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Soil Techs’ Bio-fungicide Research History

Soil Techs’ Bio-fungicide Research History

In 1989, Soil Technologies Corp. (Soil Tech), a leading research firm in the area of biological inputs for agriculture, submitted a project funding proposal to the Iowa Product Development Corporation Fund (IPDCF). In 1990, Soil Tech was awarded with a PROPEL grant of nearly $300,000 to accelerate market development of a “non-toxic, biological fungicide for the turfgrass pathogens commonly known as Leaf Spot and Dollar Spot.” 

Even though there had been earlier research on the concept of biological control of plant pathogens in agriculture, this grant marked the first documented attempt by a commercial company to bring a bio-fungicide to the T&O marketplace. The grant application stated that, “The need for a safer technology to control fungal infection on turfgrasses is in demand. Federal government agencies, activist groups, and some scientists object to the use of chemical fungicides in recreational settings. The removal or restriction of the currently used chemicals will automatically create a vacuum in the turfgrass fungicide market.”

Once the project funding had been secured, Soil Tech moved forward to determine if isolates of Pseudomonas and Streptomyces were capable of preventing Sclerotina homeocarpa (dollar spot) and Bipolalris sorokiniana (leaf spot) from infecting Poa pratensis (Kentucky bluegrass) under controlled laboratory conditions. In early 1991, a project was begun in the Horticulture Dept. at Iowa State University (I.S.U.) in Ames, Iowa. The goal was to evaluate whether the selected bacterial strains had potential as biological control agents on foliar pathogens of turf.

The co-principal investigators, were I.S.U. professors, Clinton F. Hodges and Nick E. Christians. In the July 1991 Iowa Turfgrass Research Report (pg. 155), the observations of the researchers were reported. “Preliminary laboratory studies have established biocontrol activity against dollar spot in three isolates each of Pseudomonas and Streptomyces. The isolates of both organisms substantially decrease the development of dollar spot infection. The average decrease in disease (measured as loss of chlorophyll and yellowing) by the six isolates is 97.5%. Field studies are planned for the summer of 1991 to determine the potential use of these microbes for controlling dollar spot and leaf spot in the field.” 

In November of 1991, in a letter to Soil Tech management, Dr. Hodges stated, “There are numerous unknowns associated with this type of developmental endeavor, and it is unlikely that all of the unknowns will be solved rapidly. Some of the microorganisms examined by us certainly have the ability to inhibit or compete with the pathogens examined. In the process of analyzing the field study data, we have seen that the challenge will be to get this activity to function consistently in the field.”

Over the next several years, Soil Tech worked with a research team of The Scotts Co. (Scotts) in Marysville Ohio to pursue the goal of bringing a bio-fungicide product to the professional turfgrass market. Seeing the potential of non-toxic products in the golf course market, Scotts and Soil Tech had entered into a cooperative agreement that would give Scotts the exclusive marketing rights to the technology, assuming that field trials were successful and that a product registration could be attained from the U.S.E.P.A. Together with the management of Scotts chemical product R&D, two years of field trials were undertaken in 1992 & 1993 on golf course turfgrass at the Scotts research facility in Ohio. The results of these trials led to several conclusions about the potential for these technologies. First, true biocontrol of turfgrass disease was challenging for a single species of microbe. With the wide range of variables and outdoor growing conditions, it was observed that no single strain of microorganism could produce the type of biocontrol results that had been demonstrated earlier in the I.S.U. labs. Second, any potential bio-fungicide for turf would need to employ multiple microorganisms working in tandem to have enough of a broad-spectrum result to justify product acceptance in the market. And third, the pesticide registration process with the E.P.A. would be considerably more complicated and costly for a mixture of microbes than for the registration of a single biocontrol microbial agent. 

Shortly after the completion of these field trials, and after their IPO in 1993, Scotts decided to discontinue their ProTurf division and exited the golf course product supply business. This ended the collaborative bio-fungicide research work between Soil Tech and Scotts. 

Soil Tech then took charge of the additional work that was required to complete the product development process. The company brought the development project in-house in 1994. Then, after multiple seasons of efficacy trials, in 1996, Soil Tech introduced their new product, Bac-Pack, into the golf course turf market. Bac-Pack consisted of multiple strains of beneficial bacteria that, in addition to improved recovery from various turf diseases, had demonstrated improved turfgrass health, improved rooting and had also exhibited improved (faster) recovery from pathogenic nematodes. 

In 1998, in field trials conducted by Dr. Eric Nelson and Cheryl M. Craft at the R.T. Jones Golf Course at Cornell University in New York state, Bac-Pack was measured for its ability to suppress disease symptoms from various turf pathogens. This project was designed to examine the impact of pesticide applications on the efficacy of commercial microbial inoculants used to improve plant health and recovery from turfgrass diseases.

In the report, published by the New York State Integrated Pest Management Program, Bac-Pack and conventional chemical treatments were tested for efficacy. Throughout the 1998 growing season three diseases were observed, Pythium, Brown Patch, and Anthracnose. Both the conventional treatments and Bac-Pack protocols had significant results in reducing damage by the diseases. In some cases, however, the results showed that some of the pesticides used in combination with inoculants could dramatically affect their suppressive qualities toward various diseases.              

However, as the report concluded, “our results showed that some commercially available microbial inoculants were suppressive to Brown Patch and Anthracnose diseases.”

On multiple dates during these trials the suppression by Bac-Pack of the diseases in this study was equivalent to or better than the conventional treatments available for use on turfgrass. 

Today, after 25 years of commercial application, Bac-Pack continues to be employed by golf course superintendents to improve soil health and provide a non-toxic tool to reduce the use of chemical products in the management of turfgrasses in golf and sports turf. In a recent interview of Ben Nelson, Supt. at Downriver Golf Course at the City of Spokane WA Parks Dept., he made the following comments and observations about his usage of Bac-Pack on the golf course: 

“Bac-Pack was first introduced at the City of Spokane WA golf courses back in 2017. I was skeptical about Bac-Pack at first. I am skeptical at first for many of the new products that get introduced to the market, but that doesn’t stop me from trying them. It took multiple applications here at Downriver to start to see results. Once the microbial populations started to grow in the soil is when you could see the best results. I have noticed too, that when soil temps are warmer you can see results better.    

"Being in the Pacific Northwest we see a lot of different weather extremes. Bac-Pack has been an awesome product to work alongside with our regular chemical program. At Downriver we use it on a 3-week application rotation. Since the implementation of Bac-Pack, Downriver GC went from using on average 20 chemical applications a year to an average of 12 chemical applications a year.  

"At first you see what it’s going to take out of your budget. Here at Downriver I use 5 gallons of Bac-Pack a year which is about the cost of one fungicide application. As I said previously, it has saved us on average about 6 fungicide applications a year, so there are no real budgetary considerations. It has ended up saving us money in the long run. 

"This product has saved money in chemical applications and some labor. It was easy to incorporate into my existing spray program. I started spraying it by itself at first, but now it’s just part of the program.

"It has been a great addition to our spray program in difficult conditions. A healthier plant survives in harsher environments and Bac-Pack helps make the grass plant healthier.”