|
 |
|
|
|
|
||||||||||||||||||||||||||||||||||||
|
|
Story Posted: June 09, 2010 Canola Watch 7: Tips for aerial spraying and seeding In This Issue: Tips for spraying in wet conditions, Aerial an option for WeatherMax and Liberty, Liberty: Higher rates or tank mix?, Aerial seeding is a last resort, Fertilizer top up for wet fields, See birds in the field?, Scout for cutworm, Questions and contacts. Issues of the week Crop and weather update Alberta: Seeding is wrapping up in the south and complete in central regions. In the south, 60% to 80% of the crop is emerged. We saw variable rainfall, from a couple tenths in many areas to 4" plus hail last Thursday alone in the Myrnam area. Many areas need 2 to 4 days of dry and windy conditions before sprayers can get on the fields. Read the Alberta crop report. Saskatchewan: "Uniform wet," is CCC senior agronomy specialist Jim Bessel's summary for Saskatchewan. In general, western Saskatchewan is 90% seeded but the east made very little progress in the past week. Many eastern regions are below 50% seeded and with crop insurance deadlines looming, further progress will be limited. Read the Saskatchewan crop report. Manitoba: Pockets in the west still have about 25% of the crop to seed, and areas in the east are being reseeded due to flooding. Many other saturated fields will be evaluated over the next week to see how much of the crop survived repeated heavy rains. Read the Manitoba crop report. Quick Hitters Frost has been reported in some areas of the Peace. For improved weed control after a frost, give weeds a couple days to start growing again before spraying. Flea beetle spraying is "going hard" around St. Paul and other parts of Alberta, says CCC senior agronomy specialist Doug Moisey (click to email Doug). He says flea beetles are getting ahead of the crop because of slow growth. But in Saskatchewan, many retailers and agronomists report this is the "least flea beetle damage they've seen in their careers." Click here for more on scouting for flea beetles (and cutworms). Diamondback moth trap counts are higher than usual at this stage. This could mean a high larvae population at the critical flowering and early pod stages. Owen Olfert, entomologist with AAFC in Saskatoon, says "barring natural enemies (parasitoids), population densities will increase with the subsequent generations. As a result, scouting for larvae is generally recommended during flowering and early pod formation." Many growers report thin stands for a number of reasons: seeding too deep, crusting, drowning, etc. A thin stand is more vulnerable to losses due to weed competition and insect and disease disease, so scout often. Click here for a CCC factsheet. Assess a flooded stand before putting any more money into it. When the field has dried and good growing conditions have returned, look for healthy white plant roots and growing point (as in the photo below left.) A plant with rotted roots or wirestem (shown below right) will probably die, even if the leaves appear green at the moment. For more information, click here to read a new MAFRI factsheet.
Tips for spraying in wet conditions 2. Big new sprayers have more horsepower but they weigh 30,000 pounds dry and up to 40,000 pounds with a full tank. Ideally, you don't want to go into a low spot with a full tank. So here's a tip from a Saskatchewan grower: With GPS you know where you've been, so spray all the higher ground first, then go back to the lower spots when the sprayer tank is only a quarter full. This reduces the risk of getting stuck. 3. Keep your speed up, if possible. Slippery conditions slow a sprayer down, which results in lower spray pressure as rate controllers attempt to maintain a constant application volume. This can cause nozzles to perform poorly. With low-drift nozzles, higher pressure is important to get the pesticide to work properly. 4. An option is to apply by air where product registrations allow. Aircraft can cover large areas in a short time. Most aerial applicators have all-weather airstrips. And aerial applicators can produce droplet sizes that provide the right amount of coverage for the product and crop in question. For more on early-season aerial application of herbicides, read the next article. Thanks to Tom Wolf, research scientist with AAFC in Saskatoon, for his help with this article. Aerial an option for WeatherMax and Liberty
For more on these registrations and label requirements, read product labels and the provincial guides to crop protection. For a link to your guide, click your province: Alberta , Saskatchewan , Manitoba. In summary, the benefits of aerial are: In many regions, weeds are ahead of the crop. If that's the case and fields are too wet for the sprayer, then aerial spraying may pay off. Weeds up and growing before the crop have a significant impact on crop yield. (See the table at the bottom of this article on canola losses due to wild oat, taken from page 31 of the Saskatchewan Guide to Crop Protection.) Aerial spraying also avoids wear and tear on sprayers and on the field when conditions are wet. Ground sprayers can leave deeps ruts to contend with in subsequent spray applications and at harvest. Crop once growing in those rutted areas is now gone. And getting a sprayer unstuck can be a long, messy job. In summary, the downsides to aerial are: You need to leave buffer zones. For Roundup WeatherMax, for example, the buffer zones for aerial application in Roundup Ready canola are 40 metres for shelterbelts and other fields and 5 metres for aquatic habitat. Aerial application also represents another cost for a crop that does not have the profit potential it had before the delays and the moisture stress. On that note, in very wet conditions, growers should make sure the crop has recovered before stacking on the extra expense of aerial weed control. "If that field's going to be dead a week from now, how much do you really want to invest in it?" says CCC senior agronomy specialist Derwyn Hammond (click to email Derwyn).
Liberty: Higher rates or tank mix? What about applying a high-rate of Liberty to water-stressed crop? "I am not that concerned about the plants being stressed with a high rate. If there is some injury, the injury will be transient and the crop will recover," Johnson says. As for timing, he says control the weeds as quickly as possible. "Another flush of wild oat is possible, but based on the fields I have seen, the canola emergence is excellent this year. With the good moisture conditions, the canola crop should provide total ground cover quickly and a second application may not be required." The key with tank mixing is to know the weeds you're targeting. Does the field have a lot of grassy weeds? Are the wild oats group-1 resistant? If thistles are common, consider an application of clopyralid (Lontrel). Aerial seeding is a last resort Fields too wet for ground equipment have probably been wet for a month or more. That means most of the nitrogen reserves have been lost, and since you can't put fertilizer down with a plane, the field will have very little nutrient available to it. Canola emerging in wet soil will also be oxygen deprived. This is not a hospitable environment for seedlings. Sure the seed will germinate, but the roots will likely to die. The CCC doesn't have any research on aerial seeding, but Steven Kiansky of Southeast Air Service in Altona, Man., seeded 8,000 acres by air last year. He says it works as well as floater, but as noted, aerial seeding doesn't allow for fertilizer application. It's also fast, seeding a half section in an hour, he says. Kiansky recommends growers harrow after seeding by plane. He works in the Red River Valley and canola seeded by plane only goes in to about the depth of the seed itself. He does say that depth depends on soil type. In lighter land, seed may penetrate deeper than that. He estimates the cost at $8 to $10 per acre. Growers who decide to go for it will want to hire a pilot with experience seeding canola. Fertilizer top up for wet fields If the crop is in good shape, a small nitrogen top up may help the crop. Too much and the crop is vegetative longer and matures later, increasing the risk of fall frost damage. Because sulphur deficiency can also occur after soil saturation, one top up product to consider is ammonium sulphate - which provides nitrogen and sulphur. Broadcast dry, it needs a shower shortly after application to wash it into the root zone. Symptoms of nitrogen deficiency: Nitrogen deficiency symptoms first show up in older leaves as pale green to yellow colouring, and sometimes purpling. Click here for more details from the Canola Growers' Manual. Symptoms of sulphur deficiency: With sulphur, yellowing and leaf cupping tend to occur on new leaves first. Purpling of leaf edges can show up when deficiency is fairly severe. (See the photo below.) In many fields, there is enough sulphur available initially to get the crop past the early rosette stage without visible symptoms, and then problems show up at flowering. Click here to read an Alberta Agriculture factsheet on sulphur deficiency and click here for details from the Canola Growers' Manual.
See birds in the field? Scout for cutworm Note that cutworms can cause crop damage from the surface, feeding on above-ground parts of canola plants. Even if you don't see birds, cutworm scouting is a good idea. Look first in high spots, sandier soils and south facing slopes. Wilted, cut or missing plants are signs of cutworm feeding. A number of cutworm hotspots have flared up, with reports of spraying or reseeding from many areas of Alberta, around Carrot River, north of Melfort, Cudworth and Lanigan in Saskatchewan, and from Swan River and Minto in Manitoba. When scouting, cut open cutworms and look for "green guck" inside. That means they're feeding - and still doing damage. If no green guck, then cutworms may have grown past the feeding stage or are between molting stages and there's no sense spraying at this time. Fields will be at higher risk of cutworm damage if the previous crop was canola, peas or forage, or if this year's crop was seeded early. Control: There is no established economic control threshold for cutworms in canola, but a MAFRI factsheet suggests 25% to 30% stand reduction as a time to act. In thin stands, the threshold may be lower. Apply insecticide in the evening for better results. The MAFRI factsheet says sometimes it is most economical to just treat infested patches and not entire fields. Click here for more scouting and control tips.
Questions and contacts If you have questions on regional issues, contact one of the following Canola Council of Canada regional agronomists or provincial oilseed specialists:
This report is supported by each of the provincial canola grower associations. For more information on some of their activities, check out the following links:
|
||||||||||||||||||||||||||||||||||||||
|
|
|
|
|
|
