Parasitic contamination of fresh vegetables and fruits sold in open-air markets in peri-urban areas of Jimma City, Oromia, Ethiopia: A community-based cross-sectional study.

BACKGROUND: Consuming contaminated raw vegetables and fruits is one of the primary means of parasite transmission to humans. Periodic monitoring of parasitic contamination in these food items is a crucial step in preventing the spread of parasitic disease in the community. This study was aimed at detecting intestinal parasitic contamination caused by consuming raw vegetables and fruits sold in three open-air markets and its associated factors in peri-urban areas of Jimma City, Oromia, Ethiopia. METHODS: A cross-sectional study was conducted on fruits and vegetables collected from three peri-urban open-aired markets (namely; Hora Gibe, Bore and Jiren markets) in peri-urban areas of Jimma City between July and September 2021. A total of 187 fresh vegetable samples and 188 fruits were collected and examined for intestinal parasite contamination. About 200g of fruit and vegetable samples were processed and examined microscopically for parasite contamination, utilizing direct wet mount and modified Zeihl-Neelson staining methods in accordance with standard protocols. A structured questionnaire was used to collect data on the socio-demographic characteristics of vendors and risk factors for fruit and vegetable contamination. All data were analyzed using SPSS version 20.0. RESULT: Of the 187 fresh vegetable samples and 188 fresh vegetable samples, 105 (56.1%) and 68/188 (36.2%) of vegetables and fruit samples, respectively, were found contaminated with one or more intestinal parasites. Remarkably, high level of contamination in fresh vegetable samples was recorded both in Carrot (Daucus carota) 63.8% (30/46) and Lettuce (Lactuca sativa) 63.1% (29/46) while Green pepper (Capsicum spp.) is the least contaminated. In fruit samples, Avokado (Persea americana) 42.6% (20/47) and Banana (Musa acuminata) 14.9% (7/47) were the most and the least commonly contaminated items respectively. The identified helminthes and protozoans were Ascaris lumbricoides, Strongyloides stercoralis, Hymenolepis nana, Entamoeba histolytica/dispar, Giardia lamblia, Cryptosporidium spp., Toxocara spp. And Fasciola spp. The most predominant parasite encountered was A. lumbricoides 46(12.3%) whereas both Toxocara spp. 12(6.9) and Fasciola spp. 2(0.5) were the least detected parasites. It is worth-mentioned that the rate of contamination in Bore market (38.15%) was higher compared with Jiren market (34.7%) and Hora Gibe market (27%). However, the rate of contamination in vegetables and fruit obtained from the three district was non-significant (p = 0.19). Contamination was more common in vegetables than fruits (AOR = 5.78, p<0.001). It was also observed that decreased parasitic contamination was significantly associated with washing the products before displaying it for selling (p < 0.001). CONCLUSION: The study has identified a high rate of raw vegetables and fruits contaminated with intestinal helminthes and protozoan. Contaminated fresh vegetables and fruits in open-aired peri-urban markets of Jimma city, Ethiopia may play a significant role in transmission of intestinal parasitic infections to humans, particularly A. lumbricoides infection. Therefore, it is urgently needed for health authorities to educate the public on the proper handling of vegetables and fruits prior to consumption.

Surveillance of berries sold on the Norwegian market for parasite contamination using molecular methods.

The risk of foodborne parasite infection linked to the consumption of contaminated fresh produce has long been known. However, despite epidemiological links between the outbreaks and contaminated berries, few studies have assessed the magnitude of parasite contamination on fresh produce sold in Europe. The present study was aimed to address the knowledge gap on parasite contamination of berries sold in Norway. Samples of blueberries, strawberries, and raspberries were analysed by multiplex qPCR for detection of Echinococcus multilocularis, Toxoplasma gondii, and Cyclospora cayetanensis. In addition, a simplex qPCR method was employed for detecting contamination of the berries with Cryptosporidium spp. A total of 820 samples of berries, each of around 30 g (274 samples of blueberries, 276 samples of raspberries, and 270 samples of strawberries), were analysed. We found an overall occurrence of 2.9%, 6.6%, and 8.3% for T. gondii, C. cayetanensis, and Cryptosporidium spp., respectively, whereas E. multilocularis was not detected from any of the samples investigated. Strawberries and raspberries were most often contaminated with Cryptosporidium spp., whereas blueberries were contaminated mostly with C. cayetanensis. Detection of parasite contaminants on fresh berries indicates the need for a system to ensure the parasitological safety of fresh berries.

Demography and perturbation analyses of the coffee berry borer Hypothenemus hampei (Coleoptera: Curculionidae): Implications for management.

The coffee berry borer (CBB) Hypothenemus hampei Ferrari is the most serious pest of coffee worldwide. Management of the CBB is extremely difficult because its entire life cycle occurs inside the fruit, where it is well protected. Knowing which life stages contribute most to population growth, would shed light on the population dynamics of this pest and help to improve CBB management programs. Two staged-classified matrices were constructed for CBB populations reared in the lab on artificial diets and CBB populations from artificial infestations in the field. Matrices were used to determine demographic parameters, to conduct elasticity analyses, and to perform prospective perturbation analysis. Higher values of the intrinsic rate of natural increase (rm) and population growth rate (λ): were observed for CBB populations growing in the lab than in the field (rm: 0.058, λ: 1.74 lab; rm: 0.053, λ: 1.32 field). Sensitivity values for both CBB populations were highest for the transitions from larva to pupa (G2: 0.316 lab, 0.352 field), transition from pupa to juvenile (G3: 0.345 lab, 0.515 field) and survival of adult females (P5: 0.324 lab, 0.389 field); these three vital rates can be important targets for CBB management. Prospective perturbation analyses indicated that an effective management for the CBB should consider multiple developmental stages; perturbations of >90% for each transition are necessary to reduce λ to <1. However, when the three vital rates with highest sensitivity are impacted at the same time, the percentage of perturbation is reduced to 25% for each transition; with these reductions in survival of larvae, pupae and adult females the value of λ was reduced from 1.32 to 0.96. Management programs for CBB should be focused on the use of biological and cultural measures that are known to affect these three important targets.

Region-aggregated attention CNN for disease detection in fruit images.

BACKGROUND: Diseases and pests have a profound effect on a yearly harvest and productivity in agriculture. A precise and accurate detection of the diseases and pests could facilitate timely treatment and management of the diseases and pests and lessen the resultant loss in economy and health. Herein, we propose an improved design of the disease detection system for plant images. METHODS: Built upon the two-stage framework of object detection neural networks such as Mask R-CNN, the proposed network involves three types of extensions, including the addition of additional level of feature pyramids to improve the exploration and proposal of candidate regions, the aggregation of feature maps from all levels of feature pyramids per candidate region to fully exploit the information from feature pyramids, and the introduction of a squeeze-and-excitation block to the construction of feature pyramids and the aggregated feature maps to improve the representation of feature maps. RESULTS: The proposed network was evaluated using 74 images of infected apple fruits. In 3-fold cross-validation, the proposed network achieved averaged precision (AP) of 72.26, AP at 0.5 threshold of 88.51 and AP at 0.75 threshold of 82.30. In the comparative experiments, the proposed network outperformed the other competing networks. The utility of the three extensions was also demonstrated in comparison to Mask R-CNN. CONCLUSIONS: The experimental results suggest that the proposed network could identify and localize the symptom of the disease with high accuracy, leading to an early diagnosis and treatment of the disease, and thus holding the potential for improving crop yield and quality.

Genetically Encoded CRISPR Components Yield Efficient Gene Editing in the Invasive Pest Drosophila suzukii.

Originally from Asia, Drosophila suzukii Matsumura is a global pest of economically important soft-skinned fruits. Also commonly known as spotted wing drosophila, it is largely controlled through repeated applications of broad-spectrum insecticides by which resistance has been observed in the field. There is a pressing need for a better understanding of D. suzukii biology and for developing alternative environmentally friendly methods of control. The RNA-guided Cas9 nuclease has revolutionized functional genomics and is an integral component of several recently developed genetic strategies for population control of insects. Here, we describe genetically modified strains that encode three different terminators and four different promoters to express Cas9 robustly in both the soma and/or germline of D. suzukii. The Cas9 strains were rigorously evaluated through genetic crossing to transgenic strains that encode single-guide RNAs targeting the conserved X-linked yellow body and white eye genes. We find that several Cas9/gRNA strains display remarkably high editing capacity. Going forward, these tools will be instrumental for evaluating gene function in D. suzukii and may even provide tools useful for the development of new genetic strategies for control of this invasive species.

Carbon Dioxide-Enriched Atmosphere to Control Oryzaephilus surinamensis L. On Stored Saqie Date Fruits.

<b>Background and Objective:</b> Control of the stored date insects by an eco-friendly method is essential to maintain the fruit for prolonged periods, especially that dates are eaten fresh. The search for a safe method, as an alternative to commonly used chemical pesticides, is needed. The objective is to investigate CO₂ enriched atmosphere on the Mortality Percentage (MP) of the Saw-toothed grain beetle, <i>O. surinamensis</i>, life stages with special emphasis on reducing damage to stored dates. <b>Materials and Methods:</b> The effect of high levels of CO₂ as an alternative control method against the Saw-toothed grain beetle, <i>Oryzaephilus surinamensis</i> L., at different life stages was studied on infested 'Saqie' dates. Four CO₂ pressures (25, 50, 75 and 90 kPa, balance is nitrogen) were tested for 6, 12, 18, 24, 48, 72 and 96 hrs intervals. The response of different life stages of <i>O. surinamensis</i> to the different treatments varied according to CO₂ level, developmental stage and exposure period. <b>Results:</b> Mortality (%) was higher during the larval stage, followed by adults, pupae and eggs, in descending order. The larvae and adult stages were more sensitive to CO₂ treatment than the pupal and egg. Exposure time was more effective on eggs, larval and adult MP than the CO₂ atmosphere level. Mortality% at 96 hrs exposure time was almost 100% with CO₂ atmospheres of 50, 75 and 90 kPa. Mathematical equations were developed to model the relationship between mortality% and CO₂ treatments using multiple regression analyses for each life stage. <b>Conclusion:</b> The results confirmed that CO₂ could be applied to final food products during packaging to control the residual occurrence of insect pests after storage and before the packaging process to prevent further infestation in the final packages.

Identification and characterization of a novel virus associated with an eriophyid mite in extracts of fruit trees leaves.

Eriophyid mites are commonly found on the leaf surface of different plant species. In the present study, a novel virus associated with an eriophyid mite species was detected using high-throughput sequencing (HTS) of total RNA from fruit tree leaves, primarily growing under greenhouse conditions. The complete genome sequence was characterized using rapid amplification of cDNA ends followed by Sanger sequencing, revealing a genome of 8885 nucleotides in length. The single positive-stranded RNA genome was predicted to encode typical conserved domains of members of the genus Iflavirus in the family Iflaviridae. Phylogenetic analysis showed this virus to be closely related to the unclassified iflavirus tomato matilda associated virus (TMaV), with a maximum amino acid sequence identity of 59% in the RNA-dependent RNA polymerase domain. This low identity value justifies the recognition of the novel virus as a potential novel iflavirus. In addition to a lack of graft-transmissibility evidence, RT-PCR and HTS detection of this virus in the putative host plants were not consistent through different years and growing seasons, raising the possibility that rather than a plant virus, this was a virus infecting an organism associated with fruit tree leaves. Identification of Tetra pinnatifidae HTS-derived contigs in all fruit tree samples carrying the novel virus suggested this mite as the most likely host of the new virus (p-value < 1e-11), which is tentatively named "eriophyid mite-associated virus" (EMaV). This study highlights the importance of a careful biological study before assigning a new virus to a particular plant host when using metagenomics data.

Identification and expression characteristics of putative chemosensory proteins in the peach fruit borer Carposina sasakii Matsumura (Lepidoptera: Carposinidae).

Chemosensory proteins (CSPs) are important for insect chemoreception, which bind, solubilize and transport hydrophobic chemical molecules from external environment to dendrite membrane of chemosensory neurons. Moreover, CSPs are also involved in non-sensory physiological activities. The peach fruit borers Carposina sasakii Matsumura (Lepidoptera: Carposinidae) seriously damage fruit trees and their chemoreception mainly occurs in the adult stage. We identified 10 putative CSPs (CsasCSP1 ~ CsasCSP10) from head transcriptomes of C. sasakii adult males and females, all of which are classic CSPs that have 4 conserved cysteines with a spacing pattern C1-X6-C2-X17-18-C3-X2-C4. Their phylogenetic characteristics were also described. An analysis using fluorescence quantitative PCR showed CsasCSP2 has the highest level of expression in the heads, so it is more likely to be involved in C. sasakii chemoreception than the other C. sasakii CSPs. CsasCSP1, CsasCSP3, CsasCSP4, CsasCSP6, CsasCSP7 and CsasCSP8 are expressed dominantly in the wings; CsasCSP5 and CsasCSP10 have the highest expression level in the thoraxes; CsasCSP9 is dominantly and equally expressed in the thoraxes and abdomens. This study contributes to understanding physiological functions of C. sasakii CSPs and chemosensory mechanism at C. sasakii molecular level.

The abundance and diversity of fruit flies and their parasitoids change with elevation in guava orchards in a tropical Andean forest of Peru, independent of seasonality.

Lower elevations are generally thought to contain a greater abundance and diversity of insect communities and their natural enemies than higher elevations. It is less clear, however, how changes in seasons influence this pattern. We conducted a 2-year study (2013‒2014) in guava orchards located in a tropical Andean forest of Peru to investigate differences in fruit flies (Diptera: Tephritidae) and their parasitoid communities at two elevations and over two seasons. Fruit fly traps were installed, monitored, and guava fruits were sampled from eight orchards at low (800-950 m above sea level) and high (1,700-1,900 m above sea level) elevations and during the dry and rainy seasons. At each orchard, adult fruit fly trap captures and emergence of fruit flies and their parasitoids from guava fruit were quantified to determine their abundance and species composition. There was a greater abundance and species richness of fruit flies captured in traps at lower elevations, as well as higher abundance and species evenness of fruit flies that emerged from fruit, indicating that lower elevations are associated with larger fruit fly populations. The abundance, species richness and diversity of parasitoids were also greater at lower elevations. Consequently, guava fruit infestation and fruit fly parasitism rates were also greater at lower elevations. Seasonality also influenced fruit fly populations with a greater number of flies emerging from guava fruit and more fruit infested in the rainy season. However, seasonality had no effect on parasitoid population parameters or rate of parasitism, nor did it interact with elevation as an influence of populations of fruit flies or their parasitoids in guava orchards. This study highlights the importance of examining both elevation and seasonality for a better understanding of the population dynamics of fruit flies and their parasitoids in tropical agroecosystems.

DNA screening of Drosophila suzukii predators in berry field orchards shows new predatory taxonomical groups.

Drosophila suzukii (spotted wing drosophila, SWD) is a pandemic quarantine pest that attacks mostly red fruits. The high number of life cycles per year, its ability to rapidly invade and spread across new habitats, and highly polyphagous nature, makes this a particularly aggressive invasive species, for which efficient control methods are currently lacking. The use of native natural predators is particularly promising to anchor sustainable and efficient measures to control SWD. While several field studies have suggested the presence of potential predatory species in infested orchards, only a few confirmed the presence of SWD DNA in predators' gut content. Here, we use a DNA-based approach to identify SWD predators among the arthropod diversity in South Europe, by examining the gut content of potential predator specimens collected in SWD-infested berry fields in North Portugal. These specimens were morphologically identified to the family/order, and their gut content was screened for the presence of SWD DNA using PCR. New SWD predatory taxonomical groups were identified, as Opiliones and Hemerobiidae, in addition to known SWD predators, such as Hemerobiidae, Chrysopidae, Miridae, Carabidae, Formicidae and Araneae. Additionally, the presence of a spider family, Uloboridae, in the orchards was recorded for the first time, posing this family as another SWD-candidate predator. This study sets important bases to further investigate the potential large-scale use of some of these confirmed predator taxa for SWD control in South Europe.

Contamination of fresh produce sold on the Italian market with Cyclospora cayetanensis and Echinococcus multilocularis.

To investigate the presence of Cyclospora cayetanensis, Toxoplasma gondii and Echinococcus spp. in fresh produce sold in Italy, 324 locally produced 'ready-to-eat' (RTE) mixed-salad packages belonging to three brands and 324 berries packages (blueberries and blackberries imported from Peru and Mexico, respectively, and raspberries grown in Italy) were purchased at retail. Nine individual packages from each of the six types of fresh produce were collected monthly for one year, and with the same produce pooled, this resulted in a total of 72 pools for the whole year. Using microscopy (FLOTAC), a Cyclospora-like oocyst was detected in a blueberry sample and a taeniid egg was detected in a RTE-salad sample. Molecular tools confirmed these to be C. cayetanensis and Echinococcus multilocularis, respectively. Toxoplasma gondii was not detected in any of the samples. This study shows for the first time in Europe that imported berries on the Italian market may be contaminated with C. cayetanensis and RTE salads grown in Italy with E. multilocularis. The results indicate a new epidemiological scenario and highlight that current management of fresh produce, locally produced or imported, does not ensure products are free from parasite contamination.

Contaminant organisms recorded on plant product imports to South Africa 1994-2019.

Biosecurity interception records are crucial data underlying efforts to predict and manage pest and pathogen introductions. Here we present a dataset containing information on imported plant products inspected by the South African Department of Agriculture's laboratories between 1994 and 2019 and the contaminant organisms found on them. Samples were received from border inspectors as either propagation material (e.g. plants) or material for immediate use (e.g. fruit). Material for immediate use was further divided into two sample categories, depending on if contaminants were seen/suspected by the border official or not: intervention or audit samples. The final dataset consists of 25,279 records, of which 30% tested positive (i.e. had at least one contaminant) and 13% had multiple contaminants. Of the 13,731 recorded contaminants, fungi (41%), mites (37%) and insects (19%) were most common. This dataset provides insight into the suite of taxa transported along the plant import pathway and provides an important resource for analyses of contaminant organisms in international trade, which can inform strategies for risk assessment, pathway management and biosecurity protocols.

Fragrance addition improves visitation by honeybees and fruit quality in kiwifruit (Actinidia deliciosa).

BACKGROUND: Kiwifruit is an important horticultural crop all over the world and its development is important in Argentina. This dioecious crop has a short blooming period with nectarless flowers, and its fruit production depends on cross-pollination. Here, we tested whether kiwifruit quality increases by using honeybees exposed to female flowers treated with an artificial fragrance. The three experimental treatments were: A, sprinkled female flowers with 1:1 sugar syrup + Lavandula hybrida extract solution (a new attractant substance especially developed for this study named Lavandin Grosso); B, sprinkled female flowers with 1:1 water + sugar syrup (female flowers with additional sugar syrup reward); C (control; female flowers exposed to honeybees). RESULTS: The results showed a higher number of visits of honeybees to the female flowers sprinkled with the attractant substance, Lavandin Grosso, as well as higher fruit quality (weight, number of seeds, regularity in fruit size). CONCLUSION: Our study demonstrates the potential of fragrance-treated flowers to improve yield production in kiwifruit. © 2021 Society of Chemical Industry.

Modifications of the U.S. food and drug administration validated method for detection of Cyclospora cayetanensis oocysts in prepared dishes: Mexican-style salsas and guacamole.

Although multiple outbreak clusters of Cyclospora cayetanensis have been traced back to consumption of dishes in Mexican-style restaurants, the FDA Bacteriological Analytical Manual (BAM) does not currently provide methods to detect C. cayetanensis in dishes that contain multiple produce ingredients, such as salsas and guacamole. These complex food matrices also may contain high levels of fats, which can interfere with the detection. Several modifications to the BAM Chapter 19b method (washing produce, DNA extraction, and a TaqMan real-time PCR assay targeting the 18S rRNA gene of C. cayetanensis) were assessed with the goal to detect as few as 5 oocysts of C. cayetanensis in 25 g samples of commercial salsa/pico de gallo, guacamole, and salsa verde. Both freshly prepared and frozen versions of these foods were seeded with 5, 10 and 200 oocysts. For salsa samples, using a gentler washing step than recommended by BAM, we achieved detection of 5 oocysts in the samples (81.8%, n = 11). Increasing the amount of Alconox® in the wash solution to 1%, rather than the 0.1% used in BAM, and adjusting the DNA extraction protocol to process large wash pellets, enabled detection of 5 oocysts in guacamole. To reach the desired level of detection in salsa verde, two types of modifications were necessary: gentler washing and DNA extraction modifications. The use of these same method modifications on previously frozen food samples, provided levels of detection similar to those achieved with fresh dishes. Our modifications enabled robust and reproducible detection of C. cayetanensis in multi-ingredient Mexican dishes, detecting as few as 5 oocysts in 25 g samples. Validating and deploying effective methods to detect C. cayetanensis in high risk fresh produce and prepared dishes are critically important for prevalence studies and outbreak investigations of this parasite.

Developmental stages of peach, plum, and apple fruit influence development and fecundity of Grapholita molesta (Lepidoptera: Tortricidae).

Host plant attributes are essential factors determining the population dynamics of herbivorous insects. The developmental stage of host plants, in particular, may affect the biology of Grapholita molesta (Busck), a possibility that has rarely been examined. Here we assessed the effect of developmental stage of plum, peach, and apple fruits on the development and fecundity performance of G. molesta, along with an examination of the firmness and sugar content of the fruits. Among the fruits collected earliest (May 31), plum and apple were better food sources for G. molesta compared to peach in terms of development, reproduction, and life table parameters. However, despite the higher sugar content in peach, G. molesta larvae showed a lower rate of fruit penetration in peach, probably due to fruit firmness. In the later-collected fruit (June 25), both peach and apple were better than plum, as peach and apple were softer and had higher sugar content. Nevertheless, the penetration rate of larva was still low in peach probably due to pubescence on the fruit surface. Although the plum fruits in the later collection date were softer with higher sugar content, there was a negative impact on the development and reproduction because fruits started to liquefy earlier. In conclusion, the developmental stage of fruits with changes in fruit firmness or sugar content affected the development and reproduction of G. molesta, and apple would be the best food source.

A scoping review of the detection, epidemiology and control of Cyclospora cayetanensis with an emphasis on produce, water and soil.

Cyclospora cayetanensis is a parasite causing cyclosporiasis (an illness in humans). Produce (fruits, vegetables, herbs), water and soil contaminated with C. cayetanensis have been implicated in human infection. The objective was to conduct a scoping review of primary research in English on the detection, epidemiology and control of C. cayetanensis with an emphasis on produce, water and soil. MEDLINE® (Web of ScienceTM), Agricola (ProQuest), CABI Global Health, and Food Science and Technology Abstracts (EBSCOhost) were searched from 1979 to February 2020. Of the 349 relevant primary research studies identified, there were 75 detection-method studies, 40 molecular characterisation studies, 38 studies of Cyclospora in the environment (33 prevalence studies, 10 studies of factors associated with environmental contamination), 246 human infection studies (212 prevalence/incidence studies, 32 outbreak studies, 60 studies of environmental factors associated with non-outbreak human infection) and eight control studies. There appears to be sufficient literature for a systematic review of prevalence and factors associated with human infection with C. cayetanensis. There is a dearth of publicly available detection-method studies in soil (n = 0) and water (n = 2), prevalence studies on soil (n = 1) and studies of the control of Cyclospora (particularly on produce prior to retail (n = 0)).

Separate and combined Hanseniaspora uvarum and Metschnikowia pulcherrima metabolic volatiles are attractive to Drosophila suzukii in the laboratory and field.

Drosophila suzukii flies cause economic losses to fruit crops globally. Previous work shows various Drosophila species are attracted to volatile metabolites produced by individual fruit associated yeast isolates, but fruits naturally harbour a rich diversity of yeast species. Here, we report the relative attractiveness of D. suzukii to yeasts presented individually or in combinations using laboratory preference tests and field trapping data. Laboratory trials revealed four of 12 single yeast isolates were attractive to D. suzukii, of which Metschnikowia pulcherrima and Hanseniaspora uvarum were also attractive in field trials. Four out of 10 yeast combinations involving Candida zemplinina, Pichia pijperi, M. pulcherrima and H. uvarum were attractive in the laboratory. Whilst a combination of M. pulcherrima + H. uvarum trapped the greatest number of D. suzukii in the field, the efficacy of the M. pulcherrima + H. uvarum combination to trap D. suzukii was not significantly greater than traps primed with volatiles from only H. uvarum. While volatiles from isolates of M. pulcherrima and H. uvarum show promise as baits for D. suzukii, further research is needed to ascertain how and why flies are attracted to certain baits to optimise control efficacy.

The preference of Trichopria drosophilae for pupae of Drosophila suzukii is independent of host size.

Controlling the cosmopolitan pest Drosophila suzukii (spotted wing drosophila) is a challenge for fruit growers. A promising agent for biological control of that pest are parasitoid wasps. Especially the widespread pupal parasitoid Trichopria drosophilae had shown the ability to parasitise the pest fly. However, as a biocontrol agent, parasitoids can only be effective when they prefer the pest to other insects. Until now studies have been inconsistent concerning the preference of T. drosophilae for D. suzukii and whether the preference depends on pupal volume. To clarify this inconsistency, we used video recordings of parasitisation experiments with a set up to observe the direct host preference of the parasitoid. Additionally, the volume of each host pupa was measured. We found significant preference of T. drosophilae for D. suzukii pupae independent of the pupal size and of the host species the wasps were reared on. The article also discusses the sex ratio and the success of the parasitoid in the different pupae characteristics.

A one-dimensional map to study multi-seasonal coffee infestation by the coffee berry borer.

The coffee berry borer (CBB, Hypothenemus hampei) is the most serious insect pest of coffee worldwide; understanding the dynamics of its reproduction is essential for pest management. The female CBB penetrates the coffee berry, eats the seed, and reproduces inside it. A mathematical model of the infestation progress of the coffee berry by the CBB during several coffee seasons is formulated. The model represents the interaction among five populations: uninfested, slightly infested, and severely infested coffee berries, and free and encapsulated CBBs. Coffee harvesting is also included in the model. A one-dimensional map is derived for tracking the population dynamics subject to certain coffee harvesting percentages over several seasons. Stability analysis of the map's fixed points shows that CBB infestation could be eliminated or controlled to a specific level over multiple seasons of coffee harvesting. However, the percent of coffee harvesting required is determined by the level of CBB infestation at the beginning of the first season and in some cases it is impossible to achieve that percentage.

Chitosan coatings reduce fruit fly (Anastrepha obliqua) infestation and development of the fungus Colletotrichum gloeosporioides in Manila mangoes.

BACKGROUND: Mangoes are tropical fruits appreciated worldwide but are extremely perishable, being susceptible to decay, pest infestation and fungal diseases. Using the flavorful and highly valued 'Manila' cultivar, we examined the effect of second-generation chitosan coatings on shelf-life, phenolic compound variation, phytohormones, pest infestation by fruit flies (Anastrepha obliqua) and anthracnose disease caused by the fungus Colletotrichum gloeosporioides. RESULTS: We observed almost total elimination of A. obliqua eggs with 10 and 20 g L-1 chitosan in diluted acetic acid and a five- to sixfold reduction in anthracnose damage. Treatment with 20 g L-1 chitosan also extended the shelf-life. External (skin) and internal (pulp) discoloration processes were delayed. Fruit firmness was higher when compared with control and acetic acid treatments, and total soluble solids were lower in chitosan-treated fruit. Targeted and non-targeted metabolomics analyses on chitosan-coated fruit identified some phenolic compounds related to the tannin pathway. In addition, abscisic acid and jasmonic acid in the peel were downregulated in chitosan-coated mango peels. Both phytohormones and phenolic content may explain the reduced susceptibility of mangoes to anthracnose development and A. obliqua egg eclosion or larval development. CONCLUSIONS: We conclude that chitosan coatings represent an effective postharvest treatment that significantly reduces anthracnose disease, inhibits A. obliqua egg eclosion and significantly extends 'Manila' mango shelf-life, a key factor currently inhibiting large-scale commercialization of this valuable fruit. © 2020 Society of Chemical Industry.