Egg Duration Research Articles

Thermal Stress as a Critical Factor in the Viability and Duration of Spittlebug Eggs

The spittlebug Mahanarva spectabilis (Distant, 1909) (Hemiptera: Cercopidae) is an important pest that causes significant losses in the production of forage crops for cattle feed. Information on the thermal requirements of this insect during the egg stage is crucial in assessing the interaction between insects and forage. The aim of this research was to evaluate the effects of constant and oscillating (diurnal/nocturnal) temperatures on the viability of M. spectabilis eggs and the duration of the egg stage. Temperatures of 20 °C to 30 °C were ideal for the development of this insect pest, resulting in greater viability and faster development of the embryos. In addition, it should be noted that a variation of up to 8 days is feasible for synchronizing the phenological stages of the forage plants and the eggs to be laid on these plants when subjected to 30 °C (16.6 days) or 20 °C (25.7 days) without significantly altering the viability of the eggs. Notably, a temperature oscillation of 25 °C during the day and 15 °C at night increased the viability of the eggs after exiting diapause. These results are essential for the rearing of M. spectabilis in the laboratory, allowing for the supply of eggs for experiments and contributing to advances in studies aimed at developing effective integrated management strategies for this pest.

Biological Manifestation of Different Temperature Regimes and Certain Insecticides on Cheilomenes sexmaculata (Fab.) Preying on Cowpea Aphid, Aphis craccivora Koch

Background: Ladybird beetles are great bio-control agents and campodeiform grubs of these little predators are able to devour aphids in a voracious fashion. They feed on a wide array of aphid species most noticeably on the infamous black aphids or cowpea aphids Aphis craccivora (Koch). Methods: The growth and feeding potential of C. sexmaculata were studied in the laboratory of the Department of Entomology, Faculty of Agricultural Sciences (Institute of Agricultural Sciences), SOA Deemed to be University, Bhubaneswar, India at four different temperatures 20°C, 25°C, 30°C and 35°C during 2021-2022. Result: The life history parameters indicated that the duration of eggs, larvae, pupae, adult males and adult females was longest at 30°C and shortest at 20°C. Such variations were also observed in morphometry and feeding potential. The trend was 30°C greater than 25°C greater than 35°C greater than 20°C. In the case of feeding potential the trend was adult female greater than adult male greater than 4th instar greater than 3rd instar greater than 2nd instar greater than 1st instar across all temperatures. Adult females lived longer than males and thereby consumed more aphids than males. Maximum consumption was seen in case of adult female at 30°C which was 633±5.71 aphids and least feeding was seen at 20°C by 1st instar grub which was 8.9±0.56 aphids. The effect of insecticides in direct spray method indicated that dimethoate 30EC killed more ladybirds and clothianidin 50% WDG killed the least. This trend was strong across all temperatures and insect growth stages. The feed contamination method indicated that clothianidin 50% WDG, imidacloprid 17.8% SL and thiamethoxam 25% WG produced higher mortality rates than direct contamination method. All insecticides showed increased mortality up to 72 h and the mortality trend was 72 HAT greater than 48 HAT greater than 24 HAT. The mortality rate of immature individuals is higher than that of adults.

Resistance Realized Heritability and Fitness Cost of Cyproflanilide in Rice Stem Borer, Chilo suppressalis (Lepidoptera: Pyralidae)

The rice stem borer (RSB) Chilo suppressalis is a devastating rice pest with resistance to a number of insecticides. Recently, the new meta-diamide insecticide cyproflanilide has been considered an effective insecticide to control RSB. However, its resistance risk has not been reported. In the present study, we aimed to assess the resistance risk and evaluate the fitness cost after the RSB was exposed to cyproflanilide. After five generations of selection, the resistance level of RSB increased by 1.5-fold. When h2 was 0.125, a 10-fold resistance increase in the LD50 values was expected in fourteen and thirty-one generations at the selection intensity of 90% and 50%, respectively. The selected population (RSB-SEL) had significant differences in the developmental duration of eggs, 1st, 2nd, 3rd, and 6th instar larvae, and female pupae compared to the unselected population (RSB-UNSEL). Besides, the adult longevity was shortened, and the average pupal weight of males, the emergence rate, the sex ratio, the oviposition, the mean fecundity, and the full life cycle rate were decreased in RSB-SEL. The intrinsic rate of increase (r), the net reproductive rate (R0), and the finite rate of increase (λ) of RSB-SEL were significantly lower than those of RSB-UNSEL, while the mean generation time (T) of RSB-SEL was significantly longer than that of RSB-UNSEL. Based on the results of the prediction of the generations required for a 10-fold resistance increase in the LD50, a potential risk of resistance development exists in RSB after continuous and excessive use of cyproflanilide. These results will be useful in designing the dose of cyproflanilide to control C. suppressalis in field.

Effects of Three Neonicotinoid Insecticides on the Development and Fecundity of Red Spider Mite: An age-stage two sex life table study

Red spider mite, Tetranychus urticae Koch, causes severe damage to economically important crops, fruits, vegetables, ornamentals etc. Management of red spider mite largely depends on chemicals. Application of insecticides may cause massive outbreaks of mite population. Sublethal effects of imidacloprid, thiamethoxam and acetamiprid doses were investigated on life-table parameters of red spider mite. All neonicotinoids revealed significant effects on life characteristics i.e. development duration and fecundity of red spider mite. Mites treated with imidacloprid, thiamethoxam and acetamiprid significantly reduced the net reproductive rate (Ro). No significant difference in finite rates of increase (λ) was observed among the treatments. Imidacloprid reduces the egg duration and mean generation time (T). Emerged adult longevity was shorter when exposed to insecticides. The total adult longevity was significantly reduced by the insecticides in comparison with the control. Highest mean generation time was observed in acetamiprid treated mites. The results suggested that sublethal effects of tested insecticides affected the biological parameters of red spider mite.

Biology and ecology of Zercon hamaricus Kaczmarek et al. 2021 (Parasitiformes: Zerconidae) with morphological study of all instars

We provide data on the biology of Zercon hamaricus Kaczmarek et al. 2021 with regard to duration of egg and juvenile stages, analysis of change of body size during ontogeny, population parameters and morphological analysis of egg and all postembryonic stages using scanning electron microscopy. We confirmed the effectiveness of using hexamethyldisilazane in drying of Z. hamaricus individuals for SEM (Scanning Electron Microscopy) analysis. The overall egg duration was 3.7 ± 1.8 days on average. Duration of postembryonic stages ranged from 4.1 to 4.9 days and was the longest in deutonymphs. Change in length was statistically insignificant in larvae and significant in nymphs. At the species’ type locality juveniles (protonymphs) predominated, females were more abundant than males and juveniles were more abundant than adults. The exochorion of eggs of Z. hamaricus consists of dense areola with long processes and a fine polygonal pattern. We report on the presence and arrangement of metapodal plates in protonymphs and deutonymphs, and illustrate the post-coxal cuticular spines in adults. The influence of preparation method on the shape of the peritreme, position of seta r1 and shield and body size are discussed.

Productive and Reproductive Performances and Status of Chicken Breeds in Two Districts of South-Omo Zone, Ethiopia

The study targeted the productive and reproductive performance and status of breeds was conducted in two districts of the South-Omo zone, Ethiopia. A purposive sampling method was used to select districts, kebeles, and households and then, stratified to local, exotic, and mixed-breed rearing households. The composition of pullets (3.603), chicks (3.5), and layers (3.39) were highest than that of Cockerels (2.107) and Cocks (1.79). The more eggs/clutch/hen (26.2), the highest matured body weight (3.26 Kg), and the fast age of sexual maturity (5.4 months) were recorded for exotic breeds than the hybrid and local. The hatchability difference was due to the difference in broody hen, egg source, egg duration, egg size, and the season of hatching. The traits such as mothering ability, disease resistance, and production with conditional supplementation of the local breed were diluted. The productive and reproductive performance of the local ecotypes was low and the improved breeds not expressed their full genetic potential. The population of local breeds was diluted and decreased, antagonistically, that of the exotic breeds is increasing, and if it is not terminated near future we will lose distinctive traits of local breeds. Hence, regular supplementation of feed and conservation of exploiting genes were recommended to exploit the full genetic potential of breeds and sustain the diluting genes of local breeds, respectively.

LIFE HISTORY PARAMETERS OF MELON FRUIT FLY, BACTROCERA CUCURBITAE (COQUILLETT) (DIPTERA: TEPHRITIDAE) ON FOUR ECONOMICALLY IMPORTANT VEGETABLES

The majority of plant species that are used for consumption and medicinal purposes belongs to Cucurbitaceae. These vegetables are attacked by several insect pests including Tephritid flies. Keeping in view, four economically important cucurbit vegetables such as sponge gourd; Luffa aegyptiaca, bitter gourd; Momordica charantia, musk melon; Cucumis melo, and bottle gourd; Lagenaria siceraria were selected to investigate the life-history parameters of Bactrocera cucurbitae (Coq.) (Diptera: Tephritidae) under laboratory conditions. For this purpose, B. cucurbitae was reared in the laboratory on each host vegetable and egg hatchability %, egg incubation period, larval survival (%), duration (days), length and width of larvae, pupal parameters, male-female ratio, and age-specific fecundity were recorded. The results showedno statistical difference in hatchability percentages, larval duration, and pupal survival (%) in all tested vegetables. However, greater length and width of larvae were recorded when the B. cucurbitae larvae were provided with bottle gourd. Moreover, maximum pupal recovery was recorded in bottle and sponge gourd among all the tested vegetables. Maximum females were also recorded in bottle gourd. Adult longevity and fecundity were significantly affected by the host. Maximum female longevity (52 days) was recorded when B. cucurbitae were provided with bottle gourd and minimum (41 days) on sponge gourd. Similarly, maximum fecundity (823 eggs) was also recorded when maggots were fed on bottle gourd and the lowest (611 eggs) on a sponge gourd. In conclusion, Bottle gourd is the most preferable and nutritious host among all the tested vegetables and needs effective management strategies for B. cucurbitae. The output of the present studies would be helpful for the development of an effective integrated pest management (IPM) program for B. cucurbitae in a variety of vegetables.

Alternating Low and High Temperatures Increases the Hatching Rate of Eupolyphaga sinensis (Blattaria: Polyphagidae) Eggs

The hatching rates and developmental durations of Eupolyphaga sinensis Walker eggs were studied under variable combinations of low temperatures (5 °C and 10 °C) and high temperatures (25 °C and 30 °C). Our findings were intended to provide new evidence on the effect of temperature on the hatching of insect eggs. The results showed that both low temperatures and high temperatures significantly affected the hatching rate and time of E. sinensis eggs. Further analysis revealed a significant interactive effect between low temperatures and high temperatures. The 5 °C + 30 °C treatment achieved the highest egg hatching rate (77.33%) and the shortest hatching time (44.11 ± 1.55 d), which was significant compared with three other temperature treatments. The effects of high temperatures treatments on the hatching rate and the hatching time were more significant than that in the low temperature treatments. Hatching began earlier at 5 °C + 30 °C and 10 °C+30 °C temperatures, and single-day hatching first increased rapidly before declining afterwards within a short period. Comparatively, the hatching of eggs under the (5 °C+25 °C) and (10 °C+25 °C) temperatures was initially significantly delayed, including the peak single-day hatching rate. Under these treatments, the hatching rate tended to be gradual in terms of the temporal dynamics without showing any prominent peak. These results showed that low and high temperatures significantly affect the hatching rates of E. sinensis eggs. This study provided basis for the large-scale breeding of E. sinensis.

Biological Characteristics and Thermal Requirements of Telenomus podisi and Trissolcus basalis (Hymenoptera: Scelionidae) in Fresh and Cryopreserved Eggs of Euschistus heros and Nezara viridula (Hemiptera: Pentatomidae)

Brazil is one of the largest producers of pulses globally, and soybean ranks highly in terms of production. However, pests increase crop production costs and affect oilseed production and quality. Pests are primarily controlled by chemicals, leading to changes in insect pest populations. For example, secondary pests can become primary pests because of the selection of resistant insects and the elimination of natural enemies. Farmers have widely accepted biological control because of its high control efficacy and low environmental contamination risk. Two successful biological control programs in soybean used Telenomus podisi Ashmead (Hymenoptera: Platygastridae) to manage the Neotropical brown stink bug, Euschistus heros (Fabricius) (Hemiptera: Pentatomidae), and Trissolcus basalis (Wollaston, 1858) (Hymenoptera: Scelionidae) to manage the southern green stink bug, Nezara viridula (Linnaeus) (Hemiptera: Pentatomidae), when these pests were the most abundant in soybean-producing regions. To release parasitoids, rearing protocols must be developed in order to optimize production. This study evaluated the effect of temperature on the biological characteristics of T. podisi and T. basalis when fresh or frozen E. heros eggs were provided. Fifty fresh or previously frozen eggs were placed with parasitoids for 24 h in a climate chamber (25 ± 1 °C, 70 ± 10% RH, and 14-h photophase). At the end of this period, the eggs were transferred to other chambers and maintained at different temperatures (19, 22, 25, 28, 31, and 34 ± 1 °C, 70 ± 10% RH, with a 14-h photoperiod). The number of emerging adults from eggs parasitized by T. basalis was lower than that from eggs parasitized by T. podisi. Differences in T. basalis and T. podisi parasitism were observed depending on whether the E. heros eggs were frozen or fresh, but neither development nor emergence were affected. The duration of egg–adult development and the longevity of the two parasitoids were inversely proportional to the temperature increase. The sex ratio of T. basalis and T. podisi progeny was not affected by different temperatures or by the use of frozen or fresh eggs. The estimated number of both parasitoids’ generations corresponded with temperature, reaching 14–15 generations/cycle of soybean for Rio Verde, GO, and 12–14 generations/cycle for Barreiras, BA. Given these characteristics, we conclude that a biological control program using T. podisi can benefit large areas of soybean production by controlling the eggs of phytophagous bugs in soybean crops.

Responses of two Anastrepha species' immature stages infesting preferential hosts to different temperature exposures.

Anastrepha fraterculus (Wiedemann) and A. obliqua (Macquart) are important pests of fruit crops. In Brazil, these species cause damage to fruit growing in the South (annual average temperature of 20.9°C) and Northeast (average yearly temperature of 24°C). We evaluated the effect of temperature on the viability and development time of A. fraterculus and A. obliqua immature stages in their respective preferred hosts, guava (Psidium guajava L., Myrtaceae) and mango (Mangifera indica L., Anacardiaceae). The duration of egg and pupal stages, egg to pre-pupa, and viability of egg and pupal stages under different temperatures (15, 20, 25, 30, and 35°C) were assessed. For both species, development time decreased with increasing temperature. Viability in the evaluated stages was only observed between 15 and 30°C. However, the species responded differently to the exposure temperatures (15 and 30°C), especially in the pupal stage and from egg to pre-pupa. Anastrepha fraterculus showed a lower tolerance to high temperatures, especially in the pupal stage and from egg to pre-pupa, which may explain its lower importance and economic impact in warmer Brazilian regions. Anastrepha obliqua had a lower tolerance at 15°C, indicating greater adequacy for temperatures above 20°C, characteristic of Northeast Brazil, suggesting the capacity to spread to cooler areas with rising temperatures.

The Effect of Eggshell Dipping with Various Types of Oils and Storage Duration on The Weight Loss and Shell Thickness of Table Eggs

Preserving eggs is very important to retain egg quality and increase shelf life, egg preservation is crucial. Eggs may be preserved by immersing them in several kinds of vegetable oil. The purpose of this research is to investigate the effects of dipping eggs in various types of oil and the duration of preservation on the shell thickness and weight loss of table eggs. The research material includes 45 chicken eggs, pure coconut oil, palm oil, maize (corn) oil, a screw micrometer, and a scale. The method utilized was experimental, employing factorials with a completely randomized design in a 3x5 factorial pattern and three (3) replications. Treatment A consists of oil types (A1 is pure coconut oil, A2 is palm oil, and A3 is maize (corn) oil), and treatment B: the storage duration of eggs at room temperature (including: 25 days for B1, 30 days for B2, 35 days for B3, 40 days for B4, and 45 days for B5). The variables that were noticed were the egg weight loss and shell thickness. Data were analyzed using analysis of variance and further analyzed using the Duncan Multiple Range Test (DMRT), utilizing SPSS version 16.0. The results suggest that the interaction between the kind of oil and storage length didn’t have significant consequences (P>0.05) egg weight loss and shell thickness. The type of oil significantly affects (P<0.05) shell thickness. The storage duration at room temperature significantly affects (P<0.05) on the egg weight loss and shell thickness. In conclusion, the best treatment for dipping eggs is using pure coconut oil and storing them at room temperature for up to 40 days.

DsFoxO knockout affects development and fecundity of Drosophila suzukii

Forkhead box O (FoxO), a key transcription factor in many species, participates in numerous physiological and pathological processes of organisms through a variety of signaling pathways. In the present study, we established DsFoxO knockout (DsFoxO-KO) strain using CRISPR/Cas9, and the influence on development and fecundity of mutant strain were evaluated. To clarify the corresponding mechanism, a transcriptome analysis was conducted subsequently. The results showed that the survival rates of the DsFoxO-KO strain in larval, pupal, and adult stages were all significantly lower than those of control. The duration of the pupal stage was similar between the two strains; however, durations of egg, larva, adult preoviposition period (APOP), and total APOP (TPOP) in the DsFoxO-KO strain were all significantly longer compared to those of the control strain. The fecundity of the DsFoxO-KO strain was 20.31 eggs/female, which was significantly lower than that of the control strain (430.47 eggs/female). With the transcriptome analysis, 612 differentially expressed genes (DEGs) were identified. Following COG and GO analyses, we found that most of the DEGs were associated with the metabolic process. According to the KEGG database, the mTOR signaling, MAPK signaling, Wnt signaling, and Toll and Imd signaling pathways; insect hormone biosynthesis; autophagy; and apoptosis were altered in the DsFoxO-KO strain. These results demonstrated that knockout of DsFoxO in D. suzukii significantly influenced its development and fecundity, while transcriptome analysis provided insights to explore the corresponding molecular mechanism. These findings highlighted the critical role of FoxO in D. suzukii and might contribute to the development of novel management strategies for these flies in the future.

Influence of Different Seed Colour Varieties of Sesame on the Biology of Rice Moth, Corcyra cephalonica (Noctuidae: Lepidoptera)

A laboratory experiment was conducted to study the bionomics of Corcyra cephalonica on different coloured sesame genotypes viz., Swetha (white), GT-10 (black), and YLM-17 (brown). According to the results, the duration of egg, larvae, pupae and adult were observed to be significantly longest (6.40, 31.16,14.87 and 10.70 days, respectively) in black seeded genotype GT-10. Whereas, it was shortest (3.64, 24.12, 7.80 and 7.26 days, respectively) in white seeded genotype Swetha. All tested sesame genotypes showed significant impact on the head capsule width, body length and width of different larval instars. Based on biological and morphometric parameters, black seeded genotype (GT-10) was less suitable for the Corcyra cephalonica development, while, white seeded genotype (Swetha) was most suitable.

Morphology and life cycle of Spodoptera frugiperda(J.E. Smith) (Lepidoptera: Noctuidae) with soybean leaf (Glycine max[L.] Merr.) in the laboratory

Soybean (Glycine max[L.] Merr. ) is an important vegetable source of vegetable protein for the whole world. Wilis is one of the superior varieties in great demand among farmers. However, soybean production in recent years in Indonesia has declined. One of the causes is the presence of parasites which can cause losses both in quantity and quality. The fall armyworm (FAW), Spodoptera frugiperda(J. E. Smith) (Lepidoptera: Noctuidae) is a serious pest that can attack 353 host plants from 76 plant families and one of them is the Fabaceae family. This research was conducted at the laboratory and experimental farm of Hasanuddin University Faculty of Agriculture and took place from August to December 2020. The larvae were obtained from Sidenreng Rappang regency, Watang Pulu district. Insect was reared in the laboratory to produce eggs which are used to observe the life cycle of S. frugiperda with soybean leaves as food. Biological observations were made, including the duration of each stadium, and the shape and size of the egg until it becomes an adults. The results of this study showed that the larvae of S. frugiperda consisted of six instars. The mean duration of eggs to hatching was 1.8 days, the duration of the larval was 18.78 days, the duration of the pre-pupa was 1.61 days, the duration of the pupal was 10 days and the longevityis s 9.28 days for males adults and 13.73 days for females adults.

Atlantic Oceanic Squids in the "Grey Speciation Zone".

Cryptic species complexes represent an important challenge for the adequate characterization of Earth's biodiversity. Oceanic organisms tend to have greater unrecognized cryptic biodiversity since the marine realm was often considered to lack hard barriers to genetic exchange. Here, we tested the effect of several Atlantic and Mediterranean oceanic barriers on 16 morphospecies of oceanic squids of the orders Oegopsida and Bathyteuthida using three mitochondrial and one nuclear molecular marker and five species delimitation methods. Number of species recognized within each morphospecies differed among different markers and analyses, but we found strong evidence of cryptic biodiversity in at least four of the studied species (Chtenopteryx sicula, Chtenopteryx canariensis, Ancistrocheirus lesueurii, and Galiteuthis armata). There were highly geographically structured units within Helicocranchia navossae that could either represent recently diverged species or population structure. Although the species studied here can be considered relatively passive with respect to oceanic currents, cryptic speciation patterns showed few signs of being related to oceanic currents. We hypothesize that the bathymetry of the egg masses and duration of the paralarval stage might influence the geographic distribution of oceanic squids. Because the results of different markers and different species delimitation methods are inconsistent and because molecular data encompassing broad geographic sampling areas for oceanic squids are scarce and finding morphological diagnostic characters for early life stages is difficult, it is challenging to assess the species boundaries for many of these species. Thus, we consider many to be in the "grey speciation zone." As many oceanic squids have cosmopolitan distributions, new studies combining genomic and morphological information from specimens collected worldwide are needed to correctly assess the actual oceanic squid biodiversity.

Biological Fitness Cost, Demographic Growth Characteristics, and Resistance Mechanism in Alpha-Cypermethrin-Resistant Musca domestica (Diptera: Muscidae).

Musca domestica L., a pest of animals and humans, has developed resistance to alpha-cypermethrin, a pyrethroid insecticide commonly used to control medically important pests in many countries, including Saudi Arabia. We investigated the mechanism underlying the development of alpha-cypermethrin resistance and life history characteristics of alpha-cypermethrin-susceptible (Alpha-SS) and alpha-cypermethrin-resistant (Alpha-RS) M. domestica using the age-stage, two-sex life table theory, which is crucial for developing a future rational management strategy and minimizing the negative effects of alpha-cypermethrin on the environment. Our results showed that Alpha-RS M. domestica had a 405.93-fold increase in resistance to alpha-cypermethrin relative to Alpha-SS M. domestica. This increase in the resistance toward insecticide was attributed to metabolic enzymes, such as glutathione S-transferases, specific esterases, and cytochrome P450 monooxygenases. Furthermore, Alpha-RS M. domestica exhibited lower relative fitness (0.50), longevity, survival rate, life expectancy, reproductive values, intrinsic rate of increase, net reproductive rate, fecundity, maternity, and finite rate of increase, along with shorter larval, female preadult, and adult durations than Alpha-SS M. domestica, indicating fitness costs associated with most parameters. However, no significant differences were found between the strains in the following parameters: egg, pupa, and male preadult durations; adult preoviposition, total preoviposition, and oviposition periods; female ratio; and total generation time. Additionally, Alpha-RS M. domestica had a markedly lower intrinsic rate of increase, net reproductive rate, and finite rate of increase than Alpha-SS M. domestica. The results of this study suggest that alpha-cypermethrin resistance may lead to dominant fitness costs in M. domestica. Overall, these findings will aid in the development of rational control strategies for M. domestica as well as help to reduce pesticide pollution.

Evaluation of comparative parasitic efficiency and biology of hymenopteran egg parasitoids, Trichogramma chilonis and T. japonicum on Corcyra cephalonica and Helicoverpa armigera

Aim: To evaluate the comparative parasitic efficiency and biology of Trichogrammatid wasps on noble laboratory host Corcyra cephalonica as well as on Helicoverpa armigera, the cosmopolitan, polyphagous and precarious insect pest of many cultivated crops. Methodology: The biology of Trichogramma chilonis and T. japonicum, their sex ratio, and parasitic efficiency were studied. Host insects were reared on artificial diet to obtain their eggs for initiating the experiment. Egg-card pieces were prepared with the irradiated eggs of respective host insects. Egg-cards were introduced into the tubes containing freshly emerged adult parasitoids. Parasitized egg-cards (Trichocards) were kept separately in plastic tube to study the biological attributes and percent parasitization of the parasitoids. Egg cards of different host eggs taking eggs of different age groups were prepared to study the effect of age of host eggs on the biological efficiency of the parasitoids. Results: Irrespective of Trichogramma species, the duration (d) of eggs to adult period was more when reared on the eggs of H. armigera than on the eggs of C. cephalonica. Maximum life stage duration of T. chilonis and T. japonicum from egg to adult was 8.2 days and 10.2 days, respectively, when reared on H. armigera eggs. There was maximum parasitization (84.8%) of fresh eggs of C. cephalonica by T. chilonis as compared to the egg parasitization of 73.4% by T. japonicum. Likewise, extreme parasitization of fresh eggs of H. armigera was recorded as 62.4% when parasitized by T. chilonisas against 59.7% parasitization by T. japonicum. Interpretation: According to the study, H. armigera eggs have the finest biological and parasitic features in terms of the highest adult longevity, sex ratio, mean progeny female-1, and mean adult egg-1, making them the best for mass production of the egg parasitoids, T. chilonis. Key words: Corcyra cephalonica, Host eggs, Helicoverpa armigera, Parasitization, Trichogramma

First Record of Barnyard Millet as a Host for Fall Army Worm <i>Spodoptera frugiperda</i> (J E Smith)

Damage potential of maize fall army worm (FAW), varies from 9.0 % to 62.5 % on different seasons and in different regions of India. FAW threatens food and nutritional security of millions of farmers in India. Here is the first record of FAW in a new host barnyard millet and a study on its biology. The infestation began from seedling stage and extended till reproductive stage. During seedling stage, the larva caused scrapping of leaf and cut the central shoot, resulted in drying of central shoot, which resembled dead heart symptom. In vegetative stage, it caused scrapping and defoliation of leaves and also caused whorl damage. There were no parallel hole symptoms observed as like maize. The egg duration was 2.8± 0.83 days. Larva usually had six instars with life period of 3.2± 0.83 Days, 3.0± 0.70 Days, 2.4± 0.54 Days, 2.6± 0.54 Days, 3.4± 0.89 Days and 6.0± 0.70 Days for I to VI instars respectively. The total larval duration ranged from 17 to 23 days with a mean of 20.6± 2.07 days. Pupal and adult duration were 8.8± 1.30 and 10.2± 2.04 Days respectively. The total life cycle in barnyard millet under laboratory condition was 42.2± 4.26 days.

The Effects of Duration, Location and Storage Status of Edible Eggs in Home Refrigerators on Quality Traits, Shell Traits and Biochemical Indicators of Yolk Eggs

The Effects of Duration, Location and Storage Status of Edible Eggs in Home Refrigerators on Quality Traits, Shell Traits and Biochemical Indicators of Yolk Eggs

CRISPR/Cas9-mediated knockout of NlCYP6CS1 gene reveals its role in detoxification of insecticides in Nilaparvata lugens (Hemiptera: Delphacidae).

The brown planthopper (Nilaparvata lugens) is one of the major rice insect pests in Asia. Recently, high levels of insecticide resistance have been frequently reported and cytochrome P450 monooxygenase (P450)-mediated metabolic detoxification is a common resistance mechanism in N. lugens. However, there has been no persuasive genetic method to prove the role of P450s in insecticide resistance in N. lugens. Here, CRISPR/Cas9 system was used to disrupt the P450 gene NlCYP6CS1 to elucidate its role in insecticide resistance in field populations of N. lugens. We successfully constructed a homozygous strain (Nl6CS1-KO) with a 5-bp deletion and 1-bp insertion mutation of NlCYP6CS1. Compared with a background resistant strain (Nl-R), the susceptibility of knockout strain Nl6CS1-KO to imidacloprid, nitenpyram, thiamethoxam, dinotefuran, and pymetrozine was increased by 2.3-, 3.4-, 7.0-, 4.2- and 3.9-fold, respectively, but not significantly changed to triflumezopyrim, chlorpyrifos and buprofezin. Life table analysis demonstrated that the Nl6CS1-KO strain resembled the Nl-R strain in terms of egg and nymph developmental duration and adult lifespan, but differed from the Nl-R strain in the survival rate of eggs and nymphs, reproduction, and body weight. Our study demonstrates the effect of functional deletion of NlCYP6CS1 on multiple insecticide resistance in N. lugens. For the first time, we applied CRISPR/Cas9 system to reveal the mechanism of insecticide resistance in N. lugens, which may shed light on similar studies in other hemipteran insects. © 2023 Society of Chemical Industry.