Survey for Beneficial Fungi in Turf Soils: Trichoderma

Prepared and submitted by Deborah Henderson, PhD
LEEF Regional Innovation Chair
Director, Institute for Sustainable Horticulture
Kwantlen Polytechnic University


Local strains of beneficial fungi have been little studied in Canada for development as biopesticides, however it is expected that many native isolates exist.

For example, Trichoderma is known to be one of the most common soil fungi (Harman et al 2004).  Our survey for beneficial fungi was conducted in south British Columbia in the summer and fall of 2011. The purpose was to build a bank of beneficial fungi from which to develop new native microbial biopesticides to begin to fill a gap in biological pest management products available to growers and end users and especially suited to BC. Soil is the reservoir for beneficial fungi and we collected 503 samples of soil from sites in SW BC including golf course and turf sites, conventional agriculture including some specialty soil types such as low pH cranberry farms, organic agriculture, and undisturbed sites in parks and natural areas. We fully expected to find entomopathogens like Metarhizium and Beauveria, and we did but the most common fungi found was Trichoderma, a genus which is known for having biofungicidal activity.

Trichoderma spp. are free-living, opportunistic, plant symbionts, and some are parasites of other fungi. They are known to colonize root surfaces, produce metabolites that induce localized or systemic resistance responses, and can substantially benefit plant metabolism. Root colonization by Trichoderma spp. frequently enhances root growth and development, crop productivity, resistance to abiotic stresses and the uptake and use of nutrients (Harman et al 2004). With the recovery of one hundred Trichoderma isolates, our screening widened to study the ability of these fungi to attack or inhibit the growth of a series of plant pathogens. This report describes the Trichoderma isolates recovered.

Soil samples from turf sites

A request was sent out by WCTA to members to volunteer their sites for sampling. Over the summer of 2011, almost all of these sites were visited. Turf manager identified areas of recent pest or disease (in the past year) presence at each site, and soil samples were taken from the top 10 cm at those sites. 

To begin to investigate any correlation between use of fungicide in turf and the population of beneficial fungi, samples were taken in pairs, one from the green (most problems were reported on greens), and a second from the rough close to the sampled green.  Greens are more likely to be protected by fungicides and insecticides than rough or fairway areas, so this gave us pairs of samples from the same site with different management practices. One hundred and thirty nine samples were taken from turf sites.

After fungi were extracted from soil, we identified potential beneficial isolates first by their visual appearance and then by molecular identification in 2012.

Plant disease “murder trials”

To test the antagonism of the Trichoderma isolates against plant pathogens, each Trichoderma isolate was allowed to grow from one side of a petri dish on agar while a plant pathogen was allowed to grow from the opposite side. We recorded the varying levels of inhibition of the pathogen by individual Trichoderma isolates. The entire suite of Trichoderma isolates were pitted against Fusarium, Rhizoctonia, and two species of Phytophthora. The 24 most “bio-fungicidally active” Trichoderma isolates were then grown at 0oC, 5oC, 10oC and 15oC, to predict their potential to manage disease in different seasons. 


There were generally more beneficial fungi of all types in undisturbed soil (i.e. forest soil) followed by Organic agriculture soils, then Conventional agriculture and then Turf.  This is likely related to the biodiversity of the soil and the plants that are growing in it. Most of our Trichoderma isolates appear to be T. harzianum, and T. ovalosporum, but this is likely to change as taxonomic classifications are revised based on the rapidly growing volume of molecular data.

By far the most frequent beneficial fungus isolated was Trichoderma, and turf sites yielded a similar number to the conventional agriculture sites. We did not observe a difference between soil samples from greens and rough areas in terms of the prevalence of beneficial fungi Noteably, no insect pathogenic fungi were recovered from turf sites in this survey.

Of the 24 suppressive Trichoderma isolates grown at a range of temperatures (0oC, 5oC, 10oC, 15oC), three isolates came from turf samples and represented a range of temperature growth profiles.

Trichoderma has many occupations in the soil, and only some strains attack plant pathogens. A group of 8 isolates showed excellent suppression for at least some plant pathogens in the lab and are being further studied with the objective of developing new biofungicide products. 

Production of beneficial fungi

Production is a key element in determining which beneficial fungi will be amenable to commercial production. For this reason, we are screening the most promising fungi in various production, as well as shelf life trials. Work planned for 2014 and 2015 will include formulation.


At this time, we have three Trichoderma products in early pilot development with one industry partner and additional funding from the Province of BC. These are blends of isolates chosen to combat the specific disease complexes in the target crop(s) as a result of our pathogen and temperature screening. A product for turf is definitely a possibility. We’ve learned from one field trial, that some of our BC Trichoderma isolates are not affected by some fungicides. The fact that we found a number of Trichoderma isolates in turf sites, where fungicides are used, suggests they could be compatible with some turf fungicides. Another benefit of Trichoderma, is that it has evolved in close association with plant roots and many produce metabolites used by plants and which benefit plant growth – some are rhizosphere competent.  Thus, when applying a beneficial fungus for control of a soil pathogen, it may also promote plant growth. We have noted this in some of our lab trials with turf. Trials in 2015 will define which isolates have this additional benefit.

A bank of native BC beneficial fungi has been developed as a result of the support of the WCTA and others, and the work to develop new products will continue as a core activity of the Institute for Sustainable Horticulture.

Next Steps

To develop a Trichoderma-based biofungicide for turf will require Tier 2 testing in the greenhouse with known levels of soil disease, followed by specific small scale field trials on sites where disease exists. Larger scale field trials would follow to determine if an isolate or blend of isolates would have sufficient efficacy in the field environment to manage BC turf diseases. 

It is also a goal of the Institute program to gain experience with the registration process in order to facilitate bringing these products to commercialization. At this time our first pre-registration consultation for a blend of Trichoderma isolates has been submitted to PMRA.

Reference cited

Harman, G.E., C.R. Howell, A. Viterbo, I. Chet, M. Lorito. 2004. Trichoderma species — opportunistic, avirulent plant symbionts. Nature Reviews Microbiology 2, 43-56

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