Questions of the Week

How (and whether) to put seeds in the ground this late?

Where excess moisture delayed seeding:
Planting canola half an inch to an inch deep into warm, moist soil and packing lightly offers seed the best chance for success. However, because it is now mid-June, broadcast seeding may be an ‘in-a-pinch’ option where excess moisture limits opportunity to seed properly. Broadcast seeding is not a well-researched management practice, but these tips have been developed through experience.

Where cutworms, frost or other emergence issues have compromised the crop:
There are both pros and cons to reseeding in mid-June. Due to canola’s ability to branch, an established, uniform, well-managed canola stand with as few as two plants per square foot typically has higher economic potential than a thicker stand reseeded late. To optimize a thin stand, be extra vigilant about weed control and pest management. A thin stand will be harvest-ready later (likely October) as the plants will need extra time to branch and fill in. See this week’s Community Connections for crop insurance seeding deadlines.

How to bump up fertility now?  

If canola is emerging well and there’s adequate soil moisture, there may be opportunity to push the crop’s yield potential by adding in-season nutrition. Keep 4R practices (right source, right rate, right time, right place) in mind. When applying a foliar fertilizer or mixing nutrients into a herbicide application, ask: how much nutrition is this really adding? Dribble-banded and broadcast applications are the most effective way to add additional nitrogen and sulphur, but take steps to minimize volatilization losses of nitrogen. Prioritize boosting fields with the highest yield potential, which could mean ‘borrowing’ nutrients originally intended for lower-potential, later-seeded fields. (Tips to add nitrogen and sulphur in season)

What to watch for in pests this week?

• Cutworms: there is no official threshold for cutworms. In a strong stand, a 25-30% stand reduction is a good rule of thumb. Damage tends to be patchy and progresses very quickly, so careful scouting is critical. Check cutworms for green gut contents, which indicate active feeding. Cutworms with brown gut contents are not actively feeding so may not be well-managed via insecticide. (Cutworms – timely scouting and spray decisions) (Cutworms: identification and management field guide) (Lifecycle of cutworms: know when to look for which ones)

• Grasshoppers: Most areas have now accumulated at least 100 GDD, which is the sweet spot for migratory grasshopper emergence. The cool, wet weather has not likely caused significant mortality. (Grasshopper management in canola: thresholds, identification and control strategies)

• Gophers: Zinc phosphide offers statistically similar control to strychnine (but should not be confused with aluminum phosphide, which requires special training for applicators). Young plants are full of vitamin K, which is the antidote for anti-coagulants. More control options are detailed here. Saskatchewan is offering a cost-shared rebate program for gopher control efforts. 

 Protect beneficials! 

Are unregistered tank mixes worth the risk?

Unregistered tank mixes may seem like an opportunity to save time and/or money, but the risks are high. Off-label mixes are not supported by product manufacturers, which means all risk is carried by the producer. For those who choose to tank mix despite the risks, always jar test first and be aware that mixes may impact each product’s efficacy. Mixing order matters. Foliar fertilizers and biologicals are generally benign alongside herbicides but occasionally cause compatibility issues including ‘hot’ herbicide or compromised efficacy. Be aware that PMRA is currently tightening rules and moving towards unregistered mixes being illegal. (KeepItClean.ca)