Olive Fly Research Articles

Cost Analysis of Using UAV Sprayers for Olive Fruit Fly Control

Unmanned Aerial Vehicles (UAVs) are a novel up-and-coming technology with wide applicability and great potential to be used in agricultural systems for spraying applications. However, the cost-effectiveness of this application is still rather uncertain. The present study utilized actual data from field applications to analyze the critical components and parameters in the potential case of using UAV sprayers for the control of olive fruit flies in order to assess the operational costs. The results are compared with the costs of two traditional spraying methods: manual spaying by workers using backpack sprayers and manual spraying assisted by a tractor. The case of the olive fruit fly was selected because it involves costly, time consuming, and laborious manual spraying. Furthermore, the bait character of spraying in these applications does not require full canopy coverage, making it ideal for UAV applications. A parameterized computational model was developed to assess the costs of labor, capital spending, repair and maintenance, energy, licensees, fees and taxes, and storage for each of the three methods. In addition, the cost for surveillance was also accounted for with the UAV method. Consequently, a sensitivity analysis was performed to examine the impact of the most crucial parameters. The results showed that the cost of spraying with a UAV was 1.45 to 2 times higher than the traditional methods, mainly due to the high capital spending resulting from a low economic life. There are opportunities, however, of improving the economic performance, making it compatible to the traditional methods, by using a smaller UAV with longer lasting batteries and by expanding its annual use beyond the needs of olive fruit fly control.

Remote fruit fly detection using computer vision and machine learning-based electronic trap.

Intelligent monitoring systems must be put in place to practice precision agriculture. In this context, computer vision and artificial intelligence techniques can be applied to monitor and prevent pests, such as that of the olive fly. These techniques are a tool to discover patterns and abnormalities in the data, which helps the early detection of pests and the prompt administration of corrective measures. However, there are significant challenges due to the lack of data to apply state of the art Deep Learning techniques. This article examines the detection and classification of the olive fly using the Random Forest and Support Vector Machine algorithms, as well as their application in an electronic trap version based on a Raspberry Pi B+ board. The combination of the two methods is suggested to increase the accuracy of the classification results while working with a small training data set. Combining both techniques for olive fly detection yields an accuracy of 89.1%, which increases to 94.5% for SVM and 91.9% for RF when comparing all fly species to other insects. This research results reports a successful implementation of ML in an electronic trap system for olive fly detection, providing valuable insights and benefits. The opportunities of using small IoT devices for image classification opens new possibilities, emphasizing the significance of ML in optimizing resource usage and enhancing privacy protection. As the system grows by increasing the number of electronic traps, more data will be available. Therefore, it holds the potential to further enhance accuracy by learning from multiple trap systems, making it a promising tool for effective and sustainable fly population management.

Synthesis of alkali-activated materials blended with fly ash: Optimization of curing conditions and precursor dosage

Metakaolin, calcined clay, and sodium and potassium silicates are frequently utilized materials in the alkali activation process to produce alkali-activated materials. This study investigates various approaches to enhance the reactivity of low-quality natural clay to manufacture alkali-activated bricks with improved strength. Two types of clay were employed: natural and calcined clays. The results demonstrate that the optimal compressive strength was achieved by combining non-calcined clay with chamotte, sand, and 25 % olive pomace fly ash (OPFA). This selection provides environmental and energy benefits since it reduces the energy consumption and environmental effects associated with high-temperature clay calcination. The best conditions for increasing the compressive strength of the alkali-activated binder involve curing in a dry environment at 80 °C for 8 h. The mineralogical and microstructural characterization of the optimized material revealed a more or less dense structure with the possibility of the presence of hydrated calcium silicate gel, in addition to the hydrated sodium silicate gel due to the pozzolanic nature of the olive pomace ash used.

Population Dynamics of the Olive Fly, Bactrocera oleae (Diptera: Tephritidae), Are Influenced by Different Climates, Seasons, and Pest Management

Pest management practices interact with many species and have an impact on the ecology and the economy of the area. In this paper, we examine the population dynamics of the olive fly, Bactrocera oleae (Rossi), Diptera: Tephritidae, on Samos Island, Greece, observing the spatial and temporal changes of the pest along an altitude associated with area-wide pest management. More specifically, we analyze data from an extended McPhail trap network and focus on experimental sites, where we monitor the pest population in relation to sprays, temperature, and relative humidity inside the tree canopy during the season for a three-year period. Our findings indicate that fly populations are influenced mostly by climate and altitude over longer periods in the season and from bait sprays for shorter periods of time, which appeared to be less effective in autumn, probably due to population movements and overlapping generations. Apart from the factors that were taken into account, such as the weather conditions and pest management regimes that were proven important, more factors will have to be considered for infestation level, such as fruit availability, inhibition factors (natural enemies, symbiotic agents, food supplies), and cultivation practices. Site microclimate conditions and the landscape can be used to explain changes at the plot level.

Modulation of the Irrigation Practices in Croatia for More Sustainable Olive Growing

Olive groves in the Mediterranean may lose production sustainability because of their vulnerability to climatic change. Irrigation is an important measure that could significantly affect fruit yield, olive fruit fly infestation, and oil characteristics. The aim of paper was to compare the regulated deficit irrigation with different water management practices, in consecutive years, in two locations in Zadar County (Croatia), affecting fruit morphology, olive fruit fly infestation, and quantity and quality of the extracted Coratina cultivar oil. Treatments, namely C—rainfed, T1—deficit irrigation (produce’s practice), T2—regulated deficit irrigation, and T3—full irrigation (100% ECTO), were established. Irrigated treatments had a positive effect on all morphological characteristics of the fruit. The pulp mass, independently of the year, increased in irrigated treatment (ranging from 1.04 to 1.65 in C to 2.25 and 2.30 in the irrigated treatments) and resulted in a higher oil content on a fresh weight basis (ranging from 16.39% to 17.85% in C to 19.48% to 23.26% in the irrigated treatments). However, fruit yield per tree was only location-dependent. When olive fruit fly presence was high, fruit infestation was greatest in the irrigated compared to the rainfed treatment. According to quality parameters, all oils were classified as EVOO. Individual phenols were influenced by irrigation, while the composition of fatty acids was more influenced by location than treatment. The sensory characteristics of the resulting oil were slightly reduced compared to rainfed treatment. The results indicate that regulated deficit irrigation benefits water use sustainability without compromising the quality of the oil.

Investigation of Fruit Growth Patterns, Olive Fly Bactrocera oleae (Rossi) Infestation, and Genetic Diversity in Italian Olive Cultivars

The olive fruit fly Bactrocera oleae (Rossi, 1790) poses a significant threat to oliviculture worldwide, despite extensive chemical control measures. The susceptibility of olive (Olea europaea L.) to this pest varies among cultivars, with fruit size being a key factor of interest, as it can be assessed using non-destructive automated technologies. In this study, we investigated the oviposition preferences of the olive fruit fly in six Italian olive cultivars, tracking fertile and sterile punctures in relation to the diametric growth of the drupe. Additionally, we assessed the genetic diversity among cultivars using SSR markers, aiming to uncover a potential correlation between variation in the genetic diversity patterns and infestation levels. The results revealed that the relationship between fruit size and infestation level is non-linear and varies across different cultivars. The co-inertia analysis (COIA) performed on the genetic and infestation datasets revealed possible shared patterns of diversity and relationships between the two datasets. This study emphasizes the complex and diverse nature of the interaction between the olive fruit fly and its host, underscoring the importance of comprehending non-linear relationships to develop accurate genotypic-specific predictions and models.

Impairing the development of an olive fly pest by targeting its symbiotic bacteria in egg-infested fruits

Impairing the development of an olive fly pest by targeting its symbiotic bacteria in egg-infested fruits

Isolation and identification of volatile compounds from a protein-based food lure: electrophysiological and behavioral responses of Bactrocera oleae adults

Isolation and identification of volatile compounds from a protein-based food lure: electrophysiological and behavioral responses of Bactrocera oleae adults

Brevundimonas aurantiaca M3d10, Isolated from the Olive Fly, Produces Hydroxylated Astaxanthin

In recent years, the exploitation of bacteria for the production of carotenoids has become of great interest as a sustainable alternative to chemical synthesis, which is expensive and technically challenging. This study contributes to the repertoire of carotenogenic bacteria by reporting the isolation of an orange-pigmented bacterium from the gut of adult olive flies. The novel isolate, designated as M3d10, shared 100% identity with Brevundimonas aurantiaca strain CB-R 16S ribosomal RNA, and, through a preliminary characterization, its orange pigment was predicted to be a hydroxylated astaxanthin derivative.

A shift in the paradigm? A male-specific lactone increases the response of both sexes of the olive fruit fly Bactrocera oleae to the food lure ammonium bicarbonate

The olive fruit fly Bactrocera oleae (Rossi) (Diptera: Tephritidae) is a key pest species of wild and cultivated olive trees worldwide. Contrarily to most tephritid flies, in which males release the sex pheromone, in B. oleae the female is the sex responsible of attracting the opposite sex. However, and even though vast research has been done during the last decades, we are still far from understanding the chemical signals involved in the sexual communication of this species, including those produced by males. Here, we report for the first time the presence of two male-specific volatile compounds, namely γ-hexalactone and δ-hexalactone, with the former exerting a significant attraction upon both sexes under laboratory and field conditions. Volatile collections conducted on laboratory-reared virgin individuals of both sexes revealed the presence of these two compounds only in males, regardless of their age. In double-choice behavioral assays, γ-hexalactone resulted to be attractive for virgin males and females (7–14 days old), with no attractiveness reported for δ-hexalactone. Finally, in field assays traps baited with the binary blend of ammonium bicarbonate and γ-hexalactone yielded significantly more catches per week of both sexes than those baited with ammonium bicarbonate and ammonium bicarbonate plus 1,7-dioxaspiro[5.5]undecane, the major sex pheromone component. Altogether, our results shed light on the chemical ecology of the species and represent a promising experimental basis for the development of more innovative and effective mass trapping tools based on the use of γ-hexalactone.

Chemical cues involved in the host foraging behavior of Psyttalia concolor wasps to locate the olive fruit fly Bactrocera oleae

Foraging parasitoids rely on infochemicals, derived from the habitat, host plant and/or host insect itself. Here, we studied the olive fruit fly Bactrocera oleae (Rossi) (Diptera: Tephritidae), a major pest in olive agroecosystem and its larval parasitoid, Psyttalia concolor (Szépligeti) (Hymenoptera: Braconidae), a well-established and abundant wasp in Crete. To improve parasitoid’s efficiency as biological control agent, more knowledge on its host location behavior is required. The aim of this study was to investigate the role of oviposition- (OIPVs) and herbivore-induced plant volatiles (HIPVs) emitted by olive trees upon infestation by B. oleae as well as cues emitted by B. oleae, e.g., pheromones, therein. We conducted two-choice bioassays to test the preference of P. concolor to different olfactory stimuli. Moreover, we collected headspace volatiles from olive fruits and branches to investigate whether egg or larval infestation changes volatile emissions locally or/and systemically. We found that P. concolor wasps showed a strong preference to volatiles of B. oleae larval-infested fruits (HIPVs) compared to clean air, non-infested, egg-infested, and mechanical-damaged fruits. But they were not able to discriminate between volatiles of non-infested and larval-infested branches. In addition, the wasps were attracted to cues emitted from the virgin and mated B. oleae females. They were neither attracted to cues emitted by the virgin and mated males nor to the olive fruits with or without the cues of the oviposition marking of the B. oleae. We found important qualitative differences in volatile profiles of egg- and larval-infested fruits: nineteen volatile compounds were only detected in infested fruits, such as the terpenoids (E)-β-ocimene and (E,E)-α-farnesene. Moreover, volatile analysis showed that olives change volatile emissions locally and systemically in response to larval infestation. Our results suggest that both HIPVs and host cues play an important role to P. concolor during host location. Further knowledge on the chemical compounds utilized by the parasitoid to locate infested fruits could help application in olive orchards and to improve the control of the olive fruit fly by natural enemies.

Toxicity and physiological interruptions of a proteinaceous toxin from Metarhizium anisopliae against the olive fruit pest, Bacterocera oleae (Diptera: Tephritidae)

The use of natural bioactive compounds mainly proteinaceous secondary metabolites of fungi is one of the promising pest control methods because of their lethal effects on insects in low concentration, limited persistence in environment and easily decomposition into environmentally safe compounds. The olive fruit fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae), is a destructive pest of olive fruits around the world. In the current study, the proteinaceous compounds were extracted from the two isolates (MASA and MAAI) of Metarhizium anisopliae and their effects were evaluated on toxicity, feeding performance and antioxidant system of the adult's olive flies. Both extracts from MASA and MAAI showed entomotoxicity against the adults by 2.47 and 2.38 mg/mL as LC50 concentrations. Also, LT50 values were recorded 1.15 and 1.31 days for MASA and MAAI, respectively. No statistical differences were recorded in the consumption rate of the adults on control and secondary metabolite contained protein hydrolysate. In contrast, the adults fed on LC30 and LC50 concentrations of MASA and MAAI demonstrated significant reduction in the activities of digestive alpha-amylase, glucosidases, lipase, trypsin, chymotrypsin, elastase, amino- and carboxypeptidases. Activity of antioxidant enzymes changed in the adults of B. oleae fed on the fungal secondary metabolites. Catalase, Peroxidase and Superoxide dismutase elevated in the treated adults with the highest amounts of MAAI. Similar results were found in activity of ascorbate peroxidase and glucose-6-phosphate dehydrogenase except for malondialdehyde amount in which no statistical differences were recorded between treatments and control. Relative gene expression of caspase enzymes revealed the higher expression in the treated B. oleae compared to control with the highest level of caspase 8 for MASA and caspases 1 and 8 for MAAI. Results of our study showed that the secondary metabolites extracted from the two isolates of M. anisopliae caused mortality, interrupted digestion and induced oxidative stress in the adults of B. oleae.

Developing an Open-Source IoT Platform for Optimal Irrigation Scheduling and Decision-Making: Implementation at Olive Grove Parcels

Climate change has reduced the availability of good quality water for agriculture, while favoring the proliferation of harmful insects, especially in Mediterranean areas. Deploying IoT-based systems can help optimize water-use efficiency in agriculture and address problems caused by extreme weather events. This work presents an IoT-based monitoring system for obtaining soil moisture, soil electrical conductivity, soil temperature and meteorological data useful in irrigation management and pest control. The proposed system was implemented and evaluated for olive parcels located both at coastal and inland areas of the eastern part of Crete; these areas face severe issues with water availability and saltwater intrusion (coastal region). The system includes the monitoring of soil moisture and atmospheric sensors, with the aim of providing information to farmers for decision-making and at the future implementation of an automated irrigation system, optimizing the use of water resources. Data acquisition was performed through smart sensors connected to a microcontroller. Data were received at a portal and made available on the cloud, being monitored in real-time through an open-source IoT platform. An e-mail alert was sent to the farmers when soil moisture was lower than a threshold value specific to the soil type or when climatic conditions favored the development of the olive fruit fly. One of the main advantages of the proposed decision-making system is a low-cost IoT solution, as it is based on open-source software and the hardware on edge devices consists of widespread economic modules. The reliability of the IoT-based monitoring system has been tested and could be used as a support service tool offering an efficient irrigation and pest control service.

Modeling and optimizing the changes in physical properties of olives in response to attacks of olive fruit fly (Bactrocera oleae (Gmelin))

Modeling and optimizing the changes in physical properties of olives in response to attacks of olive fruit fly (Bactrocera oleae (Gmelin))

Biological parameters of Muscidifurax raptorellus (Hymenoptera: Pteromalidae) on Bactrocera oleae (Diptera: Tephritidae), the key pest of olives

ABSTRACT The olive fruit fly, Bactrocera oleae, is one of the main pests of this crop and its control requires the development of methods environmentally safer than those used mostly nowadays, being biological control a possible alternative. Accordingly, the capacity of parasitisation and the biological parameters of Muscidifurax raptorellus, a generalist parasitoid of dipteran pupae, were evaluated on B. oleae at 25°C, 80% RH and a 16:08 h light/dark photoperiod. In a development assay, the rates of parasitism ranged 60% to 72% and the duration of the preimaginal period was between 17.0 and 18.5 days. The total mean number of adult wasps produced per pair in a reproduction assay was 50.7, with a mean daily production of 7 individuals and a mean rate of parasitism of 32.6%. The moment of maximum offspring production was estimated at 2.6 days after the beginning of the oviposition. The intrinsic rate of natural increase of M. raptorellus on B. oleae was 0.147, what determines a population doubling time of 4.7 days. The functional response was type II and the maximum attack rate in 24 h was 19.6 pupae. At host densities ranging 20–80 pupae per female, the number of adult wasps produced was around 20–22. The results obtained show the potential of M. raptorellus to be used for the biological control of B. oleae.

Quality parameters of olive oils at different ripening periods as affected by olive fruit fly infestation and olive anthracnose

Olive pests and diseases influence olive oil quality. Ayvalik olive cultivar is important between local cultivars grown in Turkey. This study aimed to monitor the effects of olive pests and diseases (olive fruit fly attack and olive anthracnose) on Ayvalik olive oil quality parameters such as free fatty acids (FFA), peroxide value (PV), specific extinction coefficients (K232, K270, and ΔK). Besides, Ayvalik olive fruits were collected at six harvest times, and the level of ripening with olive pests was also evaluated. Results showed that the FFA level influenced negatively by olive pests, mainly olive anthracnose. At the end of harvesting, FFA of oils from damaged olive anthracnose reached up to 5.42 (% oleic acid). Except for the first harvest period, the other quality parameters remained between limit values, and slight differences were observed between healthy and damaged olives. At the first harvest period, PV and K232 (7.02 mEq O2/kg, 2.22) of olive oil from fly-infected olive had higher values than the other samples. The stage of ripening, healthy, and damaged olives affected slightly certain fatty acids of the oils. Total phenolics, o-diphenol, and α-tocopherol content of oils from healthy fruits had higher values than oils from damaged olives. Besides, the antioxidant activity of oils obtained from healthy olives showed higher values compared to the oils from infected olive fruits.

Particle Films Combined with Propolis Have Positive Effects in Reducing Bactrocera oleae Attacks on Olive Fruits

The olive fruit fly, Bactrocera oleae, is a major pest of olive trees in several areas of the world. Testing novel preventive methods against B. oleae infestations is paramount. The use of particle film in eluding B. oleae and avoiding oviposition is one of the main strategies adopted by olive growers; however, choices are often limited to kaolin. Under field conditions, we tested the efficacy of novel compounds, including particle films, for their effectiveness as oviposition deterrents against B. oleae. The trial was conducted from July to October 2021 in an olive orchard located in central Italy. One olive variety, Borgiona, was selected and sprayed with propolis, rock powder, kaolin, the mixture of propolis and rock powder, the mixture of propolis and kaolin and water (control). Laboratory analyses were conducted to study the effects of the treatments on the fruit maturity index. As per the field trial, the rock powder and propolis mixture caused a reduction of B. oleae infestation with respect to the control (water), similarly to kaolin. Moreover, the mixture of kaolin and propolis exhibited the best results among all treatments. When mixed with propolis, particle films showed higher protection from B. oleae than when applied alone, suggesting a synergistic effect, and demonstrating an interesting role of propolis as an adjuvant. No delay in fruit maturity was noticed. Our results indicate that the tested products have the potential to be incorporated into management programs of B. oleae, although possible side effects on olive physiology require additional investigations.

Climate stressors modulate interannual olive yield at province level in Italy: A composite index approach to support crop management

AbstractAlthough a large part of Italy is characterized by a Mediterranean climate intrinsically highly suitable for olive cultivation, farmers may experience variable interannual yields with associated agronomic and management costs. A detailed overview of major climate stressors and their ongoing impacts on olive yield variability at a broad spatial–temporal scale across Italy could improve the understanding of how interannual olive yields are modulated by seasonal local climate and would enhance the development of actionable services to alert stakeholders of potential climate risks. We analysed aggregated olive yield data from the Italian National Statistics Institute (ISTAT) at the provincial level during 2006–2020, and several climatic variables from the Reanalysis v5 (ERA5) of the European Centre for Medium‐Range Weather Forecasts (ECMWF) as a basis to (i) explore olive yield trends and inter‐annual variations over the whole country; (ii) identify major seasonal climate stressors likely responsible for the largest variations in yield and (iii) develop a composite index that summarizes the risk of having exceptionally low yields due to the co‐occurrence of multiple stressors. To this end, we defined two extreme classes of yield, namely, exceptionally low and high yields (LY and HY, respectively) and explored the climatic variables aggregated on a bimonthly time scale that influenced yield outcomes. Our analysis showed that exceptional low yields have been erratically increasing since 2014 with temperature‐related variables having the highest impact, especially a relatively warm winter and cool early autumn. These period‐specific variables were major components of the resulting composite index predicting the likelihood of LY ranging from 28% to 49% due to increasing stress effects. Possible explanations of our findings are discussed, including the proliferation of the olive fly. We suggest the composite risk approach could lay the groundwork for an integrated meteorological seasonal forecasting system that provides timely insights on factors affecting within‐season olive yield development.

A Lifetime of a Dispenser-Release Rates of Olive Fruit Fly-Associated Yeast Volatile Compounds and Their Influence on Olive Fruit Fly (Bactrocera oleae Rossi) Attraction

The objective of this study was to evaluate the release rate, duration, and biological efficiency of yeast volatile compounds associated with olive fruit flies in slow-release dispensers, polypropylene vials, and rubber septa attached to yellow sticky traps under different environmental conditions in order to protect the environment, humans, and nontarget organisms. Isoamyl alcohol, 2-octanone, and 2-phenethyl acetate were placed in dispensers and tested over a four-week experiment. The weight loss of the volatile compounds in both dispensers was measured, and a rapid, inexpensive, and simple HS-GC/FID method was developed to determine the residual amount of volatiles in the septa. 2-Phenethyl acetate stood out in the rubber septa and showed a statistically significant difference in the release ratio compared to the other volatiles under all conditions tested. Our results showed that the attraction of olive fruit flies increased with decreasing concentrations of the tested volatiles. Regarding the number of flies attracted by rubber septa containing 2-phenethyl acetate, significantly better results were obtained than for septa containing isoamyl alcohol and 2-octanone, in contrast to the attraction of olive fruit flies to polypropylene vials containing these compounds but without significant difference. Since the presence of all tested chemicals was detected during the experiment, this opens the possibility of using more environmentally friendly and cost-effective dispensers with a significantly lower amount of semiochemicals.

Review Article Olive Fruit Fly Bacterocera Oleae Infestation of Olives: Effect on Quality and Detection in Olive Oil

Bacterocera oleae ‎ is the most common olive fruit pest in Jordan. The high incidence of olive fruit infestation with fruit fly in its stages of larvae and pupa is a common problem in olive oil production. Although not detected by simple means, it is believed to impart a “Grubby” taste that is detected only by experts and results in lowering the value of the oil from infested fruits. The effect of damage caused by B. oleae ‎ depends on the degree of infestation which is manifested in the presence of exit holes (EH) produced by the full-grown larvae which destroy the fruit skin and expose it to oxygen and other destructive factors like fungi. This results in the acceleration of hydrolytic and oxidative types of rancidity which can be estimated by measuring oil acidity (FFA) and peroxide value (PV). This review covers the literature related to the effect of olive fruit fly infestation on the quality of olive fruits and oil and the methods used in its control and detection.