Agricultural management systems affect the green lacewing community (Neuroptera: Chrysopidae) in olive orchards in southern Spain.

Green lacewings are generalist predators whose conservation is important for pest control in olive orchards (Olea europaea L.) Sustainable farming practices, as opposed to conventional management techniques, are believed to foster the presence of natural enemies. This study therefore aims to analyze the effect of 1) herbicidal weed cover removal and insecticide applications, and 2) the general management systems used in the olive orchards of southern Spain on chrysopid assemblages and abundance. Green lacewing adults and larvae were collected from olive orchards under conventional, integrated, and organic management systems. In addition, chemical analyses of residues were carried out to determine the presence of insecticidal and herbicidal residues. Eight adult species and three genera of larvae were identified. No rare species were captured from the most intensively farmed orchard, which therefore recorded the most limited chrysopid diversity with a very marked dominance of Chrysoperla carnea s.l.. No effect of dimethoate treatments on Chrysoperla larvae or C. carnea s.l. adults was observed. However, the presence of insecticide residues was associated with the depletion of Dichochrysa larvae. The absence of herbicide treatments favored C. carnea s.l. adult presence on olive trees while larval abundance decreased. Dichochrysa larvae were more abundant when weed cover received no treatment. In relation to the management systems studied, no difference in Chrysoperla larval abundance was observed between conventional and organic orchards. However, Dichochrysa larvae were more abundant in orchards under organic management.

The ladybeetle community (Coleoptera: Coccinellidae) in southern olive agroecosystems of Spain.

The aim of this survey is to faunistically describe ladybeetle assemblages from the canopies of olive orchards in southern Spain (Córdoba and Granada) and determine the indicator ladybeetle species that are representative of each region, taking into account (1) the ecological importance of predatory ladybeetle species in olive orchards and (2) the variability of ladybeetle community composition in relation to landscape configuration and different farming systems (organic, integrated, and conventional), using ordination and classification methods. The total number of coccinellids collected was 481; they belonged to 9 genera and 13 species. Canonical correspondence analysis (CCA) showed a clear separation between orchards from Granada and orchards from Córdoba, taking into account ladybeetle species, environmental variables, and sampled orchards. The land use types and geographical locations showed that Scymnus mediterraneus Iablokoff-Khnzorian 1972 and Platynaspis luteorubra (Goeze, 1777) captured at higher latitudes benefited more from a larger organic olive area and from the presence of holm oak forests in the surrounding area. Coccinella septempunctata L., 1758 and Hippodamia variegata (Goeze, 1777) were found at lower latitudes and at higher longitudes. Ladybeetle assemblages can vary in response to the type of farming system, especially with regard to pesticide use and landscape configuration. Nevertheless, evaluation of species composition might help identify the state of conservation of these agroecosystems. This knowledge could be used to improve the sustainability of agricultural landscapes to increase the presence of coccinellids and their ecological function in olive pest control.