Nutritional & Biological Seed Treatments vs. Fungicides: A Cost-Effective Approach
One of the best practices we recommend to all our clients is seed treatments. They offer the highest return on investment while being one of the lowest input-cost strategies. In this article, we compare traditional fungicide seed treatments with a nutritional and biological approach to help you make an informed decision. For this video, we’ll be using a wheat crop with a target yield of 4t/ha at a seeding rate of 85kg/ha.
First, make sure to watch our video from our YouTube channel (Agriculture Explained)
The Role of Fungicides in Seed Treatment
Fungicides are often applied as a seed coating to prevent early-stage fungal infections. They suppress pathogens on the seed and seedling, providing protection for about 4-6 weeks. However, after this period, their effectiveness significantly declines.
For this article we’ll be using a common fungicide to compare against. This common fungicide seed treatment costs approximately $12.05 per hectare and includes three active ingredients from groups 3, 4, and 7. While this can help suppress disease, fungicides come with notable drawbacks:
- Microbial Suppression: Fungicides can inhibit beneficial microbial activity, reducing colonization by mycorrhizal fungi and other beneficial microbes.
- Resistance Development: Pathogens can build resistance to fungicides over time, reducing their effectiveness and necessitating stronger applications or different active ingredients.
- Toxic Effects: Fungicides are toxins that can harm plant metabolism, requiring the plant to expend energy detoxifying itself, which can slow early growth.
- Reduced Germination: Studies show that fungicide-treated seeds exhibit lower germination rates and delayed emergence. In trials, untreated seeds had an 80% germination rate, while fungicide-treated seeds were around 70%. Additionally, untreated seeds germinated faster—by day 13, 65% had sprouted compared to only 14% of treated seeds.
- Suspected Of Causing Cancer: Don’t take our word for it, check the product label under the GHS statement for any given fungicide (or any pesticide), below is a screenshot from this particular product.
It is understandable to use fungicides when a fungal pathogen is likely to be present in the soil, however it is important to understand the consequences of these. If disease build up is so bad that without a fungicide, you’re crop would be destroyed, I would consider improving crop rotations to reduce disease burden. A diverse cover crop with inoculants can be a very effective way at reducing disease pathogens.
The Nutritional & Biological Approach
Instead of using fungicides, we advocate for a nutritional and biological seed treatment. This method enhances plant immunity, improves early root and shoot development, and fosters beneficial microbial relationships. This gives the plant the best opportunity to quickly develop a strong root system and form symbiotic relationships with beneficial microbes that will assist the plant in its growth and reproduction (Yield). Key benefits include:
- Improved Microbial Symbiosis: Mycorrhizal fungi and beneficial bacteria thrive, aiding phosphorus, zinc, and water uptake.
- Stronger Early Growth: Untreated seeds germinate faster, giving them a head start in establishing a healthy root system.
- Long-Term Plant Health: Instead of suppressing disease symptoms temporarily, biological treatments work to strengthen the plant’s natural defense mechanisms and inoculant the plant with natural disease suppressing microbes.
Below is a small trial done using the products mentioned below, on the right side is the biological and microbial seed treatment and on the left side was the control. Notice how bigger and darker green the plant on the right are, that is simply because the seed was initially supplied with nutrition and biology.
Our Recommended Products for Seed Treatments
At Agresol, we focus on seed treatments that enhance early plant vigor, microbial activity, and nutrient uptake. Our approach includes a combination of biological inoculants, microbial stimulants, and essential nutrients to support strong germination and resilient seedlings.
So here is exactly what we could recommend to some of our clients:
Nutrition
- Minerals: Applying minerals right onto the seed provides the plant with a highly accessible form of nutrition to start it’s development. Our goal for our clients is to have their crops develop a strong and robust root system, this is important to exploring as much of the soil as possible.
Minerals to consider include Calcium, Zinc, Boron, Manganese and Silicon, however any board spectrum mineral product will do well. We would suggest not to over-do it on N, P, K as the starter fertiliser will likely supply more than enough, ideally a focus on trace minerals will provide the greatest returns.
- Fish Hydrolysate: This provides a rich source of amino acids, peptides, and essential nutrients that enhance early plant development. It contains beneficial enzymes and bioactive compounds that stimulate microbial activity, improving nutrient cycling and root colonization. The slow-release nitrogen and organic matter support seedling vigor, helping plants establish quickly while increasing resistance to environmental stress. Additionally, fish hydrolysate promotes beneficial fungi and bacteria, fostering a balanced soil microbiome that enhances overall plant health.
- Kelp: Kelp is a powerful addition to seed treatments, providing natural growth hormones like cytokinins, auxins, and gibberellins that stimulate germination and root development. It enhances seedling vigor by improving nutrient uptake, boosting stress tolerance, and increasing resistance to drought and disease. The bioactive compounds in kelp also support beneficial microbial activity in the rhizosphere, promoting a healthier soil environment for early plant growth.
This study shows a significant increase of shoot length and fresh weight by 20 and 25% respectfully when seaweed was added to the substrates.
- Fulvic Acid or Humic Acid: Fulvic and humic acids play a crucial role in seed treatments by enhancing nutrient availability, stimulating root development, and improving overall seedling vigor. Fulvic acid, with its smaller molecular structure, easily penetrates seed coats, delivering essential minerals and acting as a natural chelator to improve nutrient uptake. Fulvic Acid tends to stimulate bacteria growth and is a great addition when seeking additional bacterial populations and activity. Humic acid enhances soil structure and microbial activity, specially fungi activity and populations, creating a more favorable environment for germination and early growth. Together, these compounds boost root elongation, increase stress tolerance, and improve water retention, leading to stronger, more resilient plants from the start.
This study demonstrates that the application of fulvic acid resulted in increased root development, allowing the plant to absorb more water resulting in increase spike weight and grain weight per spike, therefore resulting in higher yields and higher water use efficiency.
We recommend the product PreCede to our clients, it contains the minerals N, P, K, S, Ca, B, Zn, Cu, Mn, Fe, Co and Mo, as well as Fish, Kelp, Fulvic Acid, Aloe Vera and carbohydrates. The combination of all these into one product make it much easier to apply. We recommend applying this at around 4L per tonne, costing $2.62/ha.
Microbes
- Worm Castings Extract: This provide a rich source of beneficial microbes, enzymes, and auto-inducers that enhance seed germination and early root development. These extracts introduce diverse microbial life, including nitrogen-fixing and phosphorus-solubilizing bacteria, which support plant growth from the moment the seed is planted.
This paper shows that the microbes contained within worm castings provide a range of benefits ranging from increased nutrient availability, production of growth hormones, nitrogen fixation, suppression of fungal pathogens and the production of antibiotics. This range across bacteria species such as Pseudomonas, Rhizobium, Bacillus, Azosprillium, and Azotobacter but include many more. Likewise, this study finds an additional whole range of beneficial microbes that support plant health.
As part of our recommended seed treatment mix, we always include Mycro-Start which is a vermiculture extract. This can be applied to the seed at 2L per tonne, costing $1.39/ha
The seedlings below are oats that were treated with a liquid vermiculture extract, notice the thick rhizoshealths.
- Trichoderma spp: Trichoderma is a beneficial fungus that enhances seed germination, root development, and overall plant resilience. As a seed treatment, it colonizes the root zone, outcompeting harmful pathogens like Pythium and Fusarium while stimulating plant defenses against disease. Trichoderma also improves nutrient uptake by breaking down organic matter and making nutrients more bioavailable. Additionally, it promotes root exudation, fostering beneficial microbial interactions in the rhizosphere. This results in stronger, healthier seedlings with improved stress tolerance and increased growth potential.
Trichoderma has been found to control 29 different fungal pathogens (This study), ranging from fungi belonging to Botrytis, Fusarium, Rhizoctonia, Pythium, Sclerotinia, Pseudocercospora and Colletotrichum genera. In many cases, Trichoderma, has been just as effective as the fungicide controls.
- Bacillus spp: Bacillus species are powerful plant-growth-promoting bacteria that enhance seed germination, root development, and disease resistance. When applied as a seed treatment, Bacillus colonizes the rhizosphere, producing enzymes and metabolites that suppress harmful pathogens like Rhizoctonia and Fusarium. It also improves nutrient availability by solubilizing phosphorus and fixing atmospheric nitrogen, leading to better early plant vigor. Additionally, Bacillus stimulates plant immune responses and enhances tolerance to environmental stress, resulting in healthier, more resilient seedlings with improved establishment and yield potential.
- Pseudomonas spp: Pseudomonas species are beneficial bacteria that enhance seed germination, root growth, and plant resilience. As a seed treatment, Pseudomonas colonizes the root zone, outcompeting harmful pathogens through competitive exclusion and producing antimicrobial compounds that suppress diseases like Pythium and Phytophthora. These bacteria also stimulate plant growth by producing phytohormones and solubilizing nutrients such as phosphorus and iron, making them more available to the developing seedling. Additionally, Pseudomonas improves plant stress tolerance by inducing systemic resistance, helping crops better withstand drought, temperature fluctuations, and other environmental pressures.
Another very cost effect product we always recommend for seed treatments is Mycro-Tec SP, this contains a combination of all three beneficial microbes (Trichoderma, Bacillus, and Pseudomonas) for disease defense. We recommend to apply this at 1L per tonne costing $1.38/ha.
This provides the defense component of the overall seed treatment and provides protective benefits for the whole growing season.
At this point the combination of PreCede, Mycro-Start and Mycro-Tec SP will cost $5.39/ha, providing many benefits initially and into the season.
However, we can also apply another micobe that enhances all of these benefits.
- Mycorrhizal Fungi: Mycorrhizal fungi form symbiotic relationships with plant roots, significantly enhancing nutrient and water uptake. As a seed treatment, these fungi establish early root colonization, extending the root system through fungal hyphae that access soil nutrients like phosphorus, zinc, and nitrogen more efficiently. This leads to improved seedling vigor, drought resilience, and overall plant health. Mycorrhizal fungi also enhance soil structure by promoting soil aggregation, reducing erosion, and improving moisture retention. Additionally, they support plant immunity by triggering systemic resistance against pathogens and reducing transplant shock, making them an essential component of regenerative seed treatments.
This study found that plants inoculated with mycorrhizal fungi produced better yields and biomass under water sufficient and drought conditions.
Interestingly, the inclusion of Mycorrhizal Fungi as a seed treatment increased the effectiveness of all other treatments too (1, 2, 3, 4).
The inclusion of Mycorrhizal fungi will cost about $7/ha with Mycro-Tec VAM. This is pretty expensive, but only needs to be done initially when you know Mycorrhizal Fungi populations are low/absent, after a long fallow, or after a brassica crop (Such as Canola)
Summary Of Our General Recommendation
For a wheat crop sown at 85kg/ha:
- PreCede – 4L/T = $2.62/ha
- Mycro-Start – 2L/T = $1.39/ha
- Mycro-Tec SP – 1L/T = $1.38/ha
- Total Without MF = $5.39/ha
- Mycro-Tec VAM (Optional) – $7/ha
- Total With MF = $12.39/ha
Get Started In Regenerative Agriculture
If using seed treatments is something that you would like to try on your farm, we can assist in transitioning your farm to regenerative agriculture while maintaining yields and reducing chemical usage. You can get started for FREE with a free 30 minute consultation.
