The success in soybean production depends on the correct use of several cultural practices, among which seed treatment is a powerful tool to protect the seed from agents that cause diseases and pests that threaten the initial stage of cultivation.
However, researchers have increasingly warned about the importance of maintaining the sanity of plants throughout the vegetative stage, keeping the inoculum of diseases lower so that the plant can express maximum productive potential and that fungicides applied via the foliar are exposed to less disease pressure, allowing a better performance in controlling important diseases during the plant cycle.
During the 1st Soybean Sanity Forum, sponsored by Plant Health Care and held last July 21st, Dra. Mônica Debortoli, from Phytus Group, reinforced the importance of the first application of fungicides to be done before the canopy closure, which represents the limit for the grower to apply foliar fungicides that access the lower leaves of the soybean crop evenly. The canopy closure, depending on the planting date, will occur in Brazilian conditions, between 25 and 40 days, a period when large farmers are busy, still planting soybeans and when they usually face more rain, which makes difficult to machine to enter the field.
This is the reason why Plant Health Care (PHC) is launching in 2021 its first product with PREtec technology: Saori™, a peptide applied as seed treatment, recommended for the management of foliar diseases. Saori™ is the only registered product for seed treatment in Brazil and recommended for the control of soybean rust.
Brazil was the first country to have a PREtec peptide approved due to the priority that government agencies are giving to products recommended for Asian Soybean Rust (ASR), with an environmentally friendly profile, lack of residue, and unique biochemical mode of action. Caused by the fungus Phakopsora pachyrhizi, ASR is a devastating disease with an estimated crop yield loss of up to 90%. Brazilian soybean farmers spent US$2.85 billion on disease control in the 2019/20 season, approximately 90% of which was for ASR control.
The Saori™ brand has the meaning of “sacred soil” among others and was selected because it connects with the product’s core value proposition: protecting the plant from germination to maturity against the most important soybean diseases in Brazil.
During 4 crop seasons, Saori™ was tested in Brazil in seed treatment for ASR control in the main soybean producing regions several parameters have been evaluated, such as germination and vigor, effect on the hidden disease (not yet visible during the vegetative stage and before any fungicide application), leaf retention and overall control of ASR throughout the soybean cycle, with final evaluation of yield.
Protecting the plant from germination
One of the first parameters evaluated in Saori™ trials was germination and vigor. Evaluations made 7 and 14 days after seed treatment indicated that Saori™ improved both germination and vigor of the soybean seeds, as showed in Figure 1.
Figure 1. Effect of Saori™ in seed treatment on vigor and emergence of the plants. Itaara, RS, 2021.
Controlling hidden diseases
During the vegetative stage of the soybean cycle, Saori™ evaluations for hidden ASR were performed before any foliar fungicide application. For this purpose, trifolia were collected with no visible signs of the disease, placed in a humid chamber, and left for 48 hours at 20-25℃ and exposed to continuous light favoring sporulation. After 48 hours, the number of pustules of ASR were evaluated. Saori™ treated plants showed a reduction of the sporulation up to 80%, 48 days after the seed treatment.
In another trial, treated plants were inoculated with ASR spores, Saori™ has reduced the number of ASR pustules by 77% after 14 days of the inoculation and inhibited the fungi sporulation (Figure 2).
Figure 2. Pictures of the sporulation of the ASR pustules in the leaves of the Check treatment (left) and in the Saori™ treated plants (right), 14 days after inoculation. Rio Verde, Goiás, 2020.
Effect on leaf retention
Saori™ effects are not restricted to the vegetative stage of the crop. They stay visible to the end of the soybean cycle. Figure 3 shows the visual differences among the check plot, the treatment where the foliar fungicide program was applied without seed treatment and where Saori™ was applied in seed treatment in addition to the standard foliar fungicide program. The sanity of the plants can be observed in Saori™ treated area.
Figure 3. General view of the Saori™ seed treatment plot (right), the check treatment (left) and the standard foliar fungicide program, applied without seed treatment (center). Iracemápolis, SP, 2021.
Improve efficacy of the foliar fungicides
After consolidating the data from 4 crop seasons, Saori™ showed that not only promotes a delay of up to 14 days in the development of ASR but increases the effectiveness of the control provided by foliar fungicides by up to 45% (average of 19 to 23%) and reduces the risk of developing resistance to existing fungicides.
In addition to that, during the last season, Saori™ was evaluated against other important soybean diseases and proved to control important spot diseases such as brown spot, Cercospora spot and target spot, effectively contributing to the soybean to express its productive potential.
The use of Saori™ in seed treatment, protects soybean from germination and provides more flexibility to the farmer during the soybean vegetative cycle. Saori™ preserves the sanity of the lower leaves and promotes a better filling of the grains resulting in a consistent increasing in productivity in the last four seasons by up to 16% (average of 4 to 6%).
Saori™ is a novel biochemical seed treatment that amplifies a plant’s natural defense, increasing plant health and yield and safeguards growers’ investment.
Since 2017/18, Saori™ has demonstrated its potential to improve ASR control and avoid fungicide resistance, bringing peace of mind to soybean growers and an average gain of 3 bags/ha, representing 6x grower return on investment.
On top of ASR control, Saori™ has demonstrated efficient control of other soybean diseases that have become a big concern to the growers.
PREtec NEW TECHNOLOGIES PIPELINE
PREtec stands for “Plant Response Elicitor Technology” and defines the technology that works by inducing natural defensive and metabolic responses in crop plants so that they suffer less harm from the usual stresses (like nematodes or diseases) faced during a growing season.
Today, Plant Health Care has three platforms with PREtec technology:
Innatus 3G – Platform consisting of products serving as a plant vaccine to prevent diseases such as Asian Soybean Rust (“ASR”). The vaccinated plants also show enhanced growth, strength, and yield increase. We are currently focused on Saori™ (PHC279), which has shown remarkable activity in many crops.
T-Rex 3G – Platform consisting of products specifically for the activation of plants’ natural defense against nematode infection for both major row crops and specialty crops. The vaccinated plants also show great resistance to abiotic stress such as drought. Within T-Rex 3G, we are currently focused on PHC949. This product is showing performance comparable to that of conventional chemicals in field trials.
Y-Max 3G – Platform consisting of products as biostimulants activating plant growth genes and pathways for yield increase and quality improvement in various crops such as fruit and vegetables. We are currently focused on PHC404 and PHC414 from the Y-Max platform.
This articls was originally published in the magazine 2021 Seed Treatment Special.