Fungicide levels and arbuscular mycorrhizal fungi in golf putting greens

Abstract

Summary1. Annual meadow grass Poa annua is the most problematic weed within sports turf in temperate climates. It is so abundant that herbicides cannot be used against it because almost total loss of the sward would occur. Arbuscular mycorrhizal (AM) fungi can be used as biological control agents of P. annua , acting to reduce its growth while increasing that of desirable perennial grasses. However, natural levels of AM fungi in amenity turf are very low. Sports turf is characterized by high fungicide usage, so this study tested the hypothesis that levels of toxic elements (derived from historical fungicide applications) and / or organic fungicides are related to the low mycorrhizal abundance observed. 2. Records of fungicide applications to putting greens at four golf courses in south-east England were collected for the period 1993-2000. Soils from all 18 putting greens on each course were sampled during spring 2000. Levels of arsenic, cadmium, copper and lead were recorded, as these elements formed part of the fungicidal compounds applied in the past. Of the organic fungicides in current use, chlorothalonil, fenarimol and iprodione were found to comprise more than 70% of all compounds used and soil levels of these three chemicals were also measured. Levels of AM colonization of P. annua were recorded at every putting green. The rates of AM colonization of desirable grasses could not be obtained because these were too rare in all the swards examined. 3. There was little evidence that the abundance of AM fungi, as measured by arbuscular colonization of roots, was affected by the presence of any of the chemicals. Levels of all elements were below the ambient levels for UK soils. 4. Chlorothalonil, fenarimol and iprodione were applied to a single putting green over a 6-month period but no effects on AM colonization were found. Synthesis and applications.We have demonstrated that the low levels of AM fungi in putting greens are unlikely to be a consequence of excessive fungicide application. Levels of compounds applied in the last 20 years are very low and modern fungicides do not reduce existing AM colonization when applied to turf. Therefore, if AM fungi are added to sports turf to control P. annua , their effectiveness will not be compromised by current or past fungicide use.

Soil Microbial Communities on Roughs, Fairways, and Putting Greens of Cool‐Season Golf Courses

“…This phylum, as well as the total number of mycorrhizae genera, was highest on the putting greens of the organic course and tended to be higher on the conventional putting greens, although not statistically. Bary et al (2005) found higher numbers of these organisms on putting greens, in contrast with past studies, and speculated that potentially they had developed resistance to fungicides or that fungicides never reached them in the soil. This could be true for our study, where the additional fungicides did not affect the mycorrhizae.…”

Reproductive effects of the endocrine disruptor fenarimol on a Baltic amphipod Monoporeia affinis

“…2 and 3). The exposure concentration of 0.3 mg/ L can be compared with levels of 0.1 to 1.4 mg fenarimol/kg soil found on putting greens in southeastern England [36]. Ecdysteroid levels in male M. affinis have been observed to increase during male sexual maturation (unpublished data).…”

Foliar fungal pathogens and grassland biodiversity

“…It has also been shown to have no effect on arbuscular mycorrhizal (AM) colonization in Poa pratensis growing on golf greens (Bary et al 2005). Application of fungicide is to the leaves in a dense grassland, so little is likely to reach the soil, and fenarimol has also been shown to have low toxicity to earthworms (Leslie 1994).…”