AUGUST 14, 2024
- Crop and Scouting Update
- Successful Desiccation Decisions in Peas and Beans →
- Maintaining Pea Seed Quality
- Soybean Stem Diseases →
- MPSG’s Dry Bean Tour Recap
- Lupins: Exploring Alternative Pulse Crops
- CGC’s Harvest Sample Program →
Listen to the Radio Report:
Crop Update
- Soybeans range from R4 (full pod) to R5 (beginning seed).
- Some fields are showing signs of moisture stress and a rain would be welcome in several areas as seeds are developing and filling.
- Soybean aphids have been low overall across the province, with few fields reporting ‘sticky’ soybean leaves which are a result of honeydew from soybean aphids.
- Stem diseases are occurring in several fields, typically in the headlands. Pod and stem blight, northern stem canker, white mold and Phytophthora root rot have been more common to spot this year due to previous moisture and humidity in the crop canopy.
- Patches of potassium (K) deficiency may occur in soybeans growing on sandier soils during pod filling stages. Symptoms are chlorosis of the leaf margins are soybeans are moving K from the leaves to the seeds. In previous research in Manitoba, soybean yields have not responded to K fertilizer treatments at low-K sites. Soybeans remove large amounts of K in the seed (1.1 – 1.4 lbs K2O/bu) so it is important to balance K fertility throughout the rotation to support yields of other crops.
- Field peas range from R5 to R7 (full maturity). Pea harvest has started on earlier-seeded fields with yields ranging from 45-80 bu/ac.
- Peas have lodged in some fields due to strong winds. In some fields, stems have also been weakened by Mycosphaerella blight stem infections. Peas will lodge more often with wet weather and taller crop canopies. Vine lifters and pick up reels aid in harvesting lodged crops by lifting the canopy up over the cutting bar. Vine lifters have been found to reduce harvest losses from 5% to 1.5% of crop yield, decrease plugging and allow for faster harvest speeds (PAMI, 1990). Lifters spaced at 9-12 inches intervals were found to work best.
- Peas are ready for harvest when overall seed moisture is 18 to 20%. The maximum safe storage moisture for peas is 16%. Aeration in the bin is typically used to reach this safe storage moisture. Pea Desiccation and Harvest Guide →
- Peas usually sweat after going in the bin, so monitor for moisture build-up or spoilage post-harvest.
- Dry beans range from R6 to R7 (full seed).
- White mould is prevalent in several fields, especially those that did not receive a fungicide application. Orange larvae may be found feeding on the tufts of white mould, these are the larvae of the white mould gall midge and they are not a pest.
- Grasshoppers have been causing defoliation around field edges, but below thresholds.
- Faba beans range from R5(full seed) to R6 (beginning maturity).
- Foliar and stem diseases in faba beans have been low overall, with some symptoms of white mould, anthracnose and chocolate spot occurring.
- Lygus bugs cause perforation damage in faba beans, reducing seed quality. Faba beans are susceptible to lygus damage until seeds and pods are firm enough that lygus cannot penetrate them any longer.
Desiccation Decisions
Crop desiccation has become an increasingly hot topic. In part due to consumer demand for pesticide-free products, variable maximum residue limits (MRLs) across export markets and the negative spotlight on glyphosate. It doesn’t mean desiccation is off-limits. But we need to understand the limitations of late-season herbicide. Especially when it comes to crops destined for human consumption, including field peas and dry edible beans.
Some questions to ask before applying that late-season herbicide:
- Is it a stagey crop with areas maturing at different rates?
- How far away from harvest is the majority of the crop?
- Are there weeds that need to be controlled?
- What are the weather conditions like during maturity?
- What grade are you targeting?
- What crop are you planning to grow after?
For more discussion on these questions and more, check out Successful Desiccation Decisions in Peas and Beans →
Field Pea Desiccation Timing
Pea plants mature from the bottom of the plant to the top, so it’s important to get out into the field to properly scout and open pods to determine staging. Make sure to look in the least mature areas to compare staging and to make sure the crop is progressed enough in these areas. Doing a drive by, standing on your tailgate and or using drone imagery also helps you understand the uniformity of maturity across the field.
Pea staging is ‘just right” for desiccation, preharvest weed control or swathing when:
- At least 80% of the plant has turned yellow to brown in colour (field is at R7 – full maturity)
- Top of the plant may still be slightly green in colour
- When most pods (80%) are golden-brown
- Seed moisture is less than 30% (even in least mature parts of the field)
- Bottoms pods are ripe and will rattle, seeds in the middle pods have changed colour and seeds in the upper pods will have some colour change and will split rather than squish under pressure.
Consult the Field Pea Desiccation and Harvest Guide for photos for more information on timing desiccation applications.
Consult with your buyer on the products they accept and ensure you’re following the preharvest interval. If it’s too late to desiccate, there is the option to swath and leave them for a day or two to dry down (ensuring the winds will be minimal), then combine very soon after. Beware that pea swaths are highly prone to blowing.
Peas can be left to straight cut without desiccation and are ready for harvest when there is 100% colour change, 100% leaf dry-down and when the seed is 18-20% moisture. Once the crop is mature it can dry down quickly when the weather is warm and dry.
- Check out a Scouting Session video on Timing Desiccation and Preharvest Applications in Yellow Peas →
- Check out the 2024 Product Advisory for Keep it Clean →
Maintaining Pea Seed Quality
Your harvest operations and weather during harvest can affect seed quality which is important for marketing peas. A few grading factors to keep in mind as you set your combine, check your sample and handle your peas:
- Crack seed coats and splits: These occur when seed is too dry and/or cylinder or rotor speeds are too high. Harvesting at 18-20% seed moisture and slowing cylinder speed with drier grain can reduce seed damage. Run combine and grain cart augers at low speeds and at full capacity.
- Shrivelled seed: Seed appears dimpled and shrunken, due to plant senescence while seed was immature. Carefully timed swathing or desiccation will avoid this issue.
- Bleaching: A grading factor only in green peas, bleaching is caused by excessive moisture (rainfall or humidity) at crop maturity, causing a yellow colour on the cotyledons. Desiccation and prompt harvest can reduce the risk of bleaching.
- Earth tag: A greater issue in peas than in other crops due to the nature of harvest and the texture of the seed coat (which retains dirt). If you are finding earth tag on the seed, check for soil sticking to the flighting on your combine augers. Reduce earth tag by minimizing green or dewy plant material passing through the combine and if necessary, lift the cutting bar.
- Pink peas: Hail can damage pods and allow the bacteria Erwinia Rhapontici to enter and stain peas pink.
- Soybean contamination: Some pea buyers have strict restrictions on soybean contamination in their pea contracts due to the challenge of cleaning soybeans out of peas and since soybeans are an allergen and GMO crop. Combine Clean-Out: How to Reduce the Risk of Soybeans in Your Peas →
- Spoilage: As the peas enter the bin, measure the grain temperature and moisture. If the initial temperature and moisture are within the “no spoilage” zone of Figure 3, grain can be safely stored for up to five months. A general recommendation is to use aeration fans to condition, cool and dry the crop to at least 16% moisture and 15°C.
Dry Bean Desiccation Timing
Dry beans are ready for desiccation once they’ve reached R9 (full maturity). At this stage, plants will have:
- 80% pod colour change,
- 80-90% leaf drop, and
- <30% seed moisture in the least mature parts of the field.
- What does that mean? At <30% seed moisture, seeds will rattle within the lowest pods, upper pods will be yellow and the seeds within the upper pods will have lost their green colour when split.
Download the Dry Bean Desiccation and Harvest Guide →
Consult with you buyer about the best product option and potential product limitations. Many bean dealers are no longer accepting pre-harvest glyphosate on dry beans.
Dry Bean Tour Recap
Last week Manitoba Pulse & Soybean Growers and Agriculture and Agri-Food Canada held a dry bean tour at AAFC’s Morden Research and Development Centre. Topics ranged from dry bean diseases, the annual dry bean disease survey, MPSG’s dry bean regional variety trials and the AAFC dry bean breeding program. A big thank you to everyone who attended, planned and participated!
See our August edition of the Dry Bean Bulletin for more information on some of these topics and more. Interested in receiving our bi-annual dry bean bulletin? → Sign up here.
Soybean Stem Diseases
Stem and root diseases can have a greater impact on soybean yield and quality than foliar diseases. Stem disease symptoms typically arrive later in the growing season during mid- to late- reproductive stages, which can directly impact pod and seed production.
Stem diseases to keep an eye out for in August include:
- White mould
- Phytophthora root and stem rot
- Northern stem canker
- Pod/stem blight
- Anthracnose
- Sudden death syndrome
More Information on Soybean Stem Diseases →
Lupins: Exploring Alternative Pulse Crops
MPSG’s lupin variety trials were highlighted at MCDC (Carberry) and PCDF (Roblin) Diversification Centre Tours last week. There are three types of lupins included in these trials 1) sweet white broad-leaved lupins (Lupinus albus), 2) narrow-leaved blue lupins (L. angustifolius) and 3) yellow lupins (L. luteus). These different types of lupins are different plant species and are as different from each other as wheat is from oats!
MPSG has sponsored these trials to explore alternative pulse crop options for farmers. We’re interested in exploring these crops through small-plot trials at Diversification Centres to answer some key questions. Are these crops suitable for growing in Manitoba conditions? What are the missing pieces of agronomy to growing these crops?
Lupins are desirable since they are resistant to Aphanomyces root rot, which is a devastating pea disease. They also have great nitrogen fixation potential, provided they are inoculated with the correct inoculant (containing Bradyrhizobium lupini). And markets are interested in lupins due to their high protein potential (36% vs. 24% in peas).
Results from these regional variety trials will be available this fall in MPSG’s Pulse & Soybean Variety Guide and will report yield, days to maturity and other agronomic information.
Canadian Grain Commissions’ Harvest Sample Program
You can sign up to receive a harvest sample kit to submit your crop to the CGC for an assessment of your grain’s quality at no cost. Results can be used when marketing and delivering your grain. The deadline to sign up for a sample kit is November 13, CGC accepts samples until November 30 and results are available within 20 days.
Quality results include:
- Unofficial grade
- Protein content on barley, beans, chickpeas, lentils, oats, peas and wheat
- Oil and protein for mustard seed and soybeans
- Dockage assessment on canola
- Oil, protein and chlorophyll content for canola
- Oil and protein content and iodine value for flaxseed
- Falling number for wheat and rye
- Vomitoxin (deoxynivalenol or DON) levels for wheat, corn and barley