LC50 Concentration Research Articles

Anti-oxidative, genotoxic and mutagenic effects of idiobiont, endoparasitoid, Pimpla turionellae L. (Hymenoptera: Ichneumonidae) venom on its host Galleria mellonella L. (Lepidoptera: Pyralidae)

Parasitoid species regulate the nutritional and physiological states of their hosts to ensure their eggs and larvae successfully develop inside the host. Due to the insecticidal and paralyzing properties of venoms from idiobiont parasitoids, parasitic wasps are important natural enemies of several insect pests. For this purpose, in this report, we investigated the oxidative, genotoxic, and mutagenic potential of venom from Pimpla turionellae L. (Hymenoptera: Ichneumonidae) on the laboratory host Galleria mellonella L. (Lepidoptera: Pyralidae). The insecticidal assay showed the LC50 and LC99 values of endoparasitoid venom for G. mellonella pupal stage to be 0.44 µg and 1.17 µg in 2 µl insect saline buffer, respectively. According to the mechanical stimulus–response (MSR) assay, pupal paralysis increased significantly within four hours post-injection at LC50 and higher venom concentrations. Envenomation by LC10, LC30, and LC50 concentrations of endoparasitoid venom and parasitism reduced the activities of superoxide dismutase, catalase, and glutathione-S-transferase enzymes and the level of malondialdehyde in the hemolymph of host pupae 1, 2 and 4 h post-treatment. On the other hand, comet and micronucleus assays displayed that, envenomation by the effective concentrations of P. turionellae venom-induced concentration and time-dependent DNA and chromosomal damages in host hemocytes. Therefore, these data indicated that envenomation by P. turionellae induces anti-oxidative stress, genotoxicity, and mutagenicity which alter the hosts’ physiological state to create a suitable host environment for the successful development of their progeny. In conclusion, we suggest that this study could provide useful information for bioinsecticidal potential of idiobiont wasp venom for sustainable integrated pest management programs.

The Toxicity Effect of Certain Photosensitizing Compounds on Some Biological Aspects of Field Strain of Agrotis ipsilon (Hufnagel) Larvae

The black cutworm, Agrotis ipsilon larvae is the most serious pest around the world; it attacked the plant in the growing stage of many crops such as cotton, potato, corn, and tomato causing great damage for them and others which led to reduce the yield. So many chemical insecticides are used for controlling this pest which may buildup resistance to these pesticides Therefore, it is needed to evaluate some chemical compounds that belonged to different categories such as safranin, methylene blue and bromophenol blue against the 4th larval instars of A. ipsilon using poison baits. The results clearly demonstrated that the tested compounds had, a stomach and contact toxicity through the larval feeding on treated baits also, all these toxicants exhibited antifeedant and starvation effects in addition resulting larval paralysis post-feeding. Results on the basis the medium lethal concentrations LC50 of the tested compounds varied on the larval stage, the promising treatment among the investigated compounds were safranin that showed the lowest LC50, which was more toxic as stomach poison followed by methylene blue and the lowest effect was noticed in case of bromophenol blue treatment. The effect of both LC50 and LC25values of these compounds showed a remarkable significant increase in both larval and pupal durations with retardation in their development as well as an increase in the mortality percentage and the malformation for both the resulting pupae and adults. Also, the toxicants affected the fertility of adults. Therefore, these photosensitizers, compounds can be used for controlling the black cutworm on their hosts as toxic baits’ alternatives to traditional chemical pesticides, for increasing their toxicity and decreasing insect-resistant build up as a method implementing the integrated pest control program.

<p class="Body"><strong>The effects of bifenazate on life history traits and population growth of <em>Amblyseius swirskii</em> Athias-Henriot (Acari: Phytoseiidae)</strong></p>

Tetranychus urticae Koch (Acari: Tetranychidae) is a notorious crop pest with a worldwide distribution that has developed resistance to a wide range of acaricides. Combined tactics of pest management have special significance not only for a reduction in pesticide residues but also to maintain the natural enemy activity, which is an objective of IPM programs. Here, we investigated the effect of low-lethal concentrations of bifenazate at LC10, LC20, and LC30 on development and reproduction parameters of Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae). Lethal and sub-lethal concentrations were estimated using leaf dip bioassay method. The crude data were analyzed based on age-stage, two-sex life table analysis. Toxicological assays showed bifenazate treatments gradually decreased the longevity and total life span of both sexes. Our results indicated that reproductive and total fecundity of the next generation were also affected by sublethal concentrations. All concentrations caused a significant decline in oviposition days, compared to the control. The intrinsic rate of increase (rm) varied from 0.1344 to 0.1151 day-1 for the mites treated with distilled water and LC30 treatments, respectively. The finite rate of increase (λ) was affected by the acaricide concentration (lowest at LC30 concentration: 1.1221 day-1). Bifenazate concentration (LC10, LC20 and LC30) treatments gradually reduced the gross reproduction rate (GRR) and net reproductive rate (R0). Based on obtained results from current study, bifenazate is not a favorable acaricide with A. swiriskii and cannot be recommended to use with this predatory mite in integrated management.

Field evaluation of toxicity of plant extracts against vector of filariasis Culex quinquefasciatus Say, 1823 (Diptera: Culicidae)

Mosquito control has been facing backlashes due to the emergence of resistant varieties against synthetic insecticides. The bioactivity of five plant extracts viz., Poncirus trifoliate, Murraya paniculata, Citrus bergamia, Aegle marmelos and Limonia acidissima was studied against the filarial vector of Culex quinquefasciatus Say, 1823. Larvicidal assays were conducted under laboratory condition to evaluate the 24 h LC50 and LC90 of the selected plants against 3rd instar larvae of Cx. quinquefasciatus. The lethal concentration (LC50 and LC90) values ranged from 76.26 to 208.32 mg/L and 191.85 to 477.16 mg/L, respectively. The result of larvicidal test suggests that the larvicidal activity of the L. acidissima and P. trifoliate extracts were highly influenced. Test results showed that the flavonoid compounds exhibited larvicidal activity against 3rd instar Cx. quinquefasciatus mosquitoes. Percent reduction was recorded with an LC50 concentration of L. acidissima and P. trifoliate. A field study was carried out to evaluate larvicidal activity on 24 h, 48 h and 78 h period and percentage of larval and pupal reduction due to L. acidissima and P. trifoliate extracts in the unused cement tank and mini water pool in Puthanampatti, Tiruchirappalli district. The field tested plant extracts proved to have various activities against different life stages of Cx. spp. Therefore, flavonoid compounds from L. acidissima and P. trifoliate plant can be a potential candidate for use in the development of commercial mosquito larvicidal products that may be an alternative to conventional synthetic chemicals, particularly in integrated vector control applications.

The role of Cinnamomum zeylanicum essential oil, (E)‐cinnamaldehyde and (E)‐cinnamaldehyde oxime in the control of Meloidogyne incognita

AbstractThe search for natural nematicides that are biodegradable with little or no human toxicity has intensified in recent years. In this context, the use of essential oils has the potential to function as an alternative plant–parasitic nematode control strategy, and their characterization may identify new nematicidal molecules. In this study, the nematicidal activity of Cinnamomum zeylanicum essential oil, its most abundant biochemical component and its analogue were evaluated against Meloidogyne incognita. Mean LC50 and LC95 values for C. zeylanicum oil were 49 µg/ml and 131 µg/ml, respectively. When J2 placed in C. zeylanicum oil at its LC50 concentration were used to inoculate tomato plants, the reduction in numbers of galls and eggs versus samples inoculated using J2 and no C. zeylanicum oil was 98%. C. zeylanicum essential oil reduced levels of M. incognita J2 that hatched 38%–54%, while carbofuran (positive control) did not prevent hatching. C. zeylanicum oil applied at a concentration of 800 µg/ml to a potted substrate containing infested tomato plants significantly reduced numbers of M. incognita galls. The cinnamaldehyde molecule within C. zeylanicum oil had LC50 and LC95 values of 64 and 768 µg/ml, respectively, while LC50 and LC95 values for cinnamaldehyde oxime were 323 and 529 µg/ml, respectively. Both cinnamaldehyde and its oxime inhibited hatching in M. incognita J2. These findings indicate that C. zeylanicum essential oil, its major biochemical component, cinnamaldehyde and cinnamaldehyde oxime (a cinnamaldehyde analogue) can be used to reduce levels of M. incognita.

Bioefficacy of Lemongrass and Tea Tree Essential Oils Against House Fly, Musca domestica.

The management of house fly, Musca domestica has become immensely important to prevent epidemics of many detrimental diseases. In view of this objective, the present study demonstrates the efficacy of lemongrass (LG) and tea tree essential oils (TTEOs) against M. domestica. The TTEO proved to be more lethal against larvae and adults of M. domestica depicting an LC50 at 14.88 mg/ dm3 which was 17.19 mg/ dm3 for LGEO. In contrast, pupicidal effect of LGEO was much higher (LD50, 14.49 µl/0.25L) as compared to TTEO. The LGEO drastically reduced the total body sugar, glycogen and protein contents by 3.29, 2.95 and 7.56 fold, respectively, contrasting with high influence of TTEO on lipid content of the late 3rd instar larvae. A considerable reduction in gut enzymes secretion was observed due to treatment of EOs thereby altering gut physiology of the insect. Moreover, significant inhibition of acetylcholine esterase (AchE) was also observed with LGEO at LC50 concentration (5.33 mg/ml) inhibiting insect neurotransmission. The gas chromatography-mass spectrometric (GC-MS) analysis of the LGEO showed 12 major compounds dominated by Citral whereas TTEO contained only 5 major compounds. Further analysis by field emission scanning electron microscopy (FESEM) revealed distortion and shrinkage of larval bodies caused by the treatment of EOs. These overall observations brand LG and TT-EOs as potential organic-insecticides against M. domestica.Graphic Supplementary InformationThe online version of this article (10.1007/s40011-020-01220-z) contains supplementary material, which is available to authorized users.

Seasonal Response of Daphnia pulex to Cyanobacterial Extracts at Different Temperatures in Valle de Bravo Reservoir (Mexico)

Valle de Bravo reservoir supplies drinking water to 40% of Mexico City. Here we present data on the population growth and life-table demography of the cladoceran Daphnia pulex, cultured at temperatures of 20 °C and 25 °C and with different concentrations of the crude extracts from blooms of Microcystis aeruginosa, collected in January, and Woronichinia naegeliana, collected in September. We hypothesized that Daphnia pulex would be more sensitive at the higher temperature and to toxins from W. naegeliana as these blooms have been shown to be more toxic to rotifers. We extracted the toxins and conducted acute toxicity tests at eight concentrations of microcystins at 20 °C. The LC50 was 26.8 µg/L and 11.5 µg/L, respectively, for Microcystis and Woronichinia samples. The chronic toxicity tests included population growth and life-table demography studies at 5 and 10% of the LC50 concentration, at 20 °C and 25 °C. Four replicates for each of the three treatments, which consisted of treatments with low and high cyanotoxin levels and a control without cyanotoxins, were set up. The population growth rate ranged from 0.18 to 0.42 d−1 on the extracts from M. aeruginosa (January) and from 0.2 to 0.31 on extracts from W. naegeliana. Daphnia, being better adapted to cooler temperatures, was more adversely affected at 25 °C than 20 °C. The adverse effect of cyanobacterial extracts was greater from Microcystis than Woronichinia blooms. The tolerance of Daphnia pulex to cyanotoxins depends on the bloom-forming species and the temperature.

Metabolomic Profiling Unveils the Impact of Non-Doped and Heteroatom-Doped Carbon Nanodots on Zebrafish (Danio rerio) Embryos.

Recently, concern has been raised over the transport, transformation, and fate of carbon nanodots (CNDs) after their release into the environment. Their toxicity towards organisms and humans has recently been addressed as an important issue. In this study, a metabolomic approach was employed to obtain an insight into the effect of CNDs (either pristine or doped with nitrogen and nitrogen/sulfur) on zebrafish. Embryos were exposed to concentrations corresponding to lethal concentration (LC) LC50 (550, 400, and 150 μg mL−1), LC50/2 (275, 200, and 75 μg mL−1), and LC50/4 (138, 100, and 38 μg mL−1) of the three CNDs (non-doped, N-doped, and N,S-codoped, respectively) to scrutinize the interactions of the CNDs with the larvae. Numerous differences in the metabolic pathways were recorded in all cases. Seven metabolic pathways were detected in the control larvae. When the larvae were exposed to concentrations equal to LC50, LC50/2, and LC50/4 of non-doped CNDs, 12, 12, and 3 metabolic pathways were detected, respectively. In the case of N-doped CNDs, 4, 7, and 4 pathways were detected, while in the case of N,S-codoped CNDs, 8, 5, and 5 pathways were detected when exposed to concentrations of LC50, LC50/2, and LC50/4, respectively. In all cases, certain metabolic pathways were altered while others were either down-regulated or up-regulated. Some of these changes include the activation of alanine, aspartate, and glutamate metabolism, aminoacyl-tRNA biosynthesis, butanoate metabolism, D-glutamine, and D-glutamate metabolism, glutathione metabolism, selenoamino acid metabolism, valine, leucine, and isoleucine degradation pathways. Moreover, the deactivation of starch and sucrose metabolism, the glycine, serine, and threonine metabolism, among others, were recorded. Our findings underline the importance to further study the impact of CNDs on marine organisms. As zebrafish has been shown to share many similarities with humans in bioprocesses and genome, it can be assumed that CNDs may also pose a threat to human health.

Nuclear polyhedrosis virus DNA identification and first evaluation against Strawberry pest, Pentodon algerinum (Coleoptera: Scarabaeidae)

In Egypt, The white grub, Pentodon algerinum (Coleoptera: Scarabaeidae) damages various economic important plants recently strawberry. This study aimed to DNA identification and first evaluation of the Spodopteda littoralis Nuclear polyhedrosis virus (SpliNPV) and Pentodon algerinum Nuclear polyhedrosis virus (PNPV) against Pentodon algerinum third instar larvae in the laboratory to find successful safe alternative control method against this pest. Bioassay was made by two experiments, one used five SpliNPV concentrations, 6.7X106, 3.11X107, 1.1X108, 3.64X109 and 3.64X1010 Polyhedral inclusion bodies (PIB/ml) achieved 80, 100, 100, 80 & 90% mortality respectively during thirteen days. Another experiment used four PNPV concentrations, 8.2x107, 8.2x 108, 2.6x109 and 8.2x109 PIB/ml caused 100, 70, 67 & 72.7% mortality respectively during ten days. SpliNPV Lethal concentrations LC50 6.2x1014 & LC90 8.9x109 PIB/ml were more than PNPV LC50 2.8X109 & LC90 1.8X108 PIB/ml. Thus PNPV and SpliNPV were effective against Pentodon larvae but PNPV was effective and specific more than SpliNPV. DNA of SpliNPV and PNPV was identified by RAPD PCR using four RAPD primers, Operon A9, A20, B17 & B7 (Operon Technologies, Inc., Alameda, CA, USA) using automated (Bio Rad, USA) thermal cycler. Total 33 bands were produced including 24 PNPV bands with molecular weights between 152-1204 base pairs (bp) included between resulted 9 SpliNPV bands having molecular weights between 138 - 1767 bp. Therefore PNPV is similar to SpliNPV in almost its DNA sites and also is a polymorphic copy from SpliNPV. Thus PNPV and SpliNPV can be recommended against this pest.

Effects of Glyphosate Herbicide on Physiological Parameters of Koi Carp, Cyprinus Carpio (Linnaeus, 1758) Fingerlings

Background: Sub-lethal toxicity bioassay experiments were conducted to determine the toxicity of glyphosate herbicide on Koi carp, Cyprinus carpio fingerlings. Koi carp fingerlings with mean length 8.06 ± 0.99 cm were obtained from a freshwater fish seed hatchery of the university.Methods: The fishes were exposed to sub-lethal concentrations i.e. 1/10th (3.6 mgL-1) and 1/5th (6.6 mgL-1) of glyphosate. Oxygen consumption rate, Ammonia-Nitrogen excretion rate, Oxygen:Nitrogen ratio and food consumption rate were recorded after every 7 days for a period of 28 days.Result: Results indicated significant decrease (P less than 0.05) in oxygen consumption in 1/10th and 1/5th of LC50 concentrations. Ammonia-Nitrogen significcantly increased in exposed fishes. Oxygen : Nitrogen ratio and food consumption rate also significantly decreased (P greater than 0.05) in treated fishes. The results indicated that glyphosate had impacts on exposed fish, hence, the need of regulation of its usage to protect non-targeted species and the environment.

Lethal and sublethal effects of Chrysodeixis includens nucleopolyhedrovirus (ChinNPV)-based biopesticide infecting different larval ages of soybean looper

ABSTRACT Laboratory studies that evaluated lethal and sublethal effects of a commercial biopesticide containing Chrysodeixis includens nucleopolyhedrovirus (ChinNPV: Baculoviridae: Alphabaculovirus) infecting different larval ages of soybean looper (SBL), Chrysodeixis includens (Walker) (Lepidoptera: Noctuidae) are presented. Larvae were infected with different concentrations of ChinNPV by droplet feeding (neonates) and diet surface spray bioassays (neonates and third instar). The following biological parameters were evaluated: larval survival at 7- and 14-d post-infection and at moth eclosion; duration of larval, pupal and larval-to-adult periods; larval and pupal weights; sex ratio; moth deformities; fecundity and fertility. A fertility life table was also developed. Results indicated that neonates of SBL did not develop into adults at the highest concentrations of ChinNPV in both bioassays methods. In contrast, a proportion of the exposed larvae survived to adulthood when exposed to the lowest concentrations (neonates) and in all concentrations tested (third instar). SBL neonates surviving exposure to estimated LC50 and LC75 concentrations (droplet feeding bioassays) had low larval weight, reduced fecundity and fertility, altered sex ratio, and produced fewer females per female. Surviving third instar SBL exposed to the highest concentrations showed low weight and sex ratio alterations. Our findings indicated that, beyond lethal effects, the commercially available baculovirus-based insecticide containing ChinNPV also had substantial sublethal effects on neonates and third instar SBL. In field conditions, these sublethal effects can potentially cause a significant impact in the local population dynamics, including reduction in numbers and infestation levels.

Endophyte Pseudomonas putida enhanced Trifolium repens L. growth and heavy metal uptake: A promising in-situ non-soil cover phytoremediation method of nonferrous metallic tailing

Non-soil cover phytoremediation is the most promising method for high heavy metal contaminated, pH imbalanced and oligotrophic tailing remediation. In this study, a promising method of tailing non-soil cover phytoremediation by endophyte assisting Trifolium repens L. was established. Endophytic Pseudomonas putida strain RE02, with great heavy metal detoxification ability, could colonize in both rhizosphere and endosphere of roots. With RE02 inoculation, the germination percentage of Trifolium repens L. seeds was improved form 40.33%, 45.33% and 56.67%–60.00%, 57.00% and 73.33% in 20 mg/kg Cd, 20 mg/kg Cr and 100 mg/kg Pb contained tailing. The LC50 (concentrations causing 50% mortality of seedlings) and IC50 (concentrations inhibiting the dry biomass by 50%) of Cd, Cr and Pb increased by 6.62, 4.87, 6.27, 4.28, 22.18 and 22.63 mg/kg respectively. Moreover, RE02 inoculation improved soil fertility that the available P and available K was dramatically enhanced in endophyte inoculated groups. Thus, plant NPK concentration was significantly enhanced by 16.72%, 30.55% and 3.81% respectively, and the total heavy metal uptake by 30.03–574.58%. Taken together, Trifolium repens L. successfully grew and developed in heavy metal contaminated, oligotrophic and pH imbalanced tailing, realizing non-soil cover phytoremediation by RE02 inoculation. Overall, this study provided a feasible and promising method for in-situ non-soil cover phytoremediation of tailing, laying a foundation for ecological restoration of tailing.

Sublethal Effects of Chlorantraniliprole on Spodoptera litura (Lepidoptera: Noctuidae) Moth: Implication for Attract-And-Kill Strategy.

The integrated use of plant-derived volatile attractants and synthetic insecticides in attract-and-kill programs is a useful tool for integrated pest management programs reducing pesticide input. Efficient alternative insecticides are critically needed to replace methomyl, which has been banned on cruciferous vegetables in China because it is also highly toxic to nontarget organisms. In the present study, among 15 commonly used insecticides were screened for toxicity against S. litura moths, where chlorantraniliprole, flubendiamide, and emamectin benzoate was found to have the highest levels of toxicity (LC50 of 0.56, 3.85, and 6.03 mg a.i. L−1 respectively). After exposure to the low lethal concentration LC50 of chlorantraniliprole, fecundity of the moths was substantially reduced. Egg-hatching was lower for LC20- and LC50-treated moth pairs than for untreated control pairs. Net reproductive rate (R0), intrinsic rate of increase (r), and finite rate of increase (λ) were significantly reduced in LC50♀ × LC50♂ cohorts. Larval mortality was significantly higher in subsequent generations in pairs of LC50-treated moths. Chlorantraniliprole, which was most toxic and had significant sublethal effects on moths, can be used as an alternative insecticide to methomyl in the attracticide for controlling S. litura moths, and the LC50 indicated a high potential for efficacy in the control S. litura through attract-and-kill schemes.

Actividad de extractos de plantas y hongos entomopatógenos para el control del picudo de la guayaba (Conotrachelus dimidiatus Champion) Coleóptera: Curculionidae

El picudo de la guayaba es el principal problema fitosanitario, ocasionando pérdidas del 60% en la producción; el principal método de control del picudo de la guayaba es la aplicación de insecticidas químicos como el paratión metílico y el malatión. El objetivo del estudio fue evaluar la eficiencia de hongos entomopatógenos en combinación con diferentes extractos vegetales en el control de Conotrachelus dimidiatus. En el presente estudio se evaluó la efectividad biológica de cepas nativas de Beauveria bassiana y Metarhizium anisopliae, la susceptibilidad del picudo de la guayaba a extractos vegetales, así como la compatibilidad de B. bassiana y M. anisopliae con los extractos vegetales para el control del picudo. Se calculó la CL50 de las cepas que presentaron mayor patogenicidad sobre los adultos de C. dimidiatus; posteriormente estos fueron expuestos a las CL50 y concentraciones subletales de los extractos. Los resultados demostraron que las cepas de B. bassiana fueron patogénicas para el insecto. El extracto de pimienta y semilla de jícama mostraron actividad insecticida. Las mezclas entre los hongos y los extractos registraron mortalidades del 90 %.

Chemical composition and toxicity of some Agro waste-derived insecticides against Angoumois grain moth, Sitotroga ceralella (Olivier) [Lepidoptera: Gelechiidae] infesting stored paddy grains

BackgroundAgriculture being one of the major practices in the world has contributed to environmental pollution, especially in developing countries where there were no equipment to recycle the agricultural wastes. Considering the high level of infestation of paddy by Sitotroga cerealella and the high level of pollution caused by agricultural wastes, this research investigated the chemical composition and toxicity of agro wastes (rice husk, maize cob, groundnut and cowpea pods) as eco-friendly protectants of paddy against Sitotroga cerealella. Parameters assessed include adult mortality, oviposition, adult emergence and egg hatchability. Gas chromatography and mass spectrophotometry were used to isolate and characterize the active compounds present in the most effective crude extract.ResultsThe results of the study revealed that all agricultural wastes showed high mortality effect on S. cerealella. Cowpea pod powder was the most toxic to adult paddy moth that caused 33.33%, 36.67%, 46.67%, 50% and 60% mortality of S. cerealella at concentrations 0.1 g, 0.2 g, 0.3 g, 0.4 g and 0.5 g/20 g of paddy grains after 24 h of exposure, respectively. The Cowpea pod, groundnut pod and maize cob extracts caused 100% mortality of S. cerealella at concentration 0.5 ml/20 g of paddy grains after 96 h of exposure, respectively. The lethal concentrations LC50 and LC90 of cowpea pod after 24 h were 0.16 and 0.64 ml which were the lowest of all agro waste extract tested. GC–MS analysis revealed that 19 chemical compounds were present in cowpea pod extract, 9, 12-Octadecadienoic acid (a methyl ester) has the highest percentage total of 39.57% and 4-Pentenal, 2-methylene (0.12%) has the least percentage total.ConclusionAll the observations revealed that cowpea pod was the most effective. The findings also suggested that the selected agricultural wastes have a promising insecticidal potential and can be used as alternatives to synthetic chemical insecticides for the control of stored product insects.

Toxicity and sublethal effects of chlorantraniliprole and indoxacarb on Spodoptera littoralis (Lepidoptera: Noctuidae)

Chlorantraniliprole and indoxacarb insecticides exhibit good efficiency for control lepidopteran pests. The current study is a comprehensive analysis of the effect of lethal and sublethal concentrations of these insecticides on Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae) by using the leaf dipping technique. The LC50 values ranged from 0.06 to 1.07 mg/L, and 0.005 to 0.81 mg/L for chlorantraniliprole and indoxacarb, respectively. Our results showed that the treatment of the 2nd instar larvae with LC50 concentrations of these insecticides significantly increased the length of larval and pupal duration as well as pupal weight in most cases. While, no significant differences have been found in the percentage of hatchability except for LC50 equivalent of indoxacarb. Female behavior regarding calling activity decreased by 50–60% following exposure to the LC50 concentration of both insecticides. Gas chromatography analysis results showed that both insecticides lowered pheromone titer except at chlorantraniliprole LC50 equivalent for (Z,E)-9,12-tetradecadien-l-ol acetate, and indoxacarb LC10 equivalent for (Z)-9-tetradecenyl acetate. Additionally, the activity of mixed-function oxidases and glutathione S-transferase were elevated relative to control. The carboxylesterase activity significantly increased when assayed with both chlorantraniliprole concentrations and indoxacarb LC10 equivalent. These results indicate that chlorantraniliprole and indoxacarb could be effective for S. littoralis control.

The Contamination Effects and Toxicological Characterization of o-Chlorobenzylidene Manolonitrile

Toxicological characterization and global assessment of the toxicity of some chemicals used in the specific technique of the defense and public order system (e.g. o-chlorobenzylidene manolonitrile which enters the composition of the CS gas) is especially useful for environmental protection. Based on the results obtained, the toxicological characterization (acute lethal toxicity) and the harmful potential of some toxic substances, individual or in mixture, against euythermal sweet fish are established. The tests performed aim to change the behavior of the species studied in the presence of chlorobenzylidene manolonitrile, a substance used in the technique of defense and public order system. The tests established the toxicity values of acute lethal concentration LC50 and serve to further determine the maximum allowable concentration that inhibits the development of normal fish fauna in contaminated waters. The test results allow the toxicological characterization and measurement of the acute lethal toxicity of an inhibitor, in order to make more efficient its elimination from the contaminated environment.

Sub-lethal toxicity of alphamethrin on biochemical indices in a freshwater fish, Cyprinus carpio

The focus of the study is to evaluate the effects of a pyrethroid pesticide, alphamethrin on freshwater fish Cyprinus carpio. The LC50 of alphamethrin for 96 h was determined as 6 µg/L. For sub-lethal study, 1/10th (0.6 µg/L-Treatment I) and 1/5th (1.2 µg/L-Treatment II) of 96 h LC50 concentration were exposed to C. carpio for 35 days. At each interval period, biochemical responses such as plasma glucose, protein and muscle glycogen were determined. During the study period, plasma glucose level was significantly increased with decrease in plasma protein in both the treatment groups. The muscle glycogen content in the fishes treated with 0.6 µg/L and 1.2 µg/L of alphamethrin were also observed to decrease significantly. The overall study concludes that alphamethrin at sublethal concentration affects the biochemical indices of Cyprinus carpio. The changes in these biochemical indices can be effectively used to monitor the alphamethrin pesticide in the aquatic environment.

Gill and Muscles abrasion associated with exposure to malathion in fresh water fish

Malathion has a long range of application in agriculture, which leads its accumulation in animal tissues and may influence biochemical balance of aquatic organisms. Present study on fish gills and muscles has remarkable potential in understanding the adverse effect of selected toxicant on the biochemical and structural integrity of tissues. Twelve fingerlings were exposed to LC50 (406 ìg/L) concentration of malathion over a period of 96hrs. Periodic exposure of malathion at 24th, 48th, 72th and 96th hr, resulted in the form of reduction in gills protein content (-13.99%), (-18.56%), (-33.90%) and (48.14%) respectively. On other hand, in muscles similar reductive pattern of protein content was recorded as (-8.25 %), (-26.37%), (25.82%) and (-43.58%). Such negative protein alterations may be used as potential biomarker for pesticide toxicity in fresh water ecosystem.

In vitro evaluation of antimicrobial efficacy of silver zeolite against common oral pathogens.

Antimicrobial efficacy and toxicity analysis of 5 different concentrations of silver zeolite (SZ) compound against 5 common oral pathogens Streptococcus mutans, Streptococcus pyogenes, Lactobacillus sp., Staphylococcus aureus, Candida albicans. The antimicrobial efficacy of 5 different concentrations of SZ was tested against 5 common oral pathogens using the agar well diffusion method and the MIC and MBC values were determined using the micro broth dilution method. The toxicity of all 5 different concentrations was evaluated using brine shrimp assay and lethal concentration (Lc50) value was determined. At 10 μg/mL the antimicrobial activity of SZ was almost negligible. The antimicrobial activity was observed in an increasing trend against all the test microorganisms as the concentration increased. At 75 & 100 μg/mL the zone of inhibitions was more than the control. Furthermore, MIC and MBC values of SZ with concentrations 25, 50, 75, and 100 μg/mL were determined and recorded. SZ was equally effective against all the test organisms. The LC25 (lethal concentration25) value was 1.6 μg/mL, whereas the LC50 value was 1.77 μg/mL and the LC75 value was 1.90 μg/mL, calculated from the probit computational method. SZ has the potential to change the ongoing system and bring about a revolution as an antimicrobial drug. However, the dose must be regulated as it can be toxic in higher concentrations. SZ compounds with the correct study of physicochemical properties and toxicity analysis can increase their pharmacological use and market value.