Agronomist Notes
You may remember that I mentioned Lygus bugs should not build up to significant levels in my territory. Well, they did. In just one week. A client near Calgary reached 3 per sweep last week. The rest of my territory saw very little change in insect levels. I will begin adding another check for Bertha armyworms this week, as they tend show up late July and into August. I’ve mentioned before that Berthas can show up anytime and we need to be diligent to check fields twice a week or every three days for the next month. There was a neighboring canola field in my territory last year that was devastated because of Berthas- the field looked like a hailstorm had gone through!
Crops in general have done really well considering the monsoon rain in May and June coupled with tropical heat and humidity in July. Unfortunately, the canola has definitely lost yield potential in this heat from aborted pods. There are many canola crops in the 30 to 45 bushel yield range, but with our moisture conditions we could have had some monster yields if it had stayed cooler. The wheat and barley have come along nicely and I just wonder what affect the heat had on wheat pollination.
The stripe rust I’ve been harping about has really taken a foothold in the Rumsey area north of Drumheller. I stopped to get a few snapshots and what I found was not pretty. The heads hadn’t begun filling and there was virtually no green tissue showing on the flag leaves- stripe rust covered the entire surface. It pleased me to know that the fungicide decisions we’ve been making are paying off.
This week’s newsletter includes, estimating yield losses from cereal diseases, canola development and estimating harvest timing by growing degree-days.
Agronomy
Insect Links
Bertha Armyworms: http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex3508
Lygus Bugs: http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex741?opendocument
Diamond Back Moth: http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex2540
Cabbage Seed Pod Weevil: http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex253
Yield Loss Estimation from Crop Diseases
By now we’ve made the decision to spray or not to spray for leaf diseases in cereals. We are quickly approaching the point to which you can actually estimate whether your decisions were correct or, sadly, not.
To estimate yield loss from Net Blotch, Scald, Tan Spot or Septoria, examine crop at the milky dough stage. Assess at least 25 main stems two diagonals from one corner to the opposite corner of the field. Then assess the average percentage of the top two leaves affected. The calculation for percent yield loss is 0.66 x % area of flag leaf infected + ½ x % area of second leaf infected ÷ 2
For example:
You find disease present in wheat on 10% of the flag leaf and 20% on the leaf below.
Percent Yield loss = 0.66 x 10 + ½ x 20 ÷ 2 = 6.66% + 5% = 11.66%
Therefore, your calculated yield loss is 11.66%. At $5.40/bu wheat and a yield potential of 50 bu/ac, you have lost 5.8 bu/ac (50 x 11.66%). That loss translates to $31.32/ac (5.8 bu/ac x $5.40/bu).
The cost of a fungicide is roughly $6.20/ac plus $7.00/ac for application for a total of $13.20/ac. So, the return on your fungicide investment is $31.32/ac - $13.20/ac = $18.12/ac. I realize that spending another $10,000 on fungicide doesn’t excite anyone. However, who can afford not to protect their investment?
Summary of Yield Loss by Diseases
| Disease | Loss |
| Tan Spot | Red smudges on kernels cause loss in quality and downgrading to feed. |
| Stripe Rust | Yield losses up to 50% can occur with shriveled stained kernels. |
| Sclerotinia | Yield losses up to 20% can occur in canola. |
| Septoria Glume | Yield losses of 20% to 30% have been recorded. |
| Scald and Net | In cold wet seasons losses of up to 50% or more are possible. |
Predicting Harvest Dates Using Growing Degree Days
Here we are in the last week of July and wonder- how long until harvest? Predicting harvest dates by the calendar is impossible when you seed in June. Calculating growing degree-days provides you with a more accurate measure for harvest timing.
All plant functions, such as evapotranspiration, photosynthesis, water and nutrient absorption and transport, enzyme activity, and other biological and chemical activities are regulated by temperature. For this reason, the development of the crop is more closely related to the amount of heat the crop is exposed to than calendar days. Other factors such as moisture, light (day length), nutrition and variety also play a role, but they generally have less influence.
Canola requires 1,432 to 1,557 growing degree-days (GDD’s) to reach an optimum swathing stage of 40% seed colour change. Hard red spring wheat is similar to canola and requires 1,538 to 1,665 GDD’s to reach maturity. Barley needs 1,269 to 1,522 GDD’s. Surprisingly, peas need 1,527 to 1,686 GDD’s to reach 90% seed colour change.
Let’s do the math for wheat, barley and canola seeded near Three Hills, AB on May 15. The climate data provided on farmzone.com shows we’ve received 827 GDD’s since May 15. Now take an average of the last 30 days to predict the next 30 to 40 days of weather. The end of June was cooler and July was hot, so I will assume that August remains hot and cools off toward September. The GDD’s for the last 30 days averaged 26 GDD’s per day.
Let’s finish the math:
Canola: 1,432 - 827 ÷ 26 = 23 days until swathing or August 15
Wheat: 1,538 - 827 ÷ 26 = 27 days until maturity or August 19
Barley: 1,269 - 827 ÷ 26 = 17 days until maturity or August 9
So there you have it. I would encourage you to keep track of growing degree-days to help you estimate swath and harvest timing this fall.
Farmzone: http://www.farmzone.com/ Find your area and click on “Historical” data.
Alberta growing degree-days: http://www2.agric.gov.ab.ca/app10/acis/mapviewer/viewer.htm
Source: http://www.montana.edu/wwwpb/pubs/mt200103.pdf
Canola Development From the Onset of Flowering
To provide a refresher and help you understand canola development a little better, I’ve put together a list of how canola develops from the onset of flowering.
- Flowering stage begins when the main stem has reaches 30-60% of its maximum length.
- 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.
- Flowers begin opening on secondary branches 2 to 3 days after the main stem.
- Flowers are ready for pollination (by wind and insects) up to 3 days after opening.
- Fertilization occurs within 24 hours after pollination upon which flowers will close and petals will drop.
- Young pods are visible one day after petals drop.
- Leaves begin to drop off (senesce) from the bottom upward.
- Canola seeds begin to develop once the petals drop from the last flower on the main stem.
- The seed coat expands until the seed is almost full size within the first few weeks of seed development.
- Seed fill is complete 35 to 45 days after flower opening.
- 11. Seeds in the lower pods are ripe 40 to 60 days after the first flower.
Market News
Competing US Oilseed Output Declines
Acreage of competing oilseeds other than canola has fallen this year in the US. The acreage planted to peanuts in 2007 declined to an estimated 1.2 million acres, the lowest planted peanut acres since 1915. Acreage planted to cotton dropped to an 18-year low of 11.1 million acres, an additional 1.1 million acres down against intentions last spring. Domestic sunflower acreage slipped 4% this year to 1.86 million acres. Flax acreage sown this year is down 43% to 465,000 acres and U.S. safflower acreage declined 10% to 170,000 acres.
Source: USDA
2007-08 Soybean Ending Stocks Decline
The expected tightening of soybean stocks in the United States, Brazil, and Argentina brings the projection of 2007/08 global ending stocks down to a 3-year low of 51.9 million tons. This would represent a 19% reduction from the current year’s expected record. However, soybean oil stocks could continue to tighten in 2007/08, with demand likely to outpace production. This is nothing but good news for canola growers.
Chinese Rapeseed Production Declines
For China, 2007 rapeseed production was estimated 400,000 tons lower this month to 11.6 million. Harvested area declined more than previously believed to 6 million hectares (from 6.95 million in 2006), as grain and other crops had higher expected returns. The revision further limits the amount of vegetable oils that can be produced in China and will encourage imports.
Source: USDA
US Barley Prices Soften
Barley markets took a downward slip during the past two weeks with the start of barley harvest a couple weeks’ away, reports of good crops across the region and skidding corn prices. Feed barley prices were impacted more than the malting quotes. In addition, USDA has issued three reports in the past two weeks that will have some influence on barley prices down the road.
Full story: http://www.farmandranchguide.com/articles/2007/07/20/ag_news/markets/mark05.txt
Feed Grain Prices Projected to Increase
Reacting to higher prices than in the previous year, farmers increased plantings of most feed grains, except oats, in 2007/08, boosting forecast supplies. Continuing strong demand for ethanol and food uses plus strong expected exports and only slightly reduced feed and residual use has strengthened total use. Even with increased ending stocks, prices for corn, barley, and oats are expected to be stronger in 2007/08 than in 2006/07.
Source: USDA
Coarse Grain Production Declines in EU
Coarse grains production forecast for the EU declined 0.6 million tons this month to 144.8 million with changes to several countries and crops partly offsetting. Reduced prospects in Romania (too dry), Germany (too wet), and Poland more than offset improving prospects in Spain and other countries. The largest foreign change was a drop of 3.9 million tons in coarse grains production in the former Soviet Union, to 55.2 million tons. Another decline in coarse grains production prospects was for Canada, with lower corn area reported than earlier anticipated.
Source: USDA
Oilseed Rape Area Up 16% in the UK
The area of oilseed rape in the ground this harvest is significantly higher than last year, according to the first comprehensive plantings estimates for Great Britain. The HGCA Planting Survey showed that oilseed rape sown on non set-aside land increased 16% from 2006-07.
Source: fwl.co.uk
Torrential Rains Threaten UK Harvest – July 20, 2007
Torrential rain has swept across much of the southern half of the UK today, with flash flooding being reported in some areas.
Source: http://www.fwi.co.uk/Articles/2007/07/20/105327/torrential-rain-threatens-uk-harvest.html
Hesitant Start to UK Harvest – Yields Below Average
Farmers in the UK and France are experiencing poor weather resulting in a slow start to winter barley and oilseed rape harvest. There were reports of heavy rains earlier, which caused severe lodging in winter barley crops. Concerns of chitted barley and oilseed rape is growing if the damp weather continues.
Source: http://www.fwi.co.uk/Articles/Article.aspx?liArticleID=105287&PrinterFriendly=true
