Percentage Of Adult Emergence Research Articles

Effect of temperature on the biological parameters of pink bollworm, Pectinophora gossypiella Saunders (Lepidoptera: Gelechiidae)

Pink bollworm (PBW) Pectinophora gossypiella is an important pest cotton worldwide. There are multiple factors which determines the occurrence and distribution of P. gossypiella across different cotton growing regions of the world, and one such key factor is ‘temperature’. The aim was to analyze the life history traits of PBW across varying temperature conditions. We systematically explored the biological and demographic parameters of P. gossypiella at five distinct temperatures; 20, 25, 30, 35 and 40 ± 1 °C maintaining a photoperiod of LD 16:8 h. The results revealed that the total developmental period of PBW shortens with rising temperatures, and the highest larval survival rates were observed between 30 °C and 35 °C, reaching 86.66% and 80.67%, respectively. Moreover, significant impacts were observed as the pupal weight, percent mating success, and fecundity exhibited higher values at 30 °C and 35 °C. Conversely, percent egg hatching, larval survival, and adult emergence were notably lower at 20 °C and 40 °C, respectively. Adult longevity decreased with rising temperatures, with females outliving males across all treatments. Notably, thermal stress had a persistent effect on the F1 generation, significantly affecting immature stages (egg and larvae), while its impact on reproductive potential was minimal. These findings offer valuable insights for predicting the population dynamics of P. gossypiella at the field level and developing climate-resilient management strategies in cotton.

Impact of diet composition of <I>Corcyra cephalonica</I> (Lepidoptera: Pyralidae) on the development and reproduction of <I>Trichogramma chilonis</I> (Hymenoptera: Trichogrammatidae)

Utilizing parasitoids for augmentative biological control frequently depends on the physiological state of the parasitoids and the pest population density at the time of release. Trichogramma chilonis Ishii (Hymenoptera: Trichogrammatidae) is commonly used as an egg parasitoid for biological insect pest control via augmentation and field release. A crucial component of mass production programmes is the host’s nutritional compatibility. So, the investigations were carried out to study the effect of diet composition of Corcyra cephalonica (Stainton) (Lepidoptera: Pyralidae) on developmental and reproductive parameters of Trichogramma chilonis Ishii. The T. chilonis was reared on Corcyra cephalonica fed on different diets (D1-D7) in the laboratory at 25℃±1℃ with 75±5% RH. Based on pooled data of two generations T. chilonis had shown significantly highest parasitization of 85.80%, adult emergence percentage 75.00% and sex-ratio 1.62:1 on rice moth eggs obtained from Maize (48.5%) + Sorghum (48.5%) + Groundnut (3%) diet (D5). Trichogramma adult’s emergence was observed earlier (3.10 days) on the host’s eggs reared on the Bajra (100%) diet (D1). In case of adult longevity, the maximum longevity of 7.70 days was recorded on the host’s egg obtained from the D5 diet over the others. These findings may help to improve the developmental and reproductive performance of T. chilonis and an optimized D5 diet may be useful for mass rearing of this egg parasitoid.

ANTIBIOSIS AND ANTIXENOSIS IN TOMATO GENOTYPES AGAINST Helicoverpa armigera HUBNER

<p><strong>Background</strong>. Farmers rely on the use of synthetic insecticides in managing <em>Helicoverpa</em> <em>armigera</em>, hole-boring insect pest on tomato, but they are detrimental to human health. Therefore a more reliable and ecofriendly control measure is needed such as host plant resistance<strong>. Objective</strong>. To assess the mechanisms of resistance in tomato varieties: NGB00724, NGB00724, Anaya, Kelvin, Mona, Roma VF (susceptible varieties), Tropimech and UC82B in laboratory and screen house. <strong>Methodology</strong>. Second larval instars were fed with leaves of the different tomato varieties and their development was observed till adult stage. Study was done in the screen house where number of larvae and eggs were also observed. Larval period and weight, and percentage adult emergence were assessed in tomato varieties. Metabolites (phenol, flavonoids, terpenoids, protein, reducing sugars and total sugars) in tomato leaves were determined following standard procedures. <strong>Results</strong>. <em>Helicoverpa</em> <em>armigera</em> fed with tomato leaves, Anaya recorded the lowest larval period (9.67 days). Also, larvae fed on Anaya and Mona had the lowest larval weight (0.19 g and 0.25 g). Also significantly lower percentage of adult emergence was observed on Anaya and Mona (16.7%) Mona, NGB00725 and Anaya significantly harbored the lower number of <em>Helicoverpa</em> <em>armigera</em> adult (0.1, 0.4, 0.4). The lowest number of eggs (0.5) was recorded from adults placed on Anaya variety. There was high and negative significant correlation of r = -0.865 between phenols and adult emergence. Phenols and oviposition were significantly negatively correlated (r = -0.816). <strong>Implication. </strong>Anaya and Mona hinder the development of <em>Helicoverpa</em> <em>armigera</em> larvae when fed on it. Phenol has negative impact on the development and oviposition of <em>Helicoverpa</em> <em>armigera</em>. <strong>Conclusion</strong>. It was revealed through this study that availability of promising resistant varieties can effectively combat the damage caused by <em>Helicoverpa</em> <em>armigera</em> and lessen the shortcomings related with the application of conventional chemical insecticides in tomato production.</p>

Improving quality of stored Trichogramma evanescens (Hymenoptera: Trichogrammatidae) by inducing diapause or quiescence

BackgroundEfficacy of parasitic wasps from the genus Trichogramma to attack the eggs of numerous important pests in various agricultural crops makes them one of the most prevalent biocontrol agents. In Trichogramma, the pre-pupal stage can survive during the cold season in a dormant state (diapause or quiescence). The optimal conditions for the induction of this pause of development during mass rearing to store the parasitoid for a long time in good quality depend on the species. In the present study, four factors [the incubation periods (24 and 48 h), diapause induction temperatures (9 and 11 °C), durations of the diapause induction (from 0 to 6 weeks), and the periods of storage (from 0 to 6 months)], were experimented to force Trichogramma evanescens Westwood, reared on Sitotroga cerealella, to enter diapause or quiescence and estimating their impacts on the efficacy of stored parasitoid.ResultsResults confirmed that the life parameters of T. evanescens as the percentage of adult emergence, female percentage, rates of wing deformation of emerged adults, and fecundity of emerged females were significantly affected by all experimented factors. The pre-storage treatments made it possible to store the parasitoid for at least 2 months at 3 °C, with no much changes in their fitness, the emergence rate of adults reached more than 80%, and the egg-laying efficacy of females reached more than 42 eggs per emerged female, when diapause induction treatments were applied for 5 weeks at 11 °C after 24 h of incubation. Furthermore, there is the possibility of storage for 6 months with an acceptable level of parasitoid’s quality, when diapause induction treatments were applied for 5 weeks at 9 °C after 24 h of incubation, the emergence rate reached 70%, and the number of eggs per female was 52 eggs, while no emergence of adult insects was recorded after 3 months of cold storage without diapause induction treatments.ConclusionTwo storage programs were reached for T. evanescens (depending on the adult emergence rate and fecundity of emerged females). There is a long-term storage (6 months), when diapause was induced at a low temperature (9 °C) after 24 h of incubation. Short-term storage (from 2 to 4 months), when quiescence was induced under a higher temperature of 11 °C after both 24 and 48 h of incubation.

Single Jar for Collecting and Rearing Mosquito Life Stages: An Innovative Prototype.

Mosquitoes vectors are the key threat that spread viruses, bacteria, nematodes, protozoans, and other infections responsible for the transmission of serious public health ailments including dengue, yellow fever, malaria, chikungunya, etc. To rear and cultivate mosquitoes at multiple stages of development (egg, larva, pupa, and adult) to be employed in various biomedical research, an innovative tool mosquito larva adult 2-in-1 rearing jar was designed and developed. The eggs/larvae or adults collected from the field or laboratory cultures can be released into the lower larvae or upper adult-rearing chamber so that they can find a suitable breeding place to oviposit or metamorphose into wrigglers and tumblers attaining the adult stage. Aedes, Anopheles, and Culex are three significant genera (Diptera: Culicidae) that were reared in experiments using this jar (Method I) in contrast to other conventional instruments available (Method II). Results of one-way ANOVA showed that the prototype was compatible and competitive for rearing as the data was non-significant when compared in both groups. However, throughout the trials, it was discovered that the prototype had a greater record of mean percentage of adult emergence (98.33), which supports the novelty of the instrument. This unique device eliminates the need for multiple tools, causes minimum bodily damage to stages during handling, can be used in both the lab and the field, is inexpensive, lightweight, portable, and requires a single manpower to operate.

Development of pulse beetle Callosobruchus maculatus Fab. (Coleoptera: Bruchidae) in different pulses

Development of pulse beetle (Callosobruchus maculatus Fab.) was studied on nine different pulses viz., mungbean, urdbean, mothbean, greenpea, cowpea, horsegram, chickpea, wal and pigeonpea under laboratory conditions. The study indicated that chickpea was most preferred host by C. maculatus as it recorded highest number of eggs (290.67/100 grains), shortest total developmental period (21.33 days) and highest number of adult emergence (163/100 grains), whereas horsegram was least preferred host as it recorded lowest number of eggs (23.67 / 100 grains), lowest number of adult emergence (4.33/ 100 grains) and shortest adult longevity (4 days). The highest adult longevity was recorded in wal (10 days) followed by chickpea and mungbean (9.33 days). In the case of the incubation period, mungbean and cowpea recorded shortest incubation period (2.67 days) and followed by chickpea, green pea and pigeonpea (3.33 days) whereas it was highest in urdbean (4.67 days) followed by horsegram (4.33 days). Percent adult emergence was lowest in the case of horsegram (18.29%) followed by mothbean (19.86%) and was highest in wal (74.92%).

Maggots cannot live on meat meal alone: production parameters for mass rearing of the ovoviviparous blowfly, Calliphora dubia (Diptera: Calliphoridae).

This study determined a cost-effective larval diet for rearing Calliphora dubia Macquart for use as a potential managed pollinator in Australia. This fly has potential as a pollination species to support honey bees (Apis mellifera). Larvae of C. dubia were reared mostly in meat meals with varying amounts of either whole egg powder, whole eggs (+ shell), bran flakes, skimmed milk powder, brewer's yeast, or poultry oil. This was done from an economic and production perspective to support commercial rearing. Several laboratory-based studies determined the growth and output from various ingredient combinations. Larvae fed 90% meat meal and 10% whole egg powder developed rapidly through to pupation with a high pupation rate, adult size, and percent adult emergence. Given the high cost and difficulty in sourcing whole egg powder, media comprising mostly meat meals with the addition of bran flakes and whole eggs also supported rapid larval development, pupation rate, and adult emergence. The ideal amount of media/larvae was 0.5 g/larvae to support high pupation rates and adult emergence. Adult eclosion occurred over 4-5 days, even when larvae were laid and fed within 1 h on ample media. Commercial mass rearing would then require daily cohorts of larvae to ensure peak adult fly emergence over 1-2 days for release into a crop. Mass-rearing C. dubia should use meat meal as the base ingredient with bran flakes and whole eggs added and fed at 0.5 g of media/larvae. Based on the current media ingredient costs, rearing 1-m adult C. dubia would cost just over $500 (US$342).

Host-plant related effects on host feeding, parasitism and sex ratio of Neochrysocharis formosa (Westwood) (Hymenoptera, Eulophidae) attacking Liriomyza huidobrensis (Blanchard) (Diptera, Agromyzidae) leafminer

Liriomyza huidobrensis (Blanchard) (Agromyzidae, Diptera) was the most prevalent on crops infested with leafminers in Jordan, as it was recorded on twelve economic vegetable crops. We investigated the plant-mediated effects on the host feeding, egg laying, parasitism and adult emergence of Neochrysocharis formosa (Westwood) (Eulophidae, Hymenoptera) parasitizing L. huidobrensis larvae on seven vegetables. Results showed that the highest percentage of parasitoid feeding on L. huidobrensis larvae was on bean leaves (9.7%). The lowest percentages of parasitoid host-feeding were on the leaves of white-flowered gourd (4.5%) and eggplant (4.3%) plants. For egg laying, N. formosa females significantly preferred potato (57.7% of parasitism) and bean (46.6% of parasitism) plants. The lowest rates of parasitism occurred on eggplant (17%) and white-flowered gourd (22.3%). The full percentage of adult parasitoid emergence was in bean and broad bean. All plant hosts showed a significant superiority in the parasitoids emergence over eggplant (92.9%) and tomato (85.7%). The highest percentages of emerged parasitoid females were on potato (75%) and the lowest percentage was on eggplant (52%).

Functional response and mutual interference in the parasitoid Coptera haywardi (Oglobin) (Hymenoptera: Diapriidae) attacking Anastrepha ludens (Loew) (Diptera: Tephritidae) pupae.

Functional response and mutual interference are important attributes of natural enemies that should be analysed in species with the potential to be used as biological control agents in order to increase the predictive power of the possible benefits and/or consequences of their release in the field. Our main objective was to determine the functional response and mutual interference of Coptera haywardi (Oglobin), a pupal parasitoid of economically important fruit flies (Diptera: Tephritidae). The functional response of C. haywardi on A. ludens pupae corresponded to a type II model, with an attack rate of 0.0134 host pupa/h and a handling time of 1.843 h, which reveals a meticulous selection process of pupal hosts. The effect of mutual interference among foraging females was negatively correlated with increased parasitoid density in the experimental arena, showing a gradual decline in attack rate per individual female. The increase in the number of foraging females also had an impact on the number of oviposition scars per pupa and the number of immature parasitoids per dissected pupa, but not on the percentage of adult emergence or the sex ratio. Our results suggest that C. haywardi could act as a complementary parasitoid in the control of fruit fly pupae, since the random distribution of these pupae in the soil would decrease the possibility of aggregation and mutual interference between foraging females.

Impact of urbanization and temperature on local abundance of Drosophila repleta Wollaston (1858) in the Western Himalayas

With rising global temperatures and expanding urbanization, rapid species abundance shifts and local extinctions may occur. We have observed a notable increase in the local population of Drosophila repleta, a species adapted to warmer environments, which was never documented at higher altitudes in the Western Himalayas before 2003. This change can be attributed to the recent acceleration of urbanization and the effects of climate change. To understand the species' response to temperature variations, we conducted a comparison of life-history traits at two different temperatures: 17 °C and 25 °C. These temperatures were chosen to simulate the variations experienced in 2003 and 2017, respectively. Our findings revealed a significant decrease in trait values at 17 °C, indicating a lower evolutionary capacity for adapting to colder and drier habitats. Additionally, we simultaneously examined the performance of life-history traits in response to different food resources, which corresponded to the levels of urbanization (carbohydrate-rich vs. protein-rich). The results showed a significant increase in fecundity, viability, and the percentage of adult emergence in flies reared on protein-rich food. This suggests that D. repleta possesses the ability to survive by utilizing the available food resources in the newly urbanized habitats. Considering the projected rise in global temperatures and further urbanization in the near future, D. repleta is likely to become even more abundant in urban environments. However, this could potentially pose a health risk due to the species' ability to transmit disease-causing organisms.

Handling heatwaves: balancing thermoregulation, foraging and bumblebee colony success

Abstract Climate changes pose risks for bumblebee populations, which have declined relative to the growing frequency and severity of warmer temperature extremes. Bumblebees might mitigate the effects of such extreme weather through colonial behaviours. In particular, fanning behaviour to dissipate heat is an important mechanism that could reduce exposure of thermally sensitive offspring to detrimental nest temperatures (Tn). The allocation of workers towards fanning over prolonged periods could impact foraging activity that is essential for colony-sustaining resource gathering. Colony maintenance and growth could suffer as a result of nutritional and high ambient temperature (Ta) thermal stress. It remains uncertain whether a compromise occurs between thermoregulation and foraging under chronic, sublethal heat events and how colony success is impacted as a result. This study held colonies of Bombus impatiens at constant high Ta (25°C, 30°C or 35°C) for 2 weeks while quantifying the percentage of foragers, fanning incidence, nest temperature (Tn) and other metrics of colony success such as the percentage of adult emergence and offspring production. We found that foraging and adult emergence were not significantly affected by Ta, but that thermoregulation was unsuccessful at maintaining Tn despite increased fanning at 35°C. Furthermore, 35°C resulted in workers abandoning the colony and fewer offspring being produced. Our findings imply that heatwave events that exceed 30°C can negatively impact colony success through failed thermoregulation and reduced workforce production.

Evaluation of the efficiency of entomopathogenic nematodes exposed to different temperatures of vinasse in the control of Stomoxys calcitrans (Linnaeus, 1758) (Diptera: Muscidae).

The sugarcane industry generates byproducts that contribute to the proliferation of Stomoxys calcitrans. An analysis was carried out to verify the efficacy of Heterorhabditis bacteriophora HP88 and H. baujardi LPP7 at different vinasse temperatures to control S. calcitrans larvae. Ten fly larvae were deposited in plastic containers containing four mL of 50% vinasse. Each treatment consisted of 300 EPN/larvae of H. bacteriophora added to the containers and heated at temperatures of 25, 28, 31, 34, 37 and 40 °C. The same treatments were performed using H. baujardi. The treatments were carried out in a BOD incubator at 25 ± 1 °C and 70 ± 10% RH, and each treatment was replicated six times. The treated groups, controls and temperatures showed no statistical differences in terms of larval mortality rate (P=0.8573), percentage of dead pupae (P=0.1782) and adult emergence (P=0.4386). Larval mortality rates of 30% and 14.17% were achieved with H. bacteriophora and H. baujardi, respectively, while the control groups presented 3.89% with H. bacteriophora and 8.61% with H. baujardi. From the standpoint of temperatures, significant differences were found only at 37 and 40 °C for H. baujardi. The highest pupal mortality achieved with H. bacteriophora was 34.17% at 31 °C, while that reached with H. baujardi at 37 °C was 40%. The groups containing H. bacteriophora caused lower adult emergence rates at temperatures of 25, 28, 31 and 34 °C, while H. baujardi caused its lowest emergence rates at 37 and 40 °C. It is concluded that infection occurs in the immature stages of S. calcitrans by EPN when added to 50% vinasse solution at different temperatures and that nematodes caused negative effects on the emergence of fly larvae at varying temperatures.

The Effects of Zinc Oxide nanoparticles synthesized from Eucalyptus plant extracts against mealworm stages Tenebrio molitor L., 1758 (Tenebrionidae: Coleopetera)

Despite the widespread utilization of Zinc Oxide nanoparticles (ZnO NPs) in different areas, there have been several studies regarding their toxicity. Thus, this study aimed to produce zinc oxide nanoparticles using a simple and eco-friendly biosynthesis process, utilizing the Eucalyptus (Eucalyptus camaldulensis Dehn.) as a reducing agent. It also aimed to estimate their insecticidal efficacies toward the mealworm's stages (Tenebrio molitor L.,1758(. The produced ZnO nanoparticles were characterized by X-ray diffraction, UV–visible, and transmission electron microscopy (TEM). The laboratory experiment was carried out with one way of exposure, using the feeding method through immersing the leaf in ZnO NPs solution with different concentrations. The mortality effects on insect's stages were recorded in various periods of time. The statistical analysis results indicated the presence of noteworthy variations in the average mortality rate according to insect's stage, showing a different effect on the average of larval mortality rate. In this regard, the highest average of larval mortality rate was recorded at 5000ppm (61.25%); while the general average percentage of adult emergence was (42.53%). After three weeks, the highest general mean of adult mortality was obtained at 5000ppm (87.48%). Similarly, the LC50 value of the ZnO NPs derived from the used plant extract against the larval stage was (3630.78 ppm). This result revealed that Zinc Oxide Nanoparticles from plant extract sources have both larvicidal and adulticidal properties and they could serve as an eco-friendly alternative to synthetic insecticides for controlling insect's stages. Hence, the biogenic Zinc Oxide Nanoparticles can be used as a potential bio-insecticidal agent for the future.

The costs of transgenerational immune priming for homologous and heterologous infections with different serotypes of dengue virus in Aedes aegypti mosquitoes.

The immune system is a network of molecules, signaling pathways, transcription, and effector modulation that controls, mitigates, or eradicates agents that may affect the integrity of the host. In mosquitoes, the innate immune system is highly efficient at combating foreign organisms but has the capacity to tolerate vector-borne diseases. These implications lead to replication, dissemination, and ultimately the transmission of pathogenic organisms when feeding on a host. In recent years, it has been discovered that the innate immune response of mosquitoes can trigger an enhanced immunity response to the stimulus of a previously encountered pathogen. This phenomenon, called immune priming, is characterized by a molecular response that prevents the replication of viruses, parasites, or bacteria in the body. It has been documented that immune priming can be stimulated through homologous organisms or molecules, although it has also been documented that closely related pathogens can generate an enhanced immune response to a second stimulus with a related organism. However, the cost involved in this immune response has not been characterized through the transmission of the immunological experience from parents to offspring by transgenerational immune priming (TGIP) in mosquitoes. Here, we address the impact on the rates of oviposition, hatching, development, and immune response in Aedes aegypti mosquitoes, the mothers of which were stimulated with dengue virus serotypes 2 and/or 4, having found a cost of TGIP on the development time of the progeny of mothers with heterologous infections, with respect to mothers with homologous infections. Our results showed a significant effect on the sex ratio, with females being more abundant than males. We found a decrease in transcripts of the siRNA pathway in daughters of mothers who had been exposed to an immune challenge with DV. Our research demonstrates that there are costs and benefits associated with TGIP in Aedes aegypti mosquitoes exposed to DV. Specifically, priming results in a lower viral load in the offspring of mothers who have previously been infected with the virus. Although some results from tests of two dengue virus serotypes show similarities, such as the percentage of pupae emergence, there are differences in the percentage of adult emergence, indicating differences in TGIP costs even within the same virus with different serotypes. This finding has crucial implications in the context of dengue virus transmission in endemic areas where multiple serotypes circulate simultaneously.

Cassia tora (L.) Roxb.: An Alternate Host for Offseason Survival of Tobacco Caterpillar, Spodoptera litura (Fabricius, 1775)

Spodoptera litura (Fabricius, 1775) is a serious polyphagous pest causes serious damage to various crops like tobacco, cotton, cabbage etc. in Asia and other Indian subcontinents. Depletion in host plants may lead to adverse effect on the alternate host plants. During survey, observed S. litura larvae were feeding on Cassia tora, in this study third instar larvae of S. litura larvae were reared on the common and most preferred hosts like castor and tobacco. Larval, prepupal and pupal weight were compared with and other two common hosts. Percent pupation and adult emergence rate were also recorded. Among three hosts, insects which fed on Cassia tora have higher larval weight (0.825 mg) and also observed longer larval period compared to other two hosts. No differences were observed in prepupal, pupal (male and female) weight. Percent pupation was higher in S. litura, which were fed on castor and tobacco i.e., 100 % and 96.67 % respectively, and on C. tora recorded lowest per cent pupation (20 %). Adult emergence rate was found to be non-significant on castor and tobacco fed larvae but the lowest adult emergence was recorded on cassia about 18 %. Feeding of newly hatched instars of S. litura confirms that, it uses C. tora as an alternate host during off-season survival and complete its life cycle. Longer larval duration on C. tora may prone larvae to expose more to the external environment, results in less pupation rate.

Synthesis of Tungsten Oxide, Iron Oxide, and Copper-Doped Iron Oxide Nanocomposites and Evaluation of Their Mixing Effects with Cyromazine against Spodoptera littoralis (Boisduval).

Nanotechnology research is emerging as a cutting-edge technology, and nanocomposites have played a significant role in pest control. Therefore, the present study focuses on the synthesis of tungsten oxide (WO3), iron oxide (magnetic nanoparticle, MNP), and copper-doped iron oxide (MNP-Cu) nanocomposites and explores the different effects of their binary combinations with the insecticide cyromazine against Spodoptera littoralis. The synthesized nanoparticles were characterized by transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, and Raman spectroscopy. None of the tested nanomaterials showed any toxicity against the different stages of S. littoralis. Larval and pupal durations increased with increasing cyromazine and nanomaterial concentrations. The longest larval and pupal durations were recorded under treatment with the mixture of cyromazine (100 mg/L) + MNP-Cu (500 mg/L); the survival periods were 23.5 and 15.6 days, compared with 10.8 and 7.7 days in the control, respectively. The percentages of pupation and adult emergence were negatively affected by all treatments. Among the 500 mg/L nanomaterial combinations, only cyromazine (25 mg/L) and WO3 (500 mg/L) resulted in adult emergence (at a rate of 27.3%). Some abnormalities in the S. littoralis stages were observed following treatment with the tested materials. The glutathione S-transferase and alpha-esterase enzyme activities in S. littoralis were significantly increased after treatment with cyromazine, followed by cyromazine/MNP-Cu combinations. The quantitative polymerase chain reaction (Q-PCR) data showed that all treated insects had a higher immune response than the control. Finally, mixes of nanocomposites and cyromazine may be suggested as viable alternatives for S. littoralis management.

The lethal and sterile doses of gamma radiation on the museums pest, varied carpet beetle, Anthrenus verbasci (Coleoptera: Dermestidae)

Museums preserve historical cultural artifacts and serve as an essential resource for current and future generations seeking first-hand knowledge about the diversity of life on Earth. However, significant changes in climate from temperature and humidity cause serious biotic degradation. Despite ongoing insect control treatments, insect pests are still a major problem for museums due to the lack of suitable and unsafe environments that are provided for the storage and display of the collection. The varied carpet beetle, Anthrenus verbasci (Coleoptera: Dermestidae) is one of the major stored product pests whose larvae cause serious damage to household items and museum specimens. Therefore, this research aims to study the effect of gamma radiation on the larval, pupal and adult stages. The effects of gamma radiation have been studied on 3rd instar larvae (100, 200, 300, 400 and 500 Gy). The results showed that mortality in the larval stage significantly increased with increasing gamma radiation dose, which was reflected in the eclosion of the adult stage. The exposure of one-day-old pupae to 200, 400, 600, 800 and 1000 Gy of gamma radiation showed that the higher the dose, the lower the percentage of adult emergence. Additionally, there was a significant increase in the percentage of mortality in A. verbasci adults with increasing radiation doses when the newly emerged adults were irradiated with 200, 400, 600, 800 and 1000 Gy. The LD50 and LD90 of gamma radiation doses on larvae, pupae and adults were calculated, and the malformations in all stages were photographed. The fecundity and fertility of A. verbasci adults that were exposed to radiation as one-day-old pupae decreased gradually with increasing doses of gamma radiation and reached 100% sterility when exposed to a dose of 150 Gy. Among all the treatments, the sterile dose (150 Gy) or lethal dose (1000 Gy) showed superior performance over other treatments and was adjudged as the best treatments, which prevented the subsequent development and complete mortality of the pest.

Sterilized Anopheles funestus can autodisseminate sufficient pyriproxyfen to the breeding habitat under semi-field settings

BackgroundAnopheles funestus, the main malaria vector, prefer to oviposit in permanent and/or semi-permanent breeding habitats located far from human dwellings. Difficulties in identifying and accessing these habitats jeopardize the feasibility of conventional larviciding. In this way, a semi-field study was conducted to assess the potential of autodissemination of pyriproxyfen (PPF) by An. funestus for its control.MethodsThe study was conducted inside a semi-field system (SFS). Therein, two identical separate chambers, the treatment chamber with a PPF-treated clay pot (0.25 g AI), and the control chamber with an untreated clay pot. In both chambers, one artificial breeding habitat made of a plastic basin with one litre of water was provided. Three hundred blood-fed female An. funestus aged 5–9 days were held inside untreated and treated clay pots for 30 min and 48 h before being released for oviposition. The impact of PPF on adult emergence, fecundity, and fertility through autodissemination and sterilization effects were assessed by comparing the treatment with its appropriate control group.ResultsMean (95% CI) percentage of adult emergence was 15.5% (14.9–16.1%) and 70.3% (69–71%) in the PPF and control chamber for females exposed for 30 min (p < 0.001); and 19% (12–28%) and 95% (88–98%) in the PPF and control chamber for females exposed for 48 h (p < 0.001) respectively. Eggs laid by exposed mosquitoes and their hatch rate were significantly reduced compared to unexposed mosquitoes (p < 0.001). Approximately, 90% of females exposed for 48 h retained abnormal ovarian follicles and only 42% in females exposed for 30 min.ConclusionThe study demonstrated sterilization and adult emergence inhibition via autodissemination of PPF by An. funestus. Also, it offers proof that sterilized An. funestus can transfer PPF to prevent adult emergence at breeding habitats. These findings warrant further assessment of the autodissemination of PPF in controlling wild population of An. funestus, and highlights its potential for complementing long-lasting insecticidal nets.

Effect of Different Host Plants on Biology of Tobacco Caterpillar, Spodoptera litura (Fabricius)

The tobacco caterpillar, Spodoptera litura (Fabricius) is present as an economically important and regular polyphagous pests in India and other countries. The knowledge of biology and ecology of an insect pests is a prerequisite for its management. An experiment was conducted on biology of Spodoptera litura (Fabricius) on different host plants in laboratory of the Department of Entomology, Rajasthan College of Agriculture, Maharana Pratap University of Agriculture and Technology, Udaipur, Rajasthan. The results revealed that the minimum and maximum incubation period of S. litura was 2.98 and 3.30 days recorded on castor and cauliflower, respectively. The minimum larval and pre pupal period was 12.96 and 1.00 days recorded on castor. The minimum and maximum pupal period were recorded on cotton (8.27 days) and cauliflower (6.44 days), respectively. The adult male and female moth survival maximum larvae reared on cauliflower 5.00 and 6.90 days whereas minimum on castor 3.95 and 6.00 days, respectively. The maximum percent adult emergence was recorded larvae reared on castor (87.50%) followed by cauliflower (85.00%) whereas minimum on cotton (67.50%). The maximum fecundity was recorded on castor (886.25) followed by soybean (870.00). The entire minimum life cycle was recorded on castor (29.05 days) whereas maximum on cotton (36.50days) followed by soybean (34.24 days). It was concluded that castor is best host plant for S. litura.

Toxic effect of cyanobacterial (blue–green algae) extracts as natural pesticides for the control of Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae)

BackgroundThe Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) is a cosmopolitan polyphagous pest that feeds on nearly 80 species of plants The pest can cause upto 100% damage to crops if neglected. It is also resistant to the most of the chemical molecules available in the market, so it is necessary to identify alternate technology to combat this pest.ResultsThe crude cyanobacterial extracts of hexane, petroleum ether, ethanol and methanol extracts of Spirulina sp. and Nostoc muscorum were evaluated against second instar larvae of S. frugiperda through diet overlay method of bioassay. The results revealed that N. muscorum hexane extract and N. muscorum petroleum ether extract recorded the lowest LC50 value of 49.09 and 61.37 ppm, respectively. This was followed by Spirulina hexane extract, Spirulina petroleum ether extract, N. muscorum ethanol extract, N. muscorum methanol extract, Spirulina ethanol and methanol extract which were recorded 173.16, 227.22, 530, 730, 970 and 1000 ppm, respectively. Further, their potential effects on different biological parameters of S. frugiperda, viz. larval duration, pupal duration, percent pupation, pupal weight, pupal malformation, adult malformation, percent adult emergence, fecundity, and male and female adult longevity, were studied. The significant effects on different biological parameters were recorded by N. muscorum hexane and petroleum ether extract, followed by Spirulina hexane and petroleum ether extract. Similarly, an experiment was repeated for the confirmation of the first set of results, which followed by a similar trend. The first-ever novel study on S. frugiperda concluded that crude extracts of Spirulina sp. and N. muscorum extracts showed significant effects in causing larval mortality and affecting different biological parameters.ConclusionsThe experimental results can be recommended as a potential source of natural pesticides for the control of S. frugiperda.