In this issue: (click the bookmarked links below to move to specific sections of this report)
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
Soil moisture conditions continue to range from fair to excessive across western Canada. Precipitation this past week ranged from trace amounts to as much as 200 mm. Areas of northwestern Manitoba and east-central and northern Saskatchewan remain wet. However dry areas continue to develop across southern Manitoba and throughout much of the Peace region in areas that missed recent rain showers. Although not critically low, rainfall will be needed soon to avoid significant blossom blast and ensure good pod formation.
For current maps of moisture conditions from PFRA for western Canada,
check the following links for precipitation from September 1 to June
25 and April 1 to June 25 respectively:
http://www.agr.gc.ca/pfra/drought/prpay06_e.htm
http://www.agr.gc.ca/pfra/drought/prpgs06_e.htm
http://www.agr.gc.ca/pfra/drought/pa_e.htm
The latest crop report from Manitoba Agriculture, Food and Rural
Initiatives is available at:
http://web2.gov.mb.ca/agriculture/mwcr/
The latest crop report from Saskatchewan Agriculture, Food & Rural Revitalization is available at:
http://www.agr.gov.sk.ca/docs/reports/crop_report/crprpt060625.pdf
Additional moisture information for Alberta is available from Alberta Environment at:
http://www3.gov.ab.ca/env/water/WS/data/precipmaps/weekly.pdf
Crop development is advancing rapidly, ranging from 4 leaves or more in
the wet areas where seeding was delayed to as much as 60% bloom in a few early fields. Crop
condition generally remains good to excellent, but continuing rains in areas
like north central and northeast Saskatchewan and northwestern Manitoba are causing stress
from excess moisture. Excess moisture results in a lack of oxygen in the
root zone that causes changes in plant colour such as yellowing or purpling, stunted growth,
or premature bolting (small and spindly canola plants that are starting to
bolt). The degree of damage will depend on several factors including crop stage, soil type
and texture and time spent under water. For further information regarding the effects of excess
moisture on canola growth, refer to the following link:
http://www.canola-council.org/excessmoisture.aspx.
Areas with excess moisture may also experience substantial nitrogen losses in low-lying areas. If the excess water recedes fairly quickly and the canola recovers, growers may need to consider top dressing additional nitrogen to compensate. As well, growers who were conservative with their initial fertilizer applications for this crop and now find favorable to excellent growing conditions may also consider topping up their nitrogen and sulphur rates by top dressing. Growers concerned about the nutrient status of their crop should consider tissue testing, but for recently flooded canola it is important to remember to allow for the plant to recover and growth to stabilize before tissue testing takes place. Remember that topdressing N and S fertilizer can be successful up to the bolting stage--as long as rainfall occurs to move the fertilizer into the root zone. This helps alleviate any deficiencies and ensure optimum yields if sub-optimal fertilizer rates were applied prior to and/or at seeding, or if losses occurred due to wet or saturated soils. Also, ensure rates and field conditions are appropriate to minimize any detrimental effects to the crop, such as leaf burn. Producers who are considering top dressing to correct deficiencies should refer to the following press release for more information:
http://www.canola-council.org/growing-great/media-news/media-releases/media-jun1705.html
Wet conditions in the above mentioned areas are also still delaying herbicide applications in many fields. Second flushes of volunteer canola and other annual weeds from recent rains are also leading some growers to consider late applications of herbicide. It is important that growers consider both the size of the weed population and its stage relative to the crop to ensure that an application is required. Late applications at the bud to bolting stage are likely to cause some flower and pod abortion on the canola, especially if plants are already under environmental stress. Also, late emerging weeds will be poor competitors with canola which has already reached ground cover. To help achieve a good outcome from late herbicide applications, especially in areas affected by extreme weather (either very wet or dry conditions) ensure that the product and rate chosen are appropriate to allow good crop tolerance and adequate control of target weeds. In addition, growers who may be pressed for time due to spraying delays should not forget proper handling techniques including proper sprayer cleanout protocols when changing chemicals as well as wearing proper protective clothing.
For more information on current product recommendations, check the following links
from the provincial governments for their respective Crop Protection Guides:
http://www.gov.mb.ca/agriculture/crops/cropproduction/gaa01d01.html
http://www.agr.gov.sk.ca/DOCS/crops/cropguide00.asp
http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex32?opendocument
There are some reports of blossom blasting (flower or pod abortion) in fields in the drier areas of the prairies, most notably the Peace River region. The most likely cause in these areas is probably drought and/or heat stress. While blossom blasting is normally associated with hot and dry weather, other stresses can also contribute to an increase in the number of aborted pods. For example, in soils at or near saturation warm weather will increase the plants’ requirement for oxygen, causing increased stress and more pronounced symptoms. Other contributing factors could include heavy rain, hail or wind storms which cause flowers to drop prematurely. Insect feeding on buds, flowers and young pods can also cause blasting (buds turn white and fail to develop), flowers to fall without forming pods, or pods to drop without maturing. It is important to note that canola does have the potential to compensate right up to the end of flowering by increasing the number of branches, flowers and pods produced, provided conditions allow it to. For a detailed discussion of how canola flowers, and its ability to compensate following a period of stress, check the following link:
http://www.canola-council.org/gs_stage6.aspx
Hail was reported in parts of northwestern and southwestern Manitoba. Potential canola yield losses will depend on stage of crop and the severity of the damage. Hail damage can also allow points of entry for diseases such as sclerotinia stem rot, alternaria black spot and blackleg to infect canola plants. Further information is available at the following link:
http://www.canola-council.org/stress_hail.aspx
Remember to keep scouting fields on a regular basis to detect pest problems early. Consider establishing a scouting tramline by driving an ATV in an ‘X’ or ‘W’ pattern in the field to establish pathways for crop scouting. This will allow for easier scouting once the crop is blooming.
Early seeded fields in many regions are now well into bloom, with fungicide applications underway. This is the time to scout individual fields to assess risk for sclerotinia development and potential yield loss. The high levels of soil moisture in some areas combined with warm temperatures and crops at full ground cover may create conditions that are conducive to sclerotinia. However, with lower commodity prices many producers are questioning if spraying a fungicide to control sclerotinia will be worthwhile. Producers should carefully consider all of the factors highlighted in the sclerotinia stem rot checklist before making this decision. These factors include how heavy their crop canopy currently is, the amount of moisture received in the two weeks prior to flowering and potential for future rainfall, years since last host crop, disease incidence in the past, and the presence of apothecia in neighboring fields where host crops were grown previously. Target yield, fertility program and expected value of the canola crop are also points to consider.
A new publication called the Canola Disease Identification and Sclerotinia Risk
Assessment Card is available to assist growers and crop scouts with this decision.
It includes the stem rot checklist as well as pictures to aid in accurately identifying
the apothecia of the sclerotinia fungus. A PDF version can be found at:
http://www.canola-council.org/PDF/canola_plant_disease_risk.pdf#page=1
or contact your local Canola Council agronomist. Also, for more information and tips on
late season scouting for both diseases and insects, view the latest Canola Advantage press
release at:
http://www.canola-council.org/media_jun1906.html.
If a producer’s risk assessment based on checklist results and/or petal testing suggests that spraying may be warranted but they are still unsure, splitting fungicide applications may be an option. An initial reduced fungicide application at 20 to 30% bloom will help control early onset of the disease. If conditions become drier, a second application may not be needed. However, if this approach is taken and conditions remain wet and humid, a second application will be needed to maximize the benefits of spraying the fungicide. Producers should assess these factors and consult their local agronomist or chemical representative to determine if a single or a split fungicide application is best for their particular situation.
For growers that have decided to apply a fungicide to control sclerotinia,
determining the bloom stage of the crop is important. The
optimum stage for a single fungicide application is when the maximum number
of flowers is open but little if any petal drop has taken place, usually at
or slightly above 30% bloom. Typically at this stage in B. napus
canola there is an average of about 20 flowers open on the main stem, with
some flowers open on secondary branches but little or no pod formation.
For more information on bloom stage identification check the following
link:
http://www.canola-council.org/sclerotiniachemical.aspx.
For the current list of recommended fungicides for sclerotinia control,
refer to the 2006 Guide to Crop Protection:
http://www.gov.mb.ca/agriculture/crops/cropproduction/pdf/gcp2006/cpg2006plantdisease.pdf
Root maggots have been reported
in areas of northern Alberta, mainly in volunteer canola. The eggs are small
(1 mm or 0.04" long), white and elongated, and are deposited at or near
the base of host plants, usually just beneath the soil surface. The larval
stage is a small (6 to 10 mm or 0.2 to 0.4" long), white and legless
maggot, similar in appearance to most fly maggots. This is the damaging
stage of the insect that burrows its way through canola roots causing weak
stems and allowing access for root borne diseases such as root rot. When
searching for root maggot infestations at flowering carefully pull or dig
up several plants with the taproot intact. Carefully brush or rinse off
the soil and inspect the root for maggots or for scars caused by maggot
feeding. Check several plants in five or more locations. Cut into the
root to look for maggot damage. There are no post emergent chemical controls
for root maggot infestation. Refer to the following link for more information
on root maggot:
http://www.canola-council.org/maggot.aspx
Bertha armyworm moth traps have been placed in canola fields throughout western Canada, and adult moth emergence has increased rapidly in some areas. Counts for last week exceeded 300 in areas of Saskatchewan near Prince Albert around Birch Hills and north of Regina around Govan, as well as in northwest Manitoba around Durban and Minitonas. Growers in these areas should be especially vigilant as the moth trapping continues. All growers should be aware of increasing moth numbers and watch for further information.
For more information on the bertha armyworm, refer to the following link:
http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/prm2521
For interpreting bertha armyworm trap numbers, refer to the following link:
http://www.gov.mb.ca/agriculture/news/insect/bertha/interpret.html
Proper identification of bertha armyworm larvae is important as they can be
confused with other larvae. As significant numbers of adult bertha moths have
just started to appear over the last week, it is unlikely that any larvae found
at this time will be bertha armyworm larvae. Mating will begin within a week
of moth emergence, and egg laying will take place on the underside of leaves
shortly thereafter. Some eggs have been found in Alberta already, in the
Vermillion area. With average temperatures, eggs will hatch within a week,
but will likely take several weeks to reach the last two velvety black instars
that cause most of the damage and are easiest to recognize. Typically the time
from egg hatch to pupation is six weeks. For more information regarding bertha
armyworm identification, please refer to the Canola Scouting and Sweep Net Insect
ID Card and the following links:
http://www.canola-council.org/bertha.aspx
http://www.canola-council.org/PDF/sweepcard_pgs_04.pdf#page=1
Clover cutworms are other larvae that were reported in areas of the Peace region this week. The larvae are very similar in size and color to the bertha armyworm larvae. The most distinctive way to tell them apart is that the wide stripe along each side of the clover cutworm is yellowish pink, while it is yellowish orange on bertha armyworm. Clover cutworms feed anywhere on the canola plant and can consume entire plants if populations are heavy. First generation larvae attack canola earlier than pests like bertha armyworm, but with light infestations the plants will generally recover. More research is needed to determine a definite economic threshold for clover cutworm, but many studies have shown that it may be similar to the economic threshold for bertha armyworm. However, clover cutworm infestations are often less uniformly distributed in a field than bertha armyworm. Therefore, while some areas of a field suffer heavy damage, others may be unaffected. For more information refer to the following link:
http://www.canola-council.org/clovercutwormid.aspx.
Grasshoppers continue to hatch in areas
of the BC Peace. Since there are many species of grasshoppers in western Canada,
growers need to be sure that the grasshoppers found during scouting are indeed pest
species. Refer to the following AAFRD and SAFRR links for further information on
identification and management of pest grasshoppers:
http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/for8648
http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex6463
http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex3497
http://www.agr.gov.sk.ca/DOCS/crops/integrated_pest_management/insects/grasshopperff.asp?firstPick=
Crops&secondpick=Integrated%20Pest%20Management&thirdpick=Insects
Cabbage seedpod weevil adults continue to be reported, with spraying taking place throughout southern Alberta and southwest Saskatchewan as fields come into flower. The economic threshold for the weevil is 3 to 4 per sweep, or 30 to 40 in 10 sweeps. Research conducted by Dr. Lloyd Dosdall and Doug Moisey has shown that weevil migration into canola doesn't peak until early to mid flowering, as the weevil is attracted to the yellow color of the canola flower. It is important not to spray too soon, as the weevil will continue to invade for at least a week to 10 days beyond first flower. The optimum time to spray is at early flowering, or more specifically 10% bloom, if possible. Spraying at 10% bloom will allow the weevils more time to move into the field, while preventing significant egg laying in newly forming pods.
It is important to keep in mind the plants ability to compensate for weevil feeding on buds and stems. There have been very good moisture conditions in many areas this spring, and the crops are growing vigorously with the heat we are receiving. This will allow the plant to compensate for bud feeding that may take place prior to the beginning of flower. This is also true for lygus bugs, which are another insect that should be watched for when sweeping your canola. In particular, there may be an opportunity for some migration of lygus bugs into canola from alfalfa crops now being cut for hay. However, the threshold for lygus bugs can vary greatly, depending on the crop stage and commodity prices. For more information on lygus bugs check the following links:
http://www.canola-council.org/lygusmonitoring.aspx
For more information on identification and control of cabbage seedpod weevil refer to the following AAFRD link:
http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex2538
Check the following link for the 2006 cabbage seedpod weevil forecast map: http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/prm10585
Direct questions regarding this report to John Mayko, Agronomic Research & Extension Manager 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
Rob Park, Manitoba Agriculture, Food & Rural Initiatives,
rpark@gov.mb.ca, 204-745-5665
David Vanthuyne, Agronomist, Eastern Saskatchewan,
vanthuyd@canola-council.org, 306-782-7799
David Blais, Agronomist, Western Saskatchewan,
blaisd@canola-council.org, 306-895-2122
Jim Bessel, Senior Agronomist, Northeastern 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, Central Alberta,
moiseyd@canola-council.org, 780-645-3624
Jackie Heck, Agronomist, Peace River Region,
heckj@canola-council.org, 780-853-5261
Matthew Stanford, Agronomist, Southern Alberta,
stanfordm@canola-council.org, 403-758-6660
Murray Hartman, Alberta Agriculture, Food & Rural Development, murray.hartman@gov.ab.ca, 403-782-8024
Kerry Clark, BC Ministry of Agriculture, Food & Fisheries,
Kerry.Clark@gov.bc.ca, 250-787-3213
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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