Spraying advances get more for less

 

 

 

Traditionally, on golf courses, we tend to apply plant protection products in a high water rate (300 - 1000 l ha^-1) using conventional flat fan nozzles, reports Ruth Mann of STRI. The high water rate means it can be a time consuming job, with numerous tank refills and extra handling of the concentrated product that inherrantly creates added risk.

 

The turf management products we are applying today all have different characteristics and are being used to achieve different outcomes, so a 'one size fitting' all application technique may not always obtain optimal results.  Added to that, the potential for drift from conventional flat fan nozzles is quite high, reducing the potential spray days available in our good British weather (Plate 1).

  Plate 1: Drift from conventional flat fan nozzles.

 

Syngenta have estimated that 10% of the efficacy is obtained by applying products using the correct nozzles. This has led to extensive research into nozzles and water rates conducted at STRI for optimal application of fungicides for control of diseases on golf courses. The major outcomes of this research are the introduction of the first nozzles specifically developed for turf. Syngenta's foliar and soil nozzles have been demonstrated to effectively deliver the fungicide product to where it needs to be.

 

If you are applying a fungicide to manage disease, or Primo Maxx® for growth regulation, then keeping the droplets on the grass leaf is ideal. The Syngenta foliar nozzle has been designed to apply products at 250 l ha^-1 at 2.5 bar pressure (although we have seen good results down to 125 l ha^-1). There is also much less drift of product when applied with the foliar nozzle, compared to conventional nozzles. For example, trials at STRI on microdochium patch demonstrated that Heritage, Banner Maxx, Headway and Instrata provided equal control of microdochium patch when applied at 125, 250, 500 or 1000 l ha^-1 water rate compared to untreated plots.

 

The soil nozzle has been developed to be used where you want to get the product past the foliage and into the rootzone. Therefore, it is optimal for applying fungicides for root affecting diseases such as take-all patch, liquid fertilisers and wetting agents. Optimal results are obtained at 550 l ha^-1 water rate at 3 bar pressure.

 

  Syngenta's foliar and soil nozzles have been demonstrated to effectively deliver the fungicide product to where it needs to be, reports Dr Ruth Mann.

 

Click here for more information on Syngenta Turf Nozzles

 

For certain products, even lower water rates are possible if applied by rotary atomiser technology (as found in the Environmist) to produce low pressure, low volume application (Plate 2). This technology uses a spinning disc to produce optimum sized, evenly distributed droplets important for foliar uptake products. The shroud also ensures minimal spray drift.

 

  Plate 2: The pedestrian version of the Environmist

 

Trials at STRI investigated applying Primo Maxx® in both a golf green and fairway situation. The golf green had a grass sward consisting of bentgrass, fescue and annual meadow-grass and was mown at 5 mm. We applied Primo Maxx at 0.4 l ha^-1 by conventional pedestrian sprayer in 300 l ha^-1 water and by the Environmist in 30 l ha^-1 water. Eight applications were made at 2 - 5 week intervals between May and October 2008. The colour and quality of the turf was assessed fortnightly throughout the growing season. We saw equal improvements in terms of turf colour and quality when either sprayer applied Primo Maxx.

 

In the fairway trial (mown at 20 mm), Primo Maxx® was applied at 1.6 l ha^-1 by conventional sprayer in 300 l ha^-1 water and by the Environmist in 30 l ha^-1 water. Six applications were made at monthly intervals between May and October 2008. The colour and quality of the turf was assessed fortnightly during the growing season. Grass yield measurements were also made on 3 occasions to determine any effects on grass growth. Equal results were again observed from both sprayers. Turf colour and quality was improved following application of Primo Maxx and the reduction in grass yield reached 56% compared to untreated control plots.

 

Therefore, the Environmist allowed application of Primo Maxx® in a tenth the water rate of the conventional pedestrian sprayer, allowing effective spraying with the added benefits of reducing the water required, and potentially the time taken to complete the spraying. Further trials are continuing.

 

However, please be aware that there are rules around the use of pesticides at reduced volumes. It is not suitable for the application of certain products, such as those labelled 'toxic' or 'risk of serious damage to the eye' or where reduced volume application has been banned. Unfortunately, most of our herbicides do have the 'risk of injury to the eye' warning. Please always ensure when using pesticides to adhere to label recommendations and ensure all COSHH regulations are applied.

 

A further aspect of pesticide application that can often inadvertently result in contamination of waterways on golf courses is removal of the foils on pesticide bottles (Plate 3). Foils are used to prevent air or moisture getting into the pesticide and also act as anti tamper devices. However, while wearing thick gloves, they are difficult to remove. It is also difficult to completely wash all pesticide residues from them, which may have dried onto the foil. Current advice is to rinse the foils and either store them separately or put them into the empty, rinsed pesticide bottle, to be collected by a reputable waste contractor. New containers have been developed, such as the S-Pac from Syngenta, which has no foil seal. Instead it has a padded membrane that reseals the bottle if all the contents are not used, reducing the chance of spillage. It also has a smooth internal surface, making it much easier to rinse out once the contents have been used. 

 

  Plate 3: The small amount of pesticide present on the foil can be enough to cause environmental contamination.

Click here for more information on the S-pac 

 

Tank mixing is another method that can be used to reduce the time spent on spraying jobs. Often tank mixing of certain products is done to ensure optimal results, such as adding nutrition to Primo Maxx applications. This can be extended to adding nutrition into certain fungicide curative treatments to ensure recovery of the affected turfgrass. Tank mixing these products saves the time of applying both separately to achieve the same result. However, you need to ensure the products are compatible as tank mixing incompatible products can cause problems, such as clogging sprayers. Advice as to compatibility will be available from all companies' technical helplines.

 

Also, ensuring correct sprayer calibration is paramount to achieving good results. Help with calibration is available on the Amenity forum website (http://www.amenityforum.co.uk/), and from many other websites and product brochures, such as Syngenta. Click here to view a series of podcast on sprayer calibration and application.

 

This article first appeared in Greenkeeping magazine, published by Union Press.