While it is a long-term goal of the Scandinavian golf sector to minimize pesticide use, one or two fungicide applications against winter diseases can hardly be avoided on putting greens with a turf cover consisting of Agrostis stolonifera or Poa annua. Thus, fungicides used for this purpose should combine a high efficacy against diseases with a low susceptibility to leaching. As earlier projects showed iprodione to be susceptible to leaching from USGA greens, the objective of this project was to evaluate three other fungicides used for turf. The project was carried out at the Bioforsk research stations at Landvik (58oN, 12 m.a.s.l.) and Apelsvoll (61oN, 250 m.a.s.l.) in Norway. Two USGA-specification golf greens, one including lysimeters established without organic matter or with 2% (w/w) garden compost (Green Mix) in the rootzone, were sprayed for two consecutive years with prochloraz (450 g a.i./ha), azoxy stobin+propiconazole (200+125 g a.i./ha), or trifloxyst robin+propiconazole (187.5+125 g a.i./ha). Iprodione (2250 g a.i./ha) was sprayed outside the lysimeters due to space limitations. Compared to the unsprayed control treatment, none of the fungicides had any effect on Gaumannomyces graminis, but azoxystobin+propico nazole and trifloxystrobin+ propiconazole were more efficient than prochloraz and iprodione in controlling Microdochium nivale and Typhula incarnata. Organic matter in the rootzone enhanced tiller density and overall turfgrass quality. Neither prochloraz nor trifloxystrobin were detected in water samples. Traces of propiconazole were detected in leachate, but concentrations were mostly less than the environmental safety limit (ESL). In contrast, azoxystrobin exceeded its ESL (0.90 µg/l) on four occasions, the largest value being 2.15 µg/ l. These detections were found in leachate from straight sand rootzones: the larger soil organic matter content in the ‘Green mix’ greens efficiently prevented leaching. As azoxystrobin + propiconazole and trifloxystrobin+ propiconazole showed a similar degree of control of winter diseases, the latter should be the preferred choice for preventive fungicide applications in late autumn. Use of azoxystrobin+ propiconazole should be limited to greens with organic matter in the rootzone.
