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Agricultural land abandonment is an increasing concern in the EU, especially in Mediterranean regions where traditional perennial crops like olive groves are left unmanaged. This study focuses on the impact of land abandonment on soil-dwelling arthropods in olive groves in Monte Pisano, Tuscany, examining ants, spiders, myriapods, and carabids. Using Generalized Linear Mixed Models, the potential olive fruit fly predator community was analyzed over two sampling periods repeated over two years to assess the effects of both abandonment and its proximity to managed fields. Ants were significantly more abundant in managed fields next to abandoned ones, though there were no differences between managed and abandoned fields. Spider abundance did not respond to abandonment nor proximity. Myriapods were more abundant in abandoned fields during the first sampling period, but the proximity of an abandoned field had no effect. Carabids were more abundant in managed fields, especially those adjacent to other managed fields. These results indicate that arthropod responses to abandonment are taxon-specific, highlighting that a mosaic of managed and abandoned fields can both enhance and reduce olive fruit fly predator abundance. Conservation strategies should integrate varying management intensities to optimize biodiversity in Mediterranean agroecosystems. Future research should investigate long-term effects and specific predator responses to abandonment. [ABSTRACT FROM AUTHOR]

Agroclimatic variables may affect insect and plant phenology, with unpredictable effects on pest populations and crop losses. Bactrocera oleae Rossi (Diptera: Tephritidae) is a specific pest of Olea europaea plants that can cause annual economic losses of more than one billion US dollars in the Mediterranean region. In this study, we aimed at understanding the effect of olive tree phenology and other agroclimatic variables on B. oleae infestation dynamics in the Umbria region (Central Italy). Analyses were carried out on B. oleae infestation data collected in 79 olive groves during a 7-year period (from 2015 to 2021). In July-August, B. oleae infestation (1% attack) was negatively affected by altitude and spring mean daily temperatures and positively by higher wintermean daily temperatures and olive tree cumulative degree days. In September-October, infestation was negatively affected by a positive soil water balance and high spring temperatures. High altitude and cumulative plant degree days were related to delayed attacks. In contrast, high winter and spring temperatures accelerated them. Our results could be helpful for the development of predictive models and for increasing the reliability of decision support systems currently used in olive orchards. [ABSTRACT FROM AUTHOR]

In this study, we present the first characterization of herbivore-induced plant volatiles (HIPVs) released from infested olive leaves. The gall midge Dasineura oleae is a specific pest of Olea europaea and endemic of the Mediterranean Basin, an area in which severe outbreaks currently occurred. Little is known about the damage caused by the pest and the relationship with its host. Since gall formation and larval feeding activity may lead to the release of specific plant volatile compounds, we investigated the volatile profiles emitted from infested plants compared with healthy plants under both laboratory and field conditions. Additionally, the volatiles emitted from mechanically damaged plants were considered. A blend of 12 volatiles was emitted from olive trees infested by D. oleae. Of these, β-copaene, β-ocimene, cosmene, unknown 1 and unknown 3 were found to be exclusively emitted in infested plants. The emission of germacrene-D, (E,E)-α-farnesene, and (Z,E)-α-farnesene, α-copaene, (E)-4,8-dimethylnona-1,3,7-triene, (E)-β-guaiene and heptadecane significantly increased in infested trees. Linalool, β-copaen-4-α-ol, β-bourbonene, β-cubebene, β-elemene, β-copaene and δ-amorphene were found only in the field trial and showed differences depending on the level of infestation and the plant stage. (Z)-3-Hexenol, (E)-4-oxohen-2-enal, and 2-(2-butoxyethoxy)-ethanol, were exclusively emitted from the leaves after mechanical damage. In a field trial in Italy, we also demonstrated spring synchronization between adults of D. oleae and O. europaea trees. Analyses of morphoanatomical malformations of gall leaves showed that tissue alterations occur at the spongy parenchyma causing an increase of the leaf blade thickness. We speculate that tissue alterations may lead to HIPV release, in turn potentially attracting D. oleae natural enemies. [ABSTRACT FROM AUTHOR]

The pupae of Bactrocera oleae (Diptera: Tephritidae) complete their development during autumn and winter in the soil, rather than in the drupe, resulting susceptible to edaphic predators. Environmentally friendly methods to control this olive pest involve the identification of its natural enemies. This study evaluated the role of Ocypus olens (Coleoptera: Staphylinidae) in the predation of B. oleae pupae, by means of molecular gut content analysis. Modified dry pitfall traps were used to collect live specimens from low-input olive orchards in Tuscany (Italy). Sampling was fine-tuned with a degree-day model estimating the presence of pest pupae in the soil. PCR analyses carried out on field-collected specimens demonstrated that O. olens is a predator of B. oleae, at least during autumn. These results are consistent with predictions of the degree-day model. Knowledge on species composition, traits and complementarity of the natural enemies of B. oleae pupae needs further investigation to advance conservation biological control strategies. [ABSTRACT FROM AUTHOR]