In the present study, the potential of hedgerows from Mediterranean aromatic plant species, i.e., oregano, rosemary, sage, and savory, in orange field margins to function as reservoirs of natural enemies of citrus pests was tested in comparison to the common management practice of bare soil or weed vegetation. Assessments were based on the abundance and diversity of parasitoid wasps, spiders, and insect predators in the field margins and on the orange trees for two growing seasons. Savory plants harbored more parasitoids compared to weed vegetation and the other aromatic plants (savory > organic rosemary > sage > oregano). Weed vegetation hosted more arachnid predators than the aromatic plants in their first year in the orchard, but this was reversed with their full growth in the following year (most abundant on rosemary). Oregano and sage favor insect predators. The similarity of the natural enemy communities on the field margins and on the orange trees increased with time, indicating the insects’ movement from the field margins to the trees. The results support the use of the tested aromatic plant species in conservation practices for targeted groups of beneficial arthropods in orange orchards, also considering the exploitation of suitable wild flowering plants of the weed flora.

Cover cropping is increasingly recognized as a biodiversity-friendly practice in Mediterranean agriculture. However, its impact on ground-dwelling arthropods in olive groves remains insufficiently studied. This study assesses the effects of two perennial cover crops, tall fescue (Festuca arundinacea) and white clover (Trifolium repens) on the abundance, community composition, and functional diversity of ground-dwelling arthropods in a traditional olive grove in Crete, Greece. From April to September 2023, arthropods were sampled bi-weekly using pitfall traps and classified by taxonomic identity and functional traits, with particular focus on spiders (Araneae) and ground beetles (Carabidae). Cover cropping significantly increased total arthropod abundance compared to a control, with clover favoring omnivores and saprophages, and fescue promoting predatory taxa. Fescue plots exhibited the highest abundance of spiders and carabids, as well as greater carabid species richness and functional diversity. Although spider beta diversity differed across treatments, their functional diversity remained unchanged. Our findings indicate that perennial cover crops, especially fescue, enhance ground predator diversity and may contribute to natural pest regulation in Mediterranean olive groves, offering a sustainable alternative to conventional management.

In a two-year experiment, we examined whether increasing plant diversity in the margins of processing tomato fields could attract pollinators and natural enemies of pests compared to weed flora, and questioned the effect on crop yield. Two plant mixtures sown in winter (WM) and spring (SM) were compared with weed vegetation along a tomato crop (CT) and an adjacent irrigation channel (CC). Flower cover was higher in the sown mixtures than the weedy margins, and brought in more visits of pollinating bees (including potential tomato pollinators) than the latter. Flowering species were mainly Eruca vesicaria (WM, SM), Coriandrum sativum and Lathyrus sativus (WM), Fagopyron esculentum and Phacelia tanacetifolia (SM), and Ammi majus, Rapistrum rugosum (CC, CT). Parasitoids (Eulophidae, Braconidae, Scelionidae) were more abundant in the sown and CC margins compared to the CT margin, while the abundance of predators (Aeolothripidae, Orius sp., Thomisidae) was similar among all types of margins. Fruit weight was higher in the field with the sown margins, while pest incidence in the crop was not affected by the margin type. Our findings provide new insights into the contribution of managed and existing field margins in attracting beneficial arthropods, and their implications on yield.

Summary: Theridula aelleni (Hubert, 1970) (Araneae: Theridiidae) is a Mediterranean species with a limited known distribution, so far reported only in Tunisia, Madeira, and Spain. Here, we present the first record of T. aelleni in Greece. Two adult males were collected in an olive grove in the area of Asterousia in the Messara valley of Heraklion, Crete during pitfall trapping in 2022 and 2025. Identification was confirmed through comparison with diagnostic characters provided in the original description and subsequent taxonomic treatments. This finding significantly extends the known geographical range of the species eastwards within the Mediterranean basin and contributes to expanding our knowledge regarding the spider fauna of Greece.