Fungicide Buyers' Guide

Published online: Mar 13, 2021 Articles, Fungicide, New Products
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This buyers' guide appears in the March 2021 issue of Potato Grower.

Black dot. Late blight. Fusarium wilt. Ugly names attached to truly ugly diseases with the potential to completely wreck an entire potato crop.

Over the years, growers, researchers and chemical reps have worked tirelessly to develop sustainable, economical solutions to the problems posed by these fungal maladies. Potato Grower’s fungicide buyers’ guide showcases a few of those solutions.

Always read and follow label instructions. Some products may not be registered for sale or use in all states or counties. Please check with your state or local extension service to ensure registration status.


Westbridge Agricultural Products

(800) 876-2767

Xena Spreader-Sticker

Xena Spreader-Sticker is an effective, OMRI-listed adjuvant that increases the spreading and adhesion of insecticides, fungicides, herbicides, biostimulants, plant growth regulators and biopesticides. It is compatible with most inputs and can be used in conventional and organic farming.

Xena improves the coverage and retention of agricultural sprays on the plant surface. It is a blend of three nonionic surfactants that increase spreading of applied spray droplets. Upon drying, Xena aids in adhering agrochemicals to the plant surface by forming a thin, transparent film composed of plant-derived polysaccharides, rather than synthetic polymers.

Xena is now available in for sale in Arizona, Colorado, Idaho, Florida, Massachusetts, Michigan, Montana, Nevada, New Mexico, New York, Oregon, Texas, Washington and Wisconsin. California state registration is pending.


Oro Agri

(559) 442-4996

ORO-RZ Soil Adjuvant

Oro-RZ adjuvant improves the efficacy of soil-applied, pre-emergent fungicides while contributing to better soil health. Oro-RZ improves soil hydraulic conductivity, even in hydroscopic soils, to move the herbicide solution into soil pore spaces.

This lowering of hydraulic conductivity and movement into pore spaces helps lay down a uniform barrier in the top few inches of the soil. Because of the low surface tension of Oro-RZ, the herbicide spreads uniformly, eliminating coverage gaps.

Oro-RZ also contributes to soil health. It has very low surface tension, so it flows within the micropores in the soil, leading to better aeration and water penetration. Oro-RZ even helps penetrate and break up pockets of hydrophobic soil. These improvements to aeration and soil structure encourage microbial and adventitious root growth and, ultimately, a healthier soil environment.

Wetcit Foliar Adjuvant

Wetcit, now with TransPhloem technology, is a foliar adjuvant with great benefits for potato growers from pre-plant to harvest. Used at lower rates, it is an excellent spreader for contact herbicides. Used at higher rates, is a superior penetrant that delivers active ingredients to target sites, quicker and in higher concentrations, compared to other adjuvants such as crop oils, methylated seed oils, high-surfactant methylated seed oils, and non-ionic surfactants. This means Wetcit improves the speed and efficacy of systemic herbicides, like Roundup, compared to these other types of adjuvants.

Come harvest time, using Wetcit, with your desiccant, will help ensure a great vine kill to improve potato quality and aid in harvesting. The superior performance of Wetcit with contact or systemic pesticides simplifies choosing the right adjuvant for the job and eliminates the need to have several adjuvant products on hand.


Summit Agro USA

(984) 260-0407

Regev Fungicide

Potato growers now have access to a first-of-its-kind hybrid fungicide, Regev. This is the first product to combine the disease control activity of a botanical ingredient (tea tree oil) with a conventional fungicide (difenoconazole).

Regev controls a broad range of diseases in potatoes including early blight, brown spot, white mold, black dot and gray mold. It even controls bacterial diseases such as leaf spot and soft rot.

A primary advantage of Regev is that it has two active ingredients but only one residue. One mode of action works by cell membrane disruption (FRAC Group 46) while the other MOA affects sterol biosynthesis in membranes (FRAC Group 3). Having these two modes of action provides REGEV with its high efficacy against a wide range of plant diseases.

The natural botanical ingredient in Regev—tea tree oil—delivers activity against both fungal and bacterial pathogens.


Vive Crop Protection

(888) 760-0187

Xyler FC

Xyler FC is the best-mixing metalaxyl fungicide available. It provides the same proven control of pink rot and Pythium leak as other metalaxyl products, but with added convenience. Xyler FC can be mixed with liquid fertilizer (in-furrow or foliar), other chemistry, micronutrients and hard water. A combination of Xyler FC with AZteroid FC 3.3 provides control of pink rot, Pythium leak and rhizoctonia that’s easier to use, even through a pivot.

AZteroid FC 3.3

AZteroid FC 3.3 provides plant health benefits and disease control, resulting in higher yield and higher quality. AZteroid FC 3.3 is the best-mixing azoxystrobin fungicide available and does not require blending agents or extra equipment. It provides proven control of rhizoctonia diseases can be mixed with liquid fertilizer (in-furrow or foliar), other chemistry, micronutrients and hard water. A combination of AZteroid FC 3.3 with Xyler FC provides control of pink rot, Pythium leak and rhizoctonia that’s easier to use, even through a pivot.

All Vive Crop Protection products contain the Allosperse delivery system—new technology that changes how proven active ingredients behave in the spray tank. The days of clogged nozzles and gummed-up lines are over. With Vive products, there is no more need bulky and expensive equipment, and growers have fewer passes over the field, hassle-free performance and ultimately, higher yield and quality.


BioSafe Systems

(888) 273-3088


Guarda is a liquid bactericide/fungicide that fits perfectly into BioSafe Systems’ line of over 30 sustainable products for agriculture and horticulture crop protection.

Guarda combats plant pathogens and provides continued defense through cellular damage and inhibition of these organisms. It is the first EPA-registered crop protection tool with botanical thyme oil as the active ingredient. Its unique formulation is standardized by its reactive component, thymol, which ensures the antimicrobial qualities of the thyme oil function consistently. The power of Guarda’s active ingredient is strengthened by the unique HOLDit polymer technology, allowing it to remain active over a period of time and providing efficient killing power against pathogenic bacteria and fungi. Without HOLDit, thyme oil is rendered inefficient because the thymol would volatize in the environment, never allowing for sufficient contact time to destroy microorganisms. This minimum-risk, inert HOLDit technology safeguards the thyme oil from degrading over time to release the active ingredient, extending performance on crops without any restrictions or limitations.


Bio Huma Netics

(480) 970-7525 


Huma Gro Promax is a broad-spectrum, soil-applied fungicide and nematicide used as a preventive and curative agent. OMRI-listed and EPA-exempt, Promax can be applied at any point in the growing season. It doesn’t keep growers out of the field and is not harmful to roots. Promax has no restricted use, buffer zones, re-entry intervals or residues. It’s compatible with most other inputs, so it’s an ideal product for tank-mix strategies and rotation programs.

With Promax, growers are working toward the long term and not burning out soil for quick results. When a program is implemented that combines Huma Gro Zap seven to 10 days after the final Promax treatment, a beneficial soil biology is stimulated that will sustain fields for future crops.

Proud 3

Huma Proud 3 is an organic-listed crop protection product. It is a safe and effective, foliar-applied insecticide, miticide and fungicide. The mode of action is as a contact killer. As an insecticide, it works best on soft-bodied insects or on the juveniles.

Benefits of Proud 3 include:

  • Directly affects soft-bodied insects and mites
  • Provides excellent control against fungal and bacterial diseases 
  • Activates natural defense mechanisms in plants 
  • Offers proven control of some human pathogens found on crops
  • Safe for crops, humans and the environment
  • Fungicidal effect against all types of fungal spores
  • Natural chemistry with no documented cross-resistance
  • Cost-effective performance
  • Fast-acting upon contact
  • Zero-day restricted entry interval (REI)
  • Zero-day pre-harvest interval (PHI)

Syngenta Crop Protection



Elatus fungicide has been shown to provide excellent control of soil-borne Rhizoctonia in potatoes, and can now be used under a 2ee recommendation to aid growers in the fight against Verticillium wilt. Elatus fungicide’s recent MRL clearance in major potato-importing countries enables growers to sell to an expanded market, while the disease control offered by Elatus can help improve emergence, establish a more uniform crop stand, enhance crop health, and optimize distribution of tuber size, ultimately resulting in higher yields and optimal quality at harvest.

Vibrance Ultra Potato

Vibrance Ultra Potato seed treatment from Syngenta gives growers the disease-fighting strength they need to start the season strong. Vibrance Ultra Potato, a combination of three trusted, proven active ingredients, recently received EPA approval for use in potatoes. This all-in-one liquid formulation provides broad-spectrum protection against key seed- and soil-borne diseases, including control of seed-borne late blight and silver scurf seed decay, and suppression of pink rot.

Orondis Gold

Orondis Gold fungicide is a premix of Orondis Gold 200, containing oxathiapiprolin, and Orondis Gold B, containing mefenoxam. The combination of proven, trusted performance of two active ingredients enables Orondis Gold to deliver preventive, residual and systemic activity against pink rot and Pythium leak.

Miravis Prime

Miravis Prime fungicide is a combination of fludioxonil and Adepidyn fungicide, the latest SDHI molecule with broad-spectrum preventive and curative activity. In spray programs, Miravis Prime provides excellent control of several difficult-to-control diseases in potatoes, including early blight and white mold.

Orondis Opti

Orondis Opti fungicide combines two powerful active ingredients with systemic and contact protection to aid potato growers against oomycete diseases, including late blight. Orondis Opti protects crops when they are most actively growing to maximize marketable yields.


Wilbur-Ellis Company 

(720) 306-6340


Exclusively distributed by Wilbur-Ellis, Romeo is a preventive biofungicide that functions the same way vitamins work for humans. Romeo enables plants to develop pathogen-fighting compounds to prevent development of those pathogens into disease. By introducing plants to a non-living fungus, Romeo signals plant pathways to enable the production of a plant’s internal responses, which can then effectively prevent disease development.  

Because of its propensity for synergy with other active ingredients, Romeo can be used as a foundational component, allowing for more robust disease management programs that incorporate other products. In addition, Romeo is an all-natural product that leaves behind no residue, so it is organic-farming-ready.  


Drexel Chemical

(901) 487-6005

Chlorothalonil 720

Drexel’s Chlorothaolonil 720 is an excellent protectant fungicide for control of black dot, Botrytis vine rot, early blight and late blight in potatoes. It also provides effective suppression of Botrytis leaf blight and purple blotch in onions and shallots, and of downy mildew in onions.

Chlorothaolonil 720’s superior formulation will remain available to the plant even amid heavy rainfall and irrigation. Foliar application provides residual control, and no pathogen resistance has been documented to date.


Phiticide is a phosphite fungicide with proven control of Phytophtora infestans (the late blight pathogen) and storage rot diseases such as pink rot caused by Phytophthora erythroseptica. It is recommended for use in foliar applications and storages. Phiticide has also proven itself to control Pythium leak in foliar applications and silver scurf in storage potatoes. It is an excellent tank-mix partner with Chlorothalonil 720 for in-season foliar applications.

Phiticide is also labeled for hops.



(973) 245-6000


Provysol fungicide from BASF is the first and only isopropanol azole for potatoes that provides effective and longer-lasting early blight, brown spot and black dot control due to its unique molecular structure and steady translocation, helping growers to control diseases now and for years to come. Potato growers can confidently utilize Provysol fungicide as a foundational element of their spray program and as part of a long-term strategy to maintain the yield, quality and marketability of their crops.


Trident Ag Products

(509) 731-5424

Strike Fumigants

Strike effectively suppresses pathogenic soil fungi and helps manage soil-borne parasitic nematodes, as well as other growth-inhibiting soil pests. Pre-plant soil fumigation treatment with Strik is the first step to a successful soil health and pest management system. It has shown to lead to larger tuber set, improved crop quality, better soil health, and capability for a shorter rotation.