Authorities working to contain oak processionary moth in west and south-west London are gearing up for this year's programme of work.
An alert system is being implemented at RBG Kew this year that - it is hoped - will allow for more effective control.
RBG Kew has identified a tree with oak processionary moth eggs in it and is carrying out daily checks. As soon as the eggs start hatching, RBG Kew will immediately alert managers at all other affected sites so they can bring in pest control.
The Outbreak Management Team - chaired by the Forestry Commission - comprises representatives of Ealing, Brent, Hounslow and Richmond Upon Thames councils, the Food & Environment Research Agency (Fera), the Health Protection Agency (London region) and the Royal Botanic Gardens, Kew.
Roddie Burgess, head of the Forestry Commission's Plant Health Service, explained: "There are several large properties in the area with significant numbers of oak trees, and these give us particular issues in the programme of work that must be done to tackle this pest.
"We wanted to discuss with the managers of these properties the best way to co-ordinate our efforts this year, and find out from them what their particular difficulties are and what can be done to address them.
"This information was fed into the outbreak management team meeting, where we agreed our programme of work for this year."
Among the key properties affected are the Royal Botanic Gardens, Kew; Richmond Park, London Underground, and a number of sporting premises and visitor attractions.
The containment and eradication programme involves treating the caterpillars with a biological control agent after they hatch in the spring and begin to feed on their oak tree hosts, and removing and destroying their nests during the summer, before they pupate into adult moths. Specially equipped and trained operators removed about 700 nests in 2007, about 500 in 2008, and more than 2500 last year.
Mr Burgess said he was not overly discouraged by the increase in the number of nests found and destroyed last year.
"Although nest numbers were up, pheromone trapping of adult males last summer produced no evidence that the moth has spread significantly out of the core areas of west and south-west London to which it has been confined since it was first found in 2006. In addition, the numbers caught were about the same as 2008, suggesting there had been no real increase in the numbers of moths either," he said.
"There are also a number of explanations for our finding more nests last year. One is that we are getting better at finding them as we build up experience, so we might have been finding nests that had been missed the previous year. Another is that the weather was particularly good for the breeding success of caterpillars of all species last year."
Burgess encouraged anyone in the Richmond Upon Thames, Ealing, Hounslow, Brent and neighbouring areas to report any sightings of the caterpillars or their nests.
Sightings can be reported to the Forestry Commission's Forest Research arm by telephoning 01420 22255, or by e-mail to firstname.lastname@example.org.
Otherwise, they can be reported to the relevant council:
in Ealing Council area, call 020 8825 5000 or e-mail email@example.com;
in Richmond upon Thames, call 08456 122660 or e-mail firstname.lastname@example.org;
in Brent Council area, call 020 8937 5050 or e-mail email@example.com
in Hounslow Council area, call 020 8583 5555 or e-mail firstname.lastname@example.org.
Sightings in Richmond Park can also be reported to the park office, 020 8948 3209; email@example.com.