CARROT CROPS could be at greater risk from sclerotinia infection this season, growers have been warned.

Weather during April and May this year was not conducive for sclerotia germination, so larger numbers than last year remain intact, said ADAS plant pathologist, Peter Gladders.

These sclerotia could germinate during the early stages of carrot growth and infect the crop, so it is vital for growers to spray crops early in order to ensure effective control, he said.

“Last year we were seeing sclerotinia leaf symptoms in carrots by mid-August which meant that infection was occurring quite a bit earlier in the crop’s development.

“So for good control you’ve got to start spraying early, in late June or early July, before closure of the canopy and while you can get good spray penetration.”

In 2004 ADAS field experiments, Signum (boscalid + pyraclostrobin) showed strong activity against sclerotinia and BASF trials have also showed it to be effective against Alternaria and powdery mildew.

During rapid crop growth Dr Gladders recommends a spray interval of two to three weeks and reminds growers that fungicide cover needs to be maintained into September.