Parasitism Rates Research Articles

Primary parasitoids of Aulacaspis tubercularis Newstead (Hemiptera: Diaspididae) occurring in Spanish mango orchards

The white mango scale (WMS), Aulacaspis tubercularis, is the main pest of mango crops in Southern Spain. Field surveys were carried out from July 2019 to May 2022 to investigate the identity, seasonal abundance and active parasitism rates of A. tubercularis primary parasitoid species, using yellow sticky traps and periodic leaf sampling. The combination of morphological characters and DNA sequences of the mitochondrial cytochrome c oxidase subunit 1 (mtCOI) and 28S ribosomal (28S rDNA) genes allowed the identification of only two parasitoid species belonging to the genus Encarsia Förster (Hymenoptera: Aphelinidae). The most prevalent, E. citrina (Crawford), is a widespread species and proved to be the dominant species in the sampled mango orchards. Next, Encarsia sp., is an unidentified species genetically close to E. lounsburyi Berlese but significantly differs in the sequences of the mtCOI and 28S rDNA regions. Population abundance and active parasitism rates of Encarsia parasitoids depended on the presence of susceptible WMS stages for parasitism and on the abiotic conditions. The seasonal abundance of these parasitoid species fluctuated around the year, being lower during the winter but it increased in late spring, reaching the highest values at the end of summer. The average percentage of active parasitism was 12.48% for female scales and 13.97% for male scales but reached maximum values of 38.56 and 43.52%, respectively at specific seasons in the year. The highest rates of parasitism for female scales were observed in summer, while for male scales were observed in winter. The natural occurrence of parasitoids was unable to control the WMS populations and, consequently, complementary measures should be implemented to reduce its density levels.

Changes in longevity, parasitization rate and development time of the whitefly parasitoid Encarsia formosa under future climate conditions

Biological control by augmentative release of parasitoids is an established practice for controlling an economically very important insect pest group, whiteflies (Aleyrodidae), in protected cropping systems worldwide. One of the two most used parasitoids is Encarsia formosa. Anthropogenic climate change will modify multitrophic interactions between organisms, and sensitive biocontrol systems are not an exception. At the same time, there is a knowledge gap in our understanding of the performance of E. formosa as a biocontrol agent in mid-future climate. In the present study, we evaluate the parasitization rate, development time, and longevity of this important biocontrol agent by performing climatic chamber simulation driven by physically consistent, regionally downscaled, numerical future climate projections. The parasitoid shows 8.6 days accelerated development, 15-fold higher parasitization rate, and 38% shorter longevity under the tested future climate conditions. Challenges in conclusively assessing life parameters of this parasitoid, and the implications on whitefly biocontrol in the future are discussed.

Assessment of the risk of imidaclothiz to the dominant aphid parasitoid Binodoxys communis (Hymenoptera: Braconidae)

The neonicotinoid of imidaclothiz insecticide with low resistance and high efficiency, has great potential for application in pest control in specifically cotton field. In this systematically evaluate the effects of sublethal doses of imidaclothiz (LC10: 11.48 mg/L; LC30: 28.03 mg/L) on the biology, transcriptome, and microbiome of Binodoxys communis, the predominant primary parasitic natural enemy of aphids. The findings indicated that imidaclothiz has significant deleterious effects on the survival rate, parasitic rate, and survival time of B. communis. Additionally, there was a marked reduction in the survival rate and survival time of the F1 generation, that is, the negative effect of imidaclothiz on B. communis was continuous and trans-generational. Transcriptome analysis revealed that imidaclothiz treatment elicited alterations in the expression of genes associated with energy and detoxification metabolism. In addition, 16S rRNA analysis revealed a significant increase in the relative abundance of Rhodococcus and Pantoea, which are associated with detoxification metabolism, due to imidaclothiz exposure. These findings provide evidence that B. communis may regulate gene expression in conjunction with symbiotic bacteria to enhance adaptation to imidaclothiz. Finally, this study precise evaluation of imidaclothiz's potential risk to B. communis and provides crucial theoretical support for increasing the assessment of imidaclothiz in integrated pest management.

The hymenopterous parasitoids of the diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), on cruciferous vegetables in Delhi, India

BackgroundThe diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae), is a serious and economically important pest of crucifers in Delhi, India. Larvae and pupae of the pest were collected from the cabbage, cauliflower and broccoli crops grown in vegetable fields at the farm of ICAR-Indian Agricultural Research Institute (ICAR-IARI), New Delhi-110012, from December 2021 to June 2022. The larvae and pupae of the pest were transferred to the laboratory and reared for emergence of parasitoids’ adults at 25 ± 0.5 °C and RH 70 ± 5%.ResultsFour parasitoid species were emerged, viz. Apanteles mohandasi Sumodan & Narendran 1990, Cotesia vestalis (Haliday, 1834), Diadegma insulare (Cresson, 1865) and Diadromus collaris (Gravenhorst, 1829). Among them, A. mohandasi, C. vestalis and D. collaris were reported for the first time in Delhi, whereas D. insulare (Hymenoptera: Ichneumonidae) is recorded here for the first time in India. Additionally, the first record of parasitism by A. mohandasi on P. xylostella from Delhi was established. The highest parasitism percentage was that of C. vestalis and D. collaris. Moreover, higher parasitism rate was recorded during May 2022 in organically cultivated fields. The parasitism percentage by A. mohandasi, C. vestalis, D. insulare and D. collaris was 7.5, 22.5, 12.5 and 15%, respectively. Conversely, in conventionally farmed fields, the parasitism rates were 3.57, 16.67, 10 and 13.33%, respectively.ConclusionThe use of biological control agents particularly the parasitoids in the IPM program of P. xylostella should be considered, thereby reducing reliance on insecticides and increasing the efficacy of hymenopteran parasitoids.

Temperature-dependent effects on some biological aspects of two ectoparasitoids of Phyllocnistiscitrella (Lepidoptera: Gracillariidae)

BackgroundTemperature alters host suitability for the development of parasitoids through direct (thermal effect) and indirect (parental effect) pathways. The effects of three temperature regimes on the development and survival of two parasitoid species, Citrostichusphyllocnistoides (Narayanan) and Cirrospilusingenuus Gahan (Eulophidae: Hymenoptera) of the citrus leafminer, Phyllocnistiscitrella Stainton (Lepidoptera: Gracillariidae) was evaluated. The experiment was conducted at 20, 25, and 30°C temperatures with 65 ± 2% relative humidity (R.H.) and 16h: 8h (L: D) photoperiod.ResultsIn C.phyllocnistoides, the pre-ovipositional period was longer at 20°C, while non- significant difference was observed in the pre-ovipositional period of C.ingenuus under the effect of different temperatures (P > 0.05). The ovipositional period of C.phyllocnistoides and C.ingenuus was higher at 20°C and gradually decreased by increasing the temperature. Non- significant (P > 0.05) difference was found in post-ovipositional period of both parasitoid species. Both species exhibited the maximum fecundity at 25°C, while, the minimum fecundity was recorded at 30°C. However, the adult longevity of both parasitoid species was highest at 20°C and gradually decreased by increasing the temperature. In both parasitoids, the parasitism rate was highest at 25°C.ConclusionThis study highlighted the importance of thermal effects on some parasitoid species of insect pests to predict the future of trophic dynamics in global warming situations.

Preliminary evidence of Drosophila suzukii parasitism in Southeast England.

Controlling the invasive fruit pest, Drosophila suzukii, relies on a range of complimentary pest management approaches. However, increasing external costs (e.g., labour, exclusion mesh and fuel), are limiting the ability to control the pest via non-chemical means. Extant UK parasitoids could be exploited for the suppression of D. suzukii populations, but there is currently a lack of knowledge of the UK species utilising D. suzukii as a host or their lifecycle requirements. Between 2017 and 2020, we identified parasitoids developing in D. suzukii, in Southeast England.Sentinel traps, containing laboratory reared D. suzukii larvae/pupae in fruit, were deployed within the vicinity of commercial crops and semi-natural areas. Six generalist parasitoid species were recovered from D. suzukii sentinel traps. These included two species of larval parasitoids (Leptopilina heterotoma Thomson (Hymenoptera: Figitidae) and Asobara tabida (Nees) (Hymenoptera: Braconidae) and four pupal parasitoids (Pachycrepoideus vindemiae (Rondani) (Hymenoptera: Pteromalidae), Spalangia erythromera (Forster) (Hymenoptera: Pteromalidae), Trichopria modesta (Ratzeburg, 1848) and T. prema Nixon (both Hymenoptera: Diapriidae)).The performance of the first four species as D. suzukii parasitoids was further tested in the laboratory and then in the field to assess rates of parasitism. Pachycrepoideus vindemiae was the most abundant species recovered from field collections and had in increasing rate of population rate in the laboratory. Other species were not successful at parasitising D. suzukii. In the field, adult D. suzukii emergence from sentinel traps was reduced by ~ 21% where parasitoids could access D. suzukii larvae and pupae.Parasitoids of D. suzukii are understudied in the UK, and this research indicates where future efforts could be made in understanding the interaction between host and parasitoid and the opportunities to exploit extant parasitoids for the control of D. suzukii. We also evaluate the prospects for classical and augmented control and discuss how they may fit with current regional integrated pest management options.

Influence of temperature and exposure time of cold storage on the fitness of Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae)

Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae) is an important biological control agent that parasitizes larvae and pupae of Coleopteran pests. Cold storage can extend the shelf life of parasitoids for use in biological control programs. To understand the effects of cold storage on performance of A. calandrae, the adult survival, longevity, parasitism rate, and fecundity of A. calandrae after cold storage were investigated. Newly emerged A. calandrae females were stored at three constant temperatures (5, 10, and 15 °C) for 1, 2, 3, 4, 5, and 6 weeks. Both temperature and storage period significantly affected longevity, parasitism, progeny, and sex ratio of A. calandrae. Significant reduction in longevity was observed at 5 °C. After 1 week of cold storage, the longevity of A. calandrae at 5 °C decreased to 8 d, compared to 11 d in the control. However, there was no significant difference on the longevity and parasitism rate when the female wasps were stored at 15 °C for 3 weeks compared to control. The number of progeny gradually decreased with increasing storage period at 15 °C, and the maximum of progeny was observed for the control, 83.33 followed by 75.46 (1 week), 71.26 (2 weeks), and 68.40 (3 weeks). After cold storage at 5 °C for 1 week and 15 °C for 3 weeks, female-biased sex ratios in progeny were 0.53 and 0.55, respectively. Overall, storage at 15 °C for 3 weeks had the least negative impact on adult survival, longevity, parasitism rate, and progeny of A. calandrae wasps.

Impact of egg mass layers and scale thicknesses of the fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae), on the parasitic performance of Trichogrammatoidea bactrae (Hymenoptera: Trichogrammatidae)

BackgroundFall armyworm (FAW), Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), is one of the new alien destructive pests of maize and other 350 economic crops. The majority of farmers are still depended upon chemical insecticides to suppress the pest, but S. frugiperda has succeeded to develop resistance against most of the chemical families. Improving an effective environmentally-friendly approach is highly recommended. Therefore, the egg parasitoids are the best weapon for managing the FAW in the early egg stage due to the feeding behavior of their larvae. In this regard, the impact of FAW egg mass layers and scale thicknesses, as physical barriers, on the parasitic performance of the egg-parasitoid species, Trichogrammatoidea bactrae Nagaraja (Hymenoptera: Trichogrammatidae), in non-choice and choice tests was assessed. Besides, the efficacy of FAW-produced adult wasps on the next generation based on the rates of parasitism, adults' emergence, and female progeny was determined.ResultsObtained results exhibited that T. bactrae was able to parasitize all exposed FAW egg masses but with different rates related to the layers’ number and scales' thicknesses in both tests. One-layer (83.18, 78.24%) and two-layer egg masses (65.99, 76.42%) had significantly the highest parasitism rate, while three layers (42.15, 46.05%) was the least one, in both tests, respectively. All parasitoids emerged after 10–12 days with high rates (~ 88–98%) from all the tested egg masses, and the majority offspring were female-biased in both tests. Furthermore, parasitic performance in F1 progeny was similar with that recorded in parental generation in terms of parasitism rate, high parasitoid emergency (~ 87–95%), and strongly female-biased (~ 68–76%) in all the exposed egg masses.ConclusionsThe egg parasitoid, T. bactrae, could be an efficient and recommended bio-control agent against FAW as its greatest ability to overcome the layers’ number and scales’ thickness.

Prevalence and Epidemiology of Gastrointestinal Parasitosis Among the People of Dehradun, Uttarakhand

Gastrointestinal parasites play crucial roles in mortality and morbidity. They are most prevalent in rural areas. Parasitosis affects all age groups. Inchildren, it causes slow mental and physical growth, produces long-term effects, leads to a deficiency of vital nutrients, and hampers growth and development.This prospective study aimed to assess the prevalence of gastrointestinal parasitosis in stool samples among the people of Uttarakhand, especially of Dehradun,from January 2017 to January 2018. To identify intestinal parasites, 1528 samples were examined for consistency and the presence of any parasitic particlesusing the visual, direct wet mount, and concentration methods. The SPSS statistical program was used to conduct the statistical analysis. Differences with a pvalueof less than 0.05 were considered significant. The overall prevalence of intestinal parasitic infection rate was 32.85%. The prevalence of the parasites wasin the following order - Giardia lamblia (29.48%), Entamoeba histolytica (20.91%), Ascaris lumbricoides (18.52%), Hymenolepis nana (7.96%), Trichuris trichiura(7.56%), Taenia sp. (7.17%), Strongyloides stercoralis (5.97%), Ancylostoma duodenale (2.19%), and Enterobius vermicularis (0.19%). The chi-square test (χ2 – 30 andP-value = 0.224) was insignificant, while Levene’s test was significant (F = 10.08, P-value = 0.008) of A. duodenale in both genders. Parasitosis of high levels wasdetected among the children. Health education, personal hygiene, and safe drinking water would reduce infection. However, designing specific controlmeasures requires proper identification. The present study may prove helpful for developing such measures for Uttarakhand in general and Dehradun inparticular.

Multi-Species Host Use by the Parasitoid Fly Ormia lineifrons.

Antagonistic species relationships such as parasitoid/host interactions lead to evolutionary arms races between species. Many parasitoids use more than one host species, requiring the parasitoid to adapt to multiple hosts, sometimes being the leader or the follower in the evolutionary back-and-forth between species. Thus, multi-species interactions are dynamic and show temporary evolutionary outcomes at a given point in time. We investigated the interactions of the multivoltine parasitoid fly Ormia lineifrons that uses different katydid hosts for each of its fly generations sequentially over time. We hypothesized that this fly is adapted to utilizing all hosts equally well for the population to persist. We quantified and compared the fly's development in each of the four Neoconocephalus hosts. Cumulative parasitism rates ranged between ~14% and 73%, but parasitoid load and development time did not differ across host species. Yet, pupal size was lowest for flies using N. velox as a host compared to N. triops and other host species. Successful development from pupa to adult fly differed across host species, with flies emerging from N. triops displaying a significantly lower development success rate than those emerging from N. velox and the other two hosts. Interestingly, N. triops and N. velox did not differ in size and were smaller than N. robustus and N. nebrascensis hosts. Thus, O. lineifrons utilized all hosts but displayed especially low ability to develop in N. triops, potentially due to differences in the nutritional status of the host. In the multi-species interactions between the fly and its hosts, the poor use of N. triops may currently affect the fly's evolution the most. Similarities and differences across host utilization and their evolutionary background are discussed.

Evaluation of Pachycrepoideus vindemiae and Muscidifurax raptor (Hymenoptera: Pteromalidae) as biological control agents of Piophila casei (Diptera: Piophilidae) in ham production facilities.

Ham products play a fundamental role in the Italian economy, and attention to the problems of this sector is essential. The products of this sector can be attacked by parasites, which can cause direct and indirect damage. Piophila casei (L.) (Diptera: Piophilidae) a cheese and meat parasite, is currently responsible for hygiene problems in ham factories. The trophic activity of this pest on the products causes serious direct damage and it is a vector of various bacteria, including Clostridium botulinum. Another risk is human ingestion of the larvae, which are resistant to gastric juices action, potentially causing intestinal myiasis. Insecticide use of any type is not allowed in aging rooms, so biological control can represent a potential alternative. In this study, we investigate quality parameters such as successful rate of parasitism (SP), degree of parasitism (DP), sex-ratio (SR), life-span (LS), and emergence rates (ER) of 2 pupal parasitoids of Diptera: Pachycrepoideus vindemiae (Rondani) (Hymenoptera: Pteromalidae), currently the only known pupal parasitoid of P. casei, and Muscidifurax raptor (Girault and Sanders) (Hymenoptera: Pteromalidae). Our research confirmed P. vindemiae efficacy to parasitize P. casei and reported, for the first time, M. raptor as a pupal parasitoid of this Piophilidae. ER for both parasitoids were low, thus affecting the DP and SP estimations. This could be explained by the feeding behavior of the parasitoid host. The strongly female-biased SR for P. vindemiae supported previous studies. LS results in our experiment are crucial for determining the timing of release.

Biology and quality assessment of Telenomus remus (Hymenoptera: Scelionidae) and Trichogramma spp. (Hymenoptera: Trichogrammatidae) in eggs of Spodoptera spp. for augmentative biological control programs.

The Spodoptera complex of the family Noctuidae, represented here by S. frugiperda (J.E. Smith), S. eridania (Stoll), S. albula (Walker), and S. cosmioides (Walker), is an important group of crop pests in Brazil. Spodoptera frugiperda and S. eridania are invasive in Africa, and the former also in Asia and Oceania. The egg parasitoids Telenomus remus Nixon (Hymenoptera: Scelionidae) and Trichogramma spp. (Hymenoptera: Trichogrammatidae) are potential control agents for field use against these noctuids. We evaluated the parasitism efficiency, development, and flight capacity of an isofemale line and a regular line of T. remus, and 2 genetically variable populations of Trichogramma pretiosum Riley and Trichogramma atopovirilia Oatman and Platner (Hymenoptera: Trichogrammatidae) in these 4 members of the Spodoptera complex. All parasitoids were able to develop in the 4 hosts. The parasitoids showed good flight capacity, except for the regular line of T. remus. The Trichogramma species, despite having high viability and female:male sex ratios, showed poorer parasitism performances than T. remus. The regular T. remus line also showed good parasitism capacity and high viability but had a predominance of males. In general, the isofemale line of T. remus showed good rates of parasitism and flight capacity as well as a high viability and sex ratio, proving to be a potential candidate for an augmentative biological-control program for Spodoptera spp Guenée (Lepidoptera: Noctuidae).

Parasitoid Wasps of Green Lacewing, Chrysoperla carnea in Cotton Fields in Hama Governorate, Syria: New Records and Some Biological Aspects

Nabhan, M., Z.Sh. Khamis and B. Hawis. 2023. Parasitoid Wasps of Green Lacewing, Chrysoperla carnea in Cotton Fields in Hama Governorate, Syria: New Records and Some Biological Aspects. Arab Journal of Plant Protection, 41(3): 306-313. https://doi.org/10.22268/AJPP-41.3.306313 This study aimed to identify parasitoid species of Chrysoperla carnea stages, and to evaluate their effect on predator’s population in the field. Three hymenopteran parasitoid species of this predator were collected and identified. Telenomus acrobates Giard (Hymenoptera: Scelionidae) was found to parasitize the eggs, and was previously recorded in northern Syria. Two other species parasitized the larva-pupa stage of the predator, and are recorded for the first time in Syria in this study. The first species is Baryscapus chrysopae (Crawford, 1915) (Hymenoptera: Eulophidae), which showed a parasitism rate of 23.08% and 28.75% of the total collected eggs in 2017 and 2018 seasons, respectively, and 2-14 parasitoids individuals (males and females) emerged from each pupa. The second species was Perilampus chrysopae (Crawford, 1914) (Hymenoptera, Perilampidae), which showed a parasitism rate of 5.13% and 23.81% of the total larvae collected in the two seasons, respectively, and one parasitoid individual (male or female) emerged from each pupa. Keywords: Chrysoperla carnea, Baryscapus chrysopae, Perilampus chrysopa, Telenomus acrobates, new record, Syria

Essential oils of Ocimum gratissimum, Lippia grata and Lippia origanoides are effective in the control of the acanthocephalan Neoechinorhynchus buttnerae in Colossoma macropomum

This study investigated the in vivo efficacy of the essential oils (EOs) of Lippia grata (EOLG), Lippia origanoides (EOLO) and Ocimum gratissimum (EOOG) in the control of the acanthocephalan Neoechinorhynchus buttnerae in Colossoma macropomum (tambaqui). In addition, the parasitic and growth indices, and hematological, biochemical, enzymatic and histopathological parameters were evaluated in the tambaqui. After 30 days of feeding with diets containing 1.52 g EOLO kg−1, the length, mean weight and mean weight gain decreased. There was 100% survival of fish fed with the EOs, and a decrease in the rates of parasitism in fish fed with diets containing 0.86 g EOLG kg−1, 0.76 g EOLO kg−1, 1.03 and 2.06 g EOOG kg−1. For these concentrations, the anthelmintic efficacy of the EOLG was 62.1%, EOLO was 61.8% and EOOG was 58.7% and 59.8%, respectively. An increase in plasma levels of total protein and alkaline phosphatase was found in the fish fed with diets containing highest concentrations of EOLG and EOLO. Maintenance levels of alanine aminotransferase in plasma and aspartate aminotransferase, together with the higher frequency of mild to moderate damages in liver tissue and presence of focal point necrosis, suggest the influence of a high abundance of parasites on the biochemical and enzymatic processes of the host fish. Histomorphological and physiological indicators and a decrease in the rates of parasites with diets containing 0.86 g EOLG kg−1, 0.76 g EOLO kg−1 and 1.03 and 2.06 g EOOG kg−1 indicate that this is a promising therapeutic alternative in the control of acanthocephalosis in tambaqui.

EFFECTS OF RELEASES OF THE EGG PARASITOIDS GRYON FULVIVENTRE CRAWFORD (HYMENOPTERA: SCELIONIDAE) ON CLAVIGRALLA TOMENTOSICOLLIS STAL. (HEMIPTERA: COREIDAE), A COWPEA POD-SUCKING BUG, IN A CONTROLLED ENVIRONMENT

Clavigrallatomentosicollis Stal. (Hemiptera: Coreidae), major cowpea pod-sucking bug, causes significant economic losses. In the search for an alternative to chemicalcontrol, the use of the egg parasitoid G. fulviventre is a possibility. Given that no release strategy for G. fulviventre has yet been tested, it would seem wise, before considering large-scale use of this parasitoid, to determine an optimum release frequency. The mainof this study is to find an optimal frequency of parasitoid release. To this end, artificial infestations were carried outin a semi-controlled environment at the Centre for Environmental, Agricultural Research and Training of Kamboinse (Burkina Faso). A single release of the pest was carried outwith five release frequencies of the parasitoid. The results showed that the rate of parasitism was higher (64.57 ±4.76%) in successive releases of the parasitoid spaced one week apart and lower (42.72 ±4.99 %)in the single release.Pods were almost completely damaged without parasitoid release (91.83±1.74 %) and less damaged with successive releases (24.58 ± 1.59%). Parasitism rates did not differ significantly between two, three or four successive releases. This study is a first on the release of G. fulviventre in Burkina Faso and the results are of great importance for the implementation of an integrated management strategy of C. tomentosicollis.

Parasitism by Gryon aetherium (Hymenoptera: Scelionidae) on Bagrada hilaris (Hemiptera: Pentatomidae) eggs in northcentral California.

Bagrada bug, Bagrada hilaris (Burmeister) (Hemiptera: Pentatomidae), is an invasive pest of cruciferous crops. The parasitoid Gryon aetherium Talamas (Hymenoptera: Scelionidae) is a promising biological control agent for B. hilaris because it can forage in the soil where B. hilaris deposits most of its eggs. In this study, we assessed parasitism by G. aetherium on B. hilaris eggs in situ in northcentral California, including the Salinas Valley where most cruciferous crops in the United States are grown. Parasitism was documented by leaving soil-filled trays under infested plants for 7-14 days, then removing eggs and holding them for emergence of parasitoids. Gryon aetherium accounted for over 99% of emerged parasitoids, and occurred at 11 of the 12 sampled sites. Of the 17,729 and 31,759 B. hilaris eggs collected in 2021 and 2022, 1,518 (8.84%) and 2,654 (8.36%) were parasitized by G. aetherium, respectively. Parasitism rates were generally higher inland and ranged from 3.64% to 44.93% in 2021 and from 1.01% to 23.04% in 2022, and never exceeded 15% on any sample dates at several coastal sites in the Salinas Valley. Discovery efficiency (a measure of the ability of parasitoids to locate egg patches) reached 80% or higher at all but 1 site, but exploitation efficiency (a measure of the ability of parasitoids to exploit the egg patch after it has been discovered) was generally <20%, suggesting that G. aetherium can locate egg patches efficiently but is less efficient at finding eggs within patches.

Making of the "Pristine Vegetables": Soil-Transmitted Parasites and U.S. Military Procurement in Korea.

In the twenty-first century Korea, "Pristine Vegetables(청정채소)" refers to organic products grown without the use of pesticides and chemical fertilizers. However, the meaning of "Pristine" was radically different until 1970s. After the Korean War, the infection rate of intestinal parasite reached almost 100 percent in Korean population. Disruption in chemical fertilizers manufacturing pressured farmers to use night-soil, which was contaminated with parasite eggs, causing the vicious cycle of infection. At the same time, rapid urbanization increased the demands of fresh vegetables in the city, leading to a large amount of semi-urban agricultural practices. This was closely linked with the national economy; as most of Korean vegetable products were contaminated with parasites, they were deemed unsuitable for export. In 1957, US Army stationed in Seoul issued a guideline for producing local vegetables acceptable for US troop consumption. This gave rise to the concept of "Pristine Vegetables" that were free of any infectious materials. These practices continued well into the 1970s. Due to the lack of sewage treatment system, the waste of urban population provided necessary fertilizer for these farmers without much cost. In order to secure public health, the Korean government actively encouraged the use of chemical fertilizers, naming the vegetables "Pristine." This effort included the ban of night-soil in urban and semi-urban farms and the establishment of Pristine Vegetable Shops. However, the rapid decline of parasitic diseases in the population and the rising concerns of environmental pollutions reshaped Pristine Vegetables from chemical to organic in the 1980s. Thus, Pristine Vegetable in Korea during late twentieth century exemplifies rapid transformation of the urban environment, showing shifted concept of cleanness and contaminants among the public and policymakers, as well as acceptable risk of the urban environment in Korea.

Substantial fitness costs in terms of parasitization rates, offspring production and sex ratio of Wolbachia infection in Nasonia vitripennis without modified host preference

Abstract Wolbachia is a genus of endosymbiotic bacteria that is widespread among arthropods. It is responsible for manipulating various host phenotypes and often affects their host's fitness. We used the generalist parasitoid wasp Nasonia vitripennis and its endosymbiont Wolbachia to test whether and how Wolbachia affects the fitness of N. vitripennis by comparing the host preference and parasitization rate of cured and uncured N. vitripennis lines. We reared four genotypes of wasps, each with Wolbachia infection or cured of infection, using two different host species, namely Calliphora vomitoria and Lucilia sericata, for 3–4 generations before measuring their host preference because rearing history has previously been shown to influence host preference in N. vitripennis. We found that all experimental groups significantly preferred C. vomitoria pupae. Neither rearing history nor Wolbachia infection altered N. vitripennis female's innate host preference. Furthermore, we investigated whether Wolbachia infection may affect Nasonia's parasitization rate, offspring production and sex ratio using parasitization assays of two wasp genotypes with and without Wolbachia infection. Our results show that uncured wasps have fitness costs of harbouring Wolbachia in terms of reduced parasitization rate and offspring production in one of the host genotypes and reduced proportion of female offspring in the second host genotype tested, highlighting the context‐dependency of host–endosymbiont relationships.

Eriogynapyretorum (Lepidoptera, Saturniidae) parasitoid species investigated in Fujian, China.

Eriogynapyretorum Westwood is a notorious defoliator of Camphoraofficinarum Nees that causes large economic and ecological losses in planted forests. To understand the importance of suppressing the population of E.pyretorum on natural parasitoids, a four-years investigation was conducted in the field. Four egg parasitoid species Ooencyrtuskuvanae Howard, Trichogrammachionis Ishii, Telenomus sp. and Anastatusdexingensis Sheng & Wang were captured in the wild. One of these is the dominant endoparasitoid species T.chionis, which has a quicker developmental time (8.33 d), more offspring (8.39/egg) and a greater parasitism rate (89.54%). With different elevation distributions, the parasitism rates for Kriechbaumerellalongiscutellaris Qian & He, Gregopimplahimalayensis (Cameron), Theroniadepressa (Gupta) and Xanthopimplakonowi (Krieger) were 17.29%, 2.10%, 4.23% and 0.83%, respectively. Female longevity (47.75 d), offspring (13.36/pupa) and sex ratio (1.16:1) were compared in four pupal parasitoids and K.longiscutellaris was the most abundant species of E.pyretorum in Fujian Province.

Spatial and temporal dynamics of soybean gall midge (Resseliella maxima) parasitism by Synopeas maximum.

Soybean gall midge, Resseliella maxima Gagné (Diptera: Cecidomyiidae), is a pest that impacts soybean yield in the Midwest United States. While biological control using parasitoids may be a promising approach for managing this pest, it is crucial to have a deep understanding of parasitism dynamics to ensure effective implementation. We investigated R. maxima parasitism using a combination of three methods: rearing of field-collected hosts, dissection, and molecular assays. We confirmed parasitism of R. maxima by the recently described wasp Synopeas maximum Awad & Talamas (Hymenoptera: Platygastridae) and used our combinatorial approach to observe the spatial and temporal relationships between R. maxima and its parasitoid in the field. The number of R. maxima adults was greater in symptomatic plants on field edges than the field interior, but such a pattern was inconsistent for parasitism rates. Parasitism rates were generally highest early and late in the season, and lower in the middle of the season when the number of R. maxima was highest. In Minnesota, overall season-long parasitism rates of R. maxima were low (< 2%). To facilitate a wider investigation of the biological control of R. maxima, we designed a protocol for high throughput DNA extraction and quantitative polymerase chain reaction (qPCR) that can be used across a broader geography. Further research should evaluate how parasitism rates by Synopeas maximum could be promoted in production fields. © 2023 Society of Chemical Industry.