Weed control is a priority. Early weed control is a key step in profitable canola production. If seeding is still a few days or weeks away, walk or drive your fields to see if weeds are up and growing to determine when and if to spray. Winter annuals and dandelions will be up first and are much easier to control now, not later.

Record canola acres have prompted talk of fertilizer shortages. Chances are there will be enough fertilizer, but will it be delivered to the local retailers in timely fashion? Consider a proactive approach to make sure fertilizer is on hand when you want to seed.

Look at soil temperature, the week’s forecast and the typical last day of killing frost to decide when to start seeding. Seeding into 2-5 C soils is OK if the outlook is warm and the risk of a killing frost has dropped to an acceptable range.

U of S research on wheat shows that early weed control (EA) boost yield equally whether the crop is seeded early (ES) or late (LS)

Even if growers don’t expect to seed any time soon, they may want to consider a pre-seed burnoff now to get weeds at smaller stages and before they draw down moisture and nutrients that their canola crops will need. Products registered for use ahead of canola are CleanStart, Amitrol 240 and glyphosate.

University of Saskatchewan research shows that early weed control is more important than early seeding when it comes to yield. The study was done on wheat, but lead researcher Ken Sapsford says results would be similar for canola. Winter annual weeds like flixweed, shepherd’s purse, narrow-leaved hawk’s-beard and stinkweed can remove a lot of soil moisture in the spring as they begin to grow very early and are very inefficient water users. Early weed control stops this uptake, preserving moisture and nutrients for the crop. Read the study poster: U of S study on Winter Annual Weed Control

Growers using Amitrol 240 ahead of canola should make sure not to exceed the label rates. Amitrol breaks down in the soil relatively quickly, but it can be available for crop uptake during that time since it is not strongly bound to soil as with glyphosate. If it gets into the plant, it can remain for a long time.

Here is the Export Ready message on the Amitrol 240 page in the guide to crop protection:

The Canola Council of Canada “Export Ready Program” urges canola producers to adhere strictly to product label directions. They also suggest that producers limit applications of Amitrol 240 to the pre-planting timing, with the hope of minimizing the potential for residue in the grain. Japan, a major consumer of canola, has very low tolerance for residues of Amitrol 240 in canola.

Click a province for a link to provincial guides:  Alberta Saskatchewan Manitoba.

Cleavers and other hard to control winter annuals.  Make sure to use adequate rates to control these weeds. Include a tank mix partner with glyphosate in non-canola years to protect against the evolution of glyphosate resistant cleavers. Note that many cleavers populations are Group 2 resistant so mixes with Group 2 herbicides will not be particularly effective for protecting glyphosate against resistance development.

The ideal soil temperature for canola is 10 C but you probably don’t want to wait that long to get started. Canola can germinate in soils as cool as 1-2 C, but growth will be very slow until soils warm up. Therefore, canola germinating and growing in cool soil conditions will have prolonged exposure to diseases as well as insects. As well, the longer it takes for canola to emerge, the fewer days of flea beetle protection seed treatments can provide for emerged seedlings. Overall seedling survival can be lower in cool soils, often resulting in an uneven stand.

A good starting point for seeding canola is when the three-day average soil temperature in the seed zone is 4-5 C. This is the temperature where biological activity typically begins.

Use a soil thermometer and take readings at 8:00 a.m. and 4:30 p.m. over a few days and average the results. Because canola is seeded at 1” deep, test the soil temperature at that depth. Be consistent.

If a probe thermometer is too slow, consider an infrared thermometer — available at most hardware stores. You need to dig down to the target zone, but once there, the thermometer reading is instantaneous. A digital contact probe thermometer is pretty quick, too.

In combination with soil temperature, check the weather forecast and consider the frost risk. If soils are cold but the forecast is for warm temperatures and frost risk is acceptable to you, it may be an appropriate time to seed. The graph below, taken from Alberta Agriculture Agroclimatic Information Service , combines the soil temperature and frost risk for 5 sites in north east Alberta. While the soil temperature is good, the risk of a -3 C frost is still quite high for the next two weeks.

Plants emerging in cool temperatures are cold hardened and can tolerate a little more frost. The worst combination is a stretch of warm days followed by a drop to minus 2-3 C at night. With warms highs, plants will have lost their cold hardiness and the sudden frost can bring significant losses. If seeding early, don’t skimp on seeding rates. Consider bumping rates by 0.5 lb./ac.

Soil temperatures were good for seeding in NE Alberta yesterday, but the frost risk is still high.

Other links:

Manitoba soil temperature readings.
Effect of Seeding Date on Canola Yields as Reported by Farmers
Optimum Seeding Date and Rates for Irrigated Grain and Oilseed Crops
CCC factsheet on ideal seeding timing
MASC chart showing relationship between seeding date and yield

Seed weight can vary significantly from lot to lot. This lot is 5.03 grams per 1,000 kernels. Calibrate the drill between lots to make sure you hit the target population.

Thousand kernel weight (TKW) for canola seed can vary from less than 3 grams to more than 6 grams. This year there have been reports of wide ranges in seed size, even among seed lots of the SAME variety. Look at the TKW for each seed lot, and calibrate the drill to achieve your target plant population for each seed lot. Click here for more on drill calibration.

Seed each seed lot separately. Mark the field where you change lots. Keep a sample of each lot.

If you plan to seed at 5 pounds per acre regardless of seed size, know the risks. Large-size seed planted at 5 pounds per acre may not achieve the safe minimum plant stand of 7 plants per square foot.

Here’s why:

A 6-gram hybrid seeded at 5 lb./ac. works out to 8.7 seeds per square foot. At 60% seedling survival, which is at the high end for average conditions, those 8.7 seeds only produce 5.2 plants per square foot. At rates below 5 lb./ac., the plant stand drops accordingly. The combination of lower seeding rates and larger seed size can lead to disappointing plant populations and a significant drop in yield potential.

Yield potential drops off for plants stands of fewer than 5 plants per square foot. With at least 7 plants per square foot, you have some margin for losses to insects and disease.

In this situation, growers will need to take extra precaution to increase seedling survival. Such as:

Seed into warm soils. This will increase seed survivability, especially if you have a heavy seed lot which will result in fewer seeds per pound going into the ground.
Seed 1/2” to 1” deep. Shallow seeding is recommended for all canola because it increases seedling survival.
Keep seed-placed fertilizer at a safe level.

Bulking agents: Most drill tanks sold in western Canada are made to handle small seeds such as canola and deliver relatively uniform seed counts to each row. For a drill that cannot accurately meter small seeds and low flow rates, bulking agents such as elemental sulphur, seed-sized starter fertilizer prills, or cracked oat groats, may help.

However, the Canola Council of Canada ran trials in 2001 and 2002 to evaluate pelletized elemental sulphur at 22.5 kg/ha (20 lb./ac.) as a seed-bulking agent. This research found no consistent stand establishment or yield benefit when using the bulking agent, since the treatments without bulking agent generally produced more than adequate plant populations. Bulking agents are likely not necessary unless your drill is quite ineffective at delivering low rates of small seed. If using a bulking agent, ensure seed and bulking agent stay uniformly mixed throughout the seeding operation.

Canola patch thinned by herbicide carryover

Herbicide carryover damage to canola could present a higher risk this year because of:

The dry fall. Dry conditions can extend the period required for herbicide breakdown, especially if products applied in the fall were on acres not originally planned for canola. (See point 2.)

Last minute rotation changes. Many growers will increase their canola acres again in 2012. If this was a winter decision, then some canola will go on fields not planned for canola when growers did their herbicide applications last year. This could raise some issues with herbicide carryover. Canola going onto pulse or Clearfield stubble, for example, raises the possibility of imazethapyr carryover. Fall applied Heat or PrePass will leave residues that will be damaging to canola.

Weed management on acres unseeded in 2011. Residual herbicide breakdown in saturated soils can be as slow as breakdown in a drought year. And since the very wet spring for growers with unseeded acres was followed by a very dry late summer and fall in many regions, microbial activity would have been halted by lack of moisture shortly after it began. Also, herbicides that break down by hydrolysis (water) — certain group 2s and 5s, for example — may have broken down quickly in wet conditions but perhaps very little if applied after the rains stopped. Look at your herbicide records for fields planned for canola in 2012. Talk to a crop protection company rep for advice on any products that may have higher than expected carryover in those fields.

The healthy look of this early diamondback moth suggests it may have overwintered in Manitoba.

Diamondback moth numbers high, early

Adult diamondback moth numbers are higher than usual in the southern Prairie for this time of year. Diamondback moth larvae are not a threat to canola until later in the season, and a lot can happen between now and then. Rain can drown young larvae and natural parasitoids can feed on larvae, possibly reducing a high population to below economic levels. By scouting for early presence of adult moths and taking counts, entomologists can estimate regions where diamondback moth are at higher risk of reaching economic levels.  But whether that population gets large enough to warrant a spray will be determined by looking for larvae on the  plants .

If growers encounter diamondback larvae feeding on canola seedlings and rosettes, use defoliation thresholds similar to those for flea beetle damage. Although an economic threshold for diamondback moth on canola seedlings has never been properly tested, a nominal threshold of 25-33% defoliation, with larvae still present on plants, can be applied for canola at seedling stage.

Watch for striped flea beetles

Striped flea beetles seem to be more common each year, especially in the northern canola growing regions. Research suggests that a population of striped flea beetles may do more feeding on seed-treated canola prior to control than a similar population of the crucifer type, so look closely when scouting. Seed treatments also work best under warm dry conditions. If wet and cool, look for feeding on the underside of leaves and for girdling of stems. Listen to AAFC entomologist Julie Soroka talk about new flea beetle research on ACPC radio.

Striped flea beetle. Source: AAFC

Cutworms active already. Samples from northwest Saskatchewan confirm that cutworms are already out and active in that region. The species is probably dingy, which overwinters as larvae.

Wireworms are just one of many potential pitfalls of seeding canola into freshly-broken pasture or hayland.

Canola is not the best crop for going into freshly broken pasture because:

Competition. Pastures are primarily perennial plants and weeds, which will provide heavy competition all season long, even when using Roundup Ready canola and a glyphosate pre-seed burnoff. During pre-seed burnoff timing, flow within the perennial plant is up from the roots to the new growth. Glyphosate will provide fairly good top growth control, but the active ingredient will not move down into dormant buds on the roots — which are the key targets for effective perennial control. With in-crop glyphosate application, two one-half litre rates may not take care of perennial forage plants surviving initial management efforts.

Poor seedbed. Large chunks of sod still present in the field  can impede good seed to soil contact — which is important for canola seed survival and emergence.

Low nutrient reserves. Pasture and hayland can be very nutrient deficient. What nutrition does remain will be tied up by microbes breaking down the large amounts of plant residue.

Low moisture reserves. Subsoil moisture tends to be lower in pasture and hayland, especially following a normal to dry year.

Wireworms. Wireworm populations tend to be high in pasture and hayland. Wireworms can wipe out a whole field of canola, and no seed treatment or spray is registered for wireworm control in canola. Growers will want to get down with a trowel and sifter and look for wireworms in these fields before making the final decision to seed canola. Bait balls are unlikely to work to scout for wireworms in these fields given the high volume of decomposing plant material. Gopher and cutworm numbers also tend to be high in pasture and hayland. Cutworms can be managed with surface applied insecticide.

Carryover herbicide. If the pasture was sprayed for weeds, what product was used? For example, Escort and Telar present a herbicide carryover risk for canola.

Generally poor land. Why that field was in pasture in the first place? It may not be highly productive land. In general, growers should lower their yield expectations for canola seeded into fields taken out of pasture and hayland. They should also evaluate each field to determine if canola is really the best crop choice. Click here for more tips on sod seeding.

Growers with a few days before they expect to start seeding may want to take time to get the drill ready. To start, find a flat dry place to work, and get the drill leveled. The manual should provide instructions. A level drill is important for shallow seeded crops like canola. Also inspect openers, hoses, tank gaskets, meter rollers and manifolds for wear. Check that the electronics work properly and are calibrated. For a detailed summary of drill prep, click here to read a Canola Council of Canada factsheet and click here for an article from the Alberta Reduced Tillage Linkages archive. If you have a new drill, consider seeding wheat or peas first to work out the kinks prior to seeding canola.

Click here for other important jobs to do before seeding.

Spring fertilizer tests are the most accurate in predicting the soil nutrient situation at seeding time. Labs may be able to provide results within a few days or a week, so spring tests can be done without holding up the seeding process.

U of S research on wheat shows that early weed control (EA) boosts yield equally whether the crop is seeded early (ES) or late (LS)

Even if growers don’t expect to seed any time soon, they may want to consider a pre-seed burnoff now to get weeds at smaller stages and before they draw down moisture and nutrients that their canola crops will need. Products registered for use ahead of canola are CleanStart, Amitrol 240 and glyphosate.

University of Saskatchewan research shows that early weed control is more important than early seeding when it comes to yield. The study was done on wheat, but lead researcher Ken Sapsford says results would be similar for canola. Winter annual weeds like flixweed, shepherd’s purse, narrow-leaved hawk’s-beard and stinkweed can remove a lot of soil moisture in the spring as they begin to grow very early and are very inefficient water users. Early weed control stops this uptake, preserving moisture and nutrients for the crop. Read the study poster: U of S study on Winter Annual Weed Control

Growers using Amitrol 240 ahead of canola should make sure not to exceed the label rates. Amitrol breaks down in the soil relatively quickly, but it can be available for crop uptake during that time since it is not strongly bound to soil as with glyphosate. If it gets into the plant, it can remain for a long time.

Here is the Export Ready message on the Amitrol 240 page in the guide to crop protection:

The Canola Council of Canada “Export Ready Program” urges canola producers to adhere strictly to product label directions. They also suggest that producers limit applications of Amitrol 240 to the pre-planting timing, with the hope of minimizing the potential for residue in the grain. Japan, a major consumer of canola, has very low tolerance for residues of Amitrol 240 in canola.

Click a province for a link to provincial guides:  Alberta Saskatchewan Manitoba.

Cleavers and other hard to control winter annuals. Make sure to use adequate rates to control these weeds. Include a tank mix partner with glyphosate in non-canola years to protect against the evolution of glyphosate resistant cleavers. Note that many cleavers populations are Group 2 resistant so mixes with Group 2 herbicides will not be particularly effective for protecting glyphosate against resistance development.