A combination of Sierraform GT, Greenmaster Liquid Iron Effect and Hydraflo in trials show over 70% reduction in disease incidence
S.R. Staples1, R. Mann2 and J. Wheater2
1Scotts Professional, UK
2Sports Turf Research Institute, UK
Keywords: fertilizer, wetting agent, iron, disease, ITM
The theory and practice of integrated turf management has been used for some time (Beard, 1998 and Carrow et al, 2001), however, replicated scientific trial work to confirm these practices has been relatively limited. The need to use an integrated turf management approach is now becoming a necessity due to the introduction of new legislation in Europe, The Sustainable Use Directive, relating to the justification of Plant Protection Product use.
The trial evaluates different fertilizer programmes (slow release versus readily available fertilizer programmes), wetting agent programmes and slow release iron liquids; used in stand-alone programmes and in combination together.
The purpose of this work is to study the interaction of different product types on disease occurrence and how these could improve the efficacy of fungicides.
Materials and methods
The research was carried out from Nov 2007 to Mar 2009 at the Sports Turf Research Institute. The sward consisted of a bentgrass/fescue mix on a sandy loam rootzone with a pH of 5.9. The turf was maintained according to golf greens standards. The turf was mown at 7mm (Nov-April 2008), 5mm (Apr-Oct 2008) and 7mm (Oct – Mar 2009). The area was aerated with solid tines in July and October 2008.
Two fertilizer programmes were compared; a slow release fertilizer (SRF) programme containing N, K and Si nutrient in a slow release form (6-8 week release) and a conventional fertilizer programme (Conv) based on potassium nitrate. The slow release programme consisted of 15-0-26 (Oct 07), 16-0-16 (Apr 08), 22-5-11 (June 08) and 18-6-18 (Aug 08). The conventional fertilizer programmes consisted of potassium nitrate applied at all four treatment dates above. Total nitrogen applied was matched for both fertilizer programmes.
A wetting agent (WA) programme consisted of four applications; penetrant wetting agent (Oct 07 & Aug 08) and a water conservation wetting agent (Apr & Jun 08).
A long lasting liquid iron (6.9% Fe) with longevity of up to 6 weeks was applied in a programme at 6 week intervals throughout the trial period.
Fungicide applications consisted of azoxystrobin (Oct 07), chlorothalonil (Apr 08), propiconazole (Jun 08) and azoxystrobin (Aug 08), at times of expected high disease activity.
These maintenance programmes were also applied in combination with one another to examine the benefits of using an integrated turf management approach. The following two-way combinations were trialled; SRF & WA, SRF & Iron, SRF & Fung, Conv & WA, Conv & Iron, Conv & Fung; and three-way combinations; SRF & WA & Iron and Conv & WA & Iron. The same application timings were used as per the individual programmes.
The key assessments made during the trial were; severity of disease (% plot affected using a 0.75 x 0.75cm quadrat), Turf Quality (1-10 scale) and visual turf colour (1-10 scale). Assessments were made every two weeks during the growing season and monthly during the winter period. All data were subject to ANOVA analysis.
Results and discussion
There was continuous disease pressure from Microdochium nivale during the 16 month trial with an average disease cover of 14.1% on the untreated plots, with levels reaching their peak in late 2008 to early 2009 with 43% disease cover. The data in figure 1 represents the disease reduction (%) compared to the untreated control averaged over 27 assessments from Nov 07 to Mar 09. There was less disease with the slow release fertilizer programme compared to the conventional release fertilizer programme (Fig 1), with average disease reduction compared to the unfertilized plots of 28.2% (significant on 5 assessments) and 8.7% (significant on 2 assessments) respectively. The use of a wetting agent programme also reduced disease levels by 24.0% compared to not using a wetting agent programme (Fig 1), this was significant on 2 assessments. Disease management was further enhanced when the SRF programme was combined with a WA programme, reducing disease by 35.1% (Fig 1), this was significant on 8 occasions during the trial.
The two-way combination of SRF & Iron programme reduced disease pressure by 54.8% compared to the untreated control (Fig 1), this was significant on 12 assessments during the trial. Disease pressure was further reduced by using a three-way approach of SRF & WA & Iron which resulted in a reduction in disease by 71.4% (Fig 1), being significant on 19 assessments during the trial.
The results highlighted so far show that by optimising choice of nutrition and by using appropriate wetting agent programmes it is possible to produce turf that is more tolerant to disease pressure. However, these ITM approaches are not replacements for the use of Plant Protection Protects which are required when disease thresholds are exceeded. Therefore, the strategy of optimising the efficacy of PPPs is equally important. The trial showed that fungicide efficacy was improved when combined with a conventional fertilizer programme by 6% (significant on 11 assessments), however, when combined with a SRF programme the fungicide performance was improved by 46% (significant on 16 assessments) compared to a fungicide only treatment (Fig 2).
The research highlighted that an integrated turf management approach can reduce disease pressure through a combination of enhanced turf health and by creating conditions less conducive to disease development. The efficacy of fungicides can also be optimised by combining with slow release fertilizers.
- Beard, J.B. 1998. Turf Management for Golf Courses.
- Carrow, R.N., Waddington, D.V. and Rieke, P.E. 2001. Turfgrass Soil Fertility and Chemical Problems.
Information supplied by ICL Specialty Fertilisers Australia