A one-size-fits-all approach to treating seed doesn’t work for pulse crops.
Although they’re often lumped together, the seeds of pulse crops are unique. Yellow peas, lentils, dry beans and chickpeas may be challenged by many of the same soil- and seed-borne diseases, but how you protect them varies from crop to crop. A one-size-fits-all approach doesn’t work for pulse crops. Application strategies differ, depending on shape, texture and size. Two industry experts offer tips and recommendations for getting the most out of your seed treatment.
Understanding Size, Shape and Texture
Seed treatments adhere to seed very differently, depending on size, shape and texture, explains Bayer SeedGrowth Specialist Nicholas Petruic. Lentils, for example, can have a dry, flaky surface, while beans and peas can have a smooth, glass-like surface.
Seed size also impacts application rates, says Petruic. “Trilex EverGol has a standard application rate of 328 millilitres per 100 kilograms of seed, but if you were to try to apply just that amount of rate across a large kabuli chickpea seed your coverage would be very, very poor,” he says. “In hindsight, if you took that same amount of volume and applied it to a small red lentil, you actually could be over-applying and have too wet of a seed.”
“It’s a fine balance of understanding seed wetness to seed coverage,” he adds. “Generally, treating pulses is trial and error on your farm, and having an adaptable product — something that can be manipulated very easily — will help you achieve the best results.”
Seed shape and texture also impact coverage. Chickpeas, for example, have deep crevices on the seed’s surface, which can make complete coverage a challenge. They require a lot more water volume when mixing product to get good coverage, says Petruic.
Ensure Treatment is Dry before Seeding
Seeds that require extra coverage will need more solution to increase the application rate, but they do not require more active ingredient, Petruic clarifies. Because more volume is needed for adequate coverage, sometimes seed requires more drying time.
“If you don’t do that, it can cause you challenges when trying to put wet seeds through an air drill,” he says. “By allowing it longer time, the moisture actually moves inside the seed and it will dry on the seed’s surface.”
Seed treatment on wet seed can be lost on the surface of the auger as it moves, which means you’re not going to get what you’re paying for.
Adding or removing products from the mix can also change treatment consistency, and, therefore, how much drying time is needed.
“Everybody wants the agronomic benefit of a micro, or something like that, on the seed, and that’s fine,” says Petruic. “Realize it’s not just throw it on and go.”
Handle with Care
Pulse crop seed coats tend to be a bit more fragile too, which means they need to be handled with care and as infrequently as possible.
“Using things like conveyors help if you’re handling dry seed,” says Petruic. “And what we’ve found is when you can put a liquid seed treatment on prior to handling it with a flighted auger, it greatly reduces the amount of cracking that will happen.”
Cracks, he adds, act as gateways to disease. “It’s like an open doorway,” he says. “If you have a crack on that seed, but you’re able to fill it with seed treatment, it’s like closing the door.”
To further ensure seed quality at the time of planting, handle seed as few times as possible. Following a tough harvest, seed coats can be very brittle. Even applying a little water before moving them will help the integrity of the seed, says Petruic. He recommends using conveyors on low speed where and when you can.
Keep an Eye on Temperature
When warm liquid is applied to seed that is too cold, flash-freezing can occur. Flash-freezing will give very poor coverage. Ice crystals will form on the surface of the seed, and the seeds won’t get the smooth coverage necessary for proper protection. As seed moves through the auger, friction can remove the ice crystals, which means seed will be left untreated.
“If you’ve got seed in the bin with an aeration fan and you can warm that seed up prior to treating, great,” says Petruic.
He recommends raising seed temperature to somewhere between 3 and 5 C.
Even the Best Seed Needs Protection
It’s always recommended to plant the best seed possible, but even good seed needs protection. However, high-quality seed is only one piece of the puzzle. Crops face soil-borne disease all the time. Diseases, such as Fusarium, affect both pulse and cereal crops, making them hard to get around in tight rotations. They’re especially problematic in no-till situations, says Petruic. Tillage can break up residue, which helps manage disease.
“All the ground out there is potentially going to have soil-borne disease, and if you don’t treat for them, you’re essentially putting your high-quality seed at risk,” he says. “And pulses, because they go into cool, moist soils usually, it seems like Rhizoctonia AG 2.1 and AG4 and Pythium are two diseases that are really prevalent in those types of soils.”
Because the diseases are soil-borne, producers “can’t use a seed test for them, they’re either there or they’re not,” he adds. “Predominantly, if you’ve been growing pulses and canola, there’s a good chance they’re going to be there.”
Petruic has two last tips for growers when it comes to seed treatments: make sure the seed treatment you’re using is compatible with your inoculant of choice and know your application window.
“You don’t want to have two things on the seed that are killing each other,” he says.
To do this, he recommends checking the labelled instructions. “If it says 24 hours or 48 hours compatibility, then you adhere to that,” he says.
Use the Right Product for the Task at Hand
Nevin Rosaasen, policy and program specialist for Alberta Pulse Growers, adds a few points to this list of tips. First, he says, it’s important to make sure growers are treating seed with the correct product.
One thing producers must ensure is if they’re looking at using a fungicide, they should know what target pathogens are controlled with that seed treatment. If they have a problem with Fusarium root rot, they need to make sure the active ingredient will give them control or suppression of that pathogen.
Insecticide treatments can be quite costly. If producers are treating yellow peas with a neonicotinoid seed treatment to protect against pea leaf weevil, for example, they should make sure they’ve either had pea leaf weevils feeding on their crop or that they’ve consulted a pea leaf weevil map from the previous year to ensure the pest’s presence.
“I would strongly encourage growers to not treat seed with an insecticide if they don’t have that pest of concern,” says Rosaasen.
“It’s very important if you decide to use a seed treatment that it is because you indeed have the risk of yield reduction, either through pathogens or through an insect pest of concern,” he adds.
Insect forecast maps for 2020 can be found on Alberta Agriculture and Forestry’s website.
“Increasingly, neonicotinoidseed treatments are under scrutiny and when deciding when to use a product, it shouldn’t be a decision made on the best insurance, but rather its protection against a pest you have confirmed you have in your area,” Rosaasen concludes.
Pulse crops are grown in a wide variety of regions. They’re adaptable, but they come with their own unique set of challenges. When it comes to treating them, growers shouldn’t take a one-size-fits-all approach. Understanding how best to treat them will increase a producer’s chance of success.