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Tillage Update April 29th

30 April 2020
Type Media Article

Get the latest advice on weed control in spring cereals, using sprayers efficiently and bean weevil control in spring beans. The Tillage edge podcast Teagasc/Boortmalt programme advisor Eoin Lyons discusses weed control in spring barley. View latest videos.

Using sprayers efficiently.

Spraying plant protection products (fungicides, insecticides and herbicides) is a critical operation on most crop producing farms.

  • The annual spend of a standard programme of plant protection products can vary from €171/ha for spring barley to €292/ha for winter wheat.
  • The products must be applied to the crop evenly at the correct rate, with the correct spray quality (droplet size) in the correct volume of water and all at the right time.
  • Loss of spray product to the environment through drift, spillages or incorrect sprayer cleaning has to be avoided.


  • Nozzles determine the spray quality (droplet size); the volume to be applied, the evenness of the spray pattern; and the susceptibility to drift.
  • To select a nozzle, consult product label for guidance on water volume and the required spray quality.  
  • Nozzle charts and smart phone apps can be used to select the required nozzle and the required spraying pressure and forward speed.
  • Low drift nozzles allow more effective spraying in a range of weather conditions.  Air induction nozzles produce larger droplets which drift less, they can give less coverage which may be important for contact type products being applied to small targets. 
  • The best approach is to have standard and air-induction versions of the most commonly used nozzle fitted allowing switching depending on product and spraying conditions.

Pressure gauge forward speed and filters

  • An accurate and easy to read pressure gauge is essential for accurate spraying.  While full gauge bench-testing is best, if a new nozzle gives an incorrect output, it often indicates an inaccurate gauge or transducer.
  • Accurate forward speed indication is also essential and it should be checked; many simple GPS guidance monitors give an accurate speed output.
  • Don’t forget sprayer filters.  Blocked, broken or incorrectly sized filters (suction, pressure or nozzle body) can result in huge inaccuracies in addition to immense frustration while spraying.  

Dermot Forristal and Brendan Burke outline how to use sprayers efficiently in the accompanying video. 

The full article written by Dermot Forristal can be viewed here

Bean weevil damage in spring beans is common this year. Leaves of attacked plants show characteristic ‘U’ shaped notches around the edges, but the main damage occurs as a result of the larvae feeding on the root nodules which limits the plants ability to convert atmospheric nitrogen to plant usable nitrogen.  

Advice from PGRO is that sprays may be applied at the first sign of leaf damage and repeated after 7 - 10 days if necessary. Once the plant reaches five pairs of leaves control should not be required. Options for control include insecticides Karate Zeon, Decis Protech, etc.  Check label for rates.

Martin Bourke tillage advisor in Wicklow outlines what bean weevil damage looks like in the field and gives advice on control. 

Weed control in spring cereals. Best control of broad leaf weeds will be achieved by applying herbicides on small actively growing weeds. Thorough examination of the crop prior to herbicide application is important to establish what weeds are present but it is also important to note their size and distribution as this will influence the type of herbicide to be used and the rate required. 

It is important to note the most competitive weeds in the field as they are the weeds that will cause the most economic damage and need to be prioritised for control. Examples of highly competitive weeds in spring cereals are charlock, cleavers and wild oats.   

A mix of actives is recommended that have activity on the key weeds. For most farmers this will involve a sulfonylurea with a tank mix partner.

Wild oats are highly competitive and if abundant result large yield reductions when left uncontrolled. Recent research by Teagasc has found that resistance to some of the commonly used herbicides used in spring barley exists in Ireland. Worryingly the research found that where wild oats are resistant to Pinoxaden (Axial) they are also resistant to Fenoxaprop-P (Foxtrot), therefore a farmer will have no herbicide options in spring wheat or barley in these cases.

Applying Integrated Pest Management (IPM) techniques is vital to achieving good control and slowing resistance on your farm. Crop rotation and changing the active ingredient to control wild oats from season to season are important IPM measures. But in the short term it is vital to ensure the correct rate of herbicide is used, spray small actively growing wild oats and ensure the spraying operation is carried out effectively. Jimmy Staples advisor on the ECT project outlines some of the key points in achieving good control of wild oats.