Right timing hits blight

18 July 1997

Right timing hits blight

FOCUS on spray timings not application technique for best control of potato blight.

That is the message emerging from a trial comparing four different sprayers in West Cornwall. Interim results were presented at a demonstration organised by the EU Objective 5B-funded South West Horticulture 2000 project and PMB successor body BPC.

The trial is comparing conventional sprayers with flat fan or hollow cone nozzles, the air-assisted Hardi Twin Stream and the Benest drop-leg. Host farmer John Richards of Splattenridden, near Lelant, did all the spraying.

Foliar disease control from using blight fungicide Shirlan (fluazinam) has been equally effective irrespective of the sprayer used, ADAS plant pathologist David Lockley told visitors. But unsprayed control plots suffered almost complete foliage destruction by mid-July.

Where the fungicide was applied every 7-10 days blight damage to foliage was less than 0.2% compared with over 95% in the eight untreated plots, Mr Lockley explained.

Anglian Produce will assess the extent of tuber blight once the crop of Lady Rosetta is lifted. Heavy rain means tubers could be infected, noted Mr Lockley. &#42

John Burns


&#8226 Cornish trial, Lady Rosetta.

&#8226 Four sprayers compared:

Flat fan and hollow cone nozzle, air-assisted and drop-leg.

&#8226 Spray deposition compared.

&#8226 No difference in foliar blight – tuber blight results awaited.

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