Percentage Parasitism Research Articles

Natural incidence pattern of cotton pink bollworm, Pectinophora gossypiella (Saunders) larval parasitoids across India

Aim: To identify natural incidence pattern of pink bollworm larval parasitoids across different cotton growing zones in India. Methodology: Green bolls of cotton were collected from farmers field across India encompassing Northern, Central and Southern regions of cotton cultivation. In total 59 locations were selected for sampling and from each cotton field, five hundred matured green bolls were collected, packed and transferred to laboratory at CICR, Nagpur. Dead/inactive larvae were placed individually in plastic tubes under controlled laboratory conditions to monitor parasitoid emergence. Percent parasitization and parasitoid emergence were calculated accordingly. Results: The pink bollworm larval recovery varied among locations, with the highest average recovery and parasitised larvae observed in the Northern zone (480.50 and 12.10 larvae). Additionally, the average parasitization rate was higher in the Northern cotton zone (2.46 %) compared to the Southern (2.16 %) and Central zones (1.70 %). In terms of parasitoids, the Southern zone exhibited the highest average number of Bracon lefroyi (9.17 ± 3.59) with a range of 3.0-17.0 parasitoids, while the Northern zone recorded the highest average number of Apanteles angaleti (9.70 ± 2.83) with a range of 6.0-15.0 parasitoids. Interpretation: The natural parasitization of pink bollworm larvae by Bracon lefroyi and Apanteles angaleti ranged from 0.43 to 4.33 per cent across various cotton-growing zones. This natural occurrence presents a hopeful strategy for controlling pink bollworm populations, potentially reducing the need for chemical interventions and minimizing crop damage. Key words: Apanteles angaleti, Bracon lefroyi, Cotton, Larval parasitoid, Pink bollworm

Response of Sitotroga cerealella and Trichogramma chilonis to gamma irradiation exposure

The present study was carried out to evaluate the response of gamma irradiation on Sitotroga cerealella and Trichogramma chilnois under laboratory conditions. Two different egg stages of S. cerealella, aged 12 and 24 hours, were exposed to four levels of gamma radiation (35, 55, 75 and 95 Gy) and control (no dose). The result indicates that low irradiation doses egg viability compared to higher doses. Exposure to 35 Gy resulted in the hatching rate (55.3%) and prolonged incubation period (7.06 days) for S. cerealella eggs. In T. chilonis, parasitism percentage was significantly higher at 86%, with maximum adult emergence at 87.3% and adult longevity of 7.13 days; however, these values remain lower than those observed in the untreated (control), where maximum parasitism, adult emergence and longevity were observed. The treatment with 95 Gy resulted in the lowest values for incubation, adult emergence, parasitism, and adult longevity. Irradiation of pupae also yielded significantly higher adult emergence (86.66%) and longevity 7.46 days at 5 Gy, pupae irradiated at 20 Gy resulted in significantly lower adult emergence and adult longevity. Based on these findings, lower irradiation doses are recommended to increase shelf life of S. cerealella and T. chilonis without causing significant detrimental effects on the quality of parasitoid and its host. The approach ensures the year around availability of parasitoids in insectaries for research and field releases.

Effect of Host Pupae Cryogenic, Anesthesia, Parasitoid-to-Host Ratios to Scleroderma sichuanensis the Percentage Parasitism and Numbers of Output.

Biological control is one of the effective means of controlling forestry burrowing pests in a low-cost and efficient way. Scleroderma sichuanensis, an ectoparasitic wasp, exhibits significant potential in managing burrowing pests. Currently, the mealworm Tenebrio molitor pupae are mainly used to many insects large-scale indoor breeding of diet. Therefore, this study focused on the effects of cryogenically treated the mealworm T. molitor pupae for different times and anesthesia treatment on the percentage parasitism and the number of emergence of S. sichuanensis, optimum parasitism and emergence were achieved in the wasp with a parasitoid-to-host ratio of 2:1, anesthesia treatment of T. molitor pupae with ethyl ether fumigation for 1.5 h, and cold treatment of them at a temperature of -10°C. As a result, various methods of treating T. molitor pupae indoors were explored, and optimal conditions for indoor rearing were explored for the expansion of S. sichuanensis.

Elucidation of the Active Agents in a West African Ground Herbal Medicine Formulation That Elicit Antimalarial Activities in In Vitro and In Vivo Models.

Agunmu (ground herbal medicine) is a form of West African traditional medicine consisting of a cocktail of herbs. The goal of this study is to evaluate a formulation of Agunmu made from M. indica, A. repens, E. chlorantha, A. boonei, and B. ferruginea, sold in the open market and commonly used for the treatment of malaria by the locals, for its antimalarial effects and to determine the active principles that may contribute to the antimalarial effect. The ethanolic extract obtained from this formulation (Ag-Iba) was analyzed, using TLC, LC-MS, and Tandem-MS techniques, to determine its phytochemical properties. The extract was tested in vitro against representative bacteria strains, cancer and normal human cell lines, and susceptible (D6) and resistant (W2) Plasmodium falciparum. In subsequent in vivo experiments, graded doses of the extract were used to treat mice infected with chloroquine-susceptible (NK-65) and chloroquine-resistant (ANKA) strains of Plasmodium berghei. Bacteria growth was monitored with a disc diffusion assay, cancer cell viability was determined with MTS assay, and percentage parasitemia and parasite clearance were determined by microscopy. Bound heme content, host mitochondria permeability transition (mPT) pore opening, F0F1-ATPase, and lipid peroxidation were determined via spectrophotometry. Indices of oxidative stress, anti-oxidant activities, toxicity, cell death, and inflammatory responses were obtained using biochemical and ELISA techniques. The histology of the liver and spleen was performed using the standard method. We elucidated the structures of the critical active principles in the extract to be flavonoids: kaempferol, quercetin, myricetin, and their glycosides with little or no detectable levels of the toxic Aristolochic acids that are found in Aristolochia repens, one of the components of the formulation. The extract also showed anti-plasmodial activity in in vitro and in vivo models. Furthermore, the extract dose-dependently decreased mitochondrial dysfunction, cell death, and inflammatory and oxidative damage but increased antioxidant potentials. Presumably, the active principles in the extract work as a combinatorial therapy to elicit potent antimalarial activity. Overall, our study unraveled the active components from a commercial herbal formulation that could be reformulated for antimalarial therapy.

Demographic parameters of Pachycrepoideus vindemiae (Hymenoptera: Pteromalidae) reared on Drosophila suzukii (Diptera: Drosophilidae), Ceratitis capitata (Diptera: Tephritidae), and Anastrepha fraterculus (Diptera: Tephritidae) puparia.

Pachycrepoideus vindemiae (Rondani) is a solitary generalist pupal ectoparasitoid that parasitizes dipterans of various families and genera. This study aimed to evaluate Anastrepha fraterculus (Wiedemann), Ceratitis capitata (Wiedemann), and Drosophila suzukii (Matsumura) to determine the best host for the development and mass production of parasitoid P. vindemiae in the laboratory. The experiments were performed in air-conditioned rooms at a temperature of 25 ± 2 °C, relative humidity of 70% ± 10%, and photophase of 12h. Moreover, 24-h-old pupae of A. fraterculus, C. capitata, and D. suzukii were provided daily to 25 pairs of the parasitoid. The following parameters were determined: percentage of parasitism, percentage of emergence, hind tibia size, sex ratio, and longevity. A fertility life table was established using biological data. Notably, P. vindemiae parasitized the pupae of all 3 hosts but did not affect the sex ratio of the offspring. Parental parasitoids from the pupae of A. fraterculus and C. capitata lived longer than those from the pupae of D. suzukii. However, for all other parameters, parasitoids from D. suzukii showed better performance than those from other hosts, with shorter intervals between generations (T) and a higher net reproduction rate (Ro), intrinsic rate of increase (rm), and finite rate of increase (λ).

Kairomonal Effect of Hexane Extracts of Corcyra cephalonica and Spodoptera frugiperda on the Parasitizing Activity of Trichogramma pretiosum.

Egg parasitoids, particularly Trichogrammatidae, play a crucial role in global biocontrol efforts. Their behavior is influenced by chemicals emitted by their hosts, such as kairomones. Among them, Trichogramma pretiosum(Riley)(Hym.; Trichogrammatidae)shows promise as a biocontrol agent on destructive Fall Armyworm (FAW), Spodoptera frugiperda(J.E. Smith) (Lep.; Noctuidae). Given the invasiveness and widespread impact of FAW, early-stage prevention in the field is imperative. This study aimed to assess the potential of host insects viz.,Corcyra cephalonica (Stainton) (Lep.; Pyralidae) and S. frugiperda kairomones in optimizing the performance of T. pretiosum while parasitizing S. frugiperda.The top two hexane extracts from each host insect were also sent to JNU, AIRF in New Delhi for detailed GC-MS analysis. A four-armed olfactometer was developed to track the movements of T. pretiosum and validated with olfactory cues. Laboratory bioassays revealed that extracts from C. cephalonica and S. frugiperda eggs and moths effectively enhanced the performance of T. pretiosum. Optimal concentrations were determined through Petri dish bioassays, with C1 (10%) concentration of C. cephalonica eggs extract showing the highest Parasitoid Activity Index (PAI), percent parasitization, and adult emergence. Meanwhile, C2 (1%) concentration of S. frugiperda female extract exhibited the highest parasitization percentage and adult emergence. Further assessments in a polyhouse setting demonstrated that treated egg cards positioned 1m from the release point achieved the highest mean percentage parasitization. Chemical composition analysis via GC-MS revealed that distinctive hydrocarbon and alcohol profiles in the extracts, suggesting their potential for manipulating parasitoid activity in biocontrol efforts. In the S. frugiperda female extract, 12 hydrocarbons and 3 alcohol groups were identified, with tetracontane as the predominant hydrocarbon compound followed by octane, heneicosane, and others. Meanwhile, the C. cephalonicaegg extract displayed 9 hydrocarbons and 1 alcohol group, with dodecane leading in area percentage among the hydrocarbons followed by decane, nonane and others. The outputs of current study highlighted that T. pretiosum's utilization of kairomones from C. cephalonica and S. frugiperda, enhancing its search behavior for host eggs. The identification and synthesis of these kairomonal compounds have the potential to revolutionize pest management, emphasizing the role of kairomones in empowering natural predators and parasitoids for sustainable agriculture.

Temporal resource continuity for egg parasitoids of Dalbulus maidis (Hemiptera: Cicadellidae) during winter on irrigated maize crops and edge grasses.

Little is known about winter-season parasitism of eggs of the corn leafhopper Dalbulus maidis DeLong (Hemiptera: Cicadellidae), an important pest of maize throughout the Americas. Our study, conducted in Mexico, aimed to characterize winter-season parasitism of corn leafhopper eggs on maize crops cultivated with drip irrigation and on wild grasses that grow on the edges of maize crops when maize is not present. Maize leaves baited with D. maidis eggs were used to trap the egg parasitoids in the field. In the first year (2022), parasitism of D. maidis eggs was investigated in maize fields planted contiguously on different dates (asynchronous planting). In the second year (2023), parasitism of D. maidis eggs was evaluated in edge grasses and in adjacent maize crops planted on the same date (synchronous). The highest percentage of parasitism (53%), percentage of emergence, and total abundance of egg parasitoids were found in asynchronous maize fields. Here, Anagrus virlai Triapitsyn (Hymenoptera: Mymaridae), Paracentrobia subflava (Girault) (Hymenoptera: Trichogrammatidae), and Pseudoligosita sp. (Hymenoptera: Trichogrammatidae) wasps were found parasitizing the D. maidis eggs, with P. subflava being the most abundant. In wild edge grasses, only P. subflava was found, showing low levels of parasitism, while in synchronous maize, P. subflava increased its percentage of parasitism (up to 37%), percentage of emergence, and abundance, during winter. These results suggest that P. subflava acts as an efficient biological control agent of D. maidis in irrigation-grown maize crops during the winter season, and that edge grasses are overwinter habitats for P. subflava.

Studies of certain parameters affecting two parasitoid species, Trichogramma evanescens Westwood and Trichogrammatoidea bactrae Nagaraja (Hymenoptera: Trichogrammatidae), on egg host, Sitotroga cerealella (Olivier) (Gelechiidae: Lepidoptera)

BackgroundTwo Trichogramma spp., Trichogramma evanescens Westwood and Trichogrammatoidea bactrae Nagaraja (Hymenoptera: Trichogrammatidae), were studied to control one of the most cereal pests attacking various grains, Sitotroga cerealella (Olivier) (Gelechiidae: Lepidoptera). Experiments were carried out to evaluate S. cerealella egg-ages, parasitoids’ emergence time and cold storage host eggs on rearing the two tested parasitoids’ spp.ResultsThe age of S. cerealella eggs had significantly influenced the parasitization and adult emergence rates of the two parasitoid species. Parasitism rate resulted from old host eggs (32 h old) (44.93%) decreased than those of the fresh ones (2 h old) (95.85%). Emergence rate ranged between (62.64–97.85%) for T. evanescens and (62.90–95.54%) for T. bactrae from different S. cerealella egg-ages (0–32 h). Regardless to late emerged parasitoids, their population affected. T. evanescens parasitized rate ranged (73.79–95.06%), which comparatively lower than those of T. bactrae (88.81–96.90%), at parasitoid emerging times (0–64 h), respectively. Emergence times had significantly differences in the emergence rate of T. evanescens and/or T. bactrae. On the other hand, percentage of parasitism of the non-stored S. cerealella eggs was higher than the other cold-stored ones. The emergence rate of adult parasitoids, T. evanescens (66.00–91.16%) and T. bactrae (71.16–94.11%), was decreased at the cold storage durations (5–40 days) increased. In comparison to the tested biological aspects between the two parasitoid species, non-significant differences were recorded, at the three assessment parameters, which include host egg-ages, parasitoid emergence time and cold-stored eggs. Meanwhile, there were significant differences between F1 emerged rates for T. evanescens and T. bactrae obtained at each of the three tested parameters.ConclusionIt was concluded that low emergence time of the parasitoids, T. evanescens and T. bactrae, was relatively more effective when they parasitized the fresh egg-age and less cold storage periods of S. cerealella.

DIFFERENCES IN ANTIMALARIAL ACTIVITY OF CITRUS MAXIMA,ANREDERA CORDIFOLIA, COMBINATION SOLANUM LYCOPERSICUM-MALUS DOMESTICA-DAUCUS CAROTA IN MICE INFECTED WITH PLASMODIUM BERGHEI

Malaria drug resistance, both new and old drugs, causes severe symptoms and treatment failure. In order to develop new drug, we screen several plants that potentially used as antimalaria. This study aimed to screen and compare antimalaria activity of Citrus maxima, Anredera cordifolia, Solanum lycopersicum, combination Solanum lycopersicum-Malus domestica-Daucus carota in a mouse model. Balb/ c mice male were divided into six groups (n=5). The dried plants were extracted by maceration using 80% methanol. A 4-day suppressive test was done to ascertain the anti-plasmodial effect of those various plants. After inoculation with Plasmodium berghei, the treatment groups were given 1000 mg/kg of the extract, while 5% RPMI and DHP (Dihydroartemisinine Piperaquine) served as controls. The results of this study revealed that all extracts showed significantly lower parasitemia compared to the negative control. This study showed a percentage parasite suppression of 58.7, 84.3, 77.4, 61.4 and 83.9 % for Anredera cordifolia, Citrus maxima, Solanum lycopersicum, combination Solanum lycopersicum-Malus domestica-Daucus carota and Dihydroartemisinine Piperaquine, respectively. The highest parasite suppression (84.3%) was found in the group given Citrus maxima extract. This study concluded that the fruit extract of Citrus Maxima, Anredera Cordifolia, Solanum Lycopersicum-Malus Domestica-Daucus Carota have different antimalaria activity, Citrus maxima has the best potential as an antimalarial.

Influence of low temperature on juvenile development, adult emergence and parasitism of trichogramma chilonis in captivity

The study was conducted in mass-rearing laboratories of beneficial insects at the Nuclear Institute of Agriculture Tandojam, to determine the optimum storage temperature of parasitoid Trichogramma chilonis after parasitization on Sitotroga cerealella eggs. Two hundred host eggs were pasted on white paper card strips with Vachellia nilotica tree gum, and these card strips were offered to parasitoid T. chilonis adults confined in glass jars. Honey solution (10%) on paper strips was provided to parasitoids as an adult diet inside the glass vessels. For parasitization, the host eggs on the strip, referred to as parasitized eggs, were taken out from glass jars and kept at six different low temperatures of 10, 8, 6, 4, -6 and -4°C along with control 25±2oC temperature in complete darkness. The results showed that the weekly maximum parasitism percentage of Trichogramma chilonis under lab conditions was observed at 10oC followed by 8oC and 6oC. The minimum parasitism percentage of Trichogramma chilonis under lab conditions was observed at 4oC. Weekly maximum adult emergence of Trichogramma chilonis under lab conditions was observed at 10oC followed by 8oC and 6oC. Minimum adult emergence of Trichogramma chilonis under lab conditions was observed at 4oC. The weekly maximum juvenile development period of Trichogramma chilonis under lab conditions was observed at 4oC followed by 6oC and 8oC. The minimum juvenile development period of Trichogramma chilonis under lab conditions was observed at 10oC. While no emergence was found in -6oC and -4oC. The developmental period was positively correlated with the storage period and the duration of development significantly decreases as the temperature increases from lower to higher concentrations.

Short- and long-term effects of commercial formulations of imidacloprid, spirotetramat, and mixtures of these active ingredients on pupae of Diaeretiella rapae (Hymenoptera: Braconidae) and its progeny.

Compatibility studies of insecticides and natural enemies usually focus on short-term lethal effects, without considering the long-term sublethal effects (including progeny). Even less-explored are the effects of commercial insecticides formulated with more than one active product. Short- and long-term lethal and sublethal effects were studied for the first time on the progeny of commercial formulations of spirotetramat, imidacloprid and a commercial mixture of these active ingredients on pupae of Diaeretiella rapae (M'ntosh) (Hymenoptera: Braconidae), an endoparasitoid of aphids considered to be a potential biological control agent. Insecticides were exposed topically on aphid mummies in which the parasitoid was in the pupal stage. Imidacloprid reduced adult emergence by more than 30% and prolonged intra-host development time with respect to control from half the maximum recommended field dose (MFRD). Spirotetramat and commercial mixture only showed significant effects on these endpoints at doses above the MFRD. The tested formulations did not affect adult longevity, sex ratio, and percentage of parasitism in the exposed generation. At low concentrations the active ingredients in the commercial mixture behave synergistically, whereas at medium and high concentrations they behave antagonistically. Considering the 10% lethal dose (LD10), imidacloprid showed the highest hazard coefficient, whereas the commercial mixture was more hazardous when considering the LD50 and LD90. The commercial mixture and imidacloprid induced higher adult emergence and altered the sex ratio in the progeny. The following order of toxicity on D. rapae can be established: imidacloprid > commercial mixture > spirotetramat. Joint use of this species with imidacloprid and commercial mixture should be avoided in integrated pest management programs. © 2024 Society of Chemical Industry.

Inventory of Pests and Parasites in the Cultivation of Hotate Shellfish (<i>Patinopecten yessoensis</i>) in Funka Bay, Hokkaido, Japan

Hotate Shellfish Cultivation is the largest shellfish cultivation in the world, but many pests and parasites are found. This research aims to inventory the types of pests and parasites found in the cultivation of Hotate Shellfish (Patinopecten yessoensis) in Funka Bay, Hokkaido, Japan. The objects used for this research were 54 Hotate shellfish, consisting of three life stages of shellfish, namely seed shellfish, juvenile shellfish, and adult shellfish. This research was carried out using observation and random sampling methods to determine the types and percentages of pests and parasites present during the research. This research was carried out for seven months from 13 April to 6 December 2022 at the Daisan Matsui Company, Ohama, Oshamambe, Hokkaido, Japan. The results of this research show that there are four types of pests, namely Starfish, Purple Shellfish, Crustaceans, and Sea Pineapples as well as two types of parasites, namely Annelid Worms and Barnacles which attack shellfish cultivation. The percentage of shellfish at three life stages that were attacked by parasites was 75.93%. There are several factors that control the attachment of pests and parasites, including substrate availability, nutrient availability, and environmental considerations. The surfaces and nutrients provided by hotate culture facilities provide adequate conditions for pest settlement and growth.

Aphid parasitism in winter wheat fields in a heterogeneous agricultural landscape.

The number, timing, and fitness of colonizing parasitoids in fields of ephemeral crops often depend on factors external to the fields. We investigated cereal aphid parasitism in 23 winter wheat fields using sentinel plants infested with bird cherry-oat aphids, Rhopalosiphum padi (L.) (Hemiptera: Aphididae), and we investigated the effect of parasitoids on cereal aphid population growth using exclusion and parasitoid-accessible cages infested with bird cherry-oat aphids. Lysiphlebus testaceipes (Cresson) (Hymenoptera: Braconidae), Aphelinus nigritus (Howard) (Hymenoptera: Aphelinidae),and Diaeretiella rapae (McIntosh) (Hymenoptera: Braconidae), in decreasing order of abundance, parasitized R. padi on sentinel plants. The mean percent parasitism in parasitoid-accessible cages was 5.2% in autumn and 35.0% in spring. Aphid population intensity was greater in complete exclusion than in parasitoid-accessible cages. Measures of landscape composition and configuration were quantified, and aphid parasitism in autumn by L. testaceipes and A. nigritus was positively associated with % landcover by summer crops and patch density. Parasitism by both species was negatively associated with contagion and % woodlands. Parasitism during spring was positively associated with % grassland and fractal dimension and negatively associated with % canola. The number of braconid mummies per sentinel plant was positively correlated to the number of braconid mummies on wheat stems from parasitoid-accessible cages. Results indicate that cereal aphid mortality caused by parasitoids and their ability to exert effective biological control is related to landscape structure. Comparing this study to an earlier study in the same agroecosystem demonstrated temporal stability of the landscape influence on aphid parasitism by L. testaceipes in winter wheat.

Biorationals and Synthetic Insecticides for Controlling Fall Armyworm and Their Influence on the Abundance and Diversity of Parasitoids

Spodoptera frugiperda (fall armyworm, FAW) is a significant economic pest of maize in Uganda. Many Ugandan maize farmers employ synthetic insecticides as their main form of control despite the negative impacts of these chemicals. We tested the effectiveness of Beauveria bassiana; General Biopesticide Cocktail (mixture of B. bassiana, M. anisopliae, Isaria fumosoroseus, Lecanicillium lecani and Purporeocillium lilacanus three strains of Metarhizium anisopliae, Nimbecidine® (azadirachtin 0.03%EC), and Roket® (cypermethrin 4% and profenofos 40%); and Amdocs® (emamectin benzoate 2% and abamectin 1%) on fall armyworm and parasitoids, respectively, in 2020 and 2021. The treatments with the greatest decrease in leaf damage and infestation were Amdocs® and Roket®, followed by Nimbecidine®. The biopesticides were not always more effective than the untreated control, though; their efficacy was often lower than that of the synthetic and botanical pesticides. We recovered one egg parasitoid, Telenomus remus, and seven egg and egg-larval parasitoids (Coccygidium luteum, Coccygidium sp., Cotesia icipe, Chelonus sp., Micranisa sp., Charops cf. diversipes, and an unidentified Tachinidae). Among these, C. cf diversipes, Chelonus sp., C. luteum, C. icipe and the Tachinidae were the most abundant. Parasitism was low, averaging 10% for egg masses and 5.3% for larvae. Application of synthetic pesticides and Nimbecidine® often resulted in higher yield when compared with the untreated control. In general, a low population of parasitoids was observed. Although the parasitoid population reduced in plots treated with Amdocs® and Roket®, the percentage of parasitism of FAW was not affected. In some instances, higher yields were realized in untreated control when compared with the treated plots. Pest management practices more compatible with biological control need to be considered for the management of fall armyworm.

Effects of food resources on the longevity, survival, and fecundity of Paracentrobia subflava adults, an egg parasitoid of the corn leafhopper pest Dalbulus maidis

AbstractThe diet consumed by adult parasitoids can affect longevity, survival, and fecundity. Honeydew from sap‐sucking insects is an abundant food resource in the field; however, artificial diets such as commercial bee honey are often used in lab rearing. The parasitoid Paracentrobia subflava (Girault) (Hymenoptera: Trichogrammatidae) is a natural enemy of Dalbulus maidis (DeLong) (Hemiptera: Cicadellidae). The longevity and survival of P. subflava when fed natural and artificial diets under controlled conditions have not been studied. Further, the fecundity of P. subflava when fed a diet of honey has not been investigated. Therefore, our first objective was to analyse the longevity and survival of P. subflava when fed (1) honeydew of the corn leafhopper D. maidis, (2) honey + water, (3) honey + water + pollen, (4) water, and (5) nothing (control). Our second objective was to evaluate P. subflava fecundity upon exposure to D. maidis eggs, comparing parasitoids fed with honey + water versus controls (no food or water). In the second objective, honey was chosen since it was determined during the first objective to be the optimal food. The longevity of adult parasitoids (laboratory‐reared and field‐collected) was high when fed on honey and low when fed other diets. The highest longevity was achieved with honey + water: 17 days, while the survival of adult parasitoids was only 3 days for honeydew. Interestingly, fecundity, in terms of the percentage of parasitism and the percentage of emergence, did not differ between parasitoid females that had access to honey + water as a food resource and those that had no food or water.

Adaptation and establishment of Habrobracon hebetor Say in the population of stored moths pests of date, Ephestia kuehniella Zeller and Plodia interpunctella Hübner

BackgroundHabrobracon hebetor (Hymenoptera: Braconidae) is a larval ectoparasitoid, mainly of pyralid moths of the stored pests of date, Plodia interpunctella Hübner and Ephestia kuehniella Zeller. It has some suitable characteristics for use in biological control of stored moth pests. The aim of this study was to compare the ability of H. hebetor establishment in the population of two important date storage moth pests P. interpunctella and E. kuehniella, and its role in their population fluctuations.ResultsThe population growth trends of two host species increased in the first 6 weeks and in the 17th to 22nd weeks of the 6-month period of conducting tests. The peaks of larval population of the two species were in the 10th and 21st weeks under temperature of 25 ± 2 °C, RH of 60 ± 5% and a photoperiod of 12:12, D:L. The pattern of fluctuation in the parasitism percentage in the larval population of the two moth species host was inconsistent with each other. The parasitism percentage was higher on the larval population of E. kuehniella than larval population of P. interpunctella. In E. kuehniella, the host population change rates were − 0.1 in the 10th and 15th weeks, while the highest rates were 0.1 and 0.8 in the 12th and 3rd weeks. The lowest level of parasitoid balance in the larval population of E. kuehniella and P. interpunctella was recorded in the 11th and 15th weeks, and the highest levels were recorded in the 20th and 24th weeks, respectively. The maximum probability rate of parasitoid non-establishment in E. kuehniella larval population was zero during the entire period and for P. interpunctella until the 22nd week.ConclusionIn fact, there was a strong correlation between establishment success and the severity of host and parasitoid populations. Only in the larval population of P. interpunctella, the maximum probability of failure of establishment was 11.5%, due to the occurrence of the maximum population of parasitized larvae and the minimum ratio of non-parasitic and parasitic larvae.

Mosquito midgut stem cell cellular defense response limits Plasmodium parasite infection

A novel cellular response of midgut progenitors (stem cells and enteroblasts) to Plasmodium berghei infection was investigated in Anopheles stephensi. The presence of developing oocysts triggers proliferation of midgut progenitors that is modulated by the Jak/STAT pathway and is proportional to the number of oocysts on individual midguts. The percentage of parasites in direct contact with enteroblasts increases over time, as progenitors proliferate. Silencing components of key signaling pathways through RNA interference (RNAi) that enhance proliferation of progenitor cells significantly decreased oocyst numbers, while limiting proliferation of progenitors increased oocyst survival. Live imaging revealed that enteroblasts interact directly with oocysts and eliminate them. Midgut progenitors sense the presence of Plasmodium oocysts and mount a cellular defense response that involves extensive proliferation and tissue remodeling, followed by oocysts lysis and phagocytosis of parasite remnants by enteroblasts.

Host-instar selection, interspecific competition, and reproductive capacity of extant and novel parasitoids (Hymenoptera: Braconidae) on Egyptian cotton leafworm

Abstract Background Cotesia marginiventris (Cresson) and Microplitis rufiventris Kok. (Hymenoptera: Braconidae) are larval endoparasitoids of Spodoptera frugiperda (Smith) and S. littoralis (Boisd.), respectively. Cotesia marginiventris was introduced in Egypt to control the recent invasive pest, S. frugiperda and local one, S. littoralis. Therefore, competition between the two parasitoid species may occur. Results When single females of C. marginiventris (Exp. 1), single females of M. rufiventris (Exp. 2), and one female each of C. marginiventris and M. rufiventris (Exp. 3) were offered a choice of 60 1st, 60 2nd, and 60 3rd instars, of the tested host species, S. littoralis and different parasitization levels were obtained. In the non-competitive context (Exps. 1, 2), all instars were parasitized, but C. marginiventris and M. rufiventris parasitized primarily 2nd and 3rd instar host larvae, respectively. In the competitive context (Exp. 3), the same preference pattern emerged but the percentage of parasitism was lower than in each of the two non-competitive contexts. Conclusions M. rufiventris appears to be a superior competitor when simultaneously exploiting the host with the other parasitoid species. The knowledge of this work can be used to predict and/or understand possible outcomes of a biological control program using the two biocontrol agents against one or the two pests species, and to gain insight into possible biotic interference between species at the same trophic level exploiting the same host. Graphical abstract

Cockroaches as carriers of human medically important parasites.

Cockroaches have been identified as mechanical carriers of pathogens capable of infesting humans. The primary objective of this research was to detect and separate medically significant parasites found within the collected cockroaches. A total of 185 cockroaches were captured. In the laboratory, cockroaches underwent a series of steps. Initially, they were washed in a saturated salt solution and rinsed with 70% alcohol, dried, and subsequently dissected to examine endoparasites. In this study, a transport rate of 29.729% was documented, and four types of helminths were identified, which included Ascaris lumbricoides (47.27%), Enterobius vermicularis (30.91%), Trichuris spp. (7.27%), and Hymenolepis nana (14.55%). The parasites were more frequently found on the external surface of cockroaches (38/69.09%), compared to the internal surface (17/30.91%). Cockroaches captured in toilets were found to carry a higher percentage of parasites (31/16.75%) compared to those from kitchens (11/5.94%) and houses (13/7.02%). These findings suggest that cockroaches can serve as carriers for intestinal parasites and potentially act as mechanical agents in the dissemination of these parasites.

First record of Trichogramma pretiosum parasitizing Iridopsis panopla eggs in eucalyptus in Brazil

Abstract Iridopsis panopla Prout (Lepidoptera: Geometridae) is an important lepidopteran defoliator of eucalyptus. I. panopla eggs were collected naturally in a commercial plantation of Eucalyptus urograndis W. Hill (Myrtaceae) in Três Lagoas, Mato Grosso do Sul, Brazil. After nine days, the natural emergence of Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) occurred from I. panopla eggs. Parasitism was evaluated under laboratory and field conditions, this being the first record for eucalyptus in Brazil. Based on the biological characteristics evaluated in the laboratory, I. panopla eggs are suitable for T. pretiosum reproduction. The obtained percentage parasitism, particularly when 72,000 adult females of T. pretiosum per hectare were employed, provide valuable insights regarding the potential of T. pretiosum as an effective biological control agent against I. panopla in eucalyptus plantations.