Agronomist Notes
Fungicide applications on wheat, barley, and canola were completed last Saturday. The fields we sprayed showed excellent yield potential but had signs of disease on the upper leaves. There were a number of pea fields around the Three Hills area sprayed for powdery mildew as well. I was able to see how the Stratego worked in a field of winter wheat that had stripe rust infections on the flag leaves. I was pleasantly surprised by the control and the fungicide looks to be keeping a lid on the disease.
On a positive note, out of the 7,000 acres of canola I manage, the insect pressure has been insignificant thus far. I’m finding cabbage seedpod weevils and lygus bugs well below threshold levels. The next insect to be watching for in the coming weeks will be Bertha Armyworms. They devastated a few fields in the Drumheller area last year.
The majority of canola is now 30% to 50% bloom with the late May seeded canola at 10% to 20% bloom. The majority of early seeded wheat is now flowering and the late May seeded wheat have heads emerging. The majority of barley is between flag leaf and head emergence. Crop conditions for canola, wheat and barley seeded before May 14th are rated as good to excellent and those seeded after May 15th as fair to good condition. The nicest fields in my travels are in the Three Hills and Okotoks areas, with the Drumheller north area struggling in wet heavy clay soils.
In this week’s newsletter we’ll look at canola flowering and heat stress. I’ve also provided some pictures and a description comparing physiological leaf spot to stripe rust and other wheat diseases to help you understand the differences. I wonder how much money is wasted on misdiagnosing plant diseases?
Agronomy
Herbicide Timing in Canola
Over the years I’ve noticed a few things about spraying canola at certain stages. I’ve seen canola sprayed with RoundUp Transorb at 30% bloom without any effect on yield. I’ve also seen Round Up Ready canola sprayed at late bolting and the yield was cut in half. This spring, I noticed a few fields of Liberty Link canola that had an average of 4 to 5 aborted pods on the main stems of roughly 5% of the plants. These fields were sprayed at late bolting.
Plant genetics play a large role in herbicide tolerance and whether one can safely spray at later stages of growth. It’s best to follow herbicide label recommendations to be safe.
Heads up for Bertha Armyworm
Another potential insect to emerge in the next few weeks is the bertha armyworm. I will give you a description and more information in next week’s newsletter. To start, here's a link to information on the bertha armyworm: http://www.canola-council.org/berthaidentification.aspx
Is it Stripe Rust or Physiological Leaf Spot?
Recently, physiological leaf spot (PLS) has been showing up in some winter and spring wheat fields. Some people may misdiagnose PLS as stripe rust and try to use fungicides to reduce PLS symptoms. Because PLS and stripe rust are controlled by different methods, it is important to distinguish the two. Similarly, it is important to tell PLS from other spot/blotch diseases caused by fungal pathogens.
Physiological leaf spot is a complicated disorder and is sometimes used to describe problems of which the causes are not known. However, a typical PLS is a physiological and genetic disorder that expresses spot symptoms on leaves in fields with a deficiency of chloride. Physiological leaf spot symptoms start with tiny chlorotic (mosaic) spots, which can grow up to spots of a quarter inch in diameter. The early symptoms resemble those of the early infections of rust and some other pathogens. Early spots sometimes have a halo pattern, but mature spots usually have a distinct margin. PLS spots are usually round to oval in shape, but in severe situations, spots connect to each other, appearing to be irregular.
Strategies to manage PLS include growing tolerant varieties, rotation with other crops or fallow and the application of chloride. When the crop is growing, application of chloride is the only way to reduce PLS symptoms. Fungicides, such as Tilt, Quilt, Quadris, Headline, and Stratego, which control stripe rust and other fungal diseases, do not control PLS.
As shown in Figure 1, it is easy to differentiate PLS symptoms from the typical symptoms of stripe rust (Figure 2). It is also easy to differentiate PLS from resistant reactions of wheat to stripe rust. After the stem elongation stage, stripe rust produces white necrotic stripes without or with limited rust pustules as shown in Figure 3. Wheat crops showing resistant reactions to stripe rust usually do not need to be spayed with fungicide while those showing susceptible reactions should be sprayed with a registered fungicide such as Tilt, Quadris, Headline, Folicur or Stratego when stripe rust develops to 5-10% severity. Unlike PLS, stripe rust cannot be reduced by the application of chloride.
It is more difficult to distinguish PLS from spot/blotch diseases caused by fungal pathogens. For comparison, pictures showing symptoms of fungal spot/blotch diseases are shown in Figure 4. The major difference between PLS and these fungal diseases is that PLS does not spread from field to field while the latter group of diseases spread because they produce infectious spores. These fungal spot/blotch diseases are not as common as PLS and stripe rust in the Pacific Northwest. Fungicides that control rusts usually control the fungal spot/blotch diseases.
Another fungal disease commonly found in wheat and barley fields is powdery mildew. The fungus produces fluffy, white to grayish mold. The disease is most common in fields under irrigation. Powdery mildew usually does not cause significant yield losses in the inland Pacific Northwest and, therefore, fungicide application to control powdery mildew is generally not necessary. However, the appearance of powdery mildew may be sometimes used to justify foliar sprays of fungicides when the variety is susceptible to stripe rust and stripe rust is potentially a problem. Fungicides that control stripe rust also control powdery mildew.
Source: Xianming Chen and Richard Koenig
Canola Flowering Process
Flowers begin opening early in the morning and, as the petals completely unfold, pollen is shed and dispersed by both wind and insects. Flowers remain receptive to pollen for up to three days after opening. If favourable, warm, dry weather occurs, nearly all the pollen is shed the first day the flower opens. In the evening, the flower partially closes and opens again the following morning. Fertilization occurs within 24 hours of pollination. After pollination and fertilization, the flower remains partially closed and the petals wilt and drop (two to three days after the flower opened). The young pod becomes visible in the centre of the flower a day after petals drop.
During flowering, the branches continue to grow longer as buds open into flowers and as flowers develop into pods. In this way, the first buds to open become the pods lowest on the main stem or secondary branches. Above them are the open flowers, and above them, the buds which are yet to open. All of the buds that will develop into open flowers on the main stem will likely be visible in Argentine canola within three days after the start of flowering, and within 10 days in Polish.
Full Article: http://www.canola-council.org/gs_stage6.aspx
Heat Stress in Canola
The optimum temperature range for leaf area development in canola has been estimated at 13 to 22°C (17°C mean temperature). Higher temperatures cause faster growth that results in shorter leaf area duration. Meaning less leaf area resulting in reduced yield potential. Heat injury is commonly associated with drought injury, but excessive heat will also injure or kill plants even if moisture is plentiful.
High temperatures at flowering will speed up the plant’s development, reducing the time from flowering to maturity. However, high temperatures during flowering shorten the time the flower is receptive to pollen, as well as the duration of pollen release and its viability.
High temperatures decrease total plant dry matter, the number of pods that develop, number of seeds per pod, and seed weight resulting in lower yields. Canola is more tolerant to high temperatures when pods are formed than at flowering. Cooler night temperatures in August may also help the plant recover from extreme heat or dry weather.
Source: http://www.directfocus.com/canolamanual/chapter5.html
Market News
Corn Prices in Potential Downtrend
We expect the corn market to remain in a downtrend unless weather threatens the US corn yield. December corn could have longer-term downside to $3.00. As long as the Cornbelt receives weekly precipitation, trade ideas on the US corn yield could increase toward the 155-160 bushel per acre level.
Source: FIMAT
US Wheat Harvest Sluggish
Showers continued to scatter across the southeastern US wheat belt, preventing any notable drying and keeping late harvest progress sluggish during the past 2 days. The forecast remains wet for these areas through most of the next 10 days, and this will cause further delays and possible localized lodging damage and flooding concerns.
Source: FIMAT
Poor Weather Reduces World Wheat Production
With global ending stocks at a 30-year low, there continues to be production problems in many key wheat growing areas such as Syria, Ukraine and Europe. From one extreme to another we have the Ukraine and Russia in a drought with Europe facing excessively wet weather causing lower quality grain and yields. Couple that with a poor US winter wheat harvest in some key areas and you have the potential for strong uptrend in wheat prices.
Source: SL
US HRW Wheat Growers Debate Whether To Abandon More Acres
Major wheat-producing states, including Kansas and Oklahoma, could see growers abandon hard red winter wheat fields where excessive wetness caused lodging, weed pressure and sprouting from wheat heads. Persistent rains have hit the Southern Plains for the last several weeks, delaying harvest and flooding areas of Kansas, Oklahoma and Texas.
Source: CBOT News
European Rapeseed Harvest Update
In France a rather damp harvest has started and yields are around 2% lower than expected. It is a similar pattern across Germany and Poland and you could easily cut 500-700 thousand tonnes off the previous EU-27 production estimate of 18.3mln tonnes. This reduction will leave the EU balance sheet looking quite tight and combined with the firmness in other oilseeds markets (soya & palm oil) should underpin the market.
Source: http://www.gleadell.co.uk/MarketReport.htm
USDA Supply & Demand Report – Updated this Thursday
The trade is looking ahead to Thursday’s release of the USDA July supply and demand report. The report, due out at 8:30am EST, will include updated estimates on wheat production and carryout. With global 2007-08 wheat stocks pegged at a 30 year low, people are wondering why the market continues to fall. As one analyst put it, you can only talk that news up so far and that supportive factor (30 year lowest supply) has been built into the market already. We’re going to need some fresh news to keep the market fueled.
Source: SL
Crude Oil Price Variability: Impact on Breakeven Corn Prices
Given current projections of $65 per barrel crude oil prices, ethanol production will remain profitable. This likely will lead to growth in the capacity of the ethanol industry and to additional use of corn in ethanol production. Increasing demand for corn will likely cause corn prices to remain above historical averages.
While corn prices may be higher than historical averages, there is little reason to believe that they will be less variable. Oil prices will have increasing impacts on corn prices. Historically, crude oil prices have exhibited variability. This variability may cause more corn price variability than has occurred in the past. This variability may be further exacerbated by corn production risks and low levels of stocks, which may further contribute to corn price variability.
This suggests that risk management will be of continued importance for farmers into the future. Higher corn prices will lead to higher costs on grain farms, as cash rents and land prices adjust to those higher prices. Cost adjustments could lead to the same per acre margins as before potential ethanol-induced commodity price increases. Given the same margins, farmers will still need to protect themselves against price declines.
Full Article: http://www.farmdoc.uiuc.edu/manage/newsletters/fefo07_11/fefo07_11.html
