SCEPTREplus: Cucurbits

EAMUs secured

Authorisations secured following SCEPTREplus trials for cucurbits: 

• Wing P as a herbicide for courgette, squash, pumpkin and sweetcorn

Weed control in cucurbits

• Crop Group: Field vegetables – courgette
• Target: General broadleaf weeds and grasses
• Period: April 2017 – December 2017

Take home message

Compared to the current standard control product, Wing-P or Stomp Aqua, applied inter-row in a tank-mix with Gamit 36 CS, gave improved weed control. It was crop safe, and also gave equivalent yields to the current standard.

An EAMU for Wing-P has been secured for courgette

AHDB9987 applied in a tank mix with Gamit 36 CS post-planting shows promise in controlling weeds in courgettes with no phytotoxic effects in this trial.

AHDB9995 and Bonalan pre-planting followed by Gamit 36 CS were safe to the courgettes, but gave poor weed control of the weed species on site.

Tank-mixing or being included in sequence with other products could improve the range of weed species controlled.

Further studies should also be repeated on the newer products Bonalan and AHDB9987.

Trial summary

There are currently very few herbicide options for weed control for cucurbit growers, with only three residual herbicides approved under EAMU for use on the crop.

Diquat is also approved for inter-row application to control emerged weeds after planting, but it only offers temporary suppression and often needs to be repeated.

This limited range of herbicides leaves gaps in the weed control spectrum, and growers experience problems with a wide range of weeds. In particular; polygonum weeds, black nightshade, black bindweed, sowthistle, and a number of grass weeds including annual meadow grass, volunteer cereals (especially barley), wild oat, black-grass and brome are problematic for growers.

As well as competing with the crop for nutrients and water, these weeds also hinder pickers reducing harvest efficiency.

Black plastic mulch is commonly used in courgette crops for weed control in the row and occasionally in some pumpkin crops. This is because the crops are very sensitive to herbicides, including those currently approved. For some growers, it is therefore common practice to apply authorised herbicides via hooded tractor-mounted spray applicators to shield the crop foliage. However, problems with weed between rows are still experienced as there are weaknesses in the spectrum of weeds controlled by the few currently authorised herbicides. Further options are therefore required inter-row as well as over the row.