"Canker is one of the biggest issues in apple and pear growing today," Agrovista fruit specialist Paul Bennett told delegates. "Not a day goes by when there isn't another orchard that's been destroyed by it."
He added: "We need to think of canker as having an infection period similar to that of the primary scab season, but it (canker) goes on for 12 months."
The ideal infection conditions, he said, are when there is a wound on the tree, when spores are present, when the temperature is between 0 degsC and 16 degsC and when the leaf has been wet for six hours.
"Looking at our weather you have potential infection conditions throughout the year." But he pointed out that canker is much less of a problem in organic orchards, where low doses of copper are traditionally applied as a scab treatment.
Foliar feed product 42PHI Cu has been used in the USA for several years, where it has reduced the level of canker infections and old infections, Bennett explained.
The product, which contains about five per cent copper, is now available in the UK and it could stimulate plants' natural defences in conventional orchards.
"We are starting to use this product more and more and by next season we will start to report back on how successful it has been," said Bennett.