Early season, The Bean Report

The Bean Report – June 13, 2019

June 13, 2019

Listen to the Bean Report here:

 

Crop Update

  • Most soybeans and dry beans across the province are up and are currently at the VE to VC stages. The first trifoliate leaf is emerging in early-seeded soybeans. Field peas range from V3 to V8 and faba beans range from V2 to V7. Straggler seedlings are still coming up in both early- and late-seeded fields in all pulse and soybean crops. Be on the lookout for seedling diseases at this time.
    • Note: When staging peas and faba beans for herbicide application, be sure to count only the true leaf nodes to accurately assess node number. Growth staging guides are available here for field peas, faba beans, dry beans and soybeans.
Soybeans: VC
Dry beans: VC
Field peas: V5
Faba beans: V4
Bald head dry bean seedling with swollen hypocotyl on June 6.
  • Variable rainfall fell across the province over the weekend, giving some regions much-needed relief from the hot, dry conditions. However, the province is still only at 55% of normal precipitation from May 1 to June 9, on average.
  • Enhanced by dry conditions, variable seed depth and cutworm feeding have contributed to uneven crop development and patchy plant stands.
    • Note: Plant stand assessments should be conducted following the recent rains to account for seedlings that have emerged or are emerging late. Click here for optimum live plant stands of pulse and soybean crops.
  • Heavy winds at the end of last week (June 7) caused damage to seedlings in some dry bean fields. Frost events, as recent as June 10 in some regions, still pose a risk to soybean seedlings. Take note of damage while assessing plant stand over the coming days. Damage may appear as tattered, crispy or missing plants.
  • There has been evidence of leaf miners in the lower leaves of field pea plants. These insects do not cause economic damage. For further information on leaf miners, click here.
    Leaf miner damage in the lower leaves of field pea plants
    Leaf miner damage in the lower leaves of field pea plants

 

Cutworm scouting and management

  • Look for areas with missing plants and wilted, notched, gouged or shot-holed plant tissue.
  • Dig around in suspect areas with a trowel. Scoop soil into a container and shake loose any potential larvae. Note that cutworms move deeper into the soil during the heat of the day.
  • Identify the species and size of cutworms. Dingy, redbacked and darksided cutworms are most common and will be present at varying development stages.
  • Nominal thresholds: 1 or more cutworms (<2 cm in length) per metre of row, or 20% of plants cut in soybeans/dry beans and 2-3 cutworms (<2 cm long) per metre of row in peas/faba beans.
  • Click here for more information on cutworm scouting and management.
Regrowth of field peas following cutworm damage.
Cutworm damage in faba bean seedlings. Fabas can regrow if the main growing point remains intact.

 

Considerations for pulse and soybean crops in dry conditions

  • Tillage – Recent observations indicate that soil moisture levels are closer to the surface in fields with less soil disturbance. Assess the impact of tillage/residue management practices on soil moisture.
  • Emergence – Typically pulses and soybeans seeded in dry conditions are seeded deeper to allow for seed contact with soil moisture. Compare how different seeding depths and different seeding rates are affected by dry conditions as the season progresses.
  • Fertility – The risk of fertilizer burn is increased by dry conditions. Phosphorus and potassium fertilizers are the most concerning to pulses and soybeans. Watch for symptoms of fertilizer burn on plants if fertilizer is present in a “hot band” or is seed-placed.
  • Inoculation and Nodulation – Dry conditions have the potential to decrease the efficacy of inoculant. Evaluate inoculant efficacy in all fields by assessing nodulation during the late V to R1 stages. Take special note in fields with single inoculation. Ensure plants have at least 10 healthy nodules (appear pinkish-red inside) per plant.
  • Soil Salinity – Saline patches are typically more visible under dry conditions. Look for saline patches in all fields and take note of locations and borders of these patches for wet years when pulse and soybean crops could be negatively affected by them.
  • To read more about how dry conditions influence these areas, read the full article here.

Herbicide-resistant weeds

Scout for herbicide-resistant weeds 14 to 21 days after product application. Look for weeds that have not been killed by herbicide. If these weeds were sprayed at the correct stage for control and herbicide was applied at the correct rate under the right conditions, suspect resistance.

Another suspicious sign is variability in herbicide efficacy within a small area, where there is no specific pattern caused by a sprayer miss, nozzle issue or environmental issue. Click here for more information on scouting and management of herbicide-resistant weeds.

Weeds to watch:

  • Kochia – Glyphosate resistance has been confirmed in 12 municipalities. Suspect samples can be tested by the Pest Surveillance Initiative lab.
  • Wild oats – Resistance to six different modes of action in Manitoba (Groups 1, 2, 8, 14, 15 and 25).
  • Redroot pigweed – Group 2 resistance is expected to be a growing concern.
One suspicious sign is variability in herbicide efficacy within a small area, where there is no specific pattern caused by a sprayer miss, nozzle issue or environmental issue.
Adapted from the Pulse Beat article “Herbicide Resistance in Manitoba” by Tammy Jones.

Click field pea and faba bean for MPSG’s brand new growth staging guides, or soybean and dry bean for quick access to the other staging guides at manitobapulse.ca.