Agronomist Notes

The last week was packed with in-crop weed scouting, post-herbicide scouting, disease checks and insect monitoring. The air is extremely humid and ripe for disease development, and thankfully, excellent weed control. I’ve had a few phone calls about severe stripe rust in winter wheat, which tells me it’s only a matter of time for the susceptible CPS and HRS wheat varieties to get hit. In the last few years, stripe rust has come late in the season and done very little damage. However, producers in the Rumsey, Alberta, area saw some of their CPS yields slashed in half in 2006. Bottom line: don’t let up on your disease scouting this year. Remember the “disease triangle”: host – pathogen – environment and check all three aspects when you’re scouting. 

The wheat seeded the first two weeks of May is in full flag and the late May wheat is at 6 leaf, 2 tiller with the flag leaf to emerge this week. The barley seeded in early May is in full head and the late May seeded barley is between 5 leaf, 3 tiller and 6 leaf, 3 tiller with flag leaves about to emerge. The late seeded wheat, barley and canola are struggling due to excessive moisture; for example, 13 inches in Three Hills since May 1. Overall, my clients seeded 94% of their land base and will harvest roughly 90% of that- barring any more sever weather events.

This week’s newsletter is full of insect and disease information to help you during these warm and humid conditions. The forecast is for hot weather next week, which is favourable for insects and diseases. In this issue we’ll cover cabbage seedpod weevils, diamond back moths and stripe rust in wheat.

Agronomy

Cabbage Seedpod Weevil

The early seeded canola is now anywhere from bolting to early bloom so this is the time to begin scouting for cabbage seedpod weevils. The adult weevils are an ashy, charcoal gray colour approximately 3 mm long with a pronounced snout. The adults feed on buds, flowers, stems and pods. The adult weevils lay their eggs inside developing pods where the eggs hatch and larvae begin to feed on the seeds. Each larva can consume up to 5 seeds during its development, which can equate to a 15-20 % yield loss.

The threshold for cabbage seedpod weevil is 3 to 4 weevils per sweep. The proper technique to sweep for weevils is to do ten 180-degree sweeps in ten locations. Be sure to move away from the headlands and pick areas that are representative of the field. â–  SL

For identification, monitoring and control:
Link: http://www1.agric.gov.ab.ca/$Department/deptdocs.nsf/all/agdex2538

Diamond Back Moths

Spraying at early crop stages is unlikely to be necessary unless the larval populations and feeding damage are noticeably heavy and the crop is under stress and is having difficulty outgrowing the damage. In early crop stages, John Gavloski from MAFRI has proposed an action threshold of 25-33% defoliation with continued larval feeding. However, in later vegetative stages prior to budding, it is likely that the action threshold can be higher, due to the fact that vegetative growth is rapid at this stage, and in most cases, the crop will likely outgrow any appreciable damage.
If larval feeding continues into the bud stage, with damage to early buds, then spraying is more likely warranted. If there are about 100 to 150 larvae per square metre feeding on buds, an insecticide application may be needed to minimize yield loss.
Source: Canola Council of Canada

For identification, monitoring and control
Link:  http://www.agr.gov.sk.ca/docs/production/Diamond.asp 

Bertha Armyworm

The Bertha Armyworm flight period generally runs for eight weeks from the beginning of June through to the end of July, with peak emergence usually observed about mid-July. The larvae can cause significant damage to canola in late July and August. Crop losses can be minimized with insecticides if infestations are detected early. Forecast map will be released soon.
Source: Saskatchewan Agriculture & Food

Sclerotinia Scouting- Now is the Time

With fields entering the beginning stages of flowering, it is time to scout fields to assess the risk for sclerotinia development and potential yield loss. The high levels of soil moisture in many areas combined with warm temperatures and crops at full ground cover, creates conditions that are conducive to sclerotinia development.

Sclerotinia Stem Rot Management:

Timing of fungicide application is critical. Scout for conditions conducive for disease during the early flowering stage and apply a foliar fungicide between 20-50% bloom, with optimum timing at 30% bloom. Once sclerotinia symptoms are present in a crop, foliar fungicides will not be effective. Some fungicides are registered for split applications, providing longer protection during periods of extended bloom under cool wet conditions.
Source: Saskatchewan Agriculture & Food

The following is list covers the questions to ask before making a decision to spray a fungicide.

These factors include:

1. How heavy is the crop canopy?
2. Has there been excessive moisture prior to flowering?
3. Do they predict rain in the near future?
4. Have your canola rotations been less than 4 years apart?
5. Was there disease incidence in the past?
6. Are there apothecia in neighboring fields where canola was grown last year?
7. Also consider, target yield, fertility program and expected value of canola.

The link below is a PDF version of the “Canola Disease Identification and Sclerotinia Risk Assessment Card” and can assist growers and crop scouts with spraying decisions.
Link: http://www.canola-council.org/PDF/canola_plant_disease_risk.pdf#page=1

Bloom Stage Identification

For growers that have decided to apply a fungicide to control sclerotinia, determining the bloom stage of the crop is important. The optimum stage for a single fungicide application is when the maximum number of flowers is open but little if any petal drop has taken place, usually at or slightly above 30% bloom. Typically at this stage in Argentine canola there is an average of about 20 flowers open on the main stem, with some flowers open on secondary branches but little or no pod formation.

Source: Canola Council of Canada

For more information on bloom stage identification check the following link: http://www.canola-council.org/sclerotiniachemical.aspx.

Diseases In Wheat

The hot and humid weather has brought on diseases like tan spot and stripe rust. I’ve noticed stripe rust the last few years on our HRS and CPS wheat but it has come in so late in the growing season, it was no longer economical to spray for the disease. This year is shaping up to be different with our combination of late seeded crops and early arrival of stripe rust.  

There are producers around the Acme and north Drumheller area with stripe rust already, and they are spraying fungicides in winter wheat and hard red spring wheat. I suggest you continue to monitor your wheat crops through flag leaf and beyond to be sure this terrible disease doesn’t catch you by surprise.

Stripe Rust

Stripe rust is a disease of cereals caused by the fungus Puccinia striiformis. This disease can result in yield losses of 10-70% in susceptible varieties and a total yield loss has been reported when severe epidemics occur. Like other leaf and stem diseases, yield losses are roughly proportional to the plant area infected. Yield losses are generally most severe when the infection occurs prior to heading. Historically stripe rust has not been of economic significance in western Canada but incidences of the disease have been increasing over the past 3 or 4 growing seasons.

If you are growing a susceptible variety, it is important to scout every few days starting with the bottom leaves. Know the visual symptoms of stripe rust and monitor fields in the morning when new spores are distinctly yellow. Stripe rust can be identified as small orange yellow colored pustules forming in vertical lines along wheat leaves.

Stripe Rust Ratings

HRSW: http://www.agric.gov.ab.ca/app95/loadCrop?action=display&id=58
CPS: http://www.agric.gov.ab.ca/app95/loadCrop?action=display&id=56
HRWW: http://www.agric.gov.ab.ca/app95/loadCrop?action=display&id=59

Spraying should be done before stripe rust reaches 5% of leaf area on the flag leaf. Once this infection level is reached, stripe rust becomes very difficult to control. The period of infection to release of spores is as little as 8 days, which can result in multiple generations per growing season.

Source: Alberta Agriculture

Link: http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/faq11389

Market News

Tighter Global Wheat Stocks

The International Grain Council (IGC) has tightened their global wheat stocks estimate by 4 MMT from last month to 111 MMT. Total world grain stocks was lowered 4 MMT to 236 MMT, compared to 255 MMT last month, which is mainly because of the severe drought that Ukraine and parts of Russia have suffered over the summer. They also cut their forecast for the EU wheat crop from 131 to 129.6 million tons, due to the reduction in projections for Hungary’s and Romania’s output.

Source: AgWeb.com, FIMAT

NE China Drought Affects More Than Half Of Crop

A drought in northeast China has affected the growth of more than half of the agricultural products planted in the major corn and soybean growing area. About 2.05 million hectares, or 49% of the total farming area in Liaoning province and 2.67 million hectares, or 66.5% of the total farming area in Jilin province were affected by the drought. The drought, which started in June, is the strongest on record.

Source: CBOT News

Fundamental Wheat News

The US winter wheat harvest is still behind schedule after a summer of heavy rains, which have delayed cutting in the hard red winter wheat areas of the Southern Plains and the forecast shows no immediate relief. Statistics Canada pegged their 2007 all wheat seedings to be at 21.7 million acres, down from 23.8 million acres they estimated in April. This was 1.0 million acres below the lowest trade estimate. If USDA adopts this acreage estimate and maintains their current yield estimate of 2.58 tons/hectare for Canada, they would estimate Canadian wheat production at 22.7 mmt’s, down 1.8 mmt’s from USDA’s current estimate of 24.5 mmt’s. Anticipated lower wheat production in Canada, the Ukraine and in the US should result in a further significant decline in world wheat production and carryout stocks.

Source: FIMAT

Barley Forecast

Production is forecast to increase by 25%, due to higher area and yields, but supply is expected to increase only slightly due to significantly lower carry-in stocks. Exports are forecast to increase by 11%, while domestic use is marginally higher. Carry-out stocks are projected to increase by 15%. The average off Board feed barley price (No. 1 CW I/S Lethbridge) is forecast to decrease to $160/t, from $165/t expected for 2006-07, due to increased supply.

Source: AAFC

Wheat Price Volatility

Going back two newsletters ago, I mentioned that a short-term change in supply results in a short-term change in price. What do we have? A huge move up and a huge move down. With the poor US harvest weather combined with a surprising StatsCan spring wheat acreage down one million acres from the trades expectations, the lowest world ending stocks in thirty years, I would think we’ll see a great deal more volatility in the coming months.