Chekker is our unique formulation that provides excellent control of cleavers and a wide range of broad-leaved weeds in cereals including winter wheat, winter barley, spring wheat, spring barley, rye and triticale.

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(Active substances: iodosulfuron and amidosulfuron)

Why Chekker?

Chekker provides superior control of cleavers, particularly in cool, early spring conditions. It has flexible timing, from early spring right up to flower bud stage, and flexible dose rates to suit individual weed situations. Chekker can be used in all cereal crops except oats and its water-dispersible granule formulation makes it easy to use.

Main advantages

  • Wide range of tank-mixes available
  • Easy-to-use water-dispersible granule formulation
  • Can be applied in tank-mix or sequence with Atlantis WG, Hatra, Horus or Pacifica in winter wheat only
  • There are no restrictions on following cereal crops or crops sown in the spring of the following year
  • Winter oilseed rape and winter field beans may be sown in the same year as Chekker is applied and must be preceded by ploughing or thorough cultivation

Getting the best from Chekker

For the best results apply Chekker during warm weather, when the soil is moist and the weeds are actively growing. Levels of control can be reduced in poor growing conditions. Chekker can be applied after 1st February from two-leaf stage (GS 12) right up to GS 51, before the first spikelet of inflorescence is just visible. To reduce the risk of resistance, application should be made to young, actively-growing weeds. 

Important things to remember

  • Don’t use in tank-mix or sequence with any other ALS inhibitor except Atlantis WG (mesosulfuron-methyl and iodosulfuron-methyl-sodium), Hatra (mesosulfuron-methyl and iodosulfuron-methyl-sodium), Horus (mesosulfuron-methyl and iodosulfuron-methyl-sodium), Othello (mesosulfuronmethyl, iodosulfuronmethyl-sodium and diflufenican) or Pacifica (mesosulfuron-methyl and iodosulfuron-methyl-sodium)
  • Always add Chekker to the tank-mix first
  • Don’t tank-mix Chekker with fop/dim herbicides
  • Wherever possible, apply the fop/dim herbicides before Chekker and leave an interval of five days before applying Chekker
  • Where Chekker is applied first, always leave an interval of 14 days before applying fop/dim herbicides
  • Don’t apply to crops undersown or due to be undersown with clover and alfalfa
  • Don’t roll or harrow within one week of spraying
  • Don’t spray crops under stress, suffering drought, waterlogged, grazing, lacking nutrients or if the soil is compacted

Chekker as part of a programme

Chekker can be used in sequence on winter wheat after an autumn-applied Atlantis WG.

In spring, Chekker can be used in tank-mix or in sequence with Atlantis WG, Hatra, Horus, Othello or Pacifica at the 400g/ha rate only.

Chekker Product Summary

Active substances 12.5g/ha iodosulfuron-methyl-sodium 
  + 125g/ha amidosulfuron (+ mefenpyr safener)
Mode of Action ALS Inhibitors (HRAC Resistance Group B)
Formulation Water dispersible granule (WG)
Crops Winter wheat, winter barley, spring wheat, spring barley, rye and triticale
Maximum individual 
Active Ingredients 
delivered at 240g/ha
3g/ha iodosulfuron-methyl-sodium + 30g/ha amidosulfuron
Maximum number of 
One per crop
Application timing Apply in spring from 1st February and after the two leaf stage (GS 12) of the crop up to before first spikelet of inflorescence visible stage (GS 51)
LERAP Category B
Pack size 600g
MAPP number MAPP 10955