Arthropod populations from agricultural fields sometimes depend on the surrounding landscape structure, both composition and configuration, which affects multiple life-history traits of arthropods such as resources for survival, dispersion or death risk (e.g., predation or parasitism). Moreover, the effect of the landscape may vary with the distance to the crop, depending on factors such as the organism requirements and dispersion capabilities. This work addresses the effect of landscape (at five different scales from 250 to 1500 m) on the olive moth (Prays oleae Bernard, a key pest in olive orchards), some of its most relevant natural enemies, and biological control. The two-years study in 15 olive groves in southeastern Madrid, Spain shows that landscape complexity favours control of the olive moth, P. oleae. Simple landscapes favour P. oleae attack to the crop (measured as oviposition of the anthophagous generation) and that egg predation of the carpophagous generation is in some cases enhanced in complex landscapes. Lacewings (Neuroptera: Chrysopidae) are responsible for egg predation and populations increase in complex landscapes. On the other hand, the role of pirate bugs (Hemiptera: Anthocoridae) as a biological control agent of this part of the life cycle of P. oleae was not demonstrated. They respond primarily to Euphyllura olivina (Costa) (Hemiptera: Psyllidae) populations and are more abundant in simple landscapes. Most of the significant relationships of pest attack were detected at 750–1000 m radii buffers around the sampled olive groves suggesting that this is the main activity range for adults of P. oleae anthophagous generation. In sum, our results suggest complex configurations of the landscape enhance the biological control of P. oleae through favouring lacewings and egg predation of the carpophagous generation.
Carmen Callejas (UCM), Manuel Gonz´alez Nú˜nez (INIA), Esther
Lantero (UCM), Beatriz Matallanas (UCM), Alejandro Rescia (UCM)
Ismael S´anchez Ramos (INIA) Pablo Blas (RECESPA˜NA Cooperative,
Villarejo de Salvanés, Madrid), Esther Alonso (UCAM - Union of Madrid
Agricultural Cooperatives) provided help during the research. We thank
also the owners of the sampled olive groves. This work was supported by
the Ministerio de Economía y Competitividad of Spain and the European
Regional Development Fund by project RTA2013-00039-C03-03.
