July 31, 2012

Agronomists Notes

Hello Reader,

Last week brought cooler weather and shower events through the area along with a few severe hail storms. Crops that haven’t gotten thumped by hail are marching right along. I suspect early-seeded peas will be ready to harvest in less than two weeks. Early-seeded barley is roughly three weeks away and early wheat will be ready by the end of the month.

Disease pressure has been high in cereals but not in all areas. Sclerotinia infections are random but not severe, more around the 5% level even in sprayed fields. Pea fields are drying down quickly mostly due to disease (Fusarium root rot or sclerotinia). Many pea fields are laying six inches off the ground after a severe wind storm swept through ten days ago.

There is some talk of fertilizer purchases with urea sitting around $600 a tonne. This is a good buy given grain prices and the overall bullish out look for grains in the next six months. Some producers are locking in 2013 grain while booking fertilizer today as a hedge.

This week we’ll look at an alarming development in blackleg occurrence in tight canola rotations. Next, I’ll give you some quick tips on desiccating peas and some dry down options. I’ll provide the quick details on Bertha Armyworms and finish with some great video on CTF in a forage-silage system. We’ll finish with technical grain market news.

Have a great week.

Photo: Metcalfe malt barley at medium dough stage near Drumheller, July 30th, 2012.

Crop Staging

(Calgary to Drumheller to Three Hills)

Seeded    Apr 24-30               May 1-7                  May 8-15
Wheat      milky dough           watery ripe              watery ripe
Canola     mid pod                 early pod                 end of flower
Barley      medium dough      soft dough                watery ripe
Peas        late pod                 mid pod                    early pod

Steve's tips and tricks for the week

Follow me on Twitter for in-season updates @BeyondAgronomy

Begin scouting for blackleg symptoms in canola.
Continue scouting for diamondback moth larvae and bertha armyworm in canola.
Look for early signs of sclerotinia in canola.
Start planning for desiccation in peas.
Continue sweeping for lugus bugs.

Blackleg in canola a threat this season

Tight rotations and perfect conditions could make this disease devastating.

My partner in crime, Daryl Chubb, and I have recently inspected many fields with symptoms of blackleg. The discovery is very disturbing but not unexpected given the tightening of canola rotations over the last decade and the huge amount of volunteer canola every year. Varieties considered to be resistant to blackleg are starting to show signs of infection and decay.

The photos you see here were taken near Three Hills, AB. I suspect you could find these symptoms anywhere with tight canola rotations if you started looking. A good first clue is to look for heavily lodged fields beside other canola fields are still standing. The base of the stem will have lesions with dark outlines around it (bottom photo). Lesions will occur anywhere on the stem. In a severe case you will see a whitish-brown scar at the base of the stem that has tell tale black picnidia (looks like pepper) inside the lesion (top photo).

I won’t go into all the details of blackleg symptoms and prevention but visit this link for the information.

I can’t emphasize enough how serious an issue like blackleg is, especially as we all push canola rotations tighter. Crop losses can range between 30 to 100% depending on the severity of the infection. I urge everyone to start inspecting fields. That lodged field you thought was caused by high fertility or a freak storm may not be the case at all. Check your fields. SL

Pictured above: Blackleg damage showing on stems will cause premature mature ripening and yield loss.

Quick tips on desiccating peas

Many people confuse desiccating with pre-harvesting. Desiccating is a tool used to rapidly kill vegetation be it weeds or crops above ground. Products like Reglone or Heat could be considered desiccants, unlike glyphosate which is not a desiccant. Glyphosate is generally used for perennial weed control and controls vegetation from below the ground, slowly.

As we quickly move into desiccation season I thought I should provide you with some quick tips on application and timing.

Tips on application

If you have a buckwheat problem in peas, use Reglone versus glyphosate. Glyphosate is useless on wild buckwheat.
If you have perennial weeds like Canada thistle, quackgrass, perennial sowthistle or dandelions, glyphosate would be a better option so long as you can wait for the crop to mature which might be 10 to 14 days.
Desiccation will not help immature seeds to mature. You can lock in green seed in yellow peas by desiccating too soon.
Water volume is key with Reglone. At least 15 gal/ac should be used and even better with 20 gal/ac. It’s a contact herbicide and kills only what it touches.
Don’t forget to add a non-ionic surfactant with Reglone. If you have waxy leaf surfaces on weeds or the crop from drier weather, double the recommended surfactant rate.
Use the 700 ml/ac Reglone rate with heavier pea crops or weed infestations.
Apply in the morning or evening for best results. See photo above.

Application timing

Upper pods

Pods are fleshy green or starting to turn yellow
Seeds may be immature

Middle pods

Pods are light green to yellow
Seeds are full-size and soft, but not juicy
Seeds will split when squeezed

Bottom pods

Pods are dry and translucent
Seeds are detached from pods

You should be able to combine within 5 to 7 days after application.

Pictured above: The difference in dry down time between spraying Reglone in the daytime versus night time is significant. Photo source: Syngenta

Field pea dry down options

The standard option for drying down field peas prior to harvest has always been Reglone (Diquat). Most cringe at the $20.00/ac price tag but it works quickly, provided the timing is right. The second option is simply 1 L/ac equivalent of glyphosate at a cost of $4.00 ac, which gives you perennial weed control but a very slow dry down process. The third option being explored is applying the product called Heat (Saflufenacil) at 10.5 g/ac with 0.5 L/ac equivalent of glyphosate plus Merge at 200 ml/ac for a cost of about $6.25 ac. The goal is to offer a cost effective method of some weed control with a dry down faster than glyphosate but a little slower than Reglone.

I have a great side by side to show you the difference between the three products. In the picture above, we have Reglone on the left (700 ml/ac), Vantage Plus Max at 1 L/ac equivalent in the middle and Heat-VantagePlusMax-Merge (10.5 g/ac+0.375 ml/ac+200 ml/ac) on the right. The photo was taken ten days after application. It is clear that Reglone works and you get what you pay for. Straight glyphosate works well so long as you have time to wait for dry-down. What isn't as impressive is the Heat-glyphosate-Merge treatment. At $6.25/ac it may be cost effective, but it just doesn't give you the dry-down you need to speed up harvest nor the perennial weed control you'd want if you were adding glyphosate. Perhaps you could add another 0.5 L/ac equivalent of glyphosate to the Heat-Merge combo for another $2.00 ac or another 10.5 g'ac of Heat but the speed of dry-down will still be limited.

Ultimately, you get what you pay for. Reglone, although expensive, can really help speed up harvest provided the right conditions are present. Glyphosate works just fine so long as you have time to wait it out. The Heat-Glyphosate-Merge combo is not registered and no maximum residue limits have been set so BASF is not recommending at this time. Regardless, stick with one of the first two options for now. SL

Photo source: S. Larocque

Bertha Armyworms

Identification and control

Bertha armyworm larvae are starting to show up in my area in small numbers. They typically feed on the leaves underneath the canopy so they are hard to spot but they can quickly move up into the canopy. Here are the details.

Description
Mature larvae are green, brown or black with a light brown head and an orange stripe along each side. They are 1" to 1.5" long. The most damaging larval stages are when worms are 0.5" long and larger. Small larvae feed on the underside of leaves, but usually cause little economic damage even when population levels are high.

Threshold
At a canola price of $13 per bushel and application costs of $13 per acre, the economic threshold is 17 bertha armyworms per square metre. At that number, bertha armyworms can reduce canola yields by roughly one bushel per acre. Counts of 200 per square metre can reduce yields by 50%.

Insecticide Timing
It is important to ensure that the larvae are up on the middle to upper parts of the plant and feeding on the pods. If the larvae are still feeding on leaf material in the lower canopy or the leaf litter on the ground, there will be poorer control. Avoid spraying during high temperatures (above 25C), as the larvae are likely to be in the lower levels of the canopy. Use rates appropriate to the stage of the larvae. Most insecticides recommend a range of rates. Use higher rates when faced with high populations and/or larger stages. Also at the latest stage, ensure that the larvae are actively feeding. Larvae at the latest stage may be inactive on the ground as they prepare to pupate.

Registered Products
Lorsban: 405-607 ml/ac: preharvest interval 21 days
Decis: 40-60 ml/ac: preharvest interval 7 days
Matador: 34 ml/ac: preharvest interval 7 days

Source: Canola Council of Canada. Photo source: Manitoba AFRI

CTF system accomodates silage & grass production

I’ve often been asked during CTF discussions and presentations how to fit silage, forages or manure applications into a CTF system. Up until now I haven't seen a CTF system fit a livestock operation which is unfortunate because if any operations stand to gain from less compaction, it’s the ones with the most wheel traffic like feedlots, dairies and hog operations.

This short video shows a 38 ft CTF system that includes cutting, wind-rowing, silaging and injecting manure on a farm in Denmark. It’s very impressive to see how they manage a 38-foot system, especially when 25 or 30 ft is the norm here. There are some efficiencies to be gained in both forage yield and transportation. Take a look. SL