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Story Posted: July 14, 2010 Canola Watch 12: Identify the problem, then act In This Issue: What to do about strange growth and missing buds, Root rot suspected in wet Manitoba field, Coming events, Questions and contacts. Issues of the week Crop and weather update Alberta: Crops in south are a week to three weeks behind. Large systems dropped golf-ball sized hail on a swath east of Calgary and brought strong winds, 2" to 4" of rain and spotty hail through the central region. That said, crops are good to excellent for most of Alberta, and moving quickly through the flowering window. Spraying for sclerotinia has been common in many parts of the region. Read the Alberta crop report. Saskatchewan: Yield potential for surviving crop in the worst hit areas — Wadena — could be as low as 5 bushels/acre in some fields. But some crops in the east, particularly around Redvers, look very good. Western crops look good, too. Tests in the northwest found 60% to 100% of petals had presence of sclerotinia, and 15% to 20% of crops north of Highway 16 were sprayed for the disease. Fungicide application was the most ever for canola in the area, says Clint Jurke (click to email Clint), CCC agronomy specialist for the region. Most crops are in the flowering stages. Read the Saskatchewan crop report. Manitoba: Heavy rains last night put fields under standing water again in eastern regions. Until then, a generally drier week had allowed crops to recover from earlier moisture stress. Early fields are done flowering. Crop conditions are highly variable, particularly in the eastern and Interlake regions. In the northwest, half to 65% of fields received a fungicide treatment to prevent sclerotinia stem rot, which is probably less than typical for the region due mainly to poor crop condition in some fields. Read the Manitoba crop report. Quick Hitters Spraying for lygus bugs and cabbage seedpod weevil has begun in southern Alberta, and diamondback moth larvae are showing up in higher numbers. The critical time for diamondback moth larvae control is during pod formation. While scouting for insects, you may find tiny thrips. (See the photos below.) Thrips, which cause twisted pods on canola, have been spotted in parts of Alberta this year. There are no established thresholds for control, but if pod damage is due to thrips and not diamondback moth larvae, for example, then a spray may not help.
Export Ready: Don’t use Ronilan on canola. Canola tolerances for vinclozolin, the active ingredient in Ronilan, are no longer in place for the U.S. This means that any canola treated with Ronilan is no longer acceptable for shipment to the U.S. Click here for the latest Export Ready factsheet. Export Ready: Don’t use malathion on canola bins. Malathion cannot be used to treat bins where canola will be stored or to treat canola as it goes in to storage. This can result in residues in the canola. If the bin was treated previously, do not store canola in the bins within six months of treatment. Click here for the latest Export Ready factsheet. Prepare for 2011. A large portion of unseeded and drowned out acres in 2010 will likely be seeded to canola in 2011. In preparing the unseeded fields for next year’s canola, use herbicide products that do not leave residues harmful to canola. When you see sclerotinia symptoms - bleached white and possibly brittle areas on the stem - it’s too late to manage the disease for this year. But you can use that information to plan a more proactive sclerotinia monitoring and control plan for next year. For more on sclerotinia management, click here to hear Kelly Turkington, crop pathologist with AAFC in Lacombe, Alta., on ACPC radio. Sclerotinia survey. MAFRI, AAFC and Canola Council staff are collecting canola flower samples at 20% and 50% bloom stages to test for sclerotinia spores. The same fields will be surveyed again for disease incidence just prior to swathing. The goal is to improve sclerotinia forecasting tools. Vikram Bisht, the provincial plant pathologist with MAFRI, says every effort will be made to contact growers prior to subsequent sampling, but the rapid advancement of the crop in eastern Manitoba has necessitated random sampling of a few fields. If growers have concerns or would prefer their fields not be sampled, contact Bisht at 204-745-0260. What to do about strange growth and missing buds Until you know the cause of damage, take no action. There’s no sense spending money on fungicide, insecticide or nutrient topdress without properly identifying the target problem. Herbicide carryover is a possible cause for the lush plants with missing buds. (See the top photo.) A soil bioassay can identify the herbicides present in the soil. Alberta Innovates in Vegreville does soil bioassays. They cost $150 per sample and the turn around time is 4-6 weeks. For more information, call or email Sandi Scott at 780-632-8217 or sandi.scott@albertainnovates.ca. Other possibilities:
Swede midge has been mentioned as a cause, but that’s unlikely. Swede midge have not been reported anywhere west of eastern Saskatchewan. For a presentation on what causes blanks or flower abortion, watch the ACPC webinar with Murray Hartman, Alberta provincial oilseed specialist. For more information, download the CCC factsheet "Missing pods or blanks on the main stem: What could be the cause?"
Root rot suspected in wet Manitoba field
Based on the minimal root development and lack of root hairs, it could be brown girdling root rot - especially since it was spread throughout the field and that the area has had excess water. BGRR is rarely seen outside of the Peace region, so tests will need to be done to confirm. Nothing can be done to control it other than avoiding short rotations - but this is no guarantee. Argentine canola is much more resistant to the adult plant root rots than Polish, but with the right conditions it still can be a problem. When making an assessment on the cause of damage:
Coming events AAFC’s Scott Field Day is Friday, July 16. The event starts at 10:00 at the Scott, Sask., centre, with tours starting at 11:00. Topics include long-term crop rotations and developments in dandelion control. For more information, call Sherrilyn Phelps at 306-446-7475 or cell 306-441-0480. Other AAFC tours for Saskatchewan: AAFC and IHARF, July 20 at Indian Head; and AAFC and NERF, July 21 at Melfort. Contacts are Daphne Cruise for Indian Head, 306-694-3587; and Kim Stonehouse for Melfort, 306-878-8807. WADO’s summer tour is July 21 at Melita, Man. It begins with a free lunch at noon in the back shop of the DB Murray John Deere Dealership. Tour highlights include intercropping research with peas and canola grown together under many different combinations. For more information, call Scott Day at 204-522-3256 or cell 204-534-7633 or visit the WADO website. Combine Performance Clinic July 27 and 28 in Vegreville, Alta. CCC and Alberta Canola Producers Commission present the one-day clinic with tips to cut combine losses, which can be 3-5 bushels per acre. Click here for more information or to register online. Space is limited to 250 per day. For more on combine settings, listen to Doug Moisey on ACPC radio.
Questions and contacts If you have questions on regional issues, contact one of the following Canola Council of Canada regional agronomists or provincial oilseed specialists:
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:
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