Gypsy moth,Lymantria dispar, outbreak in northeast London, 1995 – 2003

Abstract

A small outbreak of the gypsy moth, Lymantria dispar (L.), was discovered in June 1995 in the South Woodford area of northeast London, near Epping Forest. The origin of this outbreak remains unknown, but the eggs may have been transported from continental Europe, where major outbreaks occurred in the early 1990s. A risk assessment concluded that severe defoliation by this forest pest was unlikely to occur in the UK under current climatic conditions, but if the gypsy moth did become established, then sporadic damage to amenity tree species could be expected. Therefore an eradication programme was undertaken, which involved determining the extent of the outbreak area via population monitoring, and chemical treatments of any larval infestations, to prevent further spread. A series of targeted publicity campaigns was carried out with the aim of raising public awareness of the pest in the wider outbreak area. Details of gypsy moth finds (egg masses and larvae) and pheromone trap catches (adult males) are given for the years 1995 -2003. Pheromone traps were maintained at a relatively high density (c. 188 per 1 km 2 ) in the immediate outbreak area-and similarly in an adjacent portion of the Epping Forest-and it remains a possibility that some mating disruption has occurred. Although Lymantria dispar persists at this site, the numbers of adult male moths trapped has declined markedly in comparison to the first 2 years (1995 -1996). The outbreak is, however, continuing to persist at a very low level and may be becoming more widely dispersed, albeit very sparsely. It is also possible that observed population trends in terms of pheromone trap catches reflect a natural population cycle, and for these reasons work is continuing in an attempt to eradicate this damaging broadleaf tree pest from the UK.

Inference of adult female dispersal from the distribution of gypsy moth egg masses in a Japanese city

“…The movement of Asian strains of the gypsy moth on ships, shipping containers and other objects is a recognized pathway for the entry of Asian gypsy moth populations to alien habitats (Wallner et al , 1995; Cannon et al , 2004). The proximity of gypsy moth infested forests to terminals in Asia where cargo is loaded for shipment to other continents thus represents a regulatory hazard.…”

“…Over the last 10 years, there have been several incidents in which Asian strains of the gypsy moth have been detected in the U.S.A., Canada and New Zealand, and most of these have triggered massive and expensive eradication campaigns (Gibbons, 1992; Wallner, 1996; Myers et al , 2000; Ross, 2005). The primary pathway for entry of gypsy moth egg masses from Asia is considered to be transit of cargo, including shipping containers and vessels (Wallner et al , 1995; Cannon et al , 2004). Shipping terminals tend to be brightly lit and the phototactic flight of females can lead them to these locations where they sometimes oviposit on outgoing cargo.…”

Limited Genetic Structure of Gypsy Moth Populations Reflecting a Recent History in Europe

“…Currently, L. dispar is considered one of the most notorious forest pests worldwide [4], with outbreaks in its native range being common particularly in the oak forests of the Mediterranean region, while in Asia the broader spectrum of potential hosts renders gypsy moth capable of even more massive outbreaks [5]. Nonetheless, the potential of gypsy moth populations to erupt varies greatly [6] as in cases of recent invasion an outbreak can be sustained [7]. For all these reasons, gypsy moth, has been in the spotlight of various investigations ranging from population dynamics [8] and dispersal ecology [9,10] to the distribution of its genetic diversity at a global scale [11,12].…”

Natural enemies and environmental factors affecting the population dynamics of the gypsy moth

“…; Cannon et al. ). However, there are some regional differences in the time span of two outbreaks, for example, in Slovakia and Germany, the period between two outbreaks can differ from 6 to 14 years (Grijpma ; Novotny et al.…”