Birchall said Bemisia Tabaci was one of the biggest problems this year on Mandevilla, Nerium, Oleander and hibiscus.
Meanwhile leaf miners could see a resurgence, he said. They have been intercepted in the UK but have not established.
Also on the watch list is Omnivorous leafroller which has been found on geranium, dianthus, cyclamen for 12 years in Spain.
Popillia japonica is in Italy and has 300 hosts. The chafer Japanese beetle is subject to a rapid pest risk analysis.
Birchall said UK growers are asked to notify APHA if they spot ambrosia beetle which is considered a potential future threat to the UK and can kill young trees. It causes toothpick strands of wood on trees where it is established in Italy and France.
The first Hort Science Live event, organised by ICL, heard from technical managers about pest and disease control and plant nutrition.