain the seedbed firmness and moisture. Consider increasing seeding rates slightly to reduce individual plant branching. Make sure that seeding rates are high enough to establish the target of 7-14 plants/ft2. Apply recommended rates of phosphorus fertilizer for the “pop-up effect” in cooler areas to ensure more uniform crop maturity, but watch seed-placed fertilizer rates to avoid seedling toxicity.

Growers who still have significant acreages of canola left to seed need to reassess the maturity suitability of their chosen varieties. The accumulation of temperature or Growing Degree Days (GDDs) has a major influence on days to maturity for canola. In the short and mid season zones of western Canada, maturity for B. napus varieties will range from 95 to 125 days, depending on the growing season heat accumulation. B. rapa varieties usually range from 80 to 115 days to maturity.
First, find out how many days to maturity are required for the variety that is to be seeded. Usually the variety will be rated relative to the check variety: number of days earlier (minus), later (plus). Using a typical first fall frost date, count back the days to maturity to estimate the cut-off date for seeding. For example, if the first frost is August 25 on average and maturity of the check in the area is 103 days, counting back gives a cut-off date of May 17. If the variety to be seeded is five days earlier in maturity than the check, this means that in a typical year, seeding up to May 22 would be acceptable for that variety. If the variety does not meet the requirements, ask your local retailer to suggest other suitable varieties.

Manitoba growers can check the following link to determine their frost-free days:
http://www.gov.mb.ca/agriculture/climate/waa50s00.html

Saskatchewan growers can check the following link to determine the average first fall frost date:
http://www.saskcropinsurance.com/maps/other/fallfrost.shtml

Alberta growers can check the following link to determine their frost-free days:
http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex10

The delay in seeding progress due to wet conditions has producers considering broadcast seeding. In general, broadcast seeding is not recommended. Usually, broadcast seeding results in lower yields compared to drill seeding. However, producers faced with wet conditions that limit equipment flotation plus the risk of fall frost may wish to consider broadcast seeding. Refer to the previous crop watch report for further tips on enhancing successfulness of broadcast seeding: http://www.canola-council.org/Canola_Watch_Report_2007_03.html

Temporary shortages of fertilizer and herbicide products have been reported in a number of areas. It is important for growers who are unable to access sufficient fertilizer products at the time of seeding to be aware that they have other options. Post emergent top dressing of ammonium sulphate fertilizer has been shown to be effective when applied up to the 4-leaf stage of the crop. Earlier applications generally have greater efficacy due to the increased chances of receiving adequate precipitation for movement of the fertilizer to the crop roots. It is important to use the proper type of application equipment based on the form of fertilizer being applied to ensure even distribution of product when broadcasting.

Soil crusting has been reported in a number of areas including southwestern and central areas of Manitoba and parts of southern Alberta including Lethbridge and Airdrie. The majority of crusting cases appear to have occurred after heavy rains. The larger, deeper and denser the crust, the more difficult it will be for the seedlings to emerge. Growers should be patient to evaluate the extent of the crop’s ability to push through the crust prior to taking any remedial action. If hot and dry weather occurs after the crust develops, then often the crust becomes harder and more difficult to penetrate through. However, if some rain occurs afterwards, then the rain will tend to soften the crust and then the seedlings can emerge to the surface. Although remedial action such as light harrowing has sometimes been used to break up the crusting, growers should be very cautious of this practice especially if the seed is shallow and if germination has already occurred. Reduced tillage practices and keeping crop residues near the soil surface are useful in reducing the occurrence and severity of soil crusting.

Weed growth continues in many areas due to the combination of favourable moisture conditions and relatively warm soil temperatures. In many areas of Manitoba, the combination of early seeding and the lack of pre-emergent burn-off applications have led to many fields experiencing advanced weed growth compared to the crop stage. In these cases it is especially important for growers to do an early in-crop herbicide application. Control of early germinating weeds is important in minimizing moisture and nutrient loss and reducing weed competition to allow establishment of a healthy and competitive crop stand.

Growers are strongly encouraged to assess the number, growth stage and types of weeds present prior to burn-off applications. This will assist in determining the proper product or tank-mix as well as the rate that may be required. For those growers relying on post-seeding, pre-emergent burn-off applications, keep in mind that many areas are reporting canola emergence within a week of seeding, due to ample moisture and warm soils. Monitor carefully for emergence prior to spraying to avoid crop damage.

Emergence of earlier seeded canola continues in many areas. Remember to begin scouting fields by 7 to 10 days after seeding to detect germination problems early. With ample moisture and warm soils, emergence can begin to take place within a week. Refer to the Canol@Fact “Factors affecting canola survival for seeding to 21 days after emergence” for more information: http://www.canola-council.org/PDF/seed_to_21days.pdf#zoom=100

When scouting fields with any stand establishment problems, check for the presence of the blue seed coat, at or near the root of the seedling or the depth of seeding. This will indicate whether the affected plants are from the current year’s seed, or whether the plants may be volunteers from previous years.

Flea beetles continue to be reported near Dauphin and in the southwest region of Manitoba, in Saskatchewan near Moosomin and Meota, in Alberta near St. Albert and in the BC Peace. Although most of the reports are on volunteer canola and wild mustard, early seeded fields have begun to emerge, so pay particular attention in these cases, especially on fields with tight canola rotations or where no insecticide seed treatment was used. Agronomists are encouraged to note whether the flea beetles are two-striped or cruciferous. Check the following link for help in identifying the different species:  http://www.canola-council.org/fleabeetleident.aspx
If noted, please pass this information on to your local Canola Council agronomist.

Following are tips for monitoring and assessing flea beetle damage of emerging crops. Scout fields daily in the spring, especially in areas with high flea beetle pressure last year, and assess damage to cotyledons and the first true leaves of seedlings. Continue scouting for the first 14 days after emergence, especially on sunny, calm days when temperatures exceed 14oC; scouting twice a day may be warranted when weather conditions are ideal for flea beetle feeding. Determine the extent and distribution of damage by observing plants at random while walking across the field, as well as checking all field and slough margins where the insects over-winter. Estimate the foliage damage, utilizing the visual aid at the bottom of the following web page to assist in assessing leaf area damage more accurately - http://www.canola-council.org/fleabeetlemonitoring.aspx. Flea beetles generally invade canola fields from the field edges. Damage and flea beetle numbers may be higher at the field edge than farther into the field.

Current seed treatment insecticides require flea beetles to feed on the canola in order to provide control, so seeing some flea beetle damage doesn’t mean your seed treatment insecticide is not working.  These insecticides have a limited window of efficacy and delayed emergence and growth due to cool, wet weather may allow feeding damage to build up.

Canola seedlings can withstand 50% leaf loss. However, flea beetles can locate attack and quickly injure or destroy seedlings shortly after emergence. Therefore, the action threshold for flea beetle feeding on canola is when there is 25% defoliation and flea beetles are present. Make sure to check the entire plant for signs of flea beetle feeding, the stem may also have signs of damage. Applying controls at 25% defoliation will reduce the risk of flea beetle damage reaching a level where yield loss and plant development are substantially reduced. If damage only exceeds threshold levels near the field edges, a foliar spray around the field edges may provide sufficient protection. However, on hot and calm days flea beetles are capable of moving farther distances and may cause significant damage further into the field.

When assessing economic thresholds, also consider growing conditions. When flea beetle feeding is combined with poor plant growth during hot, dry weather, canola can tolerate less feeding than if plants are growing rapidly under more ideal growing conditions.

Although seeding may be delayed this year due to the late spring and wet conditions, remember to work safely. There have been a number of cases of tow ropes and chains recoiling back into the glass of tractor cabs and also a report of a tractor using auto-steer crashing into a high tension electrical tower. Although luckily, no one was seriously hurt in these cases, remember to use caution when extricating stuck equipment and stay alert! Remember, it makes no sense to rush through seeding and not be around to enjoy the harvest.

Direct questions regarding this report to John Mayko, Senior Agronomist, Parkland West (West Central AB), with the Canola Council of Canada at maykoj@canola-council.org  ph/fax: 780-764-2593.

Direct specific questions regarding regional issues to one of the following Canola Council of Canada agronomists or provincial oilseed specialists:

Derwyn Hammond, Agronomist, Manitoba, hammondd@canola-council.org, 204-729-9011
Arvel Lawson, Manitoba Agriculture, Food & Rural Initiatives, Arvel.Lawson@gov.mb.ca, 204-745-0340
David Vanthuyne, Agronomist, Eastern Saskatchewan, vanthuyd@canola-council.org, 306-782-7799
Jim Bessel, Senior Agronomist, North-central/eastern Saskatchewan, besselj@canola-council.org, 306-373-6771
Penny Pearse/Scott Hartley, Saskatchewan Agriculture, Food & Rural Revitalization, ppearse@agr.gov.sk.ca / shartley@agr.gov.sk.ca , 306-787-4671 / 306-787-4669
Doug Moisey, Agronomist, Parkland East (East Central AB & NW SK), moiseyd@canola-council.org, 780-645-3624
Matthew Stanford, Agronomist, Chinook (Southern AB & SW SK), stanfordm@canola-council.org, 403-758-6660
Anne Vos, Acting Agronomist, Peace Region, av@summit-ag.com, 780-835-4632
Murray Hartman, Alberta Agriculture, Food & Rural Development, murray.hartman@gov.ab.ca, 403-782-8024
Kerry Clark, BC Ministry of Agriculture and Lands, Kerry.Clark@gov.bc.ca,  250-784-2559

 

The Canola Watch Report provides just-in-time information on canola production to growers and industry. Contributors to the Canola Agronomy Network are:
Manitoba Agriculture & Food; Manitoba Canola Growers Association; Agricore United; Saskatchewan Wheat Pool; United Farmers of Alberta; Saskatchewan Agriculture, Food & Rural Revitalization; Saskatchewan Canola Growers Association; Saskatchewan Canola Development Commission; Alberta Agriculture, Food & Rural Development; Alberta Canola Producers Commission; BC Ministry of Agriculture; Food & Fisheries; and the Canola Council of Canada.

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