Canola Watch
2006 Canola Watch Reports
Canola Watch Report No. 12
Western Canada – July 12, 2006
In this issue:
(click the bookmark 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
Crop development continues to advance rapidly due to above normal
temperatures across most regions. Development ranges from the bolting-early bloom
stage for late seeded fields up to podding stage for early seeded fields, and
continues to be a function of seeding date in most areas. Soil moisture in most
areas continues to decline with the hot temperatures and lack of general rain.
Only spotty thundershowers were received in most areas this past week. Rainfall
amounts varied between trace amounts to up to 50 mm in isolated thundershowers.
Areas of east-central and northern Saskatchewan remain adequate with moisture,
but conditions in central and eastern Manitoba, south west Saskatchewan and the
southern Peace region are continuing to deteriorate. Many areas are becoming quite
dry, and are in need of a general rain and more moderate temperatures to avoid
serious yield declines.
For current maps of moisture conditions from PFRA for western Canada, check the following
links for precipitation from September 1 to July 10 and April 1 to July 10 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/crprpt060709.pdf
Additional moisture information for Alberta is available from Alberta Environment at:
http://www3.gov.ab.ca/env/water/WS/data/precipmaps/weekly.pdf
Reports of heat stress (plants wilting and sometimes
taking on a bluish grey hue), blossom blasting (flower or pod abortion)
and shortened bloom period continue to be reported across western Canada.
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 more information on heat stress check the following link:
http://www.canola-council.org/temp_frost_hail.aspx
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.
Although most of the heat stress symptoms described above are likely due to the warm
temperatures, it is important to scout the affected areas to see if there may
be some other underlying contributing factors such as root damage from root
maggots or clubroot.
Hail damage from isolated scattered thundershowers
was reported in several areas including Battleford, Cut Knife, Langham and Wakaw,
SK and Didsbury, AB. 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 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 and podding.
Although the recent heat and drier weather have
continued to reduce the sclerotinia risk in many areas, growers
need to evaluate each field for its relative risk. Temperatures above 25 degrees
Celsius impair disease development. Producers should carefully consider all factors
including 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. Ensure that apothecia (mushrooms) that are found are properly identified as there can be
other mushroom fungi present that do not contribute to sclerotinia risk. A new publication
called the Canola Disease Identification and Sclerotinia Risk Assessment Card
is available to assist growers and crop scouts with these decisions. 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/about-us/media-news/media-releases/media-jun1906.html.
Severe root maggot infestations have been reported in central Alberta from
Edmonton east to Vegreville and Vermilion and south to Lacombe and Red Deer. Root
maggot populations are strongly affected by soil moisture conditions, and their numbers
were decimated by the drought across western Canada in 2002. Numbers have been
steadily building from 2003 to 2005, but the timely May and June rains experienced in
central Alberta in 2006 have caused their infestation levels to increase dramatically.
In heavy infestations, there can be more than 10 larvae per plant, and this density can
cause yield losses especially when moisture is limiting and plants can't compensate.
In Vegreville, Vermilion and Edmonton there have been many fields with close to 100% of
plants infested, and several killed plants in those fields, with as many as 18-20 larvae
per plant.
Any areas experiencing poor crop growth or poor rooting should be inspected for possible
root maggot damage. Refer to the following link for more information on root maggot:
http://www.canola-council.org/maggot.aspx. To determine whether
root maggots are a problem in a particular field, canola plants that are wilted and dying
should be dug out and their tap roots examined for white, legless larvae that are feeding
on the roots. Larvae go through three growth stages, and populations are currently
in their second and third larval stages. By the time of pod set, the larval feeding
period will be over.
There is no appropriate control strategy that can be implemented at this time of the
season. However, growers should keep in mind for future years that damage can be
reduced by maintaining recommended seeding rates, or rates slightly higher than those
recommended. Increasing soil fertility and seeding early in spring gives plants
a better ability to compensate for root maggot damage than crops that are grown with
low fertility levels or that are seeded late.
Bertha armyworm moth numbers continue
to increase in traps placed in canola fields throughout western Canada.
Cumulative counts for last week exceeded 1000 in areas of northwest Manitoba in the
rural municipality of Swan River, Saskatchewan near Lemberg, Govan, Biggar and Birch
Hills, and Alberta near Milo and Vulcan. As well increasing numbers were noted in
southwestern Manitoba and eastern Alberta near Vermilion and Wainwright, extending
eastward toward North Battleford, SK. In addition, emerging larvae were noted (up to
5 per leaf) near Durban, MB. Growers in all traditional canola growing areas
should be on the alert for this pest and watch for further information.
For more information on the bertha armyworm, refer to the following link:
http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/prm2521
For interpreting bertha armyworm trap numbers, refer to the following link:
http://www.gov.mb.ca/agriculture/news/insect/bertha/interpret.html
Refer to the following links for the current bertha armyworm count maps:
http://www.agr.gov.sk.ca/docs/crops/integrated_pest_management/insects/Berthamap20060705.pdf (SK)
http://ncrxeis4.agr.gc.ca/ppmnMaps/20060709_bertha_armyworm_ab.pdf (AB-BC Peace)
http://ncrxeis4.agr.gc.ca/ppmnMaps/20060709_bertha_armyworm_mb.pdf (MB)
http://ncrxeis4.agr.gc.ca/ppmnMaps/20060709_bertha_armyworm_pr.pdf (Overall Prairies)
Proper identification of bertha armyworm larvae is important as they
can be confused with other larvae. For more information regarding bertha armyworm
identification, please refer to the Canola Scouting and Sweep Net Insect ID Card and
the following links:
http://www.canola-council.org/bertha.aspx
http://www.canola-council.org/PDF/sweepcard_pgs_04.pdf#page=1
Cabbage seedpod weevil adult numbers continue to decline throughout
southern Alberta and southwest Saskatchewan as the crop completes flowering. For more information
on identification and control of cabbage seedpod weevil refer to the following AAFRD link:
http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex2538
Some spraying for lygus bugs continued in the central area of
the Peace region near Fairview. 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 Ensure
that appropriate thresholds are reached before considering insecticide application.
At this time of the year, growers are beginning to prepare their bins for
storage of the upcoming harvest. It is important to note that malathion and other similar
insecticides should not be used to treat grain bins for insects prior to storing canola.
Although this practice is common for cereal crops, oilseed crops like canola can absorb
the malathion from the bin surfaces and the resulting residues have been found in crop delivered
to elevators. Therefore, DO NOT use malathion to treat bins destined to store canola
in the upcoming harvest. Refer to the following link for further information:
http://www.canola-council.org/pesticide_link2.html
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
Arvel Lawson, Manitoba Agriculture, Food & Rural Initiatives,
alawson@gov.mb.ca, 204-745-0340
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, 780-835-5261
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 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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