Among these, the fungus Mycosphaerella melonis (syn. Didymella bryoniae) is the subject of extensive ongoing Horticultural Development Company research.
This involves Stockbridge Technology Centre’s Dr Martin McPherson looking at the effectiveness of chemical and biological controls, Dr Tim O’Neill of ADAS investigating the use of disinfectants and Professor Roy Kennedy of the University of Worcester studying spore trapping and monitoring.
Explaining best practice on containing the disease, CGA technical director Derek Hargreaves said: "It builds up during the season and by summer it’s a huge problem. Modern varieties have strong roots and will suck up masses of water whether they need it or not. The problem is worst when you have a bright day followed by a dull one. Then, you need to put plenty of heat on early in the second day, ventilate, and irrigate as little and as late as possible."
But he added: "Though you may know the likely -temperature and rainfall for the next day, you don’t know the radiation — will it be thick cloud or thin? So there is a fair bit of skill involved. Too little irrigation and you risk getting hollow fruit; too much and you get ‘snotty-ended’ cucumbers where Mycosphaerella can enter."
While the efficacy of rival growing media was also hotly debated at the event, Har-greaves said: "You can grow cucumbers in just about anything so long as it holds onto water, oxygen and nutrients. Peat, coir, rockwool, perlite, gels or bark each do that slightly differently and your choice will depend on how you grow."
In common with nearly every crop, cucumbers have suffered a decline in yield this year, which Cucumber Growers Association technical director Derek Hargreaves put at around six per cent on last year — "a year that was nothing to write home about either", he added. "Meanwhile, everything has gone up but our returns. It’s a huge issue."