This guidance explains the situations in which plant protection products (PPPs) can be used where more than one crop species is grown on the same land at the same time.
This can be known as:
- intercropping
- companion cropping
- undersowing
Clarification of the use of PPPs on cover crops and areas such as headlands, field margins, strips, and infield plots planted with different crop species is also included.
Before using a PPP on mixed crops you should consider whether the PPP authorisation allows it. PPPs are rarely authorised for mixtures of different crop types.
Intercropping for producing two or more different crops
If you intend to grow or have sown two or more crops together which you intend to harvest, you can only use a PPP authorised for use on all of the crop types in the mixture. But you can apply a PPP authorised for only the initial sown crop before the second crop is sown.
This applies whether you harvest the crops:
- at the same time (for example, bi-cropping oats and beans)
- one after another (for example, maize undersown with grass)
You must comply with all relevant restrictions including growth stages and following crop restrictions.
Companion plants providing support for a single harvestable crop
If you grow a companion plant with the intended crop to benefit that crop (for example planting of buckwheat with winter oilseed rape) consider the following.
If you’re going to destroy the companion plant well before harvesting the crop (either naturally or by chemical or physical means), you can consider the companion plants as ‘weeds’. This applies even if the same species or variety can be grown as a crop in its own right. In these circumstances, any PPPs used do not need to be authorised for use on the companion plant species. Any unintended effects of the PPP on these companion plants are at the grower’s own commercial risk.
If plans change and you harvest the companion plant instead of destroying it, this may breach the conditions of authorisation for the PPP. There is a risk that active substance maximum residue levels (MRLs) may be exceeded. There may, also be commercial and other implications outside of the pesticide legislation.
Cover crops grown for agronomic or environmental benefits (for example catch crops or green manures)
Cover crops are grown by farmers for a wide range of reasons, including to:
- improve soil structure
- recycle nutrients in the soil
- reduce soil and nutrient loss
- provide a habitat and food for wildlife
- manage weeds
Cover crops may consist of:
- one species, for example, a brassica grown alone
- simple mixes such as rye or oats with phacelia and/or vetch
- much more complex mixtures of plant species from a range of plant families
Where different species are planted together and are cut for forage or grazed, you can only apply PPPs which are authorised for use on all crops within the mix. You must comply with all relevant restrictions including crop growth stages.
Where you intend to destroy all components of the cover crop before harvesting, PPPs used on these areas need to be authorised for use on ‘Green cover on land not being used for crop production’.
For cover crops grown under environmental land management schemes please refer to the relevant government websites for up-to-date information on scheme rules regarding management restrictions.
Headlands, field margins, strips and infield plots planted with different species from the main crop
Where the main crop is spatially separated from other areas within the field, PPPs used on each area of the field must be authorised for that specific area .
Note that grass strips between, for example, fruit trees or bushes are considered part of the orchard, and you should only use products authorised for use around the base of fruit trees or bushes.
PPPs used on ‘headlands etc.’ which are not being used for grazing or to harvest a food or feed crop, must be authorised for use on one of the following:
- 'Green cover on land not being used for crop production'
- 'Forestry/Farm Forestry' for short rotation coppicing such as Willow (Salix spp)'
- 'Industrial Crops' for biomass planting such as Miscanthus (Miscanthus spp)'
Crop safety testing is unlikely to have been undertaken on all species which could be grown in such situations and, unless specified on the label, the impact of the pesticide on any particular species is likely to be at the grower’s own commercial risk.
Note ‘headlands etc.’ treated with PPPs authorised for use on (i), (ii) or (iii) above must not be:
- harvested for human or animal consumption
- used for livestock grazing