We evaluated the capacity of selected plants, sown along a processing tomato field margin in central Greece and natural vegetation, to attract beneficial and Hymenoptera pollinating insects and questioned whether they can distract pollinators from crop flowers. Measurements of flower cover and attracted pollinators and beneficial arthropods were recorded from early-May to mid-July, during the cultivation period of the crop. Flower cover was higher in the sown mixtures compared to natural vegetation and was positively correlated with the number of attracted pollinators. The sown Glebionis coronaria, Coriandrum sativum, Anethum graveolens, and Fagopyrum esculentum attracted mainly wild bees, which were the most abundant pollinating insects. In the natural vegetation, Rapistrum rugosum attracted mainly honeybees, while Asteraceae, Convolvulaceae, and Apiaceae species attracted wild bees. Beneficial arthropod abundance and diversity were higher in the sown mixture. Tomato flowers were visited by a small number of wild bees. Their number was not affected by the distance from the field margin, indicating no distraction effect from the sown or natural vegetation flowering plants. Our results suggest that selected flowering plants can improve the field margin habitats for pollinating insects and beneficial arthropods, but more work is needed to elucidate the effect on crop pollination.

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.

The practice of field margins management using mixtures of selected plants to provide habitats for pollinators and natural enemies of pests, and possible impact on crop yield, was studied for two mixtures (mixture A: Borago officinalis, Coriandrum sativum, Glebionis coronaria; mixture B: Vicia sativa, Sinapis alba, Phacelia tanacetifolia) in watermelon, cv. Karistan. The sown margins attracted primarily Apis mellifera and Halictidae bees (Lasioglossum spp.), and a few other Apidae (Anthophora sp., Eucera sp., Bombus sp.) over a flowering period of 6 weeks (beginning of April to mid-May). Pollinators on watermelon flowers were mainly Halictidae (Lasioglossum spp.) and fewer honey bees, from mid-May to mid-June. Shannon’s (Η) diversity index of parasitoids was higher in mixture B while their abundance did not differ between the plant mixtures, although it varied during the season. Higher weight/fruit, lower proportion of undeveloped/mature seeds per fruit, and higher Brix level in the field with the sown margins compared to a commercial watermelon, cv. Karistan, field, under common agronomic practices, suggest a positive effect of the sown margins on the crop yield.

Citrus tristeza virus (CTV) is a vector-borne virus that poses a significant threat to citrus production worldwide, inducing a variety of symptoms. Therefore, a detailed knowledge of local aphids, identification of viruliferous species, and the development of new monitoring tools are necessary to improve CTV control strategies. Herein, a 2-year survey was conducted to assess the frequency of aphid species infesting several citrus pilot orchards. Plot findings based on morphological and molecular identification revealed Aphis spiraecola (ranged from 44–100%) as the most abundant aphid species, followed by A. gossypii (<50%). Toxoptera aurantii, Myzus persicae, and A. craccivora were present in low numbers, and A. citricidus was not detected. Due to the absence of CTV detection in aphids and citrus trees from the pilot orchards, a complementary survey was conducted in CTV-infected fields. Three aphid species were identified as CTV-positive by RT-PCR, suggesting that they may be viruliferous, with A. spiraecola as predominant, followed by A. gossypii and T. aurantii. Additionally, we developed a non-invasive procedure for identifying aphid species using wingbeat analysis. This method provides a faster alternative to traditional identification techniques by taxonomic keys based on morphological features or PCR, although its accuracy is lower (approximately 95% for the two species tested). Overall, this work provides a detailed study of aphid species composition in citrus orchards, identifies the predominant local putative CTV vector, and introduces a novel sensor for aphid monitoring, contributing to improved epidemic forecasting and sustainable disease management strategies.

“Can systemic insecticides be used in bait spots in order to kill the adult olive fly?” Effort was directed toward providing an answer to that question. Both field and laboratory tests were implemented to detect the dislodgeable residues of dimethoate, phosmet and b-cyfluthrin in olive leaves and fruit using the LC-MS/MS and GC-MS/MS chromatographic techniques. Residues of dimethoate declined more over time than those of phosmet, while levels of beta-cyfluthrin remained almost stable, both in leaves and fruit. Additionally, significantly higher and faster toxicity of dimethoate and beta-cyfluthrin (>92%) compared to phosmet (80%) to fly adults was shown, which was reduced significantly after a two-week period. Conversely, 100% mortality of the larval stages within olive flesh was observed at the 2nd day for dimethoate and at the 7th day for phosmet. Although phosmet was not expected to contribute to preventing larval development, its application in bait sprays presented similar toxicity to that of dimethoate. However, no larval toxicity was recorded in beta-cyfluthrin. As a primary conclusion, we recommend the avoidance of the use of systemic insecticides in bait sprays.

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.