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Bayer Assist

For friendly informed advice about Bayer CropScience products, call Bayer Assist on:

0845 6092266

(0900-1715 weekdays)

Insecticides Molluscicides 




[Horticulture]  [Cereals]  [OSR & Mustard]  [Peas, Beans, Beet & Brassicas

Background on pyrethroids

Pyrethroid insecticides are based on pyrethrum, a natural insecticide produced by the pyrethrum plant. Pyrethrum was used for many years to control mosquitoes and other flying pests but, being unstable in sunlight, it was of little use in the protection of crops from plant-eating insects. Pyrethroids were designed to combine the outstanding insecticidal activity of pyrethrum with good light stability, thus providing lasting protection for crops.


Decis' unique advantage

Pyrethroid insecticides can exist in different shapes (conformations) which are known as isomers, and many products based on cypermethrin and other pyrethroids contain several isomers. The difference in shape of these isomers affects how they are able to bind to the active site in the insect and while some isomers are insecticidal others are not.

decis is unique in having only one isomer of deltamethrin and this is the optimum isomer for insecticidal activity. For this reason deltamethrin can be used at lower rates than other pyrethroids and you can be sure that all the active ingredient you spray will be insecticidal. This is coupled with a long duration of activity, rapid knockdown and short pre-harvest intervals.

Not only is decis effective against a wide range of insect pests but it is also selective to many important beneficial insects such as lacewings. When applied using the correct timing and dose, decis has no impact on bees. In fact, decis is specifically approved for use in flowering crops of OSR, beans, peas and cereals - unlike many other pyrethroids.

decis is endorsed by the  British Bee Keepers Association when used according to the following guidelines:

  • Spray in the evening or very early morning when fewer bees are foraging.
  • Take care to prevent drift toward hives in the treated field.
  • Avoid triazole fungicide tank mixes.
  • Give local beekeepers as much notice as possible.

This table gives a clearer indication of the pests you can expect throughout the summer months for each crop. Click on each pest to view their details within PestSpotter.

Summer pest calendar

OSRPollen beetleSeed weevilBrassica pod midgeFlea beetle
BeansWeevilBruchid beetle
PeasWeevilPea moth
Pea aphid
Pea midge
CerealsWheat blossom midge (ear emerge - early flower)Rose-grain aphid (flag), 
Grain aphid 
Bird cherry aphid



Related Documents

The list below contains documents from our library relating to Decis