City of London Corporation director of open space Sue Ireland says the Forestry and Woodlands Advisory Committee of the Forestry Commission has seen its oak processionary moth (OPM) control programme implemented as planned, with 340 sites sprayed by the end of May and then nest removal begun. But spraying has not been as successful as hoped.
A survey programme started in June focusing on the containment area and its margins and includes the use of pheromone trapping.
Ireland said: "New outbreaks have been found in the buffer zone, so early indications are this hasn't been as successful as last year, probably due to the weather. It is concerning that nests have been found in Regents Park and on one tree in the Olympic park, outside the buffer zone. There have for the first time been reports on the human health impact, with a specific outbreak in Richmond, as well as the continuing impact on arborists, for instance at Kew.
"For City of London green spaces, the proximity of sites affected is of considerable concern. We have been monitoring visually Spring Park, close to the Bromley/Croydon outbreak. Now we are adding Queens Park, Hampstead Heath and the southern part of Epping Forest to our monitoring and have offered to support the Forestry Commission's work with the use of pheromone traps.
"Weather conditions this year have supported OPM development, so infestation levels have been much higher. Until the end of the summer, we will not have a full understanding of whether we are managing to contain the spread. The next OPM Advisory group is in mid-September, when we will have a fuller picture."