Best Practice Information: Application Technique
Posted 4 years ago
18/09/2020
Equipment should be properly maintained and calibrated according to Good Agricultural Practice. Detailed practical spraying advice can be obtained from ‘Using Pesticides – A complete guide to safe and effective spraying’, published by the British Crop Protection Council, or visit the Voluntary Initiative website. Sprayers can be tested annually under the National Sprayer Testing Scheme.
All equipment capable of producing the volume and spray quality outlined below should be suitable for the application of Roundup.
The correct dose rate should be used for the degree of infestation. Where other factors such as growing conditions, weed growth stage etc are less than optimum, reduced rates are more likely to lead to disappointing results.
High water volumes >250L/ha, give drops with low concentration of glyphosate, leading to poorer results. We do not recommend more than 200l/ha except in thick oilseed rape crops where 250 litres will help coverage and penetration. In most other areas 80- 100 litres of water gives equally good if not superior results, as both glyphosate and surfactant concentrations are higher improving uptake. Where low volumes are used the margin for error is less and the equipment must be properly calibrated and maintained.
To protect high diversity found in field margins, conservation headlands and beetle banks it is essential to minimise glyphosate drift from target areas. There are now many types of low drift equipment introduced under the LERAPS scheme, which greatly reduce drift. Roundup products are designed to optimise plant deposition at the same time minimise drift.
Label recommendations are for conventional 80° or 110° flat fan nozzles, but the use of air inclusion nozzles, pre-orifice low drift nozzles and Airtec equipment is possible where target weeds are suitable.
Caution: Where targets are small, e.g. spike -1 leaf grasses in stale seedbeds, the optimum droplet size for deposition is nearer 200 microns. Where target plants are large then the 400 microns, coarse drop gives the opportunity for a wider weather window determined by wind speed. Where Black-grass at the spike stage is the target the large droplets, (300-500 microns) produced by low drift nozzles will not give satisfactory control and conventional flat fan nozzles should be used.
The aim is to produce droplets in the Medium category as defined by the British Crop Protection Council, (BCPC), (droplet diameter 200-300 microns). Water volume is 40l per hectare.