Soil moisture
conditions on the prairies continued
to deteriorate during the past week.
Light, scattered showers occurred
in some areas with only significant
amounts reported in north central
Saskatchewan. A severe hail and
windstorm severely damaged crops
in the eastern part of the Peace
River region. Some areas that continued
to receive rain in July still have
adequate soil moisture for the continuation
of crop development.
For current PFRA maps of moisture
conditions, check these Web pages:
http://www.agr.gc.ca/pfra/drought/drprec4_e.htm
http://www.agr.gc.ca/pfra/drought/drprecw_e.htm
http://www.agr.gc.ca/pfra/drought/prgrowing_e.htm
Additional moisture
information for Alberta is available
from Alberta Environment at:
http://www3.gov.ab.ca/env/water/WS/data/precipmaps/weekly.pdf
The latest crop
report from Saskatchewan Agriculture,
Food & Rural Revitalization
is available at:
http://www.agr.gov.sk.ca/docs/reports/crop_report/crprpt030622.asp
?firstPick=Reports&secondPick=Crop%20Report
Crop development in most areas has advanced significantly due to the heat and dry conditions. Swathing continues in southwestern and eastern Manitoba, southwestern Saskatchewan and southern Alberta. Swathing has started on early seeded crops in other regions with the majority of the crop out of flower and in the pod filling stage. The hot, dry weather continues to cause concern in most regions. These hot, dry conditions may not allow pods to properly fill and may cause small seed size and reduced seed yield.
Swathing
is expected to start within the
next one to two weeks for most regions
with the exception of later seeded
fields in the Peace region, which
are a couple of weeks behind. The
recommended time to swath for optimum
seed yield and quality is when the
average seed moisture content is
30-40%, or the whole plant has reached
about 35% seed colour change (SCC).
Proper assessment of a field requires
assessing maturity in several areas
within a field. In areas with lower
plant populations, the plants will
typically have more branches. When
assessing these plants, it is possible
to see 35% SCC on the main stem
while pods on the side branches
still contain translucent seed.
It is in these cases where waiting
a few extra days can allow those
seeds to mature in the side pods,
reducing the chances of green seed
and yield losses. While waiting
for the seed in the side pods to
mature, SCC on the main stem may
rise as high as 50%.
To learn more about proper field
assessment please refer to the Canola
Council publication "Time of
Swathing Guide" or visit
our Web site.
In cool moist conditions B. napus canola can take up to 22 days to go from 10% to 35% SCC on the main stem. Under dry, hot conditions, SCC can be rapid, changing from 10% to 35% SCC over a few days.
Typical recommendations have been to begin swathing when the plant has reached approximately 20% SCC with the majority of the crop being swathed at or near optimum seed colour change (30-40% SCC). However, under the current hot and dry conditions, swathing at 20% SCC may affect yield and quality. Swathing in hot (high 20’s to 30°C temperatures), dry and windy conditions may stop chlorophyll clearing due to rapid desiccation of swaths. This may result in some green seed problems since the enzyme responsible for clearing the chlorophyll requires moisture. This smaller, less mature seed can also shrivel up, which can result in throw-over during combining and lost yield. Delaying swathing to ensure that the bulk of the crop is at least 30% SCC may help reduce potential yield and quality losses in these situations.
Swathing at later stages brings on the concern of shattering and pod drop. In drier conditions, typically these factors are not a big concern. However, they can occur with windy conditions (upright stems banging into each other) or swathing at an overripe stage. A slightly lodged crop is less prone to shattering. Moisture movement into and out of the pods can also cause shattering. In dry conditions, this does not occur as much. Pod drop is a result of constant exposure to moisture (dew or rain) followed by dry cycles, which breaks down the binding agent that holds the pod on the stem.
Base the decision to swath not only on field maturity but also on such factors as how many acres need to be swathed and swathing capability (i.e. size of swather, type of reel). Delaying swathing until 35% SCC occurs on the whole plant can result in the majority of the crop being swathed at 50% SCC. This can reduce the potential for green seed and yield losses from shrivelled seed, particularly under hot and dry conditions. Swath during the cool evening hours, at night, or early in the morning to allow the seed to dry down at a slower rate and further reduce the risk.
As swathing approaches, keep in mind that seed colour change is very different from pod colour change. Over the past week, many fields have experienced sun scalding or pod bleaching that may cause the crop to appear mature. Insect damage and varietal differences will also contribute to the ripening appearance of canola fields. It is important not to be fooled by the colour of the straw and/or pods. Pods that appear ripe and ready to swath may still have green and translucent seeds. Conversely, pods that do not appear ripe may contain mature seeds that have changed colour. Walking fields and examining seeds within pods is the only way to truly assess crop maturity.
Insects reported in the past week include bertha armyworm larvae in southwest Manitoba and other isolated areas with some insecticide applications reported in Manitoba. Grasshoppers continue to be a problem in many areas with spraying of canola reported in western Manitoba. Grasshopper pressure continues to be high in areas with most drought stress. Diamondback moth larvae are now being found in western Manitoba and southern Alberta, in addition to many areas of Saskatchewan, with some spraying reported. Other insects noted over the past week include flea beetles, beet webworm and lygus bugs.
It is very important to keep scouting for insects, even if the crop has finished flowering and entered the podding stage. The early podding stage is when the crop is most vulnerable to economic losses from these insects. During this stage, the crop drops its leaves, causing the insects to move from the leaves onto the pods, where they may strip the green surface tissue off the pods or devour the pods and seeds inside. Even surface stripping can result in significant yield losses by causing poor seed formation and predisposing pods to shattering. Insect feeding at this stage causes direct yield losses, since the crop is approaching maturity and has little opportunity to recover.
It is also important
to use proper techniques when scouting
for various insects. Use a sweep
net to determine thresholds
for lygus bugs and cabbage seedpod
weevil. A sweep net cannot be used
for determining thresholds for diamondback
moth, bertha armyworm, beet webworm
or alfalfa looper larvae. An estimation
of the number of these larvae within
a square metre is a more accurate
determination of thresholds for
these insects. Also, keep in mind
that more mature stages of insects
are often harder to control. This
may affect the choice and rate of
product used. As the crop approaches
maturity, it is also important to
check the pre-harvest interval of
the product chosen, and confirm
if that interval is prior to swathing
or combining by checking the label
or contacting the company. Check
some of the previous crop reports
for more information on scouting
for these insects.
For more information and images
of the moth and larvae, visit these
Web pages:
http://vc55moths.topcities.com/imagearchive/pyralid/loxostegesticticalis.htm
http://www.canola-council.org/images_insects.html
Lygus bugs, diamond
back moth and sweep net scouting:
http://www.canola-council.org/seed/canola-watch/watch-jun25.shtml
http://www.canola-council.org/PDF/sweepcard_04.pdf
http://www.canola.ab.ca/acpc/lygus.shtml
For more information
on bertha armyworms including latest
monitoring results, check the following
links:
http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/prm2525
http://www.agr.gov.sk.ca/DOCS/crops/integrated_pest_management/
insects/Berthawo.asp?
firstPick=Crops&secondpick=Integrated%20Pest%20Management&thirdpick=Insects
http://www.agr.gov.sk.ca/docs/crops/integrated_pest_management/
insects/berthamap0107.asp
?firstPick=Crops&secondpick=Integrated%20Pest%20Management&thirdpick=Insects
http://www.gov.mb.ca/agriculture/crops/insects/fad03s00.html
Anyone scouting fields planted to a canola variety rated moderately resistant (MR) or resistant (R) who finds blackleg infected plants, is asked to send the infected plants to Dr. Dilantha Fernando, Plant Pathologist, at the University of Manitoba (fernando@ms.umanitoba.ca (204) 474-6072. University researchers are studying the blackleg races present to determine whether any have been able to overcome the resistance in current varieties.
Direct overall questions regarding this report to David Blais, Agronomist – Western Saskatchewan, blaisd@canola-council.org, ph/fax: 306-895-2122.
For specific questions regarding regional issues associated with this report, please consult one of the following Canola Council of Canada regional agronomists or provincial oilseed specialists:
Derwyn Hammond, Agronomist, Manitoba,
hammondd@canola-council.org,
204-729-9011
Rob Park, Manitoba Agriculture &
Food, rpark@gov.mb.ca,
204-745-5665
David Blais, Agronomist, Western Saskatchewan,
blaisd@canola-council.org,
306-895-2122
David Vanthuyne, Agronomist, Eastern
Saskatchewan, vanthuyd@canola-council.org,
306-782-7799
Jim Bessel, Senior Agronomist, Northeastern
Saskatchewan, besselj@canola-council.org,
306-373-6771
Bill Greuel, Saskatchewan Agriculture,
Food & Rural Revitalization, wgreuel@agr.gov.sk.ca,
306-787-2756
Doug Moisey, Agronomist, Central &
Southern Alberta, moiseyd@canola-council.org,
403-553-2829
Christine Mardell, Agronomist, Peace
River Region, mardellc@canola-council.org,
780-518-1513
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@gems9.gov.bc.ca,
250-787-3213
The Canola Crop 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, Cargill, James Richardson International, 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.