Search Results (108)

Invasive insects can cause significant economic impacts to agriculture worldwide and impact human health. Traditional pest management methods that include chemical insecticides have raised increasing environmental and health concerns, prompting the need for sustainable alternatives. The Sterile Insect Technique (SIT), which consists of releasing sterile males of a target pest to mate with wild females, is held as a promising solution. However, the success of SIT relies on the release of sterile males. The efficient separation of sexes prior to sterilization and release is necessary. This study presents SIT-ia, a software–hardware system that utilizes artificial intelligence (AI) and computer vision to automate the sex-sorting process. We showcase its use with the fruit fly pest D. suzukii. The system was able to identify males from females with a 98.6% accuracy, sorting 1000 sterile flies in ~70 min, which is nearly half the time involved in manual sorting by experts (i.e., ~112 min). This simple device can easily be adopted in SIT production protocols, improving the feasibility and efficacy of improved pest management practices. Full article

The increase in the world population and consequent rise in food demand have led to the extensive use of chemical pesticides, causing environmental and health concerns. In response, biological control methods, particularly those involving microbial agents, have emerged as sustainable alternatives within integrated pest management. This study highlights the potential of Lysinibacillus fusiformis as a biocontrol agent against the dipteran Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), a pest responsible for damaging soft-skinned fruits. Experimental treatments using vegetative cells, spores, and secondary metabolites of L. fusiformis on D. suzukii larvae demonstrated significant larvicidal effects, accompanied by observable changes in gut morphology under microscopy. Moreover, preliminary immunological assays showed the interference of this bacterium with the host immune system. All the results indicate the suitability of L. fusiformis for its possible integration into sustainable agricultural practices, although additional research is required to understand its applicability in the field. Full article

Drosophila suzukii is a key invasive pest, and infestation in peach orchards can lead to significant economic losses. This study monitored the spatial distribution and reproductive biology of D. suzukii in central Italy to inform integrated pest management (IPM) strategies. In the surveyed orchard, the pest exhibited multiple generations, with captures highest along mixed-species-orchard edges, highlighting these margins as potential hotspots for targeted mass trapping. Seasonal dissections of females revealed delayed ovarian development during winter, while maturation progressed during fruit ripening and post-harvest periods. This result provides relevant information on the likely timing of oviposition, useful for informing pest management. A laboratory oviposition trial on nectarines revealed a clear preference for healthy, mechanically damaged fruits, whereas fungal infection reduced the attractiveness. This suggests that field sanitation, especially the timely removal of damaged or fallen fruits, could reduce pest presence and inoculum for the following season. Overall, these findings offer practical insights to support sustainable IPM approaches against D. suzukii in peach production systems. Full article

Gene duplications are considered to be the major evolutionary resource of novel functions. The gene family Esf2/ABP1 is conserved in metazoan organisms from yeast to humans. Here we performed a search and characterization of Esf2/ABP1 homologs in the Drosophila genus. Whereas in the majority of Drosophila species this gene family is represented by only a single gene, in the melanogaster and suzukii subgroups recurrent gene duplications arose, providing 47 homologous genes located on the X chromosome. To study the evolutionary history of duplicates, we performed phylogenetic, functional domain, and tissue-specific expression analyses. We revealed a male-specific and testis-biased transcription pattern of duplicated copies in Drosophila melanogaster and Drosophila sechellia compared to ubiquitous expression of the parental gene. The amplification of 21 repeated paralogs within the heterochromatic piRNA cluster resulted in the ovarian-specific transformation of these repeats into piRNAs in D. melanogaster. In three species of the suzukii subgroup, Esf2/ABP1 genes evolved with domain diversification: in addition to RNA-binding ABT1-like domain preservation, all homologous proteins acquired expanded intrinsically disordered regions. By studying the duplicated copies of the Esf2/ABP1 family in Drosophila, we offer insight into how novel gene functions emerge and are maintained, contributing to life’s diversity and complexity. Full article

Drosophila suzukii is an invasive pest of many fruit crops worldwide. Employing the Sterile Insect Technique (SIT) could mitigate D. suzukii population growth and crop damage. This study evaluated the efficacy of SIT on commercial fruit, by (1) validating the quality of irradiated sterile males (male mating competitiveness, courtship, and flight performance) in the laboratory, and (2) assessing population suppression and fruit damage reduction in commercial raspberry fields. Treatment with SIT was compared to the grower’s standard chemical insecticide program throughout the season. The principal metrics of efficacy were trap counts of wild adult female D. suzukii in crops and larvae per fruit during harvesting. These metrics together with monitoring of border areas allowed targeting of high-pressure areas with higher releases of sterile males, to maximise efficacy for a given release number. The sterile male D. suzukii were as competitive as their fertile non-irradiated counterparts in laboratory mating competitiveness and flight performance studies while fertility egg-to-pupae recovery was reduced by 99%. In commercial raspberry crops, season-long releases of sterile males significantly suppressed the wild D. suzukii population, compared to the grower standard control strategy; with up to 89% reduction in wild female D. suzukii and 80% decrease in numbers of larvae per harvested fruit. Additionally, relative fruit waste (i.e., percentage of harvested fruits rejected for sale) at harvest was reduced for early, mid and late harvest crops, by up to 58% compared to the grower standard control. SIT has the potential to provide an effective and sustainable strategy for managing D. suzukii in raspberries, increasing marketable yield by reducing adult populations, fruit damage and waste fruit. SIT could therefore serve as a valuable tool for integrated pest management practices in berry production systems. Full article

The spotted wing drosophila, Drosophila suzukii is an injurious polyphagous pest threatening worldwide soft fruit production. Its high adaptability to new colonized environments, short life cycle, and wide host range are supporting its rapid spread. The most common techniques to reduce its significant economic damage are based on multiple insecticides applications per season, even prior to the harvest, which reduces agroecosystem biodiversity and affects human and animal health. Environmental concerns and regulatory restrictions on insecticide use are driving the need for studies on alternative biological control strategies. This study aimed to assess the effect of T. drosphilae in controlling D. suzukii infestations and its interaction with P. vindemiae, a secondary parasitoid naturally present in Apulia (South Italy). Field experiments were carried out in organic cherry orchards in Gioia del Colle (Bari, Italy) to test the efficacy and adaptability of T. drosphilae following weekly releases of artificially reared individuals. Additionally, the interaction between P. vindemiae and T. drosphilae was studied under laboratory conditions. Results from field experiments showed that D. suzukii populations were significantly lower when both parasitoids were present. However, T. drosophilae was less prone to adaptation, so its presence and parasitism were limited to the post-release period. Laboratory experiments, instead, confirmed the high reduction of D. suzukii populations when both parasitoids are present. However, the co-existence of the two parasitoids resulted in a reduced parasitism rate and offspring production, notably for T. drosophilae. This competitive disadvantage may explain its poor establishment in field conditions. These findings suggest that the field release of the two natural enemies should be carried out with reference to their natural population abundance to not generate competition effects. Full article

Drosophila suzukii, classified as a quarantine pest in some countries, poses a serious threat to global trade due to its ability to damage berries and cherries. Recent studies indicate that low-temperature phosphine (PH₃) fumigation effectively controls this pest without compromising fresh produce quality. However, the specific protocol for managing D. suzukii larvae in cherries using this method remains underexplored. This study evaluates the efficacy of low-temperature PH₃ fumigation in controlling D. suzukii larvae across three cherry varieties at 3 °C and investigates potential effects on key quality metrics. Tolerance assessments revealed that 3rd instar larvae exhibit the highest resistance to PH₃ among all developmental stages. A concentration of 800 mL/m³ PH₃ for 84 h at 3 °C achieved phytosanitary efficacy for 0.99997 with no negative effect on the quality attributes of the tested cherry varieties. These results support low-temperature PH₃ fumigation as a viable postharvest treatment for D. suzukii management in sweet cherries. Full article

Drosophila suzukii is a successful invasive insect species responsible for agricultural losses. The key to its prowess is the ability to swiftly adapt to new environments through various genetic mechanisms, including fast accommodation of mutations and gene expression fine-tuning. Piezo and nanchung (nan) genes are linked to circadian clock-related behaviors and, therefore, are expected to readily respond to stress stimuli. Herein, we compared the DNA sequences of Piezo, nan, and αTubulin at 67C, a highly conserved housekeeping gene, in ICDPP-ams-1, a Romanian local population of D. suzukii, and two well-annotated reference populations from the United States of America and Japan. Our results imply that short-term evolutionary accumulated single nucleotide and indel variants are overrepresented within introns, a propensity evaluated through the mutation accumulation tendency (MAT) original parameter. Piezo and nan gene expression under photoperiodicity changes challenges were assessed in a series of experiments on three groups of individuals from ICDPP-ams-1. We found that both genes are upregulated in females if their customary circadian rhythm is affected, a trend seemingly reverting if, after an initial perturbation, the circadian clock is reset to its initial timing. In conclusion, we found that both highly conserved and adaptability-related genes are rapidly evolving and that Piezo and nan have a fast functional reaction to circadian clock changes by modifying their gene expression profiles. Full article

Drosophila suzukii (Matsumura) is a relevant pest affecting berries and stone fruits globally, including in the Neotropical region, where its invasion was reported about a decade ago. Despite chemical control being the main management method for D. suzukii, data on insecticide susceptibility in Neotropical D. suzukii populations are scarce. Here, we assessed the susceptibility of three field-collected Brazilian D. suzukii populations to four insecticides (i.e., deltamethrin, permethrin, spinetoram, imidacloprid) and contrasted this with a standard insecticide-susceptible population. Using the discriminating concentration (LC₉₀) from the standard susceptible population, we identified resistant populations. Synergist exposure (piperonyl butoxide, triphenyl phosphate, diethyl maleate) indicated the role of detoxification enzymes in resistance. Our results showed that deltamethrin was the most toxic, followed by spinetoram, permethrin, and imidacloprid. While all field populations were similarly susceptible to pyrethroids and spinosyns, one population from Minas Gerais (i.e., Paula Candido) had significantly lower imidacloprid susceptibility, with only 53.4 ± 5.2% mortality at 10.0 g/L (the equivalent of 10-fold the estimated imidacloprid LC₉₀). Only piperonyl butoxide increased the imidacloprid susceptibility of Paula Candido flies. Our findings indicate the occurrence of cytochrome P450 enzyme-based imidacloprid resistance in the state of Minas Gerais, which can challenge the management of D. suzukii in Brazil. Full article

Trichopria drosophilae is a globally distributed pupal parasitoid that targets various species within the Drosophilidae family, including the invasive Drosophila suzukii. The mass rearing of T. drosophilae is a crucial step in ensuring their successful application for field D. suzukii control. The pupae of Drosophila melanogaster are currently used as a host for the mass rearing of T. drosophilae. After irradiation, the immune system function of Drosophila pupae was weakened, leading to an increase in the parasitism efficiency of the T. drosophilae. Our results showed that irradiated pupae had a significant impact on the parasitism rate, offspring eclosion rate, offspring number, and female body size of F1 T. drosophilae, all of which were significantly lower than those in the normal group. However, there was no significant difference in the parasitism rate, body size, offspring eclosion rate, offspring number, or offspring sex ratio between F2 T. drosophilae emerging from treated or untreated Drosophila pupae. Compared with F2, F1 had a significantly higher net reproductive rate (R₀), mean generation time (T), and doubling time (DT), while the intrinsic rate of increase (r) was significantly lower. Using irradiated D. melanogaster pupae provides an efficient method for the mass rearing of T. drosophilae and offers valuable insights into its potential effectiveness in field D. suzukii control. Full article

Drosophila suzukii is an invasive pest that poses a significant threat to fruit crops worldwide, leading to considerable agricultural losses and economic damage. Unlike chemical control measures against D. suzukii, integrating insect-proof nets within an IPM framework offers a more sustainable solution. This study evaluates the efficacy of nine commercial protective nets against this pest, focusing on determining optimal hole dimensions based on the effects of airflow velocity, temperature, and pest morphometry on net performance. To simulate field conditions in the laboratory, we developed a tubular device divided into three chambers with the tested net placed between the two, incorporating a fan to generate airflow and a thermo-anemometer. Our results confirm that higher air velocities and elevated temperatures reduce net efficacy. Additionally, morphometric analyses of lab-reared flies revealed significant sexual dimorphism and a strong temperature–size relationship, with flies reared at lower temperatures being consistently larger, an aspect that also affects net effectiveness. These findings highlight the importance of considering both abiotic factors and pest morphology when evaluating protective screens, challenging the assumption that exclusion net efficacy remains constant. Some tested nets proved completely effective against SWD, supporting their use as a preventive measure in IPM programs. Full article

Drosophila suzukii severely damages the production of berry and stone fruits in large parts of the world. Unlike D. melanogaster, which reproduces on overripe and fermenting fruits on the ground, D. suzukii prefers to lay its eggs in ripening fruits still on the plants. Flies locate fruit hosts by their odorant volatiles, which are detected and encoded by a highly specialised olfactory system before being translated into behaviour. The exact information-processing pathway is not yet fully understood, especially the evaluation of odour attractiveness. It is also unclear what differentiates the brains of D. suzukii and D. melanogaster to cause the crucial difference in host selection. We hypothesised that the basis for different behaviours is already formed at the level of the antennal lobe of D. suzukii and D. melanogaster by different neuronal responses to volatiles associated with ripe and fermenting fruit. We thus investigated by 3D in vivo two-photon calcium imaging how both species encoded odours from ripe fruits, leaves, fermented fruits, bacteria, and their mixtures in the antennal lobe. We then assessed their behavioural responses to mixtures of ripe and fermenting odours. The neural responses reflect species-dependent shifts in the odour code. In addition to this, morphological differences were also observed. However, this was not directly reflected in different behavioural responses to the odours tested. Full article

This study explored the thermal response of Drosophila suzukii, an injurious insect pest present in many countries worldwide, at different controlled conditions. This species is responsible for several economic losses in soft fruit cultivations, develops on ripening fruits, and has the capability to quickly adapt to new territories and climates, closing multiple generations per year. Given its high invasive potential and the increasing need for low-impact control strategies, an in-depth exploration of the biology of this species and of the stage thermal response is fundamental. Specimens of an Italian strain from Apulia were reared in growth chambers at different constant temperatures (6, 9, 13, 18, 20, 24, 25, 26, 27, 28, 29, 31, 32 and 33 °C). The life cycle of each specimen was individually tracked from the egg to the death of the adults, considering the larval stages distinction as well. Besides development and mortality, egg production over temperature has been recorded. The dataset was first analysed according to life tables studies; then, we also estimated the biological parameters of the most common equations describing development, mortality, and fertility involved in physiologically-based model applications. The results confirmed and extended the information on the thermal response already present in the literature, but with reference to a population adapted to warmer climates. The species successfully developed from egg to adult at 13–29 °C, while between 6–9 and 29–33 °C the development was limited to L2/L3 stages. Optimal temperatures are around 26–28 °C, depending on the life stage. This study provides one of the complete overviews of the thermal response of D. suzukii, which is available in the current literature, and opens the door to more accurate modelling frameworks. Full article

Background: Drosophila suzukii is a worldwide invasive species with serious economic impacts. Herein, we are presenting the first project of sequencing and assembling the whole genomes of two lines of D. suzukii derived from Romanian local populations using exclusively Oxford Nanopore Technologies data. Methods: We implemented both MinION and Flongle flow-cells and tested the impact of various basecalling models and assembly strategies on the quality of the sought-after representative genome assemblies. Results: We demonstrate that the sup-basecalling model significantly improved the read quality and that adding a relatively small collection of reads had a significant positive impact over the assembly quality. The novel dScaff bioinformatics prototype tool allowed us to perform sequence-level quality tests, as well as to represent assembly selections and display both the contig redundancy and the repeats-enriched genomic sub-sequences. Moreover, we used dScaff to propose a minimal assembly variant corresponding to one of our lines, GB-ls-coga4, which assured a basic linear coverage of the genome and exhibited quality parameters comparable with those particular to the current reference genome assembly. Conclusions: The study presents the first sequencing and assembly of a D. suzukii line in Romania and argues the efficiency of long-read sequencing strategies. Full article

Drosophila suzukii is a major pest of sweet cherries. In this study, we evaluated its oviposition preferences across six cherry cultivars and assessed the effects of the fruit traits on its growth and development. Significant differences in the color, firmness, and sugar content were observed among the cultivars and ripeness stages. The highest oviposition rates were recorded for the “Hongdeng” (HD) and “Burlat” (BLT) cultivars in both the non-choice (HD: 31.9 ± 2.0 eggs/cherry; BLT: 31.3 ± 1.9 eggs/cherry) and choice (HD: 32.4 ± 3.2 eggs/cherry; BLT: 27.6 ± 1.9 eggs/cherry) tests, largely influenced by the fruit color. While the developmental parameters showed slight variation across the cultivars, significant differences were observed in the pupation rates (ranging from 0.80 to 0.89) and survival rates (ranging from 0.51 to 0.62), with both parameters being the highest for the “Hongdeng” cultivar. The correlation analysis revealed that a darker fruit color—characterized by lower lightness (L*), lower chromaticity (b*), and a higher color index for red grapes (CIRG)—positively influenced the oviposition and pupation rates. Although the other correlations were not significant, the oviposition and developmental parameters were positively correlated with sweetness and negatively correlated with firmness. These findings enhance our understanding of how cherry traits influence D. suzukii behavior, providing critical insights for pest management strategies in cherry production. Full article