Carrying out a LERAP for horizontal boom sprayers

The processes involved in carrying out a LERAP are indicated the "decision tree" below.

It is vital to be  familiar with the contents of "Local Environment Risk Assessment for Pesticides - A Practical Guide" (available from DEFRA publications) before carrying out a LERAP.

The answers to questions posed in the decision tree (eg pesticide LERAP category and dose, size and status of watercourse), as well as any decisions taken (eg to use the standard buffer zone rather than carry out a LERAP), must be recorded. Provison is made for this in the spray record sheets we have available to download.

To arrive at the correct buffer zone required, after completing a LERAP, refer to the appropriate table below and RECORD THE RESULT.

Further guidance on assessing the need for using a pesticide, along with much other useful information on the safe and correct use of pesticides, is available in the "Code of Practice for Using Plant Protection Products"  which is also available from DEFRA publications.

Tank-mixes

For guidance on LERAPs involving tank-mixes view below.

How to calculate the LERAP buffer zone applicable to the proposed horizontal boom sprayer operation 

You will have considered three key elements required to establish what reduction in the buffer zone, if any, is applicable for the proposed spray operation: the dose to be applied; the LERAP-Low Drift rating (star rating) of spray equipment being used; and the size of the watercourse in order to calculate the reduction applicable you will need to refer to the tables below.

  1. Identify which is the appropriate table. this will depend upon the star rating of the sprayer being used:
    •     Standard reference sprayer
    •     LERAP - Low drift * sprayer
    •     LERAP - Low drift ** sprayer
    •     LERAP - Low drift *** sprayer
  2. From the first row of the table, identify which column contains the application rate that you have chosen.
  3. From the first column of the table, identify which row contains the range within which the size of the associated watercourse falls.

The box at which the column and row intersect contains the buffer zone requirement which is applicable to the proposed application.

Make a record of the conclusions reached as a results of the LERAP

It is a legal requirement of the LERAP scheme that a written record be kept of each LERAPconducted. Even if users simply decide to apply the standard 5 metre buffer zone, that decision will still need to be recorded. All records of LERAPs that have been conducted must be available for inspection for a period of three years following the spray operation.

Tank-mixes 

  • If a tank-mix contains a Category "A" product then the standard 5m (or 1m for a dry ditch) buffer zone always applies.
  • Where two or more Category "B" products are tank-mixed, the quailifying dose (ie that used in the LERAP to calculate the required buffer zone) is that of the product which is being applied at the greatest dose relative to the maximum permitted for use. For example, if product "X" at 3/4 dose is to be tank-mixed with product "Y" at 1/4 dose then only the 3/4 dose is used for the LERAP.
  • If only one of the products being mixed has a buffer zone requirement, the dose at which that product is applied will be the qualifying dose rate. For example, if product "X" (Category "B") at 1/4 dose is mixed with a 3/4 dose of product "Z" (no buffer zone requirement), then the former (i.e. 1/4) dose is the qualifying dose used in the LERAP.

N.B. Dose of application - where the actual dose being applied falls between those given above, the dose should be rounded up to the nearest stated dose category.

1: Standard reference sprayer

Dose of application full dose 3/4 dose 1/2 dose 1/4 dose
Size of watercourse        
All watercourses less than 3 metres 5m 4m 2m 1m
All watercourses 3-6 metres 3m 2m 1m 1m
All watercourses greater than 6 metres 2m 1m 1m 1m
Dry Ditch 1m 1m 1m 1m

2: LERAP - Low drift* sprayer

Dose of application full dose 3/4 dose 1/2 dose 1/4 dose
Size of watercourse        
All watercourses less than 3 metres 4m 2m 1m 1m
All watercourses 3-6 metres 2m 1m 1m 1m
All watercourses greater than 6 metres 1m 1m 1m 1m
Dry Ditch 1m 1m 1m 1m

3: LERAP - low drift** sprayer

Dose of application full dose 3/4 dose 1/2 dose 1/4 dose
Size of watercourse        
All watercourses less than 3 metres 2m 2m 1m 1m
All watercourses 3-6 metres 1m 1m 1m 1m
All watercourses greater than 6 metres 1m 1m 1m 1m
Dry Ditch 1m 1m 1m 1m

4: LERAP - Low draft*** sprayer

Dose of application full dose 3/4 dose 1/2 dose 1/4 dose
Size of watercourse        
All watercourses less than 3 metres 1m 1m 1m 1m
All watercourses 3-6 metres 1m 1m 1m 1m
All watercourses greater than 6 metres 1m 1m 1m 1m
Dry Ditch 1m 1m 1m 1m