Using SprayConnect for Site-Specific Fungicide Applications

Written By: Bryden Templeton, Manager of Ag Innovation

As June 2021 concludes in Western Canada, a changing of the guard occurs, so to speak.  Farmers and agronomists alike quietly reflect on the growing conditions thus far and optimistically await what July may bring. This demonstrates a symbolic shift as growers transition from creating the best possible environment for a seedling to thrive (think seeding, nutrition, inoculation, rolling, weed and insect removal) to protecting the precious fruits of those labors (fungicide applications, PGR’s, foliar nutrition, and before long harvest management).  My goal is to dive deeper into disease management and discuss how digital technology can further optimize our fungicide applications.

Many years ago, a group of farmers and agricultural experts started observing the often substantial differences in growing conditions that can exist within our fields.  Whether they knew it or not, this marked the conception of site-specific crop management. Perhaps this sounds like a modest evolution amongst the giants of GPS, advancements in crop protection chemistry, nutrition, equipment technology, etc. However, I have noticed a substantial change in how I view crop growth within a single field unit.  I no longer search for single answers to questions with multiple answers. Crop staging, for example – rather than seeking out the stage that best suits the average of the field, I now observe that a water-shedding knoll may be two growth stages behind the same plant located on a mid-slope.  Disease symptomology – rather than attributing a composite severity rating across the field, I now make note that disease symptoms are often presenting themselves spatially and predictably.  Portions of a field may never exhibit a single lesion whereas others can be completely destroyed.
Many of us understand the dynamics of the often-cited disease triangle.  For infection to occur, 3 conditions must be met: 

1. The presence of a susceptible host,
2. The pathogen, and 
3. Conducive environmental conditions.  

It is very unlikely that these 3 elements exist at static levels across an entire field.  Take the host for example, we can see less plants in saline areas, wet depressions, areas of higher straw production, and spots that have been ravaged by insects.  For many pathogens we would expect to see higher incidence in areas that are lower lying, exhibiting wetter conditions, and likely to be areas of historically higher disease pressure.  As for environmental conditions, we know that topography plays a tremendous role in the distribution of water throughout a field and where we are likely to see the worst effects of our several frosts this spring.  One last consideration not covered by the disease triangle has to do with risk and economics. Sometimes the host is just plain not worth protecting.  This is often because of the potential for the plant to produce yield has been negatively impacted to the point where realizing a return on investment on the application has become unattainable. Consider that knoll situation again.  Maybe the canola germinated a month late due to dry seeding conditions and lack of timely rain events.  The plants that are there are small, few and far between.  Would it be in our best economic interest to defend these hosts from the risk of infection? See figure 1 below, which demonstrates the differences that can be found across just one lentil field. 


Fig. 1: Differences in biomass across lentil field. 

Until only recently has the convergence of several technologies put us in a position to finally acknowledge this. Vegetative index data (NDVI), informed by remote imagery, is uniquely positioned to delineate these field differences.  To simplify, consider taking a picture of your field and letting mathematics differentiate spatial zones based on the amount of plant material or crop biomass.  Crop biomass data is well-suited to targeting  site-specific fungicide applications as it’s generally a strong indicator of the presence of conducive environmental conditions and an economically viable host.  Think of it as a way of asking the plants themselves to share some information about their growing environment. 

All of this means that we only need to treat the acres on the farm that demonstrate the greatest risk of infection.  In other words, rather than discussing the fields that require an investment in a fungicide application we can now discuss the acres that do.  This is noteworthy because all too often at-risk areas go untreated when growers are forced to factor-in the acres which that would receive unneeded fungicide, which further prevents achieving a meaningful ROI.

Much like everything we do at G-Mac’s AgTeam, this service operates on quality agronomy.  Without it, this service becomes very hard to do correctly.  One needs to ground truth each field individually with NDVI maps on-hand to ensure the variability is being correctly assessed by the technology.  Then, site-specific recommendations are created for the different management zones.  Manual adjustments will be completed if necessary before a prescription file is uploaded to a compatible rate controller.  Generally, most displays manufactured in the last 10 years are capable of this.  G-Mac’s AgTeam’s proficient Agronomy staff and the technical expertise of the Ag Innovation team will skillfully execute and provide support for this new and exciting service designed for our growers, while still providing timely and transparent information throughout the entire process. 

For more information on SprayConnect or to learn how you can take advantage of this new service, contact your local G-Mac’s AgTeam representative.