Sunday, 30 September 2012

Fall Herbicide Applications

Post harvest glyphosate applications are a very effective method to gain control of perennials and winter annuals before heading into the winter. Controlling them in the fall is effective because weeds such as Canada thistle, dandelions etc are beginning to shut down for winter and therefore actively translocating sugars to their roots to over winter, the glyphosate gets translocated efficiently down as well, killing the plants at their roots. This leaves a much cleaner field come spring to seed into and reduces the headache of trying to get rid of these difficult to control weeds (Note: fields should still be considered for pre burn applications in the spring).

With all of this said, the temperature fluctuations and potential frost threats in the fall make spray timing a more difficult task, so it is best to follow some simple guidelines when it comes spraying at this time of the year.

Glyphosate (like most non-residual actives) is a product that can be touchy if sprayed at a time when it is not readily absorbed and translocated within the plant. This means to watch time of day spraying (glyphosate is notorious for being less effective sprayed in the late evening or early morning) and conditions before and after the frost, on top of the weed species you are targeting and the severity and length of the frost. Lots of growers believe that if a killing frost has already hit, their post harvest spray season has ended, but that isn’t necessarily the case.

If you have a hard frost of (-4 degrees C or colder) then you must wait before going into spray any weeds. It is best to wait anywhere from 48-72 hours before going into assess the severity of the frost damage. If you go out and see the plants are still remaining over 50-60% green, there are signs of active growth and the weather conditions have begun to be more favourable, then aiming to spray the next day once temperature have risen to above 10 degrees C for over 2 hours would be your next opportunity to hit that field. Remember, there shouldn’t be frost in the forecast for the next couple days either.

If there was simply a light frost (0 to -3 degrees C), this only slightly affects perennial and winter annual weed control. With that said, time below freezing can come into play and it is still good to go out the next day and assess the plants. Typically, if it was a light frost like this and you go out and spray the following day once temperatures have reached 10 degrees for a couple of hours (and no frost in the forecast) then you should be safe. Giving the plants an extra 24 hours after a light frost can be an effective strategy though.

It is best to spray glyphosate in the middle of the day, especially late in the season like this. If you can catch a warmer, sunnier day, then it is even better. To further it even more, if you get a nice shower, go in the next day and you will see an increase in efficacy as the fall moisture gives the plants a big perk and from what I have seen significantly helps fall glyphosate effectiveness. As for rates, I personally don’t like to see less than a 1L equivalent of glyphosate used when trying to take down any perennials or winter annuals.

I always recommend putting a second chemical in with the glyphosate such as 2,4-D, Express, Dicamba, Florasulam etc. as having a second mode of action is effective in decreasing the potential of glyphosate resistance and also because these products all have a residual in some capacity. I am not going to touch on these to much as the date they are used, rates, soil texture, soil moisture, soil temperature, organic matter and more come into play when determining what can be seeded there next year, if you have any specific questions feel free to ask or talk to your local agronomist as they will be aware of what products will be effective for your situation in your area. I will note that florasulam and Express (tribenuron) typically have strong activity on asteraceae family weeds which is what family our thistles fall into.

Dandelions are generally considered to be the most frost hardy, while Canada thistle, sow thistles and perennial/winter annual grasses are thought to be less frost tolerant. Also, keep in mind if you were late harvesting you must assess the plants regrowth and you should see new leaves being put out by the plant before spraying.

Spraying in the fall is the most effective way to clean up the perrenniels/winter annuals in your field so if you can take advantage of that you’ll be happy you did come the next season.

Monday, 3 September 2012

Canola Variety Considerations

With companies starting to roll out their early booking canola information, I figured I’d put together a quick checklist for determining what variety will be best for your farm. The top varieties are also the first to sell out, so if you know what you want it is best to book them right away.

The first thing most guys look at is yield. Ultimately this is the deciding factor for a lot of growers. Don’t always listen to the seed companies themselves as sometimes I find their yield numbers to be a bit higher than you might see on your farm. Take a look at the third party canola council data, check with local retails and research programs and you should get some good answers. Lastly, talk to your neighbour, knowing what variety grows well in your area is key. Just because a variety yields like crazy in Manitoba, doesn’t mean it will yield the same in southern Saskatchewan.

Standability is something that has come to be noticed a lot this year. A variety that stands better is a lot easier to swath or straight cut and also is less prone to main stem sclerotinia infections than a variety that is laying over. I have always noticed Bayer’s Invigor 5440 to stand up well, even under high inputs (eg: fertilizer). Talk to some neighbours and see what they have noticed with varieties. Some other varieties I have noticed that consistently had good standability are VT 500, Canterra 1900 series, Brett Young 6060 and Invigor L130 and L120.

Shatter resistance is another thing to watch for when choosing a variety. This is especially true for those that want to try some straight cutting. This trait is one that a lot of breeders are building up in their lines as losses due to shattering show up not just in loss bushels, but weed control in the years to come.

Disease resistant is becoming talked about more and more every year. Almost all varieties these days come resistant to Fusarium Wilt and Blackleg. With that said, when it comes to blackleg ratings there is something to note. The first off is that even an ‘R’ rating can still have up to 30% infection of blackleg (this is why you will hear company reps saying it is a “strong R rating”, meaning their variety will only have up to 10% infection vs a weaker R rating having 27% infection). Moderately resistant or ‘MR’ can have anywehere from 30 to 49% infection. On top of this blackleg strains continue to develop and evolve in western Canada and can overcome some of the resistance genes that are put into our canola. These different strains belong to different pathogenicity groups or PG’s, this is important because you may have a variety that is resistant to a couple PG’s, but not another one which is potentially the strain of blackleg you will see develop in your canola. On a side note, Dekalb is coming out with an exciting variety called BL 74-44 which has multi group black leg resistance. Sclerotinia resistance is becoming talked about as well in a number of varieties, I have minimal experience with them, but be aware they come at a premium cost and are only resistant up to about 65% (meaning under a high risk year you can still have up to 35% infection). This means you may still have to spray a fungicide. The other concern I have been hearing is a yield drag, meaning to get the Sclerotinia tolerant gene into the variety they may be giving up some of the superior yield genetics you would find in a non resistant crop. With that said, I have read plenty of research without any indication of yield drag, so something to look into more. Club root resistance has been developed into varieties for a couple years now with the Peace River region being the main target. If you are concerned with clubroot at all, these varieties may be good candidates to look into. Remember, disease resistance genes are not a substitute for a good rotation.

Herbicide tolerance is something else to consider, you may want to mix up the herbicide groups on your farm so an Invigor variety that is tolerant to Liberty (glufosinate ammonium group 10) might be a good route for you. Some growers may have had a group 2 residual issue from having lentils or peas on the land the year before, but want to put canola on that piece. A Clearfield (group 2 tolerant) variety will grow through the group 2 residual with no issues. Then there are the group 9 glyphosate tolerant varieties which allow for a very effective herbicide product to be sprayed on a piece allowing you to do a good job of cleaning up a dirtier field.

Last thing to note are premiums. Some specialty oil varieties such as Nexera and the new Invigor 156H offer premiums based on a per bushel or per tonne basis. This can be very lucrative, but remember try not to give up to much yield potential if you do opt to go this route. An extra dollar a bushel is always nice, but if you can grow a variety that may yield 10% more, you may see a higher return from that variety on the yield vs. the variety with the yield and the premium, so keep that in mind.

One quick thing to watch for, especially if seeding begins to drag out is days to maturity. A variety like Invigor L120 is going to save you a number of days vs an variety like L150.

The amount of research going into canola these days is extremely exciting. Yield potential is going up and variety traits such as drought tolerance and increased herbicide tolerance are right around the corner meaning higher yields, less susceptibility to yield threats and more money in your pocket.

Here is a list of 3rd party data from 2011 to check out: