An empty nest was discovered on Christmas Eve after potentially releasing dozens of queens, which may go on to form new nests in the spring.
Asian hornet volunteers are now undergoing training to detect the creatures and Islanders have been urged to play their part.
Alastair Christie, the Island’s Asian hornet co-ordinator, confirmed that the final nest discovered in 2019 was spotted in a wooded area of St Lawrence by a National Trust for Jersey ranger.
He said: ‘The significance of the nest is that as it was not discovered earlier in the autumn, it was allowed to mature and release a new generation of queens to hibernate, and then emerge this coming spring to build new nests for 2020.
‘It is thought that as many as 300 queens can be produced from a single nest, although only a small proportion will be likely to survive to produce successful nests this year.’
However, the amount of surviving queens could be far greater should the current mild winter weather continue into the spring.
A total of 83 nests were discovered in 2019, with 53 having been found in the previous year. Mr Christie added that he expected the first queens to emerge from hibernation at around the end of March, depending on when the weather started to warm up. He said: ‘I would ask members of the public to continue to be vigilant. At this time of year, queen Asian hornets are in hibernation. However, if people are clearing out a store shed or moving a dry wood pile, for example, it is possible that they may come across a hibernating queen wasp or hornet in a dry crevice or corner.
‘I would encourage them to report any such findings if they are uncertain about what they have found, so that I can rule it out as an Asian hornet.’
Last May, Mr Christie began the fourth year of a battle to contain the spread of the invasive insect, working alongside the Environment Department.
In addition to deploying traps designed to capture Asian hornet queens as they emerge from hibernation to set up new colonies, Mr Christie and his team are being trained in finding nests using radio tracking. Earlier this week, seven volunteers underwent training with tracking equipment, which was delivered by Liz Corry, a senior keeper from Durrell.
Mr Christie added: ‘I’ve seen the radio tracking work really well so far. Last year we suffered from a lack of equipment, but this year we have everything we need and I’m confident it will work well.’