Operational monitoring of the nun moth Lymantria monacha L. (Lepidoptera: Lymantriidae) using pheromone-baited traps - a rationalization proposal

Abstract

The annual risk assessment of Scots pine (Pinus sylvestris L.) stands in the federal state of Brandenburg and subsequent decisions on the application of insecticides are based on operational surveillance data on L. monacha. The objective of the study was to rationalize the operational pheromone capture method. Data from operational monitoring with pheromone-baited traps in Brandenburg were analyzed. The records included data from a total of 11,761 traps and covered the development of populations of this insect from normal to outbreak densities and back during the years 2000–2009. Statistical analysis of the data suggested that a capture period of 15 June to 10 August, which is shorter than the period used hitherto, is sufficient to determine whether more precise monitoring by a census of adult females is required at a given site in the following year owing to increasing population densities. If this suggested shorter capture period had been implemented in 2000–2009, approximately 33% fewer trap inspections would have been required.