Evaluation of the effects, on canopy arthropods, of two agricultural management systems to control pests in olive groves from north-east of Portugal

Abstract

This study aims to investigate the effect of management regime on canopy arthropod community of the olive tree (Olea europaea L.). Field studies were performed in two successive years, 2002 and 2003, in two olive groves, one under organic farming and the other under integrated protection. The integrated protection grove was sprayed once a year in June, with dimethoate, to control the anthophagous generation of the olive moth, Prays oleae (Bern.). From April to November of each year, the canopy arthropods were sampled weekly. PRC method was used to analyse the effect of management regime at the community level and results showed that taxa responded differently to insecticide application suggesting that the organic grove was a more suitable habitat for the arthropods than the integrated protection grove. Abundance of arthropods peaked in May and June for both years but, after spraying with dimethoate, decreased significantly in integrated protection grove, recovering very slowly thereafter. Psocoptera, Miridae, Formicidae and Coccinellidae were the most sensitive taxa to insecticide application. Their decreasing in abundance was more evident in the second year of the trial. On the other hand chrysopids showed some tolerance to insecticide applications. These results suggest that the timing of spray is of utmost importance in reducing the side effects of spraying on beneficial arthropods. Moreover, differences in population susceptibility as well as in life cycle patterns must be considered.

Short term response of ants to the removal of ground cover in organic olive orchards

“…In general, the degree of biodiversity in these systems depends on four main characteristics of the agroecosystem: the diversity of vegetation within and around the system, the permanence of the different crops within the system, the intensity of management and the extent of the separation of the system from natural vegetation (Southwood & Way, 1970). In relation to the intensity of management in conventional olive farming, in which synthetic pesticides and fertilizer are allowed and the soil is frequently deeply ploughed, the abundance and richness of ant species is lower than on land organically farmed (Redolfi et al, 1999;Santos et al, 2007b). Research has demonstrated that the timing of spraying is of utmost importance if negative side effects are to be minimized (Santos et al, 2007b), but in the case of soil management the effect of different strategies on beneficial arthropods is less well known.…”

“…In relation to the intensity of management in conventional olive farming, in which synthetic pesticides and fertilizer are allowed and the soil is frequently deeply ploughed, the abundance and richness of ant species is lower than on land organically farmed (Redolfi et al, 1999;Santos et al, 2007b). Research has demonstrated that the timing of spraying is of utmost importance if negative side effects are to be minimized (Santos et al, 2007b), but in the case of soil management the effect of different strategies on beneficial arthropods is less well known. If available, this type of information could be used to plan any necessary disturbances (Gliessman, 2007).…”

Effects of kaolin particle films on the life span of an orb-weaver spider

“…However, numerous negative effects resulting from the use of synthetic pesticides include risks for non-target organisms and persistence in the environment (Geiger et al, 2010;Sanchez-Bayo et al, 2013;Santos et al, 2007). Technology developed on mineral particle films can represent an alternative to some pesticides used in the control of pests (Glenn et al, 1999;Glenn and Puterka, 2005).…”

Response of coccinellid community to the dimethoate application in olive groves in Northeastern Portugal

“…Among the most frequent disturbances occurring in an agro-ecosystem is the use of synthetic pesticides to control pests or diseases that can also be toxic to beneficial arthropods (Rodríguez et al, 2003;Ruano et al, 2004;Cardenas et al, 2006;Santos et al, 2007). After the application of a pesticide, the natural control exerted by predators over the pests is broken up either by direct pesticide-induced mortality (Walker et al, 1996) or by lowering the number of preys (Obrycki and Kring, 1998).…”

“…In the olive tree (Olea europaea L.) canopy, coccinellids are among the most abundant groups of predators where they can have a potential function on the natural control of pests which often cause some economic losses in the crop yield (Morris et al, 1999;Soares et al, 2005;Santos et al, 2007).…”