Percentage Of Adult Emergence Research Articles

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.

Life table study of Sitotroga cerealella on different cereals and its implications on the performance of the egg parasitoid (Trichogramma chilonis) under laboratory conditions

Sitotroga cerealella is one of the major pests of cereals in the field and storage conditions throughout the world. The main objective was to study the life tables of S. cerealella on wheat, maize and barley and its implications on percent parasitism of Trichogramma chilonis. S. cerealella is reared under lab conditions as its eggs are utilized for rearing T. chilonis. Fresh eggs of S. cerealella were collected and after hatching the neonate larvae of S. cerealella were transferred onto each host plant species for obtaining first (F1) generation (G). Seventy eggs were used for each host and each egg was used as a replicate. Daily observations were made for recording the life-table parameters of the S. cerealella. The data showed that the developmental time of S. cerealella eggs and pupae was maximum (5.68 and 7.75 days) when reared on wheat, while the maximum larval duration (19.77 days) of S. cerealella was recorded on barley. The maximum fecundity (290.30 ± 22.47 eggs/female) was recorded on maize, while minimum fecundity per female was recorded on barley (159.30 eggs/ female). The S. cerealella reared on maize had significantly higher values of finite rate of increase (λ), intrinsic rate of increase (r), and net reproductive rate (Ro) (0.14 ± 0.04 day− 1, 1.16 ± 0.05 day− 1, and 136.85 ± 20.25 eggs/ female) respectively. The mean generation time (T) (35.18 ± 0.61 days) was higher on wheat. Likewise, the gross reproductive rate (GRR) and the age-stage specific reproductive values (vxj) of newly oviposited eggs of S. cerealella were recorded higher (136.85 ± 20.25; 1.160 offspring) on maize. The data regarding the efficacy of T. chilonis for different parameters were recorded higher on maize i.e., percent parasitism (89.00 ± 2.30%), percent adult emergence (81.60 ± 1.20%), adult longevity (3.80 ± 0.10 days) and total adult longevity (9.90 ± 0.20 days) as compared to wheat and barley. Our findings revealed that S. cerealella can be best reared on maize under laboratory conditions as it prefers this host as compared to wheat and barley. Therefore, assigning the most susceptible and favorite host (maize) would help us to improve T. chilonis mass production under laboratory conditions.

In vitro Studies on the Biology and Predatory Potential of Commonly Occurring Ant Species in a Selected Agro-ecosystem of the Himalayan Range, India

Four commonly occurring species of queen ants were collected after their nuptial flight from an agroecosystem in Lehri Sarail village of Himachal Pradesh (31°32’03.9”N 76°38’57.7“E) using light traps. Queens named HAC1, HAC2, HAC3, and HAC4 were placed individually in a test tube with water sources. Once the queen started laying eggs, and a few workers emerged, they were transferred to an artificial formicarium. HAC1 and HAC2 were identified as Camponotus compressus, while HAC3 and HAC4 were identified as Polyrhachis thompsoni and Pheidole minor, respectively. In the study period of one year between July 2020 and July 2021, offspring from all colonies were found to be workers. HAC1, HAC2, and HAC4 produced dimorphic workers, the majors and minors. Studies on colony establishment, biology, and behavior were carried out with colonies from HAC1, HAC2, and HAC3, while a colony from HAC4 failed to establish. All species showed similar types of colony founding, nesting, brood management, necrophorosis, and hibernation. C. compressus showed higher fecundity, while percent hatchability was higher in P. thompsoni. Percent pupation and adult emergence were higher in C. compressus and lower in P. thompsoni. P. thompsoni was observed to be more aggressive with a high predation rate, followed by C. compressus. P. minor showed aggressiveness initially but was unable to incapacitate the host larva. Understanding ant biodiversity, biology, behavior, predatory potential, etc., will allow us to use the native ants in the agroecosystem as biological control agents. Methods of rearing ants under the artificial setup described here enable laboratory culturing of ants with biocontrol potential and using ants as model organisms to study the bio-efficacy of agrochemicals and pharmaceutical drugs.

Compatibility of commercially available biopesticidal formulations with Temperature Tolerant strain of <i>Trichogramma chilonis</i> (TTT) in pre- and post-release situations in laboratory

Laboratory experiments were conducted to evaluate the effect of some commercially available biopesticidal formulations, such as Bacillus thuringiensis var. kurstaki (2g/l), Bacillus sphaericus(2g/l), Beauveria bassiana (5g/l), Metarhizium anisopliae (5g/l), Lecanicillium lecanii (5g/l) on the Temperature Tolerant strain of Trichogramma chilonis (TTT). Two sets of experiments were conducted, in the first experiment, all the test biopesticides were sprayed on the egg cards prepared from Corcyra cephalonica eggs (pre-release situation) and percent parasitisation and adult emergence were recorded; in the second one, test bio pesticides were sprayed on the parasitized cards (post release situation) and adult emergence was recorded. The results revealed that percent parasitisation and adult emergence from treated cards in both the experiments are on par with the untreated control, hence they are considered safe and can be used along with TTT.

Toxicity and Influence of Sublethal Exposure to Sulfoxaflor on the Aphidophagous Predator Hippodamia variegata (Coleoptera: Coccinellidae).

Hippodamia variegata (Goeze), the variegated ladybug, is a predator of many insect pests, especially aphids. Sulfoxaflor is a chemical insecticide that can be used to control many sap-feeding insect pests, for instance, plant bugs and aphids, as an alternative to neonicotinoids in different crops. To improve the combination of the H. variegata and sulfoxaflor in an IPM (integrated pest management) program, we studied the ecological toxicity of the insecticide to the coccinellid predator at sublethal and lethal doses. We examined the influence of sulfoxaflor on larvae of H. variegata using exposure doses of 3, 6, 12, 24, 48 (maximum recommended field rate (MRFR)), and 96 ng a.i. per insect. In a 15-day toxicity test, we observed decreased adult emergence percentage and survival, as well as an increased hazard quotient. The LD50 (dose causing 50% mortality) of H. variegata due to sulfoxaflor decreased from 97.03 to 35.97 ng a.i. per insect. The total effect assessment indicated that sulfoxaflor could be grouped as slightly harmful for H. variegata. Additionally, most of the life table parameters were significantly decreased after exposure to sulfoxaflor. Overall, the results present a negative influence of sulfoxaflor on H. variegata when applied at the recommended field dose for controlling aphids in Greece, which demonstrates that this insecticide may only be employed with care when used in IPM programs.

Seed storage proteins and seed coat compounds additively influence Callosobruchus maculatus Fab. tolerance in selected cowpea (Vigna unguiculata L. Walp.) varieties

AbstractThe cowpea weevil, Callosobruchus maculatus, is a major threat to stable cowpea production, especially in storage, and has been reported to facilitate postharvest losses in cowpea grains. Host resistance has been suggested as the best control method but with conflicting knowledge on the source of resistance. Hence, the study seeks to evaluate seed storage proteins (SSPs) and seed coat compounds (SCCs) associated with tolerance to C. maculatus. SSPs and SCCs were assayed and associated with C. maculatus tolerance in 19 cowpea varieties with varied tolerance levels using a stepwise multiple regression analysis. Top C. maculatus tolerants were TVu‐2027, TVu‐11952, TVu‐11953, and TVu‐145. The protein fraction with a mass of 51 kDa was a significant predictor associated with percentage adult insect emergence (PAE) and host suitability index (H.S.I.), and 57 and 71 kDa were associated with mean development period (MDP) whereas 59 and 131 kDa were associated with seed damage tolerance (TolSD). Several SCCs identified were associated with the C. maculatus tolerant measures used in the study. However, Thiazole, tetrahydro‐ and Undecane were consistently identified with C. maculatus tolerance. Higher phenotypic variability was accounted for by SCC than SSP fractions associated with C. maculatus tolerance in the study indicating that SCCs contributed more to the C. maculatus tolerance than the SSPs identified. These compounds can be incorporated into breeding for C. maculatus tolerant in cowpea and biopesticide formulations whereas cowpea varieties with the high or significant amount of these compounds can also be recommended to the farmers or to the cowpea producers.

CHILO INFUSCATELLUS SNELLEN'S (LEPIDOPTERA: PYRALIDAE) BIOLOGY AND ITS MANAGEMENT

SUGARCANE stem borer, Chilo infuscatellus is the most devastating pest, causing huge economic losses in the sub-tropics and therefore requiring effective management strategies. The current research was conducted to study the biology and management of C. infuscatellus. Moreover, we checked the efficacy of Trichogramma chilonis and granular insecticides against this key pest. Theincubation period for C. infuscatellus was 2.30 days, with a total developing time of 23.30 days for the larvae and 5.90 days for the pupa. Male and female C. infuscatellus had a 36.80-day and 38.00-day total life span, respectively, with the female living longer (4.8 days) than the male (3.90 days). The total female fecundity was 315.90 eggs with a 90.87 egg hatchability rate. The mean percent parasitism (87.01%) and percentage of adult emergence (76.11%) of T. chilonis on C. infuscatellus were both very high, with a total developmental time of 8.74 days in laboratory environment. Additionally, there were notable differences between the findings on the effectiveness of granular pesticides and T. chilonis in the field. The plot treated with Fipronil had the least mean percent infestations (3.58%), followed by Carbofuran (4.26%), and T. chilonis (5.63%). The control plot had the highest mean incidence of infestations (13.34%). Future IPM initiatives should incorporate the introduction of Trichogramma or the utilization of Fipronil @ 16 kg ha-1 for the treatment of C. infuscatellus. This practice will play a critical role in environmental protection and natural resource conservation against insecticides.

Toxicity of some Biocides in the Tomato leaf Miner Tuta Absoluta Meyrick (Lepidoptera: Gelechiidae) in Laboratory

The experiment was conducted in the Entomology Laboratory/Plant Protection Department/College of Agriculture and Forestry/Mosul University/Iraq in the year 2021, to evaluated the toxicity of biocides, Beauveria bassiana (Bals.) Vuill, (conc. 1, 3, 5 g/L) Bacillus thuringiensis var. kurstaki (conc. 1, 3, 5 g/L), Spinosad (conc. 0.15, 0.30, 0.60 ml/L) and Neem plant extract (Azadirachta indica) (conc. 0.25, 0.50, 1.00 ml/L) on the third larval instar and pupal stage of tomato leafminer (TLM) under laboratory conditions, 25 - 27 °C, and the average relative humidity was 60 - 65%. The results of the study showed that the treatment with Spinosad at a concentration of 0.60 mm/L was significantly superior compared to the rest of the biocides, with an average mortality of 86.67% and 90.67% for larvae and pupae, respectively. All biocides differed significantly compared to the control, which amounted to 0.00%, and the highest mean of larval mortality was 71.67% for the reading after ten days of treatment, which differed significantly compared to the reading after one and three days of treatment, which amounted to 23.89 and 50.56%, respectively. While the reading after nine days of treatment outperformed significantly, and recorded the highest average of pupal mortality, which amounted to 68.00%, compared to the lowest average reading after seven days of treatment, which amounted to 44.00%. The treatment with the biocides B. thuringensis at a concentration of 1, 3 and 5 g/L was superior, with the lowest average percentage of transformation of larva to pupal stage reaching 15.56, 2.22 and 0.00%, respectively, compared to the rest of the concentrations of other biocides and the control, which was 73.33%. The biocides B. thuringensis was significantly superior to the rest of the biocides, and the lowest average percentage of emergence was recorded, as it reached 6.67% in the third concentration 5 g/L, which did not differ significantly compared to the third concentration of the rest of the biocides, however, it differed significantly compared to the rest of the concentrations of other biocides, and the control, as the highest mean of the percentage of emergence rate was 76.67%. It is noted from the study that all biocides had a significant effect on their toxicity to TLM compared to the control, and that the toxicity of biocides for the third larval instar and pupa of TLM increased with increasing concentration and number of days after treatment, and led to a decrease in the average percentage of adult emergence with an increase in concentration used compared to the control. From the results of this study, it is possible to introduce these pesticides in the integrated pest management programs for TLM in open fields and protected cultivation.

Comparative study of three plant-derived extracts as new management strategies against Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae)

Finding innovative eco-friendly agents for pest control may be aided by investigating the plant-derived extracts’ properties on economic pests. Therefore, the insecticidal, behavioral, biological and biochemical effects of Magnolia grandiflora (Magnoliaceae) leaf water and methanol extracts, Schinus terebinthifolius (Anacardiaceae) wood methanol extract, and Salix babylonica (Salicaceae) leaf methanol extract in comparison with a reference insecticide novaluron against S. littoralis were evaluated. The extracts were analyzed by High-Performance Liquid Chromatography (HPLC). The most abundant phenolic compounds were 4-hydroxybenzoic acid (7.16 mg/mL) and ferulic acid (6.34 mg/mL) in M. grandiflora leaf water extract; catechol (13.05 mg/mL), ferulic acid (11.87 mg/mL), and chlorogenic acid (10.33 mg/mL) in M. grandiflora leaf methanol extract; ferulic acid (14.81 mg/mL), caffeic acid (5.61 mg/mL), and gallic acid (5.07 mg/mL) In the S. terebinthifolius extract; cinnamic acid (11.36 mg/mL), and protocatechuic acid (10.33 mg/mL) In the methanol extract from S. babylonica extract. S. terebinthifolius extract had a highly toxic effect against second larvae after 96 h and eggs with LC50 values of 0.89 and 0.94 mg/L, respectively. Despite M. grandiflora extracts didn’t show any toxicity against S. littoralis stages, they had an attractant effect on fourth- and second larvae, with feeding deterrence values of − 2.7% and − 6.7%, respectively, at 10 mg/L. S. terebinthifolius extract significantly reduced the percentage of pupation, adult emergence, hatchability, and fecundity, with values of 60.2%, 56.7%, 35.3%, and 105.4 eggs/female, respectively. Novaluron and S. terebinthifolius extract drastically inhibited the activities of α-amylase and total proteases to 1.16 and 0.52, and 1.47 and 0.65 ΔOD/mg protein/min, respectively. In the semi-field experiment, the residual toxicity of tested extracts on S. littoralis gradually decreased over time compared to novaluron. These findings indicate that extract from S. terebinthifolius is a promising insecticidal agent against S. littoralis.

Parámetros Biológicos de Spodoptera frugiperda1 Alimentado con Tres Hospederos

Spodoptera frugiperda (J.E. Smith) is the most important pest of maize and constitutes an ideal host for mass rearing of some natural enemies. Three substrates were tested: Zea mays, Cucurbita pepo, and Racinus communis to produce a more efficient and cheaper diet for mass production of S. frugiperda to be used as host. The life cycle of S. frugiperda did not differ in the duration of adult emergence between Z. mays (32.3 ± 0.4) and R. communis (32.8 ± 1.4), while C. pepo had the longest duration (37.0 ± 0.5). The difference in its biological cycle was observed when feeding larvae with R. communis leaves, which presented the best biological attributes such as higher percentage of egg hatching (95%), higher percentage of pupae (93%), higher percentage of adult emergence (78%), and higher number of eggs in the next generation (1,569 ± 32). Life tables showed low mortality rate (qx) and high life expectancy when fall armyworm larvae were fed R. communis. The logrank test indicated a difference between the different life tables between C. pepo and Z. mayz; C. pepo and R. communis; and R. communis and Z. mayz, with R. communis a better substrate for rearing S. frugiperda.

Efficacy of indigenous plant powders and cow dung powder on lesser grain borer, Rhyzopertha dominica (Fabricius) in stored wheat

Studies on the efficacy of indigenous plant products and cow dung powder on the lesser grain borer, Rhyzopertha dominica (Fabricius) in wheat (Triticum aestivum), were conducted to determine the effects of the aforementioned plant products and cow dung powder on Percent Mortality, Adult Emergence, and Percent Weight loss. This experiment was carried out using a Completely Randomized Design (CRD). Rhyzopertha dominica orientation was found to be maximum in control and minimum in Mustard oil treatments. Mustard oil treated wheat grains showed the minimum amount of Adult Emergence and Weight loss when compared to control. The wheat treated with Mustard oil (100.00%) had the maximum percentage mortality rate. As a result, the current laboratory investigations amply demonstrated the practically complete efficacy of native plant products and cow dung powder on wheat. Accordingly, it can be said that these products were affordable, convenient, and eco-friendly. It's indeed simple to implement for controlling the stored pest in wheat.

Test of Pathogenicity of Bacillus thuringensis (Berliner) in Biological Control for the Cotton Leaf Worm, Spodoptera littoralis (Boisd.)

The study was carried out to evaluate the pathogenicity of the bacteria, Bacillus thuringensis of the cotton leafworm, Spodoptera littoralis (Boisd) at the rate of 1x106 spores/ml Laboratory results revealed that egg hatching percentage, at the age of 1-2 days were 0.0, 0.0 and 8.2 % 2 and 4 days after application respectively. While the hatching percentage of the 3-4 days old eggs was 6.8% at the age of 2-4 days after 2 days' treatment. The mortality rate of larval stages (2, 4, 6 instars) was 100% 14 days after application. When pupae were treated with the bacteria adult emergence percentage was 51.3 % 15 days after treatment compared to 100% emergence for the control treatment. The results in greenhouse show that the entomopathogenic bacteria also achieved mortality rate for 2, 4, 6 larval instars of the pest were 94.4, 91.8, 100, 88.4, 85.6 and 81.3 % for the soil and plant treatments respectively, 14 days after application.
 

Seasonal changes in the habitat characteristics on survivability and adult emergence of Aedes albopictus (Skuse) from rural and urban environments of northern Kerala, India

The range and spread of dengue cases can be ascribed to the breeding habitat of Aedes albopictus. There is a paucity of scientific information on the influence of the water quality of breeding habitats on adult emergence in Aedes albopictus. The objective of the present study was to evaluate the water quality characteristics responsible for the adult emergence of Aedes albopictus confining to selected urban and rural habitats of northern Kerala, India. Larvae of Aedes albopictus were collected using the dipping method, along with the collection and analysis of water samples following APHA (2017). The larvae were retained in controlled environmental conditions to assess the magnitude of adult emergence. The average larval productivity in both rural and urban areas was almost the same and exhibits a particular seasonal pattern. Both the rural and urban sectors showed substantial variations in the magnitude of adult emergence. The percentage of adult emergence followed a pattern of pre-monsoon > post-monsoon> monsoon season. With a correlation coefficient of 0.036, larval productivity and adult emergence were shown to be positively correlated. EC, TDS, salinity, Na, K, and NO3 showed a positive correlation while temperature, pH, turbidity, chloride, and DO showed a negative correlation with the adult emergence. Multiple regression models revealed temperature (p=0.00), DO (p= 0.007), NO3 (p=0.007), and chloride (p=0.030) as the distinguishing elements in the adult emergence of Aedes albopictus.

Endophytic fungi from South Sumatra (Indonesia) in seed-treated corn suppressing Spodoptera frugiperda growth

Abstract. Herlinda S, Gustianingtyas M, Suwandi S, Suharjo R, Sari JMP, Suparman, Hamidson H, Hasyim H. 2022. Endophytic fungi from South Sumatra (Indonesia) in seed-treated corn suppressing Spodoptera frugiperda growth. Biodiversitas 23: 6024-6031. The aim of this research was to evaluate the effect of endophytic fungi in seed-treated corn on S. frugiperda growth. A total of 20 isolates of endophytic fungi were molecularly identified, namely Chaetomium sp. (GaTpeOi, JgTjPr, PiCrPga, and CaCjPga isolates), Aspergillus niger (PsgTjPr, JgByU, and JaBuBys isolates), Beauveria bassiana (JgSPK, JaGiP, JaSpkPGA(2) isolates), JgCrJr, dan JaTpOi (1) isolates), Curvularia lunata (JaGiPRB, CMTJP, JaMsBys, JaSpkPga(3), and JgTgSr isolates), Aspergillus flavus (JgPWSR isolate), Penicillium citrinum (JaTpOi(2) isolate), and Metarhizium anisopliae (CaTpPGA isolate). Of the 20 isolates, 4 isolates (JgSPK, JaGiP, JgCrJr, JaTpOi (1)) of B. bassiana and one isolate of each C. lunata (JaSpkPga (3)), and M anisoplae (CaTpPga) were found to be more pathogenic to S. frugiperda larvae. The endophytic fungi had negative effect on S. frugiperda growth. B. bassiana, M. anisopliae, and C. lunata decreased the percentage of pupal and adult emergence, and the number of eggs laid by treated female adults. The fungi also shorten the adult longevity and increased the larval mortality. This is the first report of pathogenicity of C. lunata against S. frugiperda. These findings highlight the potential of endophytic fungi, namely B. bassiana, M. anisopliae, and C. lunata from South Sumatra to protect young maize plant against S. frugiperda by seed treatment.

Hundreds of billions of silent outbreaks: A historic outbreak record of the gall midge Schizomyia castanopsisae (Diptera: Cecidomyiidae) on the Izu Islands, Tokyo, Japan, and its potential mechanism

AbstractHerbivore outbreaks cause serious damage to forest trees. In recent decades, outbreaks of the gall midge Schizomyia castanopsisae (Diptera: Cecidomyiidae) inducing inflorescence galls on Castanopsis sieboldii (Fagaceae) occurred in the Izu Islands, Tokyo, Japan. We investigated the gall density on the islands and estimated the larval population on Miyakejima Island. We also surveyed seasonal changes in larval age structure, presence of natural enemies, larval cold tolerance, and thermal effects on the adult emergence. In addition, we conducted molecular phylogenetic analyses of S. castanopsisae populations among different localities. The gall density was particularly high in southern parts (from Miyakejima to Aogashima) of the Izu Islands. The gall midge seemed to have been expanding its range toward northern parts in recent years. On Miyakejima, the larval population was estimated to be approximately 158 and 36 bn in 2017 and 2018, respectively. Parasitoids were not found in the dissection of galls. A cold temperature treatment did not affect the percentage of adult emergence. Developmental zero and thermal constant during the period from larval departure to adult emergence were estimated to be 4.7°C and 588.2°C‐days in males and 7.4°C and 476.2°C‐days in females, and the adults were predicted to emerge in April. Populations in Kyushu were genetically distinct from those in Okinawajima and the Izu Islands, but a common haplotype was found between the latter two localities. These imply that S. castanopsisae on the Izu Islands may be a recent invasion, and the absence of natural enemies causes its outbreaks.

Evaluation of Cowpea [Vigna unguiculata (L) Walp.] Germplasm against Pulse Beetle, Callosobruchus chinensis (L.) and Correlation with Morphological Seed Characters

Background: In India, cowpea (Vigna unguiculata (L) Walp) is a minor pulse and is cultivated mainly in arid and semi arid tracts. Cowpea grains are often completely destroyed by bruchids both quantitatively and qualitatively making them unfit for planting, marketing and human consumption. Therefore, development and use of tolerant/resistant cowpea cultivars offer a simple, cheap and attractive way for reducing bruchids damage. Hence, the present study was aimed to identify new sources of insect resistant traits against Callosobruchus chinensis in cowpea germplasm so as to incorporate them in cowpea crop improvement programmes to evolve resistant or tolerant varieties against bruchids. Methods: Twenty seven cowpea genotypes were evaluated for resistance or susceptibility to pulse beetle, C. chinensis (Coleoptera: Bruchidae) using no-choice artificial conditions. Various parameters viz., oviposition, adult emergence/20 seeds, percent adult emergence, mean developmental period, per cent seed weight loss and growth index were determined for each genotype. Result: Significant differences were observed among cowpea accessions in terms of growth index (GI) of bruchid. Based on GI, one accession (IC 257844) was found moderately resistant (MR). Although, cowpea accessions showed variation in physical seed characters viz., seed coat colour, shape, seed length, seed width, seed thickness and 100 seed weight, they could not exert significant influence on any of the insect biological characters. Based on the study, it was demonstrated that IC 257844 (categorized as moderately resistant) could be used as potential donor for the development of bruchid tolerant cultivars.

Omani Frankincense nanoemulsion formulation efficacy and its latent effects on biological aspects of the spiny bollworm Earias insulana (Boisd.).

Our research shed light on the perspective of formulation technology regarding its responsibility to provide phyto-insecticides that are worthy of research into potential novel applications. There has been an increase in interest in using nanoemulsion as a new formulation in a variety of sectors during the last several decades. Boswellia sacra essential oil (Fam: Burseraceae) from the resin of frankincense trees has been recently proposed as a promising ingredient in a new generation of botanical insecticides. Frankincense nanoemulsion was formulated in 5% ratios comprising frankincense oil, surfactants, and water. A frankincense nanoemulsion was prepared using a high-energy ultra-sonication process and characterized by dynamic light scattering transmission electron microscopy surface tension, viscosity, and zeta potential value. Gas chromatography/mass spectrometry (GC/MS) was used to identify the chemical profiles of frankincense essential oil. Furthermore, insecticidal effects against second instar larvae of the spiny bollworm, Earias insulana, as well as their latent effects on the larvae were studied. In the present study, the formulation was a good nanoemulsion. The surface tension was 53.69, the viscosity was 4.76 cPs, the zeta potential was-10 mV, and the size distribution was 41.30 nm. The polydispersity index (PDI) of the nanoemulsion was found to be 0.26, and the morphology of the frankincense nanoemulsion was visualized in a spherical shape. The main constituents identified in frankincense oil were α-pinene (15.52%); monolinolenin (12.92%); and geranylgeranyl acetate (9.99%). The results showed significant insecticidal activity against the larval stage and considerably decreased the pupation percentage with increasing the volume of the frankincense nanoemulsion. On the other hand, the latent effects of the frankincense nanoemulsion on E. insulana resulted in a higher prolongation of larval and pupal durations as well as a significant reduction in the weight of larvae and pupae of E. insulana. Additionally, frankincense nanoemulsion dramatically influenced the adult emergence percentage. It also caused a significantly lower hatchability percentage compared to the untreated control. The concentrations used and the types of mating combination have a significant effect on the fecundity of E. insulana. This novel frankincense nanoemulsion formulation could be used in strategies to control the spiny bollworm on cotton plants.

P378 Insecticidal potential of isolated fungal species in targeting Drosophila melanogaster and Zaprionus indianus

Poster session 3, September 23, 2022, 12:30 PM - 1:30 PM ObjectivesFruit flies are polyphagous insects that attack a variety of commercially significant plants, which resulted in the build-up of insecticide resistance making the research focus shift toward alternative pest management tools in order to reduce risks to humans, environment, and non-target organisms.MethodsFungal species were isolated and molecularly characterized from Drosophila culture medium. Virulence assay was conducted against third instar larvae and adults of Drosophila melanogaster and Zaprionus indianus. Percent adult emergence and larval mortality were calculated.ResultsThree species: Meyerozyma caribbica, Pichia kudriavzevii, and Aspergillus flavus were identified by ITS region sequencing. A. flavus was the most virulent against larvae and adults of D. melanogaster and Z. indianus followed by P. kudriavzevii and M. caribbica (44%-100% mortality). Lethal time to 90% mortality (LT90) ranged from 4.5 to 7 days (P. kudriavzevii) and 3.2 to 4.5 days (A. flavus).ConclusionThese preliminary findings suggest that the isolated fungal species can be deployed in targeting the developmental life stages of Drosophila species and hence, controlling invasive insect pests in an eco-friendly way. The use of these biological control agents could further minimize the use of harmful insecticides which has substantial global health benefits.

The Impact of Magnetic Field on Insecticide Toxicity Measured by Biological and Biochemical Parameters of Earias insulana (Boisd).

This study illustrates the effect of magnetic field (MF) on the toxicity of two insecticides, emamectin benzoate (Emazoate 2.15% EC) and spinosad (SpinTor 24% SC), and determines their adverse effects on the bollworm (Earias insulana) through various biological and biochemical assays. The investigation indicated that exposure to the insecticides in a MF of 180 mT resulted in stronger toxicity, with LC50 values of 0.162, 1.211, and 1.770 ppm, respectively. In addition, the results showed that magnetized insecticides significantly increased in the duration of the total immature stages (larvae and/or pupae) 32.1 and 36.6 days, compared with 27.9 and 30.5 days, respectively, in the nonmagnetized insecticides, while untreated check was 21 days. Also, the magnetized insecticides reduced the percentage of adult emergence, and increased deformations in the larval and pupal stages. Furthermore, sex ratio was greatly affected by exposure to both insecticides in conjunction with the MF. Exposure of the larvae of E insulana to magnetized insecticides can bring about malfunction in some biochemical process and significantly decreased the invertase activity, and decreased the total protein and carbohydrates. In contrast, it can increase amylase compared with nonmagnetized insecticides and untreated controls. Results concluded that the two insecticides' MF affected growth, survival time, and biological and biochemical parameters of E. insulana. © 2022 Bioelectromagnetics Society.

Genetic variability, heritability and genetic gain of common bean (Phaseolus vulgaris L.) genotypes in response to Mexican bean weevil (Zabrotes subfasciatus Boheman) infestation

The aims of the study were to determine expected genetic gains from selection and the extent and pattern of genetic diversity of common bean genotypes to Mexican bean weevil. Three hundred bean genotypes were artificially infested with the Mexican bean weevil. The experiment was laid out in a randomized complete block design with three replications. Data on thirteen insect and seed related traits were recorded and subjected to statistical analysis. The broad-sense heritability values ranged from 68.5%–93.9% for the traits studied. The expected genetic gains from selection ranged from 5.9%-67.1% for insect related traits and from 0.2%-82.2% for seed related traits. Seed weight loss showed significant positive phenotypic and genotypic correlation with number of eggs, number of adults emerged, percent adult emergence, index of susceptibility, number of holes and first and second progeny damage. Cluster analysis classified the 300 genotypes into two major clusters and seven sub-clusters. Mahalanobis’s D2 value calculated among the sub clusters ranged from 5.6 to 191.6. There was no defined relationship between geographic origins and the pattern of genetic diversity in response to Mexican been weevil infestation. Therefore, parental selection should be made based on genetic diversity and other special merits of the genotype for the resistance attributes. The introgression of the resistance gene into the adapted improved varieties and landraces, and increasing the frequency of resistance genes through selection could be used as a strategy to improve bruchid resistance in the future