Population dynamics and economic losses caused by Zeuzera pyrina, a cryptic wood-borer moth, in an olive orchard in Egypt

Abstract

The leopard moth Zeuzera pyrina L. (ZP) is an invasive pest from Europe of increasing significance in North Africa, in particular for olive cultivation. We followed the temporal dynamics by combined light/pheromone trapping over a 10-year period (2002-2011) in a 240-ha olive farm in Northern Egypt. The ZP had an annual cycle with one or two peak flights, from late April until October. Time series analysis showed a 2-year cycle of trap catch. This cycle is likely related to the 'on/off' bearing pattern of the olive, where years of high and low yield are observed to alternate. Larval damage in both 'on' and 'off' years in the infested trees gave fruit yield losses of 37-42%. The loss was estimated to 2.1-4.8 t/ha among susceptible varieties. The relative losses were the same during on and off years. Infestation of four susceptible and five resistant olive cultivars in different cropping systems varied within and between adjacent plots. The results suggest less infestation by intercropping of resistant varieties, which could assist in ZP management. Both temporal and spatial dynamics strongly influence population dynamics and the dynamics are related to variation in the moth host plant.