Olive Fly Research Articles

Bactrocera oleae Control and Smart Farming Technologies for Olive Orchards in the Context of Optimal Olive Oil Quality: A Review

Bactrocera oleae Control and Smart Farming Technologies for Olive Orchards in the Context of Optimal Olive Oil Quality: A Review

Explainable olive grove and grapevine pest forecasting through machine learning-based classification and regression

Pests significantly impact agricultural productivity, making early detection crucial for maximizing yields. This paper explores the use of machine learning models to predict olive fly and red spider mite infestations in Andalusia. Four datasets on crop phenology, pest populations, and damage levels were used, with models developed using the Python package H2O, which focuses on interpretability through SHAP values and ICE plots. The results showed high precision in predicting pest outbreaks, particularly for the olive fly, with minimal differences between models using feature selection. In the vineyard dataset, the selection of characteristics improved the performance of the model by reducing the MAE and increasing R2. Explainability techniques identified solar radiation and wind direction as key factors in olive fly predictions, while past pest occurrences and wind velocity were influential for red spider mites, providing farmers with actionable insights for timely pest control.

Inhibitory activity of some short-chain aliphatic aldehydes on pheromone and ammonium carbonate-mediated attraction in olive fruit fly, Bactrocera oleae.

The olive fruit fly (OFF), Bactrocera oleae (Rossi), is the main insect pest of olive trees worldwide. Legislation limits to the use of some synthetic larvicidal insecticides is leading to the development of new control options for preventive control of adult flies. In the present study, the biological activity of four short-chain aliphatic aldehydes, namely hexanal, (E)-2-hexenal, heptanal and (E)-2-heptenal, previously reported as repellents to the OFF adults was investigated. Electroantennography (EAG) recordings showed that antennae of OFF males and females are able to perceive the test compounds in a wide range of doses. In field trapping experiments, reservoir-type polypropylene (PP) membrane dispensers loaded with individual compounds did not elicit a significant attraction of OFF males and females. On the contrary, a significant reduction of male catches was noticed when sex pheromone dispensers and PP membrane dispensers, loaded with one of the test compounds, were applied on the same white sticky traps ≈20 cm apart. Likewise, male and female catches in yellow sticky traps baited with ammonium carbonate (AC) dispensers as food attractant were significantly reduced by the presence of PP membrane dispensers of individual aliphatic aldehydes on the same traps. In small plots control trials, solid formulations of the four aldehydes into a bentonite clay support induced a significant reduction of the OFF active infestation mainly when C6 and C7 aldehyde-activated bentonites were used. Short-chain aliphatic aldehydes showed inhibitory effects on sex pheromone and food attractant-mediated attraction of OFF. Results of field trials suggest potential of short-chain aliphatic aldehydes to develop new semiochemical-based OFF control options. © 2024 Society of Chemical Industry.

The biogeographic patterns of the olive fly and its primary symbiont Candidatus Erwinia dacicola across the distribution area of the olive tree.

The olive fly, Bactrocera oleae (Rossi, 1790), is the major insect pest of olives attacking both cultivated and wild olive. Bactrocera oleae carries a primary and vertically transmitted symbiont, the bacterium Candidatus Erwinia dacicola. As any primary symbiont, it plays an important role in the reproduction and lifespan of the fly. The genetic 16S rRNA diversity of the primary symbiont and the mitochondrial haplotype variation of the insect host were simultaneously examined in 54 olive fly populations. The aim was to unravel the biogeographic patterns of this economically relevant host-bacteria interaction across a wide distribution area. Three symbiont haplotypes were identified. The primary symbiont showed a lower haplotype diversity than that of its host, a characteristic indicative of a long-term interaction. A significant genetic and geographic association between host and primary symbiont was observed, with an East-West genetic differentiation pattern in the Mediterranean basin, coinciding with the historical genetic distribution of the olive tree. The study shows promise, informing and aiding the development of future tools for the control of the olive fly.

Use of micro-computed tomography to monitor olive fruit damage caused by three insect pests

A complete three-dimensional reconstruction of the internal damage (oviposition holes, entry and exit galleries, cavities caused by fungal infection) of three destructive pests of olive fruit was obtained using micro-computed tomography. In the case of the olive fruit fly (Bactrocera oleae), complete reconstruction of the galleries was achieved. The galleries were colour-coded according to the size of the internal lumens produced by larval instars. In the case of the olive moth (Prays oleae), we confirmed that the larvae only consume olive stones, leaving pulp tissue intact. This study revealed the evolutionary defensive adaptation developed by larvae, creating entrance/exit gallery in the form of a zigzag with alternating angles to avoid the action of possible parasitoids. In the case of olive fruit rot, caused by fungal infection transmitted by the midge (Lasioptera berlesiana), microtomography revealed the infection cavity, which was delimited by a protective layer of tissue produced by the plant to isolate the infection zone, which contained fungal hyphae and reproductive organs of the fungus. Two ovoid cavities were observed below a single external orifice in the concave necrotic depression. These results were interpreted as successive ovipositions of B. oleae, followed by the parasitoid L. berlesiana. High-resolution 3D rendered images are included as well as supplementary videos that could be useful tools for future research and teaching aids.

Performance of Artificial Diets for Zelus renardii (Hemiptera: Reduviidae) Rearing.

Mass production is a prerequisite for using natural enemies in integrated pest management and organic farming. Natural enemies in agroecosystems include predators that prey on insects, which they can subdue while maintaining adequate pest population densities. The Leafhopper Assassin Bug (LAB), Zelus renardii, can be a natural enemy in agroecosystems, selecting its prey for size and mobility. Some of LAB's prey include Philaenus spumarius (L.), Bactrocera oleae (Rossi), Drosophila suzukii (Matsumura), and Macrohomotoma gladiata Kuwayama, suggesting this reduviid for biocontrol agent in various contexts. We reared LABs for two subsequent broods offering living prey and artificial diets. Our data show that the rearing of Z. renardii is feasible with oligidic, meridic, and holidic artificial formulations. Four artificial diets allowed the complete post-embryonic development of LABs in captivity for two successive generations. The accumulated degree-days (ADDs) accurately predict the growth of LABs based on heat accumulation, estimating that up to three generations could grow per year in captivity at the experimented T°C.

Does biodiversity affect Olive fly populations? Evidence from different understorey treatments

The agricultural industry is intensifying production methods to increase crop yields. Olive cultivation, the prevalent permanent crop in Europe and the Mediterranean area, involves intense practices with heavy agrochemical use. This significantly impacts agroecosystem biodiversity and its ecosystem services. In this study, we explore how biodiversity influences the adult olive fly (Bactrocera oleae (Rossi)) population in Lesvos Island, Greece, under different understorey management practices in olive groves. Our findings show that increased plant and arthropod abundance and diversity negatively affect the olive fly. The results suggest that maintaining undisturbed plant cover enhances olive grove biodiversity, ecosystem services, and biological control of the olive fly. Moreover, this practice is in line with Integrated Pest Management principles and Conservation Biological Control approach.

Effectiveness of four Turkish entomopathogenic nematode isolates against Bactrocera oleae (Diptera: Tephritidae) pupae at different temperatures

Türkiye, is the country of origin of the olive tree and is among the world’s leading olive producers. Most of the olive production in Türkiye is concentrated in Izmir, Aydın, Çanakkale, Balıkesir, Muğla and Bursa Provinces. Bactrocera oleae (Diptera: Tephritidae), being one of the main pests of olive trees, is an important problem in olive cultivation in Türkiye. The efficacy of four Turkish populations of entomopathogenic nematodes against B. oleae pupae was determined under laboratory conditions. They were Steinernema feltiae/12, S. carpocapsae/1133, Heterorhabditis bacteriophora/70, H. bacteriophora/91, which were collected in different regions of Türkiye during our earlier studies. They were tested against the pest by using a single dose at 5 different temperatures (10, 15, 20, 25 and 30 °C). The highest infection rate was observed forH. bacteriophora/91 isolate at 25 °C, and the lowest infection rate was observed for S. feltiae/12 isolate at 10 °C.

Evaluation of the effect of agroclimatic variables on the probability and timing of olive fruit fly attack.

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 winter mean 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.

Factors Affecting Water Deprivation Resistance in Bactrocera oleae (Olive Fruit Fly)

Factors Affecting Water Deprivation Resistance in Bactrocera oleae (Olive Fruit Fly)

Exogenous systemin peptide treatment in olive alters Bactrocera oleae oviposition preference

AbstractThe olive fruit fly, Bactrocera oleae (Rossi), is a key pest of the olive crop, whose control relies mostly on the use of insecticides. Plant peptides may represent a more environmentally-friendly tool to manage olive fly, due to their recognized role to activate and/or prime plant defence responses against pests. In this work, behavioural experiments (no-choice and two-choice) and analysis of volatile compounds were carried out to evaluate the impact of the exogenous application of the peptide systemin to olive tree on olive fly infestation, and to elucidate its mode of action to prime plant defence. The treatment of olive branches with 10 nM systemin showed to confer protection against olive fly, by reducing significantly the ovipositions (up to 3.0-fold) and the number of infested fruits (up to 2.9-fold) when compared to non-treated branches. This protective effect was even detected in neighbouring non-treated branches, suggesting the ability of systemin to trigger plant-to-plant communication. The deterrent activity of the primed olives was associated with the emission of the volatiles 2-ethyl-1-hexanol, 4-tert-butylcyclohexyl acetate and 1, 2, 3-trimethyl-benzene, which were negatively correlated with oviposition and fly infestation. Systemin has also showed to trigger the biosynthesis of specific volatiles (esters) in olives in response to fly attacks. Overall, the observed protection conferred by systemin against olive fly is likely due to the emission of specific volatiles that can act as a defence and/or as signalling molecules to upregulate the plant defence response. Thus, systemin represents a novel and useful tool to manage olive fruit fly.

Diversity of arthropods subservient to olive groves in arid region (Northeastern Algeria)

Olea europaea L. 1753, is one of the oldest and most distinctive trees in the Mediterranean region. Its nutritional, social, cultural, and economic value is very important for populations in arid regions, where it is widely distributed. A sign of a sustainable environment in many agricultural regions is the existence of a wide variety and abundance of arthropod groups. The main objective of the study is to evaluate the diversity of arthropods subservientin in olive agro-systems in the arid region by using several sampling techniques, namely classic sight hunting, visual inspection, Barber pots, and yellow traps. The inventory is carried out over a period of 5 months, from February to June 2023, in three stations in M’Sila (northeastern Algeria). Three classes of arthropods were found: Insecta, Arachnida, and Malacostraca. Captures were numerically dominated by Insecta, representing 96.88% of total captures. Arachnida and Malacostraca classes represented about 2.74 and 0.38%, respectively. During this research, a total of 1861 arthropod individuals were collected and identified into 83 species, 79 genera, 53 families, and 15 orders. The most abundant orders were: Diptera (42.56%), Hymenoptera (28.11%), and Coleoptera (7.32%). However, we found a significant difference in species composition according to habitat (P 0.01). The species were determined, and the ecological indices were calculated (Shannon Value, Evenness values and Simpson reciprocal index). The dominant functional feeding groups were phytophages (41.91 %), predators (32.94%), and polyphages (22.14%). The arthropods included several olive pests such as Euphyllura olivina (Costa) (Hemiptera: Liviidae), Bactrocera oleae (Rossi) (Diptera: Tephritidae), Prays oleae (Bernard) (Lepidoptera: Praydidae), Liothrips oleae Costa (Thysanoptera: Phlaeothripidae), and Oxycenus maxwelli (Keifer) (Arachnida: Eriophyidae). Keywords: diversity, arthropods, pests, olive grove, species richness, arid land.

Super high-density olive orchard system affects the main olive crop pests

The increasing use of the super high-density (SHD) olive orchard system requires a careful assessment of its potential impact on the main olive pests. The purpose of this study is to evaluate the SHD effect on Bactrocera oleae and other harmful phytophagous species by assessing damages caused by each pest. For three years, in three different sites in Tuscany established with Italian selection or Spanish Arbequina cultivars, the SHD management system was compared to an adjacent traditional olive orchard system in which the same soil and phytosanitary management were applied. Samplings of twigs and fruits from spring to fall together with adult monitoring of B. oleae, Prays oleae, and Palpita vitrealis by pheromone traps were used to determine infestation percentages and insects’ population dynamics. Bactrocera oleae, Liothrips oleae, and Euphillura olivina were negatively affected by the SHD olive orchard system, while P. vitrealis and Otiorhynchus cribricollis were favoured by this management. Bactrocera oleae total infestation was reduced to almost 50 % in the SHD system. In contrast, Palpita vitrealis showed high infestation levels in more vigorous cultivars. Further studies are required for a complete evaluation of the impact of SHD management on olive pests.

Spatial analysis of olive fly on Samos island

Cultivation of olive-trees is one of the landmark land-uses and agroecosystems of the Mediterranean. The single most important factor of production-loss is infestation by the olive fruit fly (OLF, Bactrocera oleae). We examine the spatiotemporal dynamics of OLF populations on Samos Island by employing spatial-analysis methods for a focused estimation on olive plantations. The case study includes a variation of areas across altitude. We use data for three years (2017–2019) from 399 trap locations that are not associated with farms or other major anthropogenic installations and measure temperature and humidity in 24 locations across the island to: examine the temporal variation of OLF populations, to check the relationship of temperature, humidity, and geomorphological characteristics and calculate the estimated spatial distribution of OLF. Results show small differences of annual averages, but very important spatiotemporal differences and micro hot/cold spots of OLF populations. Findings suggest significant movement of OLF populations across landscape. This approach can help achieve a deeper understanding of OLF behavior in Mediterranean ecosystems and contribute toward new approaches in pest management of olive trees.

How the "Olive Oil Polyphenols" Health Claim Depends on Anthracnose and Olive Fly on Fruits.

Olive anthracnose, caused by Colletotrichum fungi, and the olive fruit fly Bactrocera olea are, respectively, the most important fungal disease and pest affecting olive fruits worldwide, leading to detrimental effects on the yield and quality of fruits and olive oil. This study focuses on the content of hydroxytyrosol (HYT) and its derivatives (the "olive oil polyphenols" health claim) in olive oils extracted from fruits of 'Galega Vulgar' and 'Cobrançosa' cultivars, naturally affected by olive anthracnose and olive fly. The olives, with different damage levels, were harvested from organic rainfed orchards, located in the center of Portugal, at four harvest times over three years. Galega oils extracted from olives with a higher anthracnose and olive fly incidence showed no conformity for the extra virgin olive oil (EVOO) and virgin olive oil (VOO) categories, presenting high acidity and negative sensory notes accompanied by the disappearance of oleacein. Conversely, no sensory defects were observed in Cobrançosa oils, regardless of disease and pest incidence levels, and quality criteria were still in accordance with the EVOO category. The total HYT and tyrosol (TYR) content (>5 mg/20 g) allows for the use of the "olive oil polyphenols" health claim on the label of all the analyzed Cobrançosa olive oils.

Deep Learning-based Lightweight Models for Bactrocera Oleae Detection

The detection of Bactrocera oleae (BO), an invasive pest that poses a serious threat to olive tree cultivation, is crucial for ensuring the quality and quantity of olive oil production. This study explores the application of deep learning with lightweight models for BO detection in olive trees. The DIRT Dataset, consisting of 841 images obtained from traps, was used for training and evaluation. Different combinations of Faster R-CNN and SSD models with various backbone architectures, including EfficientNet B0, MobileNet v3, ResNet-18, and ResNet-50, were assessed. The combination of Faster R-CNN with ResNet-18 achieves comparable results to Faster R-CNN with ResNet-50 but with lower latency and a reduced parameter count. These findings highlight the potential of deep learning-based object detection models for BO detection in olive trees, offering efficient and accurate identification of infestations.

Locomotor Activity of Adult Olive Fruit Flies Recorded under Conditions of Food or Water Deprivation

The olive fruit fly, known as Bactrocera oleae (Rossi) (Diptera: Tephritidae), is causing substantial economic losses in olive crops worldwide. Studying the activity patterns of the insect may expand our knowledge to eventually adopt more sustainable and effective pest control approaches. In the present study, we investigated the impact of food and water deprivation on the mobility of olive fruit flies using a modified version of the LAM25 system (locomotor activity monitor)—Trikinetics, an automated locomotor activity electronic device. Both male and female flies at four different age groups, reared on olives in the laboratory, were individually placed in glass tubes. Their locomotor activity was recorded every minute by three monitors within the digital device over a three-day period. Our observations revealed that adults exhibited significantly reduced movement during nighttime compared to daytime. The greatest mobility was observed during the period of 15:00 to 20:59. Additionally, younger flies demonstrated higher levels of mobility compared to older ones. Flies subjected to both food and water deprivation exhibited higher mobility compared to the control group. These insights offer valuable insights for enhancing pest management strategies aimed at controlling olive fruit flies adopting a more sustainable approach.

Serratia montpellierensis sp. nov., Isolated from Laboratory-Reared Parasitic Wasps Psyttalia lounsburyii Silvestri and Psyttalia ponerophaga Silvestri (Hymenoptera: Braconidae).

Two strains of bacteria, PsyLou2AT and PsyPon4B, were isolated from adult braconid wasps Psyttalia lounsburyii and Psyttalia ponerophaga, respectively. These laboratory-reared wasps were investigated as agents for biological control of the olive fruit fly, Bactrocera oleae. Analysis of 16S rRNA genes of the two isolates demonstrated that they were highly related and belonged to the genus Serratia. Genomic sequencing of these isolates revealed genomes of 5,152,551bp and 5,154,385bp for PsyLou2AT and PsyPon4B, respectively, and both genomes had a mol% G+C content of 59.6%. Phylogenetic analyses using BLAST-based average nucleotide identity (ANIb), and digital DNA-DNA hybridization methods indicated that PsyLou2AT was most closely related to Serratia nevei S15T, producing ANIb and dDDH values of 96.11% and 70.2%, respectively. Since these values were literally on the species cutoff threshold, additional S. nevei genome assemblies were analyzed using ANIb and dDDH calculations. This revealed that among assemblies that were clearly identifiable as S. nevei, S. nevei S15T was the most closely related to PsyLou2AT, and that a majority of assemblies produced dDDH values of 68.3-68.7% relative to PsyLou2AT. Additionally, PsyLou2AT differed biochemically from S. nevei S15T in that it produced positive Voges Proskauer tests, produced protease, lacked arginine dihydrolase, and did not utilize D-lactose. Hence, PsyLou2AT represents a novel taxon within the Serratia, for which we propose the name Serratia montpellierensis sp. nov. The type strain is PsyLou2AT (=LMG 32817T =NRRL B-65689T).

Oviposition-Deterrent Effect of a High-Quality Natural Zeolite on the Olive Fruit Fly Bactrocera oleae, under Different Conditions of Temperature and Relative Humidity.

In recent years, the number of available chemical pesticides has been dramatically reduced, urging the need for the discovery of alternatives to chemical pesticide products such as, among others, natural zeolites (zeolitic rocks). We determined the mineralogical and chemical composition of a specific and continuous layer of zeolitic rock sample (ZeotP) from Petrota, Evros, Greece, and evaluated its oviposition-deterrent effect on the olive fruit fly Bactrocera oleae Gmelin (Diptera: Terphritidae). The tested natural zeolite contained 70 wt. % clinoptilolite, 18 wt. % amorphous material, 7 wt. % feldspars, 4 wt. % cristobalite, and 1 wt. % quartz. We tested the oviposition-deterrent effect of ZeotP mixed or not with an emulsifier adjuvant, NU-FILM-P®, in water and applied it to the surface of olive fruits. The ZeotP oviposition-deterrent effect on the olive fly was very high under a series of tested temperatures (17 °C, 20 °C, 25 °C, and 30 °C) and RHs (23%, 33%, 55%, 75%, and 94%). In addition, the ZeotP residual deterrent effect after equable water spraying was high, like the respective effect of the pyrethroid insecticide Decis® (deltamethrin). Our results may contribute to the effective control of the olive fruit fly using an alternative to chemical pesticides: natural zeolite (zeolitic rocks) products.

Comparison of different trapping devices for the capture of <em>Bactrocera oleae</em> (Rossi) and other non-target insects in the Mediterranean basin

The present study aimed to compare some commercial traps baited with ammonium carbonate for their efficacy in monitoring Bactrocera oleae (Rossi) and their selectivity toward beneficial insects, under the conditions of olive groves located in five Mediterranean countries (Greece, Italy, Lebanon, Spain, Tunisia). The selectivity of the devices was evaluated toward several groups of non-target insects, namely lacewings (Chrysopidae), hoverflies (Syrphidae), ladybirds (Coccinellidae), bees (Apoidea) and hymenopteran parasitoids. The following devices were compared: yellow sticky panel, green sticky panel, Jackson trap with different combinations of yellow and white colours of the device and/or the panel, and McPhail trap. In most cases, the McPhail trap and the yellow panel showed the highest efficacy in monitoring male and female B. oleae flies; however, the yellow panel was most attractive for some groups of non-target insects, particularly the hymenopteran parasitoids, whereas the comparative non-target effects were sitespecific for the other arthropod groups. In the case of Chrysopidae, McPhail caught more individuals than the other traps in Italy and Spain, whereas in Lebanon and Greece, the highest number of individuals was captured in the two sticky panels. Coccinellidae were found in very low numbers only in Lebanon on yellow panels. Syrphidae were captured mainly on sticky panels in Greece and Tunisia. Apoidea were found only on yellow panels in Lebanon. The choice between the McPhail trap and the yellow panel should be made on the basis of various evaluations carried out at the site, including operational ones.