LERAPS Guide - Horizontal Boom Sprayers (PB5621)

How to Carry out a LERAP


If you choose to use a LERAP qualifying product, the following 4 steps will guide you in carrying out a full LERAP and show you if and by how much you can reduce the Statutory pesticide buffer zone.

Step 1

You will need to gather some information:

  • Will you be spraying near a watercourse?

The size of the buffer zone reduction may depend on the width of the watercourse so you will need to measure this. Measure it at its narrowest point next to the spray area; you only need to find out if the narrowest point is less than 3 metres, between 3 and 6 metres, or wider than 6 metres at the time of spraying. You must record this measurement as part of the LERAP record. If it helps you, you can mark it on your field or farm map but this is not compulsory. You do not need to measure watercourses every time you spray if the width of the water has not increased or decreased. Figure 1 on page 6 explains in a diagram the buffer zone, watercourse widths and measurements.

  • What dose of pesticide will you use?

The need for a buffer zone is assessed using the maximum permitted dose for a single application to any crop. If you intend to use less than the maximum dose then you may be able to reduce the buffer zone. If unsure, seek advice on the most appropriate dose to control the target weed, pest or disease.

Calculate the dose you intend to use as a percentage of the maximum dose shown on the label for any crop. For the purposes of a LERAP: 0-25% is considered to be 1/4 rate; 25.1-50% is considered to be 1/2 rate; 50.1-75% is considered to be 3/4 rate and 75.1-100% is considered to be full rate.

Using a 1/4 rate of any category B product allows you to apply the minimum buffer zone of 1m for all types of equipment and all watercourses.

If you use a reduced dose rate to reduce the buffer zone you cannot repeat an application of that product within 48hrs on that same area.

  • Will you use a LERAP-Low Drift' sprayer?

Manufacturers of ground crop sprayers can apply to have their equipment granted an official star rating for LERAP-Low Drift status. Equipment that offers the greatest reduction in spray drift gets a 3-star rating. You must use the equipment according to the conditions applied to the official grading, which are usually a standard forward speed and boom height with certain pressure limits (refer to the operating instructions supplied with individual types of equipment).

Using 3-star equipment always allows you to apply the minimum buffer zone of 1 metre for all Category B products alongside all watercourses regardless of their width.

Dont forget to record the LERAP-Low Drift star rating as part of your LERAP record. A list of spray equipment that has achieved a star rating is on the Pesticides Safety Directorates web page. It may be sufficient just to change the nozzles, but always check with your adviser.

Step 2

Work out the width of the buffer zone for your intended spraying operation

Using the information from Step 1, you can now work out what unsprayed buffer zone reduction may be allowed. If you intend to use a LERAP Low-Drift 3-Star-rated sprayer, apply a 1-metre buffer zone for all dose rates regardless of the width of watercourse or pond. In this case you dont need to refer to the tables. If a ditch is dry at the time of application simply apply a 1-metre unsprayed buffer zone .

In other cases:

  1. Identify the appropriate table. This will depend on the star rating of the equipment you intend to use.
  2. From the first downward column of the table, identify the size of the watercourse.
  3. Reading across the top row of the table, identify which column applies to the dose rate you intend to use.
  4. The box at which the row and the column crosses, gives the width of the buffer zone in metres.

If you are applying more than one product in a tank mix the product with the widest buffer zone requirement will determine the buffer zone for the tank mix as a whole. You do not have to add the buffer zones of the individual products together.

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Step 3


The LERAP scheme legally requires you to record each LERAP you conduct. Even if you decide merely to apply the standard 5-metre buffer zone, you must still record this decision.

Your LERAP record must include the following information as a minimum:

  • date of assessment
  • type of sprayer used (in particular any LERAP-Low Drift star rating)
  • the pesticide product you applied
  • the dose at which it was applied
  • the result of the LERAP decision (i.e. the width of unsprayed buffer zone set )
  • the name of the person who carried out the LERAP
  • width of the watercourse

You will already be recording much of this information as part of your standard operating procedures for applying pesticides anyway, as recommended in Part 4 of the Green Code. An example record layout is shown at figure 1, which you could photocopy and use if you wish.

You must keep all records of LERAPs conducted on your land for 3 years from the date of the spray operation for inspection because it is a legal requirement to do so (see Part 4 of the Green Code Record Keeping for further details).

However you decide to apply the pesticide, you are legally required to RECORD YOUR DECISION.

Step 4

carry out the spray operation

Check that the spray operation is carried out according to the results of your LERAP and that the spray operator knows the width of the unsprayed buffer zone to be used.

If you use LERAP Low-Drift spraying equipment to reduce the width of a buffer zone, the same equipment must be used to spray the 12 metres nearest to the watercourse measured from the top of the bank.

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