Applying soybean fungicides in-crop has proven to be an effective defense against yield-robbing diseases like white mould.
Syngenta’s Agronomic Service Manager Eric Richter believes fungicides will play an increasingly important role as growers climb up the soybean yield curve and set their sights on putting more bushels per acre in the bin. But as yield expectations rise, he reminds growers that they can’t just rely on that last line of defense that fungicides bring to their fields.
“There really are four pillars that we need to focus on when it comes to managing disease. It starts with genetics and cultural practices. Then we have to consider seed treatments and finally, fungicides,” notes Richter.
Genetics is the first line of defense
Protecting yield potential starts with variety selection. “At Syngenta, we've worked very hard to categorize and to rate our varieties for resistance to diseases like sudden death syndrome, or white mould tolerance,” says Richter who urges growers to consult these ratings when selecting seed. When fighting disease, growers also have to be mindful of seed quality. “A number of the soybean diseases can be transmitted on the seed. It's important to use certified seed, clean seed, and seed treated with a fungicide. That gives you critical protection and can help break that disease cycle in your new crop.”
When it comes to cultural practices there are three major considerations, starting with rotations. “You really need a good rotation,” says Richter. Lengthening your rotation to include corn, wheat or other crops will help lower the disease inoculum and disease incidence. Fertility also plays a key role. Good fertility will help the plant start strong and stay strong, allowing the plants natural immune system to protect against diseases.
Manage crop canopy
Canopy management is also critical. When growers effectively manage populations, they can optimize canopy for both yield production and disease management. “We don't want too much vegetative growth, we want to really find that ideal spot between vegetative growth and reproductive growth. That, in turn, will minimize some of the disease potential,” explains Richter.
At this point it’s time to focus on in-crop fungicides. Richter stresses that it’s important for growers to understand that higher soybean yields create environments that are more conducive to disease. “That’s why it’s important to be proactive with our scouting and ensure we apply fungicide at the right timing.”
Timing fungicide application
Richter is a proponent of a two-pass fungicide approach if disease is a concern. He notes that OMAFRA plant pathologist Alberta Tenuta recommends that growers can optimize control of white mould when flowers emerge at the R1 to R1.5 growth stage. “That’s the timing we should target for a first application,” says Richter. A second fungicide application should be timed for the R2.5 stage to maximize yield.
“Fungicides are your last line of defense, whether it be Allegro as a white mould specialist or Trivapro as a broad spectrum,” says Richter. “In areas where we know we've got a high risk of disease, that use of fungicide can really help increase yields and maximize profitability at a really good return on investment.”