Haulm destruction in potatoes can be achieved by mechanical or chemical methods or using a combination of the two.
Bed formation and machinery set-up
If considering a combined mechanical and spray approach, check bed formation against the flail set-up. Destoners and planters operate on a single bed, but flails may operate over two or three beds, so it’s important to match the topper to the rows.
Field layout
Leave enough space to turn a flail at the edges of fields. This may mean not planting the headland.
Nitrogen rates
Review nitrogen rates to try to keep haulm to a minimum and avoid over-vigorous crops at the time of haulm destruction.
Variety choice
While there is often limited variety choice for growers, knowing your cultivar (e.g. its determinacy rating) is important. Consider haulm destruction when deciding what variety to plant where. Some soils will not bear the weight of a flail well under wet conditions. Such land is better planted with varieties that are easier to finish, with the difficult varieties allocated to drier more resilient fields.
Practical recommendations on dessication:
- Quick canopy kill does not necessarily mean quick skinset
- Aim to apply PPO desiccants early to mid-morning, ideally on a sunny day
- Wet soils mean slower skin set, so stop irrigation 7 days before desiccation
- Expect a one to four day delay to skinset when using alternatives to diquat
- Slower canopy death means you will need to manage disease risk until all ‘green material’ is gone.
Reference: https://horticulture.ahdb.org.uk/knowledge-library/
