Science Into Practice - Downy mildew control in basil

PE 024: Basil - Improving knowledge and control of downy mildew in protected and outdoor crops

Estimates indicate the value of sweet basil (Ocimum basilicum) grown in the UK to be in the order of tens of millions of UK sterling. Sweet basil crops under protection and outdoors are now subject to infection by basil downy mildew, caused by the oomycete pathogen Peronospora belbahrii. The disease was first reported in the UK during the summer of 2010 and given quarantine status, with infected crops being subject to statutory action. The status was lifted in 2012. AHDB-funded project PE 024 aims to improve knowledge and control of this disease.

Work to date suggests that where the downy mildew pathogen is detected in seed, it is carried internally rather than as an external contaminant. Agastache, lavender, sage and catnip can all act as alternate hosts for P. belbahrii so growers could consider growing these separately from basil. Weed species tested were not found to be alternate hosts.

Incubation in the light for 18 hours after inoculation resulted in no plants developing downy mildew symptoms, yet more than 50 per cent incubated in the dark developed the characteristic yellow discoloured areas on the upper leaf surface and brown downy sporulation on the underside of leaves. Infections are therefore most likely to occur overnight. Infection occurred when plants were incubated at temperatures of 5-25 degsC and required a minimum of four hours leaf wetness duration.

An outdoor fungicide efficacy trial, on a crop with low disease pressure, showed that a programme with Revus (mandipropamid) and a coded product HDC F226 was most effective. Other effective programmes were Fubol Gold (metalaxyl-M + mancozeb)/Revus or Fenomenal (fenamidone + fosetyl-aluminium)/Revus.

Have you registered with us yet?

Register now to enjoy more articles and free email bulletins

Sign up now
Already registered?
Sign in

Read These Next

Product Special: protected crop structures - LEDs good for business

Product Special: protected crop structures - LEDs good for business

Concerns over climate, light levels and seasonal variability can all be overcome by using LEDs and they can deliver production benefits, Sally Drury reports.



Stocking a wide range of these impressive flowers from early March until June can boost sales, Miranda Kimberley reports.

Winning designs

Winning designs

Student anniversary collaboration generates outstanding work.

Opinion... Why flower shows need to evolve

Opinion... Why flower shows need to evolve

While the number of regional flower shows at stately homes and municipal public areas grows, the number of nurseries trading at these events reduces.

Opinion... Standardisation good for the trade

Opinion... Standardisation good for the trade

Horticulture could benefit from streamlining in the supply chain.

Opinion... Get rid of plastics in Horticulture

Opinion... Get rid of plastics in Horticulture

Blue Planet II eloquently showed the rich tapestry of life in the oceans. It also focused public awareness on plastic pollution damaging wildlife.

Follow us on:
  • Facebook
  • LinkedIn
  • Twitter
  • Google +
Horticulture Jobs
More Horticulture Jobs

Horticulture Week Top 60 Ornamentals nurseries

See our exclusive ranking of ornamentals nurseries by annual turnover. 

Tim Edwards

Boningales Nursery chairman Tim Edwards on the business of ornamentals production

Read Tim Edwards

Pest & Disease Tracker bulletin 

The latest pest and disease alerts, how to treat them, plus EAMU updates, sent direct to your inbox.

Sign up here

Are you a landscape supplier?

Horticulture Week Landscape Project Leads

If so, you should be receiving our new service for Horticulture Week subscribers delivering landscape project leads from live, approved, planning applications across the UK.

Peter Seabrook

Inspiration and insight from travels around the horticultural world

Read more Peter Seabrook articles