Scattered showers fell over a number of locations this past week, however, with the hot temperatures soil moisture conditions are adequate to dry throughout all regions in western Canada. Areas that have received little to no moisture in the month of July include Manitoba, eastern Saskatchewan and southern Alberta.
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.
Some early seeded canola crops
in south western and eastern Manitoba
and southern Alberta are already
being swathed. Crops in most other
areas are nearing the end of flowering
and reaching early pod development.
Hot weather continues to cause
bud and flower blasting throughout
many canola growing regions of
western Canada. These hot, dry
conditions continue to cause the
premature end to flowering in
some fields. Refer to the July
8 Canola Crop Watch Report for
more information on flower blast:
http://www.canola-council.org/seed/canola-watch/watch-jul8.shtml
Swathing is expected
to start within the next 2-3 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 to 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 website.
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 to 40% SCC). However with 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 over-ripe stage. A slightly lodged crop is less prone to shattering. The other cause of shattering is from moisture movement into and out of the pods. In dry conditions, this does not occur as much. Pod drop is a result of constant exposure to moisture (dew or rain) and then dry cycles, which breaks down the binding agent that holds the pod on the stem.
Do not base the decision to swath 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 the 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.
Don't be fooled by the colour of the straw and/or pods. Seeds in the pod can be fully mature (completely black seed) and still have a green coloured pod. Conversely, pods showing a yellowing colour can still have seeds showing no colour change or completely translucent seed. Walking the fields and examining the seeds is the only way to truly assess the maturity.
Bertha armyworm larvae are emerging in southwest Manitoba with some insecticide applications reported. 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 the 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 meter 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, which 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/agdex3508
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
With swath stage approaching, growers should consider a valuable weed control tool for next year's crop - pre-harvest glyphosate . Pre-harvest glyphosate is the most consistent and effective treatment for many perennial weed problems. In early fall, perennial weeds are moving nutrients down into roots and rhizomes in preparation for winter. This period is when they are most vulnerable to herbicide translocation to the roots and better control is possible. Weed control in the year after pre-harvest glyphosate are as follows for several perennial weed species: quackgrass and toadflax -- verygood (>90%); Canada thistle, dandelion and perennial sow thistle -- good(>85 %); and field horsetail -- fair (suppression only). Not only is the control better than in-crop choices, but it is also much more economical.
If a Roundup ReadyŽ canola variety has been grown, a pre-harvest application will assist in some dry down of green weeds and offer perennial weed control, but it will not dry down the crop. Apply when the crop has 30% or less moisture content. At this stage, the pods are green to yellow and most seeds have turned from green to yellow or brown. Wait three full days (72 hours) after application before swathing to allow thorough translocation for extended long-term weed control.
Do not use pre-harvest glyphosate on canola seed crops.
One of the most valuable tools a grower can use is proper record keeping. Since swathing is quickly approaching in most regions, it's an opportune time to add valuable information to the farm records that may influence some decision making in the upcoming season. While assessing seed colour change, be on the lookout for weeds, insects and disease incidence. Current weed identification can help weed control next spring. This is also a critical time for insect pressure and may give an indication of future pressures. For example, high flea beetle numbers this fall may indicate similar pressures in the spring. As a result, seed treatments with extended flea beetle control may have to be considered. Scouting for disease incidence is also very important during this time. As the crop approaches swathing, assess sclerotinia levels. This may be valuable information for next year's crop when assessing sclerotinia risk if it is cool and damp during the bloom stage.
Anyone scouting fields that were planted to a canola variety rated moderately resistant (MR) or resistant (R) and finds blackleg infected plants, is asked to send these 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 present with current varieties.
Direct overall questions regarding this report to Christine Mardell, Agronomist - Peace River Region, mardellc@canola-council.org, ph: 780-518-1513 or fax: 780-402-3937
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