Egg Age Research Articles

Baked Egg Oral Food Challenges: Modifying Decision Points for Success

Including baked egg into the diet for children with egg allergy has nutritional and quality of life benefits. Current data on recommended IgE decision points for baked egg challenges are variable. We investigated whether specific egg white IgE and age are associated with passing a baked egg food challenge and if our institutional decision point of 10-15 kU/L should be modified.

Identification of Chelonus sp. from Zambia and Its Performance on Different Aged Eggs of Spodoptera frugiperda

The fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), is a migratory pest endemic, to tropical and subtropical regions of America. Biological control can effectively and sustainably control pests over a long period of time while reducing the frequency of pesticide use and ensuring the safety of agricultural produce. In our study, the egg-larval Chelonus species (Chelonus bifoveolatus) from parasitized eggs of Spodoptera frugiperda in Zambia were described and identified based on morphological and genetic characteristics. To evaluate the efficiency of C. bifoveolatus, their parasitism suitability on 0- to 2-day FAW eggs under laboratory conditions was compared. The results showed that C. bifoveolatus could accept all FAW eggs at 0-, 1- and 2-day-old age and complete development successfully. Significant differences were found among 0-, 1-, and 2-day-old host eggs with respect to egg-larva developmental duration of C. bifoveolatus, and the egg-larva developmental duration on 2-day-old eggs was significantly lower than those on 0- and 1-day-old eggs. No significant differences were observed in the parasitism, pupation, emergence, and female rates for C. bifoveolatus on various age eggs of FAW. Generally, the parasitism rate, pupal rate, and emergence rate at various ages of FAW eggs were higher than 90%, 75%, and 82%, respectively, and the longevity of female parasitoids was longer than male parasitoids, and the sex ratio of females to males was nearly 1:1. Our results indicate that C. bifoveolatus performed well on various ages of FAW eggs and is a potential biological control agent against FAW in Africa.

Efficiency of the Egg Parasitoid Trichogramma evanescens for the Control of Potato Tuber Moth, Phthorimaea operculella under Laboratory Conditions

Mohamed, H.Z., S.M. Ali and H.M. Khodair. 2023. Efficiency of the Egg Parasitoid Trichogramma evanescens for the Control of Potato Tuber Moth, Phthorimaea operculella under Laboratory Conditions. Arab Journal of Plant Protection, 41(4): 391-397. https://doi.org/10.22268/AJPP-41.4.391397 The efficiency of the egg parasitoid Trichogramma evanescensin controlling the eggs of the potato tuber moth, Phthorimaea operculella, was evaluated at two temperatures 20 and 25ºC and using different ages of host eggs in the laboratory. The temperature of 25˚C was the best for the period required for blackening of the host's eggs, parasitism efficiency and adult’s emergence rate. The results also showed the use the 396 مجلة وقاية النبات العربية، مجلد ،41 عدد 4 ) 2023( host's eggs age of 24, 48 and 72 hours led to a parasitism rate of 83.33, 68.33 and 58.33%, respectively, at temperature of 25ºC. The results also showed the importance of the age of the host eggs age in determining the parasitoid emergence rate, which reached 75.9% when 24 hours old eggs were used. Results obtained indicated that the parasitoid Trichogramma evanescens can be used as a biological control agent of the potato tuber moth. Keywords: Trichogramma evanescens, Phthorimaea operculella, biological control

Egg Freshness Indexes Correlations with Ovomucin Concentration during Storage

The relationship between protein changes and egg quality during storage is a critical area of investigation in both basic science and egg product preservation. Viscosity changes in albumen are a sensitive sign of the deterioration process. Ovomucin, which is present in albumen, plays an important role in the gelation of the albumen. Egg freshness indices and ovomucin concentration will alter in response to storage time. This paper analyzed the correlation and gray relational degree between the Haugh unit (HU), yolk index, albumen pH, and ovomucin concentration. We studied the differences in the ovomucin concentration at different levels of HU, yolk index, and pH during storage. We established an equivalent egg age prediction model using ovomucin concentration as the independent variable. The findings indicated a correlation between the freshness indices and the ovomucin concentration. There was a good, significantly positive relationship between HU and ovomucin concentration (r = 0.713, P < 0.01 ), a positive correlation between the yolk index and ovomucin concentration (r = 0.699, P < 0.01 ), and a negative correlation between albumen pH and ovomucin concentration (r = −0.683, P < 0.01 ). The highest Pearson correlation coefficient (r = 0.970, P < 0.01 ) was obtained between the albumen and ovomucin concentration. Significant differences in ovomucin concentration were observed when HU, yolk index, and pH were varied. The gray relational degree between each freshness parameter and ovomucin concentration was greater than 0.8. Between the HU and ovomucin concentration, there was a gray correlation degree of 0.885, indicating that the HU was the primary factor affecting ovomucin concentration variation during storage. During storage, at 22°C, the ovomucin concentration in albumen was significantly and negatively related to storage time (r = −0.926, P < 0.05 ). The coefficient of determination for the equivalent egg age prediction model with ovomucin concentration as the independent variable was 0.985 ( P < 0.05 ), indicating strong reliability. The study’s findings show the possibility of nondestructive prediction of an egg’s internal microscopic protein composition using its freshness index value.

Pengaruh Variasi Usia Telur, Higiene Dan Sanitasi Terhadap Kualitas Fisik Dan Mikrobiologis Telur Ayam Ras Yang Beredar Di Pasar Tradisional Kota Kupang

This study aims to determine and identify the effect of variations in the age of broiler eggs on the physical and microbiological quality of eggs as well as the state of hygiene and sanitation at the traditional market for selling eggs in Kupang City (Pasar Kasih-Naikoten 1, Pasar Oeba, Oebobo Market, Oesapa Market, and Pasar Oesapa). Penfui). The samples used in this study were 68 respondents and 68 samples of broiler eggs. Data were analyzed descriptively. Variations in egg age are divided into producers and distributors. Physical quality parameters observed were egg weight, egg yolk index, egg white index, Haugh Unit, and pH. The microbiological quality parameter observed was the amount of microbial contamination in eggs. The results of the physical and microbiological quality test of eggs from producers have a better value than distributors because the age of eggs from producers is younger than distributors. The effect of variations in egg age on physical and microbiological quality showed that the longer the age of the eggs, the egg weight, egg white index, yolk index and Haugh Unit decreased. Meanwhile, the longer the age of the eggs, the pH and the amount of microbial contamination will increase. Of the five markets where samples were taken, eggs in the Oebobo Market that came from producers had a shorter egg age variation so that the results of the physical quality test (meets all 6 parameters) and microbiological (1.8x104 cfu/gr) were the best. Meanwhile, hygiene and sanitation factors are more at risk of affecting the microbiological quality of eggs. The hygiene and sanitation of broiler eggs in the Kupang City Traditional Market is quite low due to the lack of information on handling good hygiene and sanitation for broiler egg traders.

Hadronotus pubescens (Motschoulsky) (Hymenoptera, Scelionidae): Redescription, biological attributes, and parasitism on eggs of Riptortus pedestris (Fab.) (Hemiptera, Alydidae)

Riptortus pedestris (Fab.) (Hemiptera, Alydidae) is one of the most damaging insects of leguminous crops in Eastern Asia but has only recently emerged as a pest in Bangladesh. Eggs, nymphs and adults of R. pedestris are here reported from mung bean (Vigna radiata (L.)) fields in Bangladesh. Two parasitoid species were reared from field-collected eggs of R. pedestris, the solitary Hadronotus pubescens (Motschoulsky) (Hymenoptera, Scelionidae) and a gregarious species of Ooencyrtus Ashmead (Hymenoptera, Encyrtidae). Here we redescribe H. pubescens, treat H. hogenakalensis (Sharma) as a junior synonym, and report aspects of its biology that were investigated under laboratory conditions. The number of eggs parasitized by H. pubescens was constant with eggs up to 48 hours in age, decreasing by 14% for 96 hour-old eggs. As host egg age increased, the parasitoid mean development time increased and the longevity of the parasitoids decreased.

Cold plasma disinfestation of Callosobruchus maculatus infested soybeans: Its subsequent impact on soymilk extraction yield and quality

AbstractSoybeans play a vital role in the world economy as an essential food commodity by fulfilling human dietary needs. Hence, the seeds are commonly transported and stored in bulk quantities in various parts of the world which ultimately results in infestation issues. Callosobruchus maculatus is one of the major storage pests that infest the soybean seeds and cause losses in both the quantity and quality of the seeds. Cold plasma (CP) is an emerging non‐thermal disinfestation technique that can disinfest food grain. Hence, we have used low pressure (<2 mbar) CP at different voltages (1.0–2.0 kV) and exposure times (2–24 min) to disinfest the C. maculatus from soybeans. The maximum mortality of 100.00 ± 0.00%, 98.89 ± 1.92%, and 37.33 ± 8.08% was achieved in adult, pupae, and egg stage insects, respectively, after 24 min of prolonged CP exposure at 2.0 kV voltage. However, CP treatment (1.5 kV–18 min) induced only 11.11 ± 3.85% mortality in larval stage insects as they were well protected under soybean seed coat. During the experiment, we also identified the impact of insect sex and egg age on the CP treatment effectiveness. Further, we have also analyzed the egg‐producing capacity of CP‐treated adult insects before their death. Apart from disinfestation, the CP treatment also assisted the soymilk extraction and increased the extraction yield from 92.44 ± 1.02% (control) to 97.22 ± 0.19% after CP treatment (2.0 kV–12 min). Nevertheless, the FTIR and SDS PAGE results had not shown any changes in the quality of soymilk extracted after CP treatment.Practical applicationsSince the lab scale study was found to be effective against most of the C. maculatus life stages, it is possible to adapt the CP for large‐scale disinfestation applications with essential modifications (i.e., pressure, conveyors) in the system's designs. Apart from that, CP also modifies the surface nature of the grains, hence the treatment also assists in increasing the extraction yield (milk, oil, and protein) and germination percentage of food grains.

Different processing methods of pigeon pea (Cajanus cajan) seed meal: Effect on nutritive value, growth and production performance of commercial layers

The experiment was conducted with 150 Bovans brown pullets to evaluate the performance of grower pullets and layers fed raw or processed pigeon pea seed meal diets from 18th week stage of life. Each treatment had three replicates and ten birds per replicate in a completely randomized design (CRD) with pullets and layers fed comprised of 20% pigeon pea seed meal diets that were isoenergetic and isonitrogenous. Live weight, feed intake, live weight gain, egg production and mortality parameters were measured. Pullets fed 20% boiled and soaked PPSM diets attained significantly higher (P<0.05) final body weight at point of lay and daily feed intake than those fed control, raw and toasted PPSM diets. Results revealed that non-significant (P>0.05) differences among the layers fed PPSM diets in hen-day egg production, average daily feed intake and average mortality parameters but significant differences (p<0.05) were observed on hen-housed egg production and age at first egg lay parameters. It was concluded that PPSM could be a good protein source for grower pullets and layers, which could be incorporated into the diets at 20% of the whole diet without any adverse effect on growth and egg production performance.

Performance of hilly and naked neck hilly chicken at Naikhongchari of Bangladesh

A study was conducted to evaluate the production and hatching performances of hilly chickens and naked neck (NN) hilly chickens at the hilly areas of Naikhongchari regional station research farm of Bangladesh Livestock Research Institute (BLRI). The experimental chickens were reared in an open-sided poultry house under an intensive management system for a period of 18 month. The birds were allowed to take feed and clean drinking water ad libitum. Data on productive and reproductive performances of hilly and NN hilly chickens were recorded regularly. Result revealed that no significant (P>0.05) difference on body weight of day old, 2nd weeks and 4th weeks of age but significantly (P<0.05) differ on 6th to 12th weeks of age on hilly and NN hilly chicken. Result also showed that average feed intake and mortality percentage at day old to 12th weeks of age were significantly (P<0.05) differ among hilly and NN hilly chicken. It was found that no significant (P>0.05) difference of egg weight and chick weight between hilly and NN hilly chicken but significantly (P<0.05) differed in hatchability percentage. On the other hand, result exhibited that average body weight (ABW) of cock and hen, feed intake and mortality were significantly (P<0.05) differed among hilly and NN hilly chicken. Hen days egg production was significantly (P<0.05) differed between hilly and NN hilly chicken but no significant (P>0.05) difference of average total egg weight and age at first egg. These findings imply that Hilly chicken performance was better than NN hilly chicken in terms of body weight (BW), age at first egg (AFE) and egg production. Both hilly (feathered) and NN hilly chickens need to be conserved and improved further through selective breeding and a better management system.
 Bangladesh Journal of Animal Science 51 (3): 133-137, 2022

Evaluación de actividad ovicida de extractos vegetales en Tetranychus urticae Koch (Acari: Tetranychidae)

The ovicidal activity of ethanol and hexane extracts of Azadirachta indica A. Juss., Trichilia havanensis Jacq., Roldana ehrenbergiana (Klatt) H. Rob. & Brettell, Argemone mexicana L., Schinus molle L. y Gliricidia sepium (Jacq.) Kunth ex Walp. was evaluated in the laboratory on Tetranychus urticae Koch (Acari: Tetranychidae). The extracts (treatments) were applied by spraying at a concentration of 1,000 mg.L-1 to a known number of eggs (age <18h) on leaf discs of bean (Phaseolus vulgaris L.) (10 leaf discs per treatment), and the percentage of egg mortality was recorded after six days of the treatment. The corrected mortality (percentage) was obtained for each test unit, and a simple ANOVA, followed by multiple comparison of means by the Tukey method (α=0.05), were used to find statistically significant differences between treatment effects. The ethanol and hexane extracts of T. havanensis seeds caused an average corrected egg mortality of 77.7±3.5 and 58.0±3.4 %, respectively, which was significantly higher than the egg mortality caused by the other extracts. The ethanol extracts of the other plant species caused a corrected egg mortality, which ranged from 8.8±9.6 to 42.9±8.3 %, while the corrected mortality of the hexane extracts ranged from 0.2±2.3 to 30.1±4.0 %. The results show that the ethanol extract of T. havanensis seeds has good potential for the development of products with biological activity for the management of T. urticae.

Generating Ectropis obliqua axenic larvae in support of functional microbiome studies

AbstractEctropis obliqua Prout (Lepidoptera: Geometridae) is a serious leaf‐eating pest in tea gardens throughout China, with rich bacterial communities in the larval gut. Few studies have investigated whether these bacteria play an important role in growth, development, and adaptability of E. obliqua. Axenic larval models are a useful tool for the study of interactions between gut bacteria and host insects. At present, artificial diet and antibiotics are typically used to remove larval gut bacteria for study; however, this method may change the natural food of insects and the habitat provided by their host plants, and cannot completely eliminate insect gut bacteria. Therefore, in order to establish an axenic insect feeding model, we first investigated the effects of egg age, different disinfectant concentration, and treatment time on the eggs of E. obliqua through orthogonal experiments. Next, we fed E. obliqua larvae tissue‐cultured tea seedlings under aseptic conditions. Thus, we successfully generated a feeding model of gut axenic larvae in the laboratory. Based on it, we then compared the mortality of axenic and non‐axenic E. obliqua larvae infected with the entomopathogenic fungus Beauveria bassiana (Balsamo) Vuill. These results demonstrated the feasibility of this axenic larval model and that B. bassiana is a broad‐spectrum entomogenous fungus with a toxic effect on E. obliqua.

P-368 Serum progesterone on the day of embryo transfer in stimulated cycles does not correlate with pregnancy outcomes

Abstract Study question Is the chance of positive hCG, clinical pregnancy or live birth in a fresh embryo transfer (ET) IVF cycle, affected by day of transfer serum progesterone (P4) level? Summary answer There is no correlation between P4 level on the day of ET and pregnancy outcomes. What is known already Data from studies of frozen–thawed embryo transfer cycles suggest that low as well as high P4 levels during the mid-luteal phase may decrease the chance of pregnancy. The altered P4 pattern may disrupt the endometrial maturation leading to asynchrony between embryonic development and endometrial receptivity, thereby, compromising implantation and early development of pregnancy. Study design, size, duration A monocentric retrospective study of prospectively collected data, of women undergoing IVF or ICSI treatment July 2019-July 2020, and having a fresh day 5 single embryo transfer (SET). 825 first and second stimulation cycles were included. Patients underwent a GnRH-antagonist protocol and were triggered for final oocyte maturation with hCG (OvidrelR). All patients received vaginal luteal support. The study population was unselected, treated with the unit’s usual stimulation protocols, representing an everyday patient cohort. Participants/materials, setting, methods Serum P4 levels on the day of ET were correlated with positive hCG, clinical pregnancy (CP) and live birth (LB) rates. Based on previously defined P4 thresholds, patients were divided into four P4 groups based on serum levels (P4<150 nmol/l, P4 150–250 nmol/l, P4 251–400 nmol/l and P4>400 nmol/l). The data was further interrogated using additional P4 cut offs, to confirm that there were no discernible differences based on P4 levels. Main results and the role of chance There was no level of P4 below or above which the chance of pregnancy was consistently reduced. The chance of a positive hCG-test in the whole cohort was 51%, (95% CI: 47.1-54) following blastocyst transfer and was not different across the four groups (50, 48.2, 51.1, 52%, P = 0.88). Likewise, there was no difference in CP 41.8% (CI 38.4-45.3%) and LB 30.4% (27.3-33.7%), between the four groups. No negative association between P4 and chance of pregnancy when the other thresholds, described above, were applied. All estimates were adjusted for maternal age, maternal BMI, eggs retrieved and number of eggs fertilised, with the outcome remaining unchanged. Limitations, reasons for caution The finding of no difference in pregnancy outcomes across P4 ranges in this study, only applies to fresh blastocyst transfer IVF cycles, using hCG trigger and vaginal LPS, and should be corroborated in future clinical trials. Also, there is possible inaccuracy in P4 levels due to diurnal variability. Wider implications of the findings Future studies are necessary to explore the diurnal variability, and its possible contribution to these results. Trial registration number retrospective study, institutional ethics approval

Differential Transcriptional Responses in Two Old World Bemisia tabaci Cryptic Species Post Acquisition of Old and New World Begomoviruses.

Begomoviruses are transmitted by several cryptic species of the sweetpotato whitefly, Bemisia tabaci (Gennadius), in a persistent and circulative manner. Upon virus acquisition and circulative translocation within the whitefly, a multitude of molecular interactions occur. This study investigated the differentially expressed transcript profiles associated with the acquisition of the Old World monopartite begomovirus, tomato yellow leaf curl virus (TYLCV), and two New World bipartite begomoviruses, sida golden mosaic virus (SiGMV) and cucurbit leaf crumple virus (CuLCrV), in two invasive B. tabaci cryptic species, Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED). A total of 881 and 559 genes were differentially expressed in viruliferous MEAM1 and MED whiteflies, respectively, compared with their non-viruliferous counterparts, of which 146 genes were common between the two cryptic species. For both cryptic species, the number of differentially expressed genes (DEGs) associated with TYLCV and SiGMV acquisition were higher compared with DEGs associated with CuLCrV acquisition. Pathway analysis indicated that the acquisition of begomoviruses induced differential changes in pathways associated with metabolism and organismal systems. Contrasting expression patterns of major genes associated with virus infection and immune systems were observed. These genes were generally overexpressed and underexpressed in B. tabaci MEAM1 and MED adults, respectively. Further, no specific expression pattern was observed among genes associated with fitness (egg production, spermatogenesis, and aging) in viruliferous whiteflies. The weighted gene correlation network analysis of viruliferous B. tabaci MEAM1 and MED adults identified different hub genes potentially implicated in the vector competence and circulative tropism of viruses. Taken together, the results indicate that both vector cryptic species and the acquired virus species could differentially affect gene expression.

Optimization of the application of the CRISPR/Cas9 system in Mythimna separata

AbstractMythimna separata (Walker) (Lepidoptera: Noctuidae) is one of the most destructive phytophagous pests. Here we present detailed instructions to achieve successful application of CRISPR/Cas9‐mediated genome editing on M. separata. We optimized procedures, including egg collection and incubation. We further successfully conducted microinjection on the washed eggs by applying water on the egg surface. We then evaluated the effects of injection timing on both egg viability and genome editing efficiency using NPC1b as the target gene. We observed that Cas9 protein injection had significantly less effect on the viability of the eggs at the earlier stage (<2 h old) than at later stages, although no significant effect was observed on the postembryonic development between different egg ages. All larvae were edited when the eggs were <6 h old, and the editing efficiency decreased when older eggs were used. Moreover, mutants were detected among G1 progenies, which demonstrated that the mutation generated by the Cas9/sgRNAs system on M. separata was heritable. As far as we know, this is the first report of CRISPR/Cas9 for this important pest. The successful application of genome editing on M. separata is essential to understanding its biology and developing novel control methods.

Development, Validation and Preliminary Experiments of a Measuring Technique for Eggs Aging Estimation Based on Pulse Phase Thermography.

Assessment of the freshness of hen eggs destinated to human consumption is an extremely important goal for the modern food industry and sale chains, as eggs show a rapid natural aging which also depends on the storage conditions. Traditional techniques, such as candling and visual observation, have some practical limitations related to the subjective and qualitative nature of the analysis. The main objective of this paper is to propose a robust and automated approach, based on the use of pulsed phase thermography (PPT) and image processing, that can be used as an effective quality control tool to evaluate the freshness of eggs. As many studies show that the air chamber size is proportional to the egg freshness, the technique relies on the monitoring of the air chamber parameters to infer egg aging over time. The raw and phase infrared images are acquired and then post-processed by a dedicated algorithm which has been designed to automatically measure the size of the air chamber, in terms of normalized area and volume. The robustness of the method is firstly assessed through repeatability and reproducibility tests, which demonstrate that the uncertainty in the measure of the air chamber size never exceeds 5%. Then, an experimental campaign on a larger sample of 30 eggs, equally divided into three size categories (M, L, XL), is conducted. For each egg, the main sizes of the air chamber are measured with the proposed method and their evolution over time is investigated. Results have revealed, for all the egg categories, the existence of an analytic relationship and a high degree of correlation (R2 > 0.95) between the geometric data of the air chamber and the weight loss, which is a well-known marker of egg aging.

Simulation analysis and freshness prediction of eggs laid at room temperature.

Respiration is an important physiological activity of eggs and is closely related to their freshness. To further observe the diffusion of carbon dioxide released by egg respiration, we used a respirometer to measure the respiration parameters of eggs stored at room temperature and performed a respiration simulation using Fluent software. This paper also explores the relationship between respiratory intensity, freshness, and storage period. The results demonstrate that the diffusion of carbon dioxide released from the respiration of eggs is related to the characteristics of heavy gas diffusion. By comparison, the simulated value (0.0199 m s-1 ) is close to the experimental value (0.0208 m s-1 ), which indicates that the simulation and analysis results are valid. In addition, the logarithmic model was used to assess the relationship between respiration intensity, Haugh unit, and the yolk index (R2 values 0.89 and 0.87). The R2 of the relationship between the real and the predicted Haugh unit value and the yolk index are 0.9 and 0.84 respectively, indicating that the model is a good fit. The equivalent egg age model was established using nonlinear regression, where the correlation coefficient R was 0.888 and P < 0.01, indicating it was both stable and reliable. The standard k-ε model is suitable for egg respiration simulation analysis. Respiratory intensity can be used as a potential index for nondestructive testing of egg freshness, which is a new method for nondestructive testing of egg freshness and storage period. © 2022 Society of Chemical Industry.

Evaluation of egg parasitoid Hadronotus pennsylvanicus as a prospective biocontrol agent of the leaffooted bug Leptoglossus zonatus

The western leaffooted bug, Leptoglossus zonatus (Dallas) (Heteroptera: Coreidae), is a key pest of almonds and pistachios in the USA. With limited monitoring strategies and no economic threshold developed, the use of broad-spectrum insecticides remains the primary control tactic for L. zonatus. In pursuit of more sustainable management options, experiments were carried out to assess the biocontrol potential of the egg parasitoid Hadronotus pennsylvanicus (Ashmead) (Hymenoptera: Scelionidae) against L. zonatus. Biological and demographical attributes of H. pennsylvanicus were evaluated under controlled laboratory conditions. Mated females lived on average 116 days. However, female longevity declined by 74% when provided with host eggs, and by 97% when deprived of a suitable diet. Females produced an average 39.70 offspring, with peak fecundity observed within the first week of their lifespan. The total progeny was on average 92.75% female. Non-reproductive host mortality accounted for > 52% of the total egg mortality observed within the first two weeks, and represented the majority of total host egg mortality thereafter. Age of host eggs did not influence parasitism rates. Under laboratory conditions, H. pennsylvanicus exhibits suitable demographic and reproductive traits as a candidate biocontrol agent of L. zonatus. Further research is needed to determine how to best manipulate and enhance H. pennsylvanicus populations to promote biocontrol of L. zonatus under field conditions.

Trichogramma ostriniae Is More Effective Than Trichogramma dendrolimi As a Biocontrol Agent of the Asian Corn Borer, Ostrinia furnacalis.

Simple SummaryThe performance of two egg parasitoids T. dendrolimi and T. ostriniae were compared on Asian corn borer (ACB) Ostrinia furnacalis eggs of different ages under choice and no-choice conditions. Both parasitoid species showed significant preferences in parasitizing ACB eggs of different ages. Younger ACB eggs (0–8-h-old) showed high suitability while eggs older than 8 h were not suitable for T. dendrolimi. The age of ACB eggs did not affect the biological parameters of T. ostriniae. Overall, our results highlighted the T. ostriniae species as the best candidate biocontrol agent for managing ACB populations.The Asian corn borer (ACB), Ostrinia furnicalis, is a serious corn pest in south-east Asia, causing huge economic losses every year. Trichogramma dendrolimi and Trichogramma ostriniae, two egg parasitoids, have previously been identified as key biological control agents. To determine the age impact of ACB eggs on their effective biocontrol potential, herein we compared the biological parameters (i.e., number of parasitized eggs, emergence, developmental time, and sex ratio) of both parasitoids on ACB eggs of various ages (i.e., 0–4, 4–8, 8–12, 12–16, 16–24, 24–36, and 36–48 h old), respectively. Our results showed that the age of ACB eggs had a significant impact on the parasitization activity of T. dendrolimi in both choice and no-choice conditions. Trichogramma dendrolimi preferred to parasitize 0–8-h-old ACB eggs, and its parasitization dramatically declined on ACB eggs older than 8 h under choice and no-choice conditions. On the other hand, T. ostriniae showed high preference to parasitize all tested ACB egg ages. The age of ACB eggs had no significant impact on the parasitization of T. ostriniae under choice and no-choice conditions. Furthermore, the female progeny of T. dendrolimi decreased as the age of ACB increased, while no differences were found in female progeny of T. ostriniae. Trichogramma ostriniae also developed faster on each ACB egg age group in comparison with T. dendrolimi. Overall, the age of ACB eggs had a significant impact on T. dendrolimi performance, leading us to conclude that T. ostriniae is more effective than T. dendrolimi as a biocontrol agent of the ACB.

Preliminary project design for insect production: part 5 – models and simulation of insect production – organism development

The issue dealt with here is the rearing of an organism from egg to larva to pupa as is commonly done with various mealworms and black soldier flies, while organism development is the principal subject of interest. In order to obtain a uniform product at harvest time, the population should be synchronised as much as possible and this means that variability in development in the population must be reduced to the greatest possible extent. Four main sources of variability in development were identified, two of them operational and two biological in nature. These are: (1) distribution of the initial ages of the eggs; (2) distribution of incubation temperatures of the organisms; (3) inherent variability in the development rate of individual organisms; and (4) distribution in temperature sensitivity of the organisms. The combined effects of the various sources of variability on production and productivity were examined by means of simulation. This kind of exercise is useful in a number of contexts: (a) during the very early stage of project planning, as part of preliminary project design, before any formal design work is started and well before any major financial commitments are made; (b) during trouble-shooting of a low-performing process in order to upgrade its product quality; (c) to develop specifications for egg age distribution, design specifications for incubation equipment, etc.; (d) to better understand what data are required about the organism of interest so as to facilitate process design; and (e) to set objectives for organism breeding efforts. Examples are presented of how variabilities in the various factors can combine to yield organism development distributions at harvest time and how understanding the interactions between factors can help in designing a better production process.

Age-Dependent Variation in Infectivity of Moniliformis moniliformis (Acanthocephala) Eggs

The degree to which infectiveness to intermediate hosts is retained as eggs of Moniliformis moniliformis (Acanthocephala) age was studied by determining the prevalence and mean intensity of cystacanths produced in the cockroach (Periplaneta americana) intermediate host. Eggs up to 9 wk old resulted in more prevalent and intense infections than did older eggs. After this initial flush of infectiveness, prevalence and mean intensities did not decline gradually to uninfectiveness, but rather they quickly fell to a relatively stable level that was maintained for another 69 wk before eggs became uninfective. Thus, except initially and at the end of infectivity, there was a period of more than a year when the age of eggs played no role in determining their infectivity. No infection was produced by eggs older than 82 wk.