Tuta absoluta has wiped out crops in Spain and is believed to have spread to the UK on imported Mediterranean produce.
It lays up to 260 eggs on a plant's surface, from which caterpillars hatch. After two weeks of feeding, they turn into moth-like chrysalises, and these can drop to the floor and get into packing materials such as crates.
Food & Environment Research Agency (FERA) plant health and seeds inspector Marcus Lazenby told growers at last week's tomato pest and disease seminar — run by the Horticultural Development Company and the Tomato Growers' Association (TGA) — in Stoneleigh that many of these outbreaks could have been avoided had the industry been more vigilant.
The biggest problems, he said, have been the arrival of infected crates at growing sites from packhouses, and the storage of clean boxes near infected produce.
"Tuta is hitching a lift," said Lazenby. "It is the responsibility of the whole industry here to mitigate the risk of infection - and infection from packhouses to growing sites can be reduced if regular risk assessments are carried out."
Lorries, for example, should be checked thoroughly before they travel to a growing site from a packhouse to deliver empty boxes or collect produce.
"One outbreak has already been linked to transport. There needs to be some type of risk assessment in place. What was the lorry carrying beforehand? Every lorry needs to be meticulously pressure washed."
He added that crates and boxes used for foreign produce should be cleaned before they are sent to a UK producer.
The pest can also be controlled by storing tomatoes in non-returnable boxes and by making up new boxes in an area of the packhouse away from infested crates.
"Some boxes have been made up in the centre of the packhouse and become infected," he said.
Lazenby told growers at the seminar that another "burning problem" is that packhouses are often in close proximity to one another — as are many growers to packhouses.
"One of the biggest problems is direct flight," he said. "It's not a big trip for a Tuta to make. So it's an important task to keep packhouses completely sealed. You may have to invest in screened vents."
Waste management is also important, he added, because the insects can fly out of skips containing infested produce if covers are not properly fitted.
"Within a few days of starting to survey, we had reports from packhouses that they had a confinement heavily infected with Tuta."
10 Jan 2008 FERA warns about Tuta at TGA disease seminar.Lazenby said: "This is when it was present in Spain, but at this stage we did not believe it would be a massive threat."
5 Feb 2009 Dutch notification of Tuta at a packhouse for Spanish produce.
16 Feb 2009 Survey of packhouses in the UK.
27 Feb 2009 First UK finding.