Story Posted: May 26, 2010

Canola Watch 5: Tips for late seeding, N top up, insect scouting

In This Issue: Tips to help canola mature faster, Volunteer canola is a high-risk crop, If growers must broadcast seed..., Strategies to improve weed control in Liberty Link, Tips for a nitrogen top up, Watch for cutworm damage after emergence, Questions and contacts.

Issues of the week
May 26, 2010 - Rain ranged from a few tenths to 3" across much of the Prairies last week, including the Peace region. For those canola acres not seeded, growers need to take steps to speed emergence and tighten maturity. For example, find an early-maturing variety, seed shallow, and seed at a higher rate.

Crop and weather update
Peace (B.C. and Alberta): The region received 1" to 3" of rain in the past week, including snow in areas. This was welcome as the region, in general, has been dry. Canola seeding is wrapping up.

Alberta: Rain was fairly general, with up to 2" in many areas. Frost west of Edmonton and east around Provost should have minimal damage since most canola was not emerged at the time. Seeding progress is near complete through most of the province, with some pockets (around Boyle, north of Edmonton) at around 70% complete. Read the Alberta crop report.

Saskatchewan: Seeding progress varies widely, with some regions in the west near complete and some areas in the east barely started. A pocket around Kinistino, Melfort and St. Brieux is about 30% complete and another pocket around Yorkton, Canora and Foam Lake is at less than that. With rain accumulation of 2" or more in the past week in many eastern regions, seeding will not resume for a few days at the earliest. Read the Saskatchewan crop report.

Manitoba: Across the south, seeding is 85% complete or better. Average progress in the northwest is 70%. Eastern Manitoba had 3" of rain in the past week, and the west had 1" to 2". Winds of 80 km that came in ahead of the rain damaged some emerging crops in the Swan River Valley, cutting off plants and moving soil and seed. Read the Manitoba crop report.

Quick Hitters
Canola stands of 1 plant per square foot usually have 50-75% of the yield potential of an optimal stand density (greater than 6 plants per square foot) at the same stage of maturity. But there is usually a yield advantage of earlier seeded crops. Therefore, a thin stand can have 90% of the yield potential of a thicker stand seeded 2 weeks later. By the end of May, established thin stands usually will outyield canola reseeded at that time and will save the extra costs due to reseeding! Murray Hartman, oilseed specialist with Alberta Agriculture and Rural Development, says growers tempted to reseed fields with thin stands should think twice.

MCPA and 2-4,D are not registered for use ahead of canola. The residual can be deadly to emerging canola plants. Growers with big canola volunteers to control ahead of the crop may have heard that MCPA is safer than 2,4-D and that MCPA Ester is safer than Amine, but none is registered - or recommended.

Early-seeded crops are being spraying for flea beetle damage. The action threshold for spraying is when 25% of the leaf area is damage or missing. Economic threshold is considered to be 50% of leaf area missing or damaged. When damage covers 25% of leaf surface area, on average, and if flea beetles are still actively feeding, arrange to spray the affected field. Flea beetles slow down in cool, wet weather, but may take refuge on stems and the undersides of leaves. Watch for stem feeding. Click here to read more.

After a damaging frost, give canola crops 3 to 4 days to recover prior to assessing damage. If it remains cool recovery maybe longer. If after 4 days, you don’t see signs of new green growth on at least 1 plant per square foot, then reseeding may be the best option. (The same goes for wind damage, which was reported in part of Manitoba last week. Some seed may still be emerging and if growing points of damaged plants remain intact, recovery is possible, but plants cut off below the growing point will likely die.) After a frost, also remember to wait 2 or 3 days before spraying herbicide. Giving time for canola and weeds to recover reduces stress on the canola and improves herbicide efficacy. If frost has been heavy and there is significant leaf damage, foliar (post-emergent) herbicide applications will not successfully control the damaged weed until they have recovered and grown new leaves.

Something to think about for next spring: About 10,000 acres of canola in the Peace region are being reseeded due to early season stressors such as flea beetle pressure and damping off, which may be a result of deep seeding into cool soils. Most of those acres were seeded April 20-25 and emergence was delayed and patchy. By the time the crop emerged, seed treatment protection had tapered off.

Crop insurance cut off dates for full coverage are June 1 in Alberta, June 20 in Saskatchewan and June 10 for northern Manitoba and June 15 for southern Manitoba. Click your province for a link to crop insurance details: Alberta , Saskatchewan , Manitoba.

Growers who are seeding canola on fields originally planned for cereals need to consider their herbicide use last fall and this spring. Did they use products with residual activity that are not registered for use ahead of canola?

Adult diamondback moths have already been found in pheromone-baited traps in several areas of Manitoba and Alberta. This does indicate an early arrival of the moths. Scott Meers, insect management specialist with Alberta Agriculture, says the early arrival means we’ll probably have issues as the season progresses. Listen to his interview at Alberta Agriculture’s website. Be prepared to watch closely later in the season when the next generation of larvae emerge and start feeding.

Tips to help canola mature faster
When assessing how late is too late to seed Argentine canola, start with the average date of the first fall frost. Here are maps showing average dates for first fall frost in each province: Alberta , Saskatchewan , Manitoba. Most fall frosts occur within two weeks either side of the average date for your area. Next, look at days to maturity for the variety, adjusting for regional differences, and work back from the frost date. For example, if the mean date for first fall frost in northeast Saskatchewan is the week of August 31 to September 6, according to the map, then an Argentine canola variety with 100 days to maturity should be seeded by May 20 to be at lower risk of fall frost damage. The Saskatchewan crop insurance deadline is June 20. Growers seeding in that May 20 to June 20 window can take these steps to reduce their risks:

1. Switch to an earlier-maturing variety. Switching from a long-season Argentine to an early-season Argentine can gain a week. Switching to a Polish variety can gain two weeks, but Polish canola has lower yield potential to start with and doesn't offer the weed control options.

2. Seed shallow. Canola seeded half an inch deep can emergence 3 or 4 days earlier than canola seeded deeper. Increase the seeding rate. A higher rate means a more dense stand, which means less branching and overall earlier maturity. This can gain a day or 2.

3. Pop-up phosphate fertilizer applied with the seed can gain a day or 2.

4. Reduce nitrogen rates. Nature has already taken care of this, to some extent. With the wet conditions, losses for pre-applied nitrogen will be higher than normal, which is the equivalent of cutting rates. And with heavy weed growth, those weeds have also cut into nitrogen reserves. Lower nitrogen availability means the crop will not be vegetative for as long, which means the crop will mature a day or 2 earlier.

Thanks to Murray Hartman, oilseed specialist with Alberta Agriculture and Rural Development, for help with this article.

Volunteer canola is a high-risk crop
With high emergence rates of volunteer canola, some growers with many acres still to seed may be tempted to leave these volunteer "crops" to maturity. Volunteer canola is not a hybrid anymore, so yield potential of each individual seed is lower and not all plants will have herbicide tolerance. And with distribution concentrated in the windrows, the stand is not uniform. That means crowding in some areas and patchy emergence in others, both of which will reduce yield potential. This also means highly variable crop staging, creating a challenge for pest control and harvest. Also, a volunteer crop has no flea beetle protection and no applied fertilizer. And finally, growers who plan to harvest a volunteer crop will need to alert the seed company. Most seed will have legal restrictions on reuse, even if the seed comes from the volunteer seed bank.

Murray Hartman, oilseed specialist with Alberta Agriculture and Rural Development, says the better option is to control the volunteer canola and seed a proper crop using the advice in the previous article.

Or if conditions are too wet to use the drill and time is tight, read the following article on broadcast seeding.

If growers must broadcast seed...
Broadcast seeding usually results in lower yields compared to drill seeding. But when wet conditions limit equipment flotation and when time is running out to get the crop in, growers may wish to consider broadcast seeding. Here are some tips:

1. Increase seeding rates slightly to compensate for non-uniform seed depth.

2. Consider lightly cultivating (two to four cm) or harrowing to incorporate the seed into the soil if field conditions allow. However, avoid creating lumps or clods during cultivation or straw piles with harrows or cultivators.

3. If broadcasting fertilizer as well as seed, be aware that broadcast phosphorus is only about half as efficient as banded phosphorous. There also can be greater risk of denitrification on saturated soils, reducing N fertilizer efficiency. Adjust fertilizer rates accordingly, keeping in mind a realistic target yield based on the time of year and field conditions.

Strategies to improve weed control in Liberty Link
Liberty works best when applied with water volumes of 10 gallons per acre and when temperatures are warm. "When I worked in retail, we eliminated almost all Liberty performance issues by going to 10 gpa (Imperial)," says Ingrid Kristjanson, crop specialist for Manitoba Agriculture, Food and Rural Initiatives.

Clark Brenzil, weed management specialist with Saskatchewan Ministry of Agriculture, adds: "Most control issues for herbicides that rely heavily on contact activity, such as Liberty, are related to insufficient water carrier volumes or late staging. Growers almost need to treat carrier water as their other active ingredient."

Kristjanson and Brenzil provide further tips for weed control in a Liberty Link system:

• If wild oats and other grassy weeds emerge before broadleaf weeds, it might be a good option to go in with a Group 1, then follow up later with Liberty. With heavy grass populations, the mix of Liberty plus Select or Centurion works well. Note: Producers should realize that if Liberty alone is not giving adequate control of their wild oats, a Liberty plus Select or Centurion tank mix is not a good strategy for managing Group 1 resistant wild oats.
• With the movement of the technology fee from the Liberty herbicide to the seed and the option for higher use rates of Liberty, better control of grass weeds may be achieved with Liberty alone, improving options for Group 1 wild oat management while remaining economical.
• When using Lontrel to manage Canada thistle, it should be a split application before or after Liberty. When applying a systemic such as Lontrel on thistles, it should be done before the Liberty application otherwise it needs to wait until the thistles recover following the Liberty application so that it can be taken into the plants. For decent control, Canada thistle should have good leaf area for contact. Remember that Canada thistle is 3 to 4 times more competitive than wild oats. Research from AAFC in Lacombe, Alta., shows it only takes 10 Canada thistle shoots per square metre to cause a 10% yield loss in canola. For more on this, read the Canola Council of Canada factsheet, "How many weeds are too many?"

For the final word on herbicide rates and timing, consult the provincial guide to crop protection. Click on your province for a link to your guide: Alberta , Saskatchewan , Manitoba.

Tips for a nitrogen top up
Growers who reduced nitrogen rates at seeding and now would like to top up can see good results from dribble banding liquid nitrogen on the soil surface. Cindy Grant, research scientist with Agriculture and Agri-Food Canada in Brandon, provides these tips:

• Urea is less prone to losses when dribble banded in the liquid UAN form than when broadcast in dry form.
• When CCC senior agronomy specialist John Mayko asked Grant how Agrotain coated urea broadcast would compare with liquid dribble banded, she said both would be about equal in terms of effectiveness. Consider relative cost when making the decision.
• For phosphorus, the economic value of a top up application is questionable. Phosphorus needs to be in the soil and as close to the seed as possible to maximum benefit. "Also, as the soil warms up, P effectiveness is lowered due to more conversion in the soil, so it’s likely that unless the soil was very deficient in P, one would likely not get an economic benefit to broadcasting or dribble banding P," Grant says.

For more tips on fertilizer application in a wet spring, click here for a Manitoba Agriculture, Food and Rural Initiatives factsheet.

Watch for cutworm damage after emergence
John Gavloski, provincial entomologist with Manitoba Agriculture, Food and Rural Initiatives (MAFRI), says crop insurance assessed a field of canola south of Bagot, Man., last week because of cutworm damage. Scott Hartley, provincial entomologist with the Saskatchewan Ministry of Agriculture, recommends that growers scout closely for cutworms based on their higher activity in 2009 and preceding years.

Start scouting for damaged or missing plants on a weekly basis once the crop starts to come up. Cutworm feeding results in notched, wilted, dead, or cut-off plants, as shown in the photo. Patches of missing plants in the field are signs of early cutworm damage. For more on scouting and control trips, click here to read the full article at the Canola Watch website.

Questions and contacts
If you have general questions about Canola Watch, direct them to Jay Whetter, whetterj@canolacouncil.org or 807-468-4006.

If you have questions on regional issues, contact one of the following Canola Council of Canada regional agronomists or provincial oilseed specialists:

• Derwyn Hammond, senior agronomy specialist, Manitoba, hammondd@canolacouncil.org, 204-729-9011
• Jim Bessel, senior agronomy specialist, Central Saskatchewan, besselj@canolacouncil.org, 306-373-6771
• Tiffany Martinka, agronomy specialist, Eastern Saskatchewan, martinkat@canolacouncil.org, 306-231-3663
• Clint Jurke, agronomy specialist, Western Saskatchewan, jurkec@canolacouncil.org, 306-821-2935
• Troy Prosofsky, agronomy specialist, Southern Alberta, prosofskyt@canolacouncil.org, 403-332-1412
• Doug Moisey, senior agronomy specialist, North East and East Central Alberta, moiseyd@canolacouncil.org, 780-645-9205
• John Mayko, senior agronomy specialist, West Central Alberta, maykoj@canolacouncil.org, 780-764-2593
• Erin Brock, agronomy specialist, Peace Region, brocke@canolacouncil.org,
  780-568-3326
• Murray Hartman, Alberta Agriculture and Rural Development, murray.hartman@gov.ab.ca, 403-782-8024
• Kerry Clark, B.C. Ministry of Agriculture and Lands, Kerry.Clark@gov.bc.ca, 250-784-2559
• Venkata Vakulabharanam, Saskatchewan Ministry of Agriculture, Venkata.Vakulabharanam@gov.sk.ca, (306)787-4668
• Ingrid Kristjanson, Manitoba Agriculture, Food and Rural Initiatives, ingrid.kristjanson@gov.mb.ca, 204-746-7504

This report is supported by each of the provincial canola grower associations. For more information on some of their activities, check out the following links:

• The Alberta Canola Producers Commission (ACPC) has a free e-newsletter called Alberta Canola Connections. Visit canola.ab.ca and click the sign-up icon on the right site of the homepage.
• In Manitoba, sign up for the Manitoba Canola Growers Association newsletter at Canola Growers E-update by visiting www.mcgacanola.org.

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