July 3, 2012

Agronomists Notes

Hello Reader,

Timely rains and warm temperatures have made for another excellent week. It’s a greenhouse out there and crop potential is huge in some areas. Humid conditions have pushed disease pressures sooner in tight cereal rotations and peas are even showing signs of early disease presence. Fungicide season is here.

I’m seeing a great deal of tan spot and septoria show up in volunteer wheat, which usually indicates disease pressure will be high. There is a lot of talk about stripe rust but I’ve yet to see any.

In this issue of Beyond Agronomy News, we’ll look at where we are for heat units and rainfall to estimate yield potential. We’ll also look at canola fungicide efficacy, canola insect thresholds, bloom staging in canola and tips for insect spraying. We’ll finish with technical grain market news.

Interested in checking out the latest on our farm? We’re hosting a field day Wednesday, July 4th, to look at fields and equipment. Please come out and join us for a chat and a few bevy’s afterward.

Have a great week.

Pictured above: Metcalf barley in a high yield trial near Strathmore, AB.

Crop Staging

(Calgary to Drumheller to Three Hills)

Seeded    Apr 24-30               May 1-7                  May 8-15
Wheat      heads emerging     flag leaf                   flags emerging
Canola     20% bloom             5% bloom                bolting
Barley      heads emerged      heads emerging      flag leaf
Peas        5% bloom               1% bloom th node   12th node

Steve's tips and tricks for the week

Follow me on Twitter for in-season updates @BeyondAgronomy

Look for patchy head emergence to pin point air drill issues or residue issues.
The conditions for disease (host-pathogen-environment) have all lined up and disease risk is high.
Stripe rust reports have been more frequent in our area. Try to allow all flag leaves to emerge before you spray fungicide if possible.
Start sweeping early flowering canola for cabbage seedpod weevils.
Continue timing flag leaf emergence in wheat and barley to properly time fungicides.
Look for late flushing weeds in cereal crops and peas.

CTF tour Wednesday, July 4th at 1pm

We are hosting a field day with CTF Alberta this Wednesday from 1pm - 4pm at our farm NW of Morrin, AB. Please join us!

When: 1:00 PM to 4:00 PM, Wednesday, July 4th, 2012
Where: One mile west of Morrin, AB on HWY 27 and 1.5 miles north on RR 20-4 (N 51 40.234 and W 112 47.543) Google map
What:
• Third-year in observations
• Equipment modifications: air distribution on drill, liquid injection kit, GreenSeeker
• Soil, soil compaction: soil pit
• Roots, root growth
• Inter-row seeding
• Yield data row by row across drill
• Controlled Traffic Farming Alberta project update.

There is no charge for the event. Refreshments will be provided.

Three Soil & Water CEUs pending.
Check the CTFA web site for additional tours July 9 at Dapp and July 11 at Lacombe.

Where do we sit for crop maturity?

Crop maturity is directly affected by the number of growing degree days received each year. Growing degree days is simply the calculation of the highest daily temperature plus the lowest daily temperature divided by two and subtracting five (as it is assumed that plant growth does not occur at less than five degrees Celsius). Example: 20oC + 10oC ÷ 2 - 5 = 10 GGD

Historical growing degree days and precipitation from May 1st to July 3rd:
2012: 549 + 8.0 inches rain
2011: 543 + 4.6 inches rain
2010: 495 + 6.0 inches rain
2009: 551 + 2.9 inches rain
2008: 602 + 6.3 inches rain
2007: 628 + 7.5 inches rain
2006: 717 + 4.3 inches rain
2005: 589 + 4.0 inches rain
2004: 537 + 2.8 inches rain

9-year average: 579 GDD's and 5.15 inches of rain.

To date we're 5% below the nine-year average for growing degree days and have received 155% of the nine-year average for rainfall. Barley requires 1,300 GDD's to mature, hard red spring wheat requires 1,600 GDD's and canola requires 1,500 GDD's. If the average GDD for the rest of the season is 11.5 (23oC + 10oC ÷ 2 - 5), then we should expect harvest to start within 70 days. We have huge yield potential on our hands but it’ll take steady temperatures in the mid 20's to speed maturity up. SL

Maximizing fungicide efficacy in canola

Spray when the maximum numbers of flowers are open, but prior to significant pod formation and petal drop. Decaying petals provide the initial food source for spores, and carry those spores down into the crop canopy.
Use higher water volumes and appropriate nozzles like to ensure good spray coverage. This is especially important in crops with very dense canopies.
Don't overestimate bloom stage in stands with uneven maturity, as a significant number of plants hidden in the canopy may not have completed bolting. If more mature plants are starting to drop petals, take into consideration the weather conditions.
If conditions have been drier and less conducive to infection, it may be all right to delay a single fungicide application to target an average of 30% bloom. However, if conditions have been wet and odds of significant infection are high, it will be those early infections from the initial petal drop that are likely to do the most damage. Spraying a little early is probably wise.
Consider split applications, especially in fields with uneven maturity, which will lengthen out the bloom period substantially. For most products registered for split application it is recommended to make the initial application at about 20% bloom, followed by the second application at around 50% bloom if conditions are still conducive to sclerotinia infection.

Registered fungicides for control of sclerotinia
Astound: 314g per acre
Lance: 142g per acre
Proline: 127ml per acre
Quadris: 404ml per acre
Rovral: 850ml per acre
Vertisan: 500ml per acre

Source: Canola Council of Canada

Canola insect thresholds

Beet Webworm: 2 per ft2
Bertha Armyworm: 2 per ft2
Cabbage Seedpod Weevil: 2 per sweep
Diamondback Moth: early flower: 1.5 per plant
Diamondback Moth: mid to late flowering: 2 to 3 per plant
Lygus Bugs: 1.5 to 2 per sweep

For more information on identification and control of canola insect pests see the Canola Council of Canada.

Bloom staging in canola

To help you time your fungicide application properly, here is a simple guide to stage flowering in canola.

Count the open flowers on the main stem including the aborted flowers and newly formed pods.
It generally takes 2 to 4 days for the main stem to move from first flower to 10% bloom.
10% bloom has 10 open flowers on the main stem.
20% bloom has 14 to 16 flowers on the main stem.
30% bloom has 20 flowers on the main stem. Six to eight days after the start of flowering.
50% bloom has more than 20 flowers on the main stem.
Flowers open from the bottom to top on the main stem at a rate of 3 to 5 flowers per day for 14 to 21 days.
Bloom stage can progress at a rate of 3 to 5 % per day. Faster under warm conditions.

Photo source: S. Larocque

Steve's tips for insect scouting and spraying on canola

Do not spray for cabbage seedpod weevils past 30% bloom. Why? Because the damage has already been done. Spraying should have happened before 30% bloom which is the time weevils deposit their eggs inside the developing pods. Damage occurs in August when weevil larvae eat seeds then leave exit holes that cause premature shattering.
When spraying for lygus bugs remember the economic threshold of 1 to 2 lygus per sweep begins at the end of flowering and not before.
Sweep inside the field and away from the headlands. Insect counts are always highest along the headlands where insects like lygus and weevils land first. I check one spot on the headland to see what insects have entered the field and then walk in to do my sweeps.
You cannot count Diamondback Moth, Bertha Armyworm or Beet Webworms thresholds using a sweep net. Count these insects by the square metre or square foot and multiply by 10. SL