SCEPTREplus: Carrots and Parsnips

EAMUs secured

Authorisations secured following SCEPTREplus trials for carrots and parsnips: 

• Flexidor as a herbicide for carrot, horseradish and parsnip
• Gamit as a herbicide for carrot
• Hurricane as a herbicide for carrot
• Emerger as a herbicide for root crops, alliums and celery

Weed control in carrots

• Crop Group: Field vegetables – Carrot (apiaceae), other umbelliferous root vegetables
• Target: General broadleaf weeds and grasses
• Period: Apr – Dec 2017, May 18 - Mar 2019 and Apr 2019 - Mar 2020 

These trials concentrated on potential new herbicides which may be used to partly or fully replace the current use of linuron.

Conclusions

Year one: 

• Seven treatments show promise as alternatives to linuron at a pre-emergence timing but more work is needed to give growers confidence in safety and placement in current programmes.
• Applications for EAMUs have been submitted for the products: Hurricane SC, Cleancrop Amigo and Intruder (chlorpropham) and Gamit 36 CS. The latter application is for post-emergence application.
• An EAMU for Flexidor 500 was obtained in January 2018, Flexidor 500 was only tested up to a rate of 0.075 L/ha in the trials and gave a slight scorch on leaf tips. Care needs to be taken with application timing when heavy rain is forecast.
• Tri-allate was crop safe to use in a tank-mix with Stomp Aqua and Gamit 36 CS, and would provide growers with an alternative option and mode of action to clethodim for grass weed control.
• Four treatments showed promise as possible alternatives to linuron at a postemergence timing but further work is required on rates and timing to improve crop safety.
• Further studies should be carried out to explore treatments for volunteer potato control, plus understand how the experimental treatments can be used safely in current programmes.

Year two: 

Including Emerger or Hurricane SC (both approved under EAMU) at a pre-emergence timing in a tank mix with pendimethalin would improve weed control in carrots. An approval for AHDB 9998, AHDB 9918 or AHDB 9917 would also be useful. At post-emergence, Sencorex Flow gives good weed control and can be included in programs immediately. EAMU authorisations for Emerger, AHDB 9981 or AHDB 9993 for post-emergence use should also be applied for, to give growers a wider range of actives to choose from and reduce the risk of resistance development. 

Year three: 

EAMU authorisations for post-emergence use of Hurricane SC, AHDB9981, and AHDB9993 should be applied for, to expand the range of actives available to parsnip growers. This would improve weed control and reduce the risk of resistance development.

• Crops: Parsnip other umbelliferous root vegetables
• Target: General broadleaf weeds and grasses
• Period: Apr 2019 and Mar 2020

These trials concentrated on potential new herbicides which may be used to partly or fully replace the current use of linuron.

Conclusions

Year one

Emerger is authorised under EAMU 1601/19 for pre-emergence use on parsnip and is a useful addition to programmes which growers can use immediately, but it has only been tested in tankmix with pendimethalin, and other mixes would need to be tested carefully before use on a large area of crop. A post-emergence EAMU authorisation for Emerger would also improve weed control, and it was one of the best performing products at this timing. Authorisations for pre-emergence use of Hurricane SC, chlorpropham, AHDB9998, AHDB9999 and AHDB9917 would improve weed control for parsnip growers, while AHDB9981 and Hurricane SC would be useful post-emergence products to pursue for EAMUs.

Year two – early parsnips

EAMU authorisations for post-emergence use of Emerger, AHDB9860 or AHDB9993 should be applied for, to expand the range of actives available to parsnip growers.

Year two – late parsnips

EAMU authorisations for post-emergence use of Emerger, AHDB9981 or Hurricane SC should be applied for, to expand the range of actives available to parsnip growers.

• Crops: Parsnips and other umbelliferous root vegetables
• Target: Volunteer potatoes
• Period: May 2018 – Mar 2019 and Apr 2019 – Mar 2020

The aim of this trial was to screen herbicides that show potential for volunteer potato control when used in tank mixes with Defy and adjuvants, looking to identify any that can replicate the effects of the linuron + prosulfocarb standard.

A further study looked at the crop safety and efficacy of various novel actives and adjuvants, applied post-emergence, aiming to identify new control options.

Conclusions

Hurricane + Phase II had a moderate and persistent effect on the volunteer potatoes, causing white blotches and a check to the growth.

Smaller and younger potatoes were more severely affected than those which were at rosette stage at the first application.

There was significant crop damage in the plots where Hurricane SC, AHDB 9993 or AHDB 9981 were applied, and these effects persisted until two weeks after application.

The chosen herbicide had a greater effect on the potatoes than the choice of adjuvant, though Phase II increased the herbicides’ effects slightly.

Post-emergence

Hurricane SC and AHDB9976 are promising products for post-emergence control of volunteer potato control in parsnips and were shown in this trial to be particularly effective and crop safe in repeated low-dose applications.

EAMU authorisation for post-emergence use of these products in parsnips would help growers improve weeds control.

Post-emergence application of AHDB9976 + AHDB9984 was not crop safe to parsnips.

Aphid control

• Crops: Carrots, lettuce, brassicas
• Target: Myzus persicae, Brevicoryne brassicae, Cavariella aegopodii, Nasonovia ribisnigri
• Period: Dec 2017 – March 2019

Conclusions

Evaluation of a range of insecticide and bio-insecticide treatments for their efficacy against four species of aphid infesting vegetable and salad crops.

The main study showed that a number of ‘novel’ insecticides and a few bio-insecticides were effective against one or more species of aphid. Some of the insecticides showed good persistence. The study also highlighted the importance of product formulation and adjuvants in increasing levels of control.

The additional study showed that a number of products were effective as foliar sprays and that some of them may also control foliage aphids when applied as phytodrip treatments, although it would obviously be advisable to test such treatments in the field and to evaluate the persistence of such treatments.