Seed treatments can help producers protect seed from pathogens and diseases
by Trudy Kelly Forsythe
Seed treatments are a valuable resource for producers looking to protect the viability of their seed, and there are a variety of seed treatments for pulse crops on the market these days.
“Seed treatments protect against seed- and soil-borne pathogens, and provide some protection to poor quality seed and to seed germinating in poor conditions,” says Barb Ziesman, the Provincial Specialist, Plant Disease with the Saskatchewan Ministry
of Agriculture (SMA). “But, they will not cure a poor seed lot with high levels of dead, damaged, or infested seed.”
Protecting the seed where there is disease pressure will help to improve seedling emergence and seedling vigour. The economic benefits are highest when there is high disease pressure and/or when the crop is growing in adverse conditions. Ziesman
says producers need to judge whether to treat their seed based on seed test results and the history of the field.
Think About It
There are a number of factors producers need to keep in mind as they consider seed treatments. For example, many of the treatments have more than one active ingredient in them — such as a combination of insecticide and fungicide. Often more than one fungicide is included because not all fungicides are effective against all pathogens or diseases. As a result, the SMA encourages producers to know what disease they want to manage, and to choose the treatment that is going to be effective against that disease.
Producers also need to keep in mind that products can be systemic or contact. “Only systemic fungicides are effective against pathogens occurring in the seed or embryo,” says Ziesman. “With contact fungicide, the level of seed coverage is more important. You want to ensure you get complete coverage.”
And, it is important to look at the level of control or suppression. “If possible, producers want a treatment that is registered for control, not just suppression, because they want a product that is going to give the highest level of protection,” Ziesman says, pointing out there are no seed treatments registered for control of Aphanomyces root rot, only treatments registered for suppression.
Growers should also get seed tested for germination, vigour, and disease levels as this will help them decide whether to use the seed or to get the seed treated.
Finally, producers need to remember that treatments will only be effective when the crop is in the seed to seedling stage. “That is because the active ingredient is only active for a finite period of time,” says Ziesman. “If they are treating on farm, they need to ensure a good level of seed coverage since seed coverage will impact seed efficacy.”
When To Treat
Dale Risula, a Provincial Specialist, Special Crops with the SMA, says many of today’s seed treatments require commercial application. This means it is important for growers to book times with their dealers well in advance so they will not miss out on seed protection that is required for the coming year.
“Seed treatments are applied following consideration of seed-borne as well as soilborne organisms that may cause a problem to their specific crop planned for the coming season,” Risula says. “Pulse crops are legumes that require inoculation with
Rhizobium bacteria, a living organism that is probably very sensitive to seed treatments, particularly those containing fungicides.”
Producers should also look for compatibility ratings on the seed treatment label, but consider treating the seed first with the fungicide, or multi-purpose, seed treatment before inoculating with the Rhizobium bacteria as recommended by the SMA. “This will give the bacteria a better chance to survive and do their job,” Risula says.
Most seed treatments will only last about two to three weeks in the soil and they are variable in their times of effectiveness. That is why it is important to follow the directions on the label for the best results and to remember that there is some variation
“Some products may still be available for home application but having the correct equipment to apply the product is essential,” Risula adds. “Coverage is essential too as you must ensure complete coverage to get the results you need. Incomplete coverage is basically as good as not treating at all.”
While there are no set thresholds for tolerance levels in pulse seed for planting, the SMA maintains an updated list of recommended thresholds and products for producers to refer to. But, Ziesman stresses, “they should only be used as guideline, or rule of thumb, because they are not true thresholds, but more of a general guide.”
Part of the issue is changing conditions causing moisture and temperature conditions after planting to vary from year to year. The levels of moisture and temperature will impact the critical level needed for seed treatment.
Producers can learn more about seed treatments recommended for pulses at saskpulse.com or the SMA website.