Dr-Gamal Abouelghar | Menoufiya University (original) (raw)

Papers by Dr-Gamal Abouelghar

Journal of Asia-Pacific Entomology, 2005

Resistance to several classes of insecticides was diagnosed in the cotton leafworm (CL W), Spodop... more Resistance to several classes of insecticides was diagnosed in the cotton leafworm (CL W), Spodoptera littoralis (Boisd.), from cotton fields in the Nile Delta Egypt through 2002-2004 seasons. Two types of laboratory bioassays were used for the detection of insecticide resistance. Leaf-dip larval bioassay and discriminating concentration (LC9 9 for susceptible laboratory strain) technique revealed the presence of resistance to insecticides tested. Both larval and adult stages showed relatively similar response to most insecticides tested. However, the glass vialdiscriminating concentration technique is particularly more useful when resistance is related to the target-site insensitivity rather than to increased metabolism. The pattern of reversion of resistance to five insecticides was determined in two field strains that have been released from continuous insecticide application and then reared under laboratory conditions for 6-8 generations in the absence of insecticide pressure. It was considered that losing of resistance to cypermethrin in both resistant field strains seemed to be quicker than other insecticides tested, in which resistance ratios decreased from 47.7-fold (F0-parents) to 17.8-fold (F6 generation) in MNF-strain, and from 38.5-fold (Fs-parents) to 10.7-fold (F6 generation) in KFR-strain. On the other hand, biochemical assays indicated that both MNF-and KFR-field strains, expressed higher levels of acetylcholinesterase (AChE) activity by 13.2-and 8A-times, respectively, than that of the susceptible strain. AChE activity was sharply decreased to 1.01-and 1.92-times in MNF-and KFRstrains, respectively, compared to that of susceptible strain, following insect rearing for six successive generations without insecticide pressure. Esterases activity was also decreased 2.02-times (F0) to 1.41 (F 6) in MNF-strain and from 2.0-times (F o) to 1.21-times (F 6) in KFR-strain, compared to that of susceptible strain. On the other hand, analysis of esterases by native polyacrylamide gel electrophoresis

Archives Of Phytopathology And Plant Protection, 1991

Anzeiger für Schädlingskunde Pflanzenschutz Umweltschutz, 1992

Studies on the application of a nuclear polyhedrosis virus to control population of the Egyptian ... more Studies on the application of a nuclear polyhedrosis virus to control population of the Egyptian cotton worm, Spodoptera littoralis.

Iranian Journal of Fisheries Sciences, 2020

Fish have been widely documented as useful bioindicator model for ecotoxicological studies becaus... more Fish have been widely documented as useful bioindicator model for ecotoxicological studies because of their differential sensitivity to pollution. Thus, the present study was carried out to determine the sublethal effects of commercial herbicide thiobencarb (Saturn®, 50 EC) on the African catfish (Clarias gariepinus). Fish females were exposed to sublethal concentration of thiobencarb (½ LC50, 0.72 ppm) for 3, 9 and 15 days. Severe abnormality in swimming behavior was observed in fish groups exposed for 9 and 15 days. Biometric parameters, e.g. condition factor, gonadosomatic index and hepatosomatic index were analyzed. An adverse effects on the ovary and liver weights were observed. A significant decrease in absolute fecundity was remarked after exposure to thiobencarb at all three periods. Thiobencarb significantly decreased the activities of serum aspartate aminotransferase and alanine aminotransferase as well as protein and glucose levels. Histopathological changes in the live...

Advanced Journal of Toxicology: Current Research, 2020

The Neonicotinoid insecticides are presently used in great amounts, but this can be a problem whe... more The Neonicotinoid insecticides are presently used in great amounts, but this can be a problem when the possible risks of occupational and environmental contamination are considered. The objective of this study was to investigate the potential adverse effects of sublethal doses of Thiamethoxam insecticide on serum biochemical, oxidative stress and histological alterations in male albino mice via 28-day repeated-dose oral toxicity study. The possible ameliorative effect of selenium plus vitamin E against the harmful effects of Thiamethoxam was also investigated. Mice in Thiamethoxam-treated groups received three sublethal doses (6, 12, and 30 mg/kg b.w./day). Animals in another group were orally co-administered selenium + vitamin E with the higher dose of insecticide. The results showed that Thiamethoxam significantly (p < 0.05) increased cholesterol levels and liver enzyme activities, in dose-dependent manner, compared to those of the control group. Levels of creatinine were not s...

Environmental science and pollution research international, Jan 18, 2018

The aim of this research is to investigate the teratogenic effects of chitosan oligosaccharide in... more The aim of this research is to investigate the teratogenic effects of chitosan oligosaccharide in Wistar female rats (Rattus norvegicus). Chitosan LD50 value was calculated by probit analysis. High dose, 1/10 LD50 which equal to 150 mg/kg body weight, and low dose, 1/30 LD50 which equal to 50 mg/kg body weight, were administrated orally to Wistar female rats to examine the teratogenic effect during organogenesis period from 6th day to 15th day of gestation. Treated and control rats were sacrificed and their foetuses were examined for external, skeletal and visceral anomalies, number and length of foetuses and their weights. Obtained results showed toxicity and teratogenic effects of chitosan on treated rats and their progenies, i.e. high fetal mortality, offspring's weight and length reduction, and high incidence of fetal external, skeletal and visceral abnormalities. This suggested that chitosan is a teratogenic compound, restricted to current results from orally treated Wistar...

Pest Management Science, 2010

Pediculosis is the most prevalent parasitic infestation of humans. Resistance to pyrethrin- and p... more Pediculosis is the most prevalent parasitic infestation of humans. Resistance to pyrethrin- and pyrethroid-based pediculicides is due to knockdown (kdr)-type point mutations in the voltage-sensitive sodium channel alpha-subunit gene. Early detection of resistance is crucial for the selection of effective management strategies. Kdr allele frequencies of lice from 14 countries were determined using the serial invasive signal amplification reaction. Lice collected from Uruguay, the United Kingdom and Australia had kdr allele frequencies of 100%, while lice from Ecuador, Papua New Guinea, South Korea and Thailand had kdr allele frequencies of 0%. The remaining seven countries investigated, including seven US populations, two Argentinian populations and populations from Brazil, Denmark, Czech Republic, Egypt and Israel, displayed variable kdr allele frequencies, ranging from 11 to 97%. The newly developed and validated SISAR method is suitable for accurate monitoring of kdr allele frequencies in head lice. Proactive management is needed where kdr-type resistance is not yet saturated. Based on sodium channel insensitivity and its occurrence in louse populations resistant to pyrethrin- and pyrethroid-based pediculicides, the T917I mutation appears to be a key marker for resistance. Results from the Egyptian population, however, indicate that phenotypic resistance of lice with single or double mutations (M815I and/or L920F) should also be determined.

Journal of cutaneous medicine and surgery

Most people in the United States and Canada with pediculosis will be treated with neurotoxic pedi... more Most people in the United States and Canada with pediculosis will be treated with neurotoxic pediculicides containing pyrethrins or pyrethroids. Their widespread use led to significant resistance reported from various countries. Although treatment failures are frequently observed in Canada, the resistance frequency to pyrethroid pediculicide of human head lice (Pediculus humanus capitis) has not been determined. To determine the knockdown resistance (kdr) allele frequency in human head louse populations in Canada. Patients infested with Pediculus humanus capitis, aged 4 to 65 years, residents of Ontario, Quebec, and British Columbia, were participants. Head lice were collected by combing and picking the enrolled subjects' hair. Lice were analyzed by serial invasive signal amplification reaction (SISAR) for genotyping the T917I mutation of lice indicating permethrin resistance. The permethrin-resistant kdr allele (R allele) frequency could then be evaluated in the head lice colle...

Journal of Plant Protection Research, 2013

Abamectin (Avermectin B1a), is a natural fermentation product derived from the soil bacterium Str... more Abamectin (Avermectin B1a), is a natural fermentation product derived from the soil bacterium Streptomyces avermitilis. Abamectin (Avermectin B1a) is widely used as an insecticide, acaricide, and anthelmintic. The present study assessed the effects of repeated subacute and subchronic exposure to the commercial formulation of abamectin (Vertemic, 1.8% EC) in albino male rats. The toxic effects of abamectin were studied. The various biochemical parameters and histopathological changes were noted. A stomach tube was used to orally administer sublethal doses of abamectin suspended in corn oil to the rats. The animals were divided into four groups. Rats of the group T1 were orally administered a sublethal dose of 30 mg/kg body weight (b.wt.) (1/10 LD50) three times a week for 30 days and the animals in group T2 were exposed to 10 mg/kg b.wt. (1/30 LD50) for 210 days, once a week. Two control groups (C1 and C2) were used in parallel studies, where animals were administered a corn oil vehi...

Journal of Plant Protection Research, 2013

The effects of sublethal concentrations of spinosad (Tracer®) on development, fecundity, and food... more The effects of sublethal concentrations of spinosad (Tracer®) on development, fecundity, and food utilization, in the cotton leafworm, Spodoptera littoralis (Boisd.) were investigated. The fourth-instar larvae were fed on castor bean leaves treated with LC25 (13.9 ppm) or LC50 (57.8 ppm) of spinosad. Pupation and pupal weight were significantly reduced in both LC25 and LC50 treatments, compared with those of the controls. The fecundity rates of females in either LC25 or LC50 treatment were also reduced, compared with the controls. The residual activity of spinosad, applied on cotton at labeled field- and subfield-rates (200 and 70 g active substance (a.s.)/ 200 l water, respectively), was examined against the fifth-instar larvae of S. littoralis. Feeding deterrent effects were significantly demonstrated in larvae that fed on leaves collected from field plots with residual deposits of spinosad at 3 and 7 days old after application (DAA). The residual activity of spinosad on feeding a...

Pesticide Biochemistry and Physiology, 2003

The rapid wide-scale spread of fall armyworm (Spodoptera frugiperda) has caused serious crop loss... more The rapid wide-scale spread of fall armyworm (Spodoptera frugiperda) has caused serious crop losses globally. However, differences in the genetic background of subpopulations and the mechanisms of rapid adaptation behind the invasion are still not well understood. Here we report a 393.25-M chromosome-level genome assembly of fall armyworm with scaffold N50 of 13.3 M consisting of 23281 annotated protein-coding genes. Genome-wide resequencing of 105 samples from 16 provinces in China revealed that the fall armyworm population comprises a complex inter-strain hybrid, mainly with the corn-strain genetic background and less of the rice-strain genetic background, which highlights the inaccuracy of strain identification using mitochondrial or Tpi genes. An analysis of genes related to pesticide-and Bt-resistance showed that the risk of fall armyworm developing resistance to conventional pesticides is very high, while remaining currently susceptible to Bt toxins. Laboratory bioassay results showed that insects invading China carry resistance to organophosphate and pyrethroid pesticides, which is consistent with the results of molecular scanning of resistance-related genes, but are sensitive to genetically modified maize expressing Cry1Ab in field experiments. Additionally, we found that two mitochondrial fragments are inserted into the nuclear genome, and the insertion event occurred after the differentiation of the two strains. This study represents a valuable advancement toward the analysis of genetic differences among subpopulations and improving management strategies for fall armyworm.

Pesticide Biochemistry and Physiology, 2000

Glutathione S-transferases (GSTs) isolated from larval midguts of the fall armyworm, Spodoptera f... more Glutathione S-transferases (GSTs) isolated from larval midguts of the fall armyworm, Spodoptera frugiperda, were used to study their sensitivity to inhibition by 44 chemicals, most of which were plant allelochemicals. Many flavonoids, other phenols, and ␣,␤-unsaturated carbonyl compounds were potent inhibitors of the enzymes. For the flavonoids, apigenin was the best inhibitor among those studied, showing an I 50 value of 8.2 ϫ 10 Ϫ7 M. In general, flavonols exhibited higher inhibitory potencies than flavones; flavonoid glycosides were less inhibitory than their corresponding aglycones. In the case of phenols, tannic acid was the best inhibitor among those tested, showing an I 50 value of 2.0ϫ 10 Ϫ7 M. The organotin compound chlorotriphenyltin was an potent as tannic acid in inhibiting the transferases. For the ␣␤-unsaturated carbonyl compounds, ethacrynic acid was the most potent inhibitor among those examined, showing an I 50 value of 1.5 ϫ 10 Ϫ7 M. However, the isothiocyanates were found to be marginal inhibitors of GSTs. GSTs isolated from larval fat bodies showed differential sensitivity to inhibition by some selected inhibitors compared with midgut GSTs. Kinetic studies of midgut GSTs revealed that ellagic acid exhibited a noncompetitive inhibition toward 1-chloro-2, 4-dinitrobenzene (CDNB) but a competitive inhibition toward glutathione (GSH). In contrast, inhibition by tannic acid and ethacrynic acid were noncompetitive toward both CDNB and GSH. Diethyl maleate did not affect GSH levels in midguts when larvae were topically treated with this compound for up to 24 h.

Pest Management Science, 2003

Three insect growth regulators (IGR), the chitin synthesis inhibitors (CSI) teflubenzuron and hex... more Three insect growth regulators (IGR), the chitin synthesis inhibitors (CSI) teflubenzuron and hexaflumuron and the juvenile hormone mimic (JHM) pyriproxyfen, as well as the organophosphate (OP) pirimiphos-methyl, were evaluated for their activity against the cowpea weevil, Callosobruchus maculatus (F), in cowpea seeds stored for up to 8 months post-treatment. The initial activity data showed that, based on LC50 level, teflubenzuron had strong ovicidal activity (LC50 = 0.056 mg kg −1) followed by pirimiphos-methyl (1.82 mg kg −1) and pyriproxyfen (91.9 mg kg −1). The residual activity data showed that none of the IGRs tested had strong activity when applied at 200 mg kg −1 in reducing the oviposition rates of C maculatus at various storage intervals up to 8 months post-treatment. However, teflubenzuron reduced adult emergence (F1 progeny), achieving control ranging from 96.2% at 1 month to 94.3% at 8 months. Hexaflumuron showed a similar trend in its residual activity, ranging between 93.8% control at 1 month to 88.2% control at 8 months post-treatment. However, pyriproxyfen was more active than the CSIs tested and caused complete suppression (100% control) of adult emergence at all storage intervals. Unlike the IGRs tested, pirimiphos-methyl applied at 25 mg kg −1 was more effective in reducing oviposition rates of C maculatusup to 8 months post-treatment. A strong reduction of adult emergence was also observed at various bimonthly intervals (98.6% control at 1 month to 91.6% control at 8 months post-treatment). The persistence of hexaflumuron and pirimiphos-methyl in cowpea seeds was also studied over a period of 8 months. The loss of hexaflumuron residue in treated cowpeas (200 mg kg −1) was very slow during the first month post-treatment (4.43%). At the end of 8 months, the residue level had declined significantly to 46.4% of the initial applied rate. The loss of pirimiphos-methyl residue in treated cowpeas (25 mg kg −1) was relatively high during the first month post-treatment (36.7%) and increased to 81.6% after 8 months.

Insect Biochemistry and Molecular Biology, 2004

Diflubenzuron (DIMILIN 1) is a powerful insecticidal chemical which has been known for many years... more Diflubenzuron (DIMILIN 1) is a powerful insecticidal chemical which has been known for many years to inhibit chitin synthesis in vivo in insects and related arthropod species. However, its action mechanism has remained unresolved partly because of its inaction on any of the enzymes involved in chitin synthesis in vitro. Based on our previous work (Diflubenzuron affects gamma-thioGTP stimulated Ca 2+ transport in vitro in intracellular vesicles from the integument of the newly molted American cockroach, Periplaneta americana L. Insect Biochem. Mol. Biol. 24 (1994) 1009) showing that diflubenzuron inhibits Ca 2+ uptake by vesicles obtained from the integument of American cockroach, Periplaneta americana (L.), in vitro, we tested the hypothesis that the action site of diflubenzuron is an ABC (ATP binding cassette) transporter, probably a sulfonylurea-sensitive transporter. Glibenclamide, one of the most commonly used sulfonylureas for type II diabetes treatment, was the positive control. When given to immature insects, glibenclamide clearly caused toxicity, with symptoms indicating molting abnormality comparable to diflubenzuron. Its LD 50 (0.472 lg/nymph) was approximately 2.8 times the value obtained for diflubenzuron (0.17 lg/nymph, topical) in German cockroach, Blattella germanica (L.). However, in terms of the inhibitory activities on chitin synthesis, in isolated integuments glibenclamide showed an identical potency to diflubenzuron in B. germanica nymphs. A competitive binding assay with [ 3 H]-glibenclamide and unlabeled diflubenzuron clearly established that the latter is capable of competitively displacing the former radioligand. The K D values observed for vesicles prepared from fruit fly larvae, Drosophila melanogaster M., were 44.9 nM for glibenclamide and 65.0 nM for diflubenzuron, respectively. Furthermore, glibenclamide was found to affect Ca 2+ uptake by isolated cuticular vesicles from B. germanica in a manner very similar to diflubenzuron. These results support our conclusion that the sulfonylurea receptor (SUR) is the target of diflubenzuron in inhibition of chitin synthesis in these two insect species.

Anzeiger für Schädlingskunde Pflanzenschutz Umweltschutz, 1994

The deterrent effects of nine herbicides on feeding and growth of cotton leafworm, Spodoptera lit... more The deterrent effects of nine herbicides on feeding and growth of cotton leafworm, Spodoptera littoralis (Boisd.), larvae were investigated. Fourth-instar larvae were fed on castor-bean leaves treated with recommended field rates of selected herbicides. Nutritional indices were measured regularly throughout the feeding tests until pupation. The food consumed by larvae in most herbicide-treatments was below that of control. Fluazifop [500 active ingredient (AI)], bentazon (250 AI), ametryne (800, 1600 AI), flamprop (130 AI), and isoxynil (187.5 AI) treatments seemed to be the best feeding deterrents. Relative growth rates of larvae fed on leaves treated with bentazon (250 AI), ametryne (1600 AI), gluphosate (1440 AI), glufosinate (800 AI), and bromoxynil (120 AI) were significantly reduced compared to that in control. Likewise, both the efficiency of conversion of ingested food to body substance (ECI) and the efficiency of conversion of digested food to body substance (ECD) were reduced with herbicide treatments below that in control. Approximate digestibility (AD), however, was significantly increased with most herbicide treatments. Moreover, feeding on herbicide-treated leaves resulted in a significant reduction in both pupation and adult emergence compared to that in control.

Pesticide Science, 1992

Five insecticides were tested in the laboratory for their selective activities between the cabbag... more Five insecticides were tested in the laboratory for their selective activities between the cabbage aphid, Brevicoryne brussicae (L.), and its associated parasitoid, Diaeretiella r a p e (M'Intosh). Based on the concentration/mortality regressions, the synthetic pyrethroids tralomethrin and cypermethrin were the most active insecticides against both the cabbage aphid and the parasitoids within the mummified aphids, whereas the carbamate methomyl was the least active. Selectivity ratios, at LC,,, for B. brassicae vs. D. r a p e in the mummified aphids showed that all insecticides tested were more active against E. brassicae than against the parasitoids. All insecticides used at the recommended field rates reduced the emergence of adult parasitoids from mummified aphids by 55-97 O h of that of control. Survival and longevity of emerged D. r a p e were significantly reduced by all insecticides and rates used. Consequently, the latent effects of these insecticides applied at and below the recommended field rates were estimated on the parasitoids through two successive generations. The recommended rates used for both methomyl and cypermethrin reduced fecundity of D. rapae recorded at the F,-generation by 75% of that of control. The emergence of F,-progeny D. rapae was not significantly affected in any treatment, whereas the survival and longevity of adult parasitoids were reduced by most treatments. At the F,-generation, the fecundity of parasitoid females was still lower than in the untreated control. Emergence and survival of adult parasitoids seemed to be slightly affected, whereas the adult longevity was highly affected in all treatments. Methomyl, tralomethrin and cypermethrin might be preferred because they had minimal adverse effects on emergence of parasitoids from the mummified aphids and their subsequent survival, longevity and fecundity, when applied at rates little below the recommended field rates.

Archives Of Phytopathology And Plant Protection, 1994

... GAMAL ES ABO EL-GHAR, ABD EL-GHANY M. EL-SAYED*, ANWAR E. EL-SHIEKH and HOSNY SA RADWAN ... D... more ... GAMAL ES ABO EL-GHAR, ABD EL-GHANY M. EL-SAYED*, ANWAR E. EL-SHIEKH and HOSNY SA RADWAN ... Dr. Gamal ES Abo El-Ghar, Department of Pesticides, Faculty of Agriculture, Minufiya University, Shibin El-Kom, Egypt 531 Page 2. ...

The effectiveness of two synthetic pyrethroids, cypermethrin and fenvalerate, and of methomyl app... more The effectiveness of two synthetic pyrethroids, cypermethrin and fenvalerate, and of methomyl applied to cabbage plants was tested against the cabbage aphid, Brevicoryne brassicae (L.), and its parasitoid, Diaeretiella rapae (M 'Zntosh). Dosage rates chosen were equivalent to the manufacturer'.s maximum and minimum recommendations. Methomyl was considerably more toxic to B. brassicae adults than the two synthetic pyrethroids used. Fenvalerate, at the lowest rate used (71 g h a-') , showed satisfactory effectiveness in reducing aphid adult population on treated plants by c. 77% below that of the control. All insecticides and rates used significantly reduced the emergence of parasitoid adult D. rapae f o m mumm$ed aphids compared to the control. Fenvalerate clearly had less impact on emergence than cypermethrin or methomyl at any dosage used, while methomy1 has appeared to be the most toxic compound in this respect. Longevity of parasitoid adults was highly affected by insecticide application, particularly those adults emerging from mummified aphids exposed to methomyl or cypermethrin. However, only a slight difference in longevity was seen at the lower rate of 71 g ha-' of fenvalerate. At the lowest dosage rates used, methomyl and cypermethrin reduced the F,-progeny of adult parasitoid females by 70,5% and 58.3%, respectively, of the control, whereas fenvalerate reduced the progeny by only 36,4%.

Journal of Asia-Pacific Entomology, 2005

Resistance to several classes of insecticides was diagnosed in the cotton leafworm (CL W), Spodop... more Resistance to several classes of insecticides was diagnosed in the cotton leafworm (CL W), Spodoptera littoralis (Boisd.), from cotton fields in the Nile Delta Egypt through 2002-2004 seasons. Two types of laboratory bioassays were used for the detection of insecticide resistance. Leaf-dip larval bioassay and discriminating concentration (LC9 9 for susceptible laboratory strain) technique revealed the presence of resistance to insecticides tested. Both larval and adult stages showed relatively similar response to most insecticides tested. However, the glass vialdiscriminating concentration technique is particularly more useful when resistance is related to the target-site insensitivity rather than to increased metabolism. The pattern of reversion of resistance to five insecticides was determined in two field strains that have been released from continuous insecticide application and then reared under laboratory conditions for 6-8 generations in the absence of insecticide pressure. It was considered that losing of resistance to cypermethrin in both resistant field strains seemed to be quicker than other insecticides tested, in which resistance ratios decreased from 47.7-fold (F0-parents) to 17.8-fold (F6 generation) in MNF-strain, and from 38.5-fold (Fs-parents) to 10.7-fold (F6 generation) in KFR-strain. On the other hand, biochemical assays indicated that both MNF-and KFR-field strains, expressed higher levels of acetylcholinesterase (AChE) activity by 13.2-and 8A-times, respectively, than that of the susceptible strain. AChE activity was sharply decreased to 1.01-and 1.92-times in MNF-and KFRstrains, respectively, compared to that of susceptible strain, following insect rearing for six successive generations without insecticide pressure. Esterases activity was also decreased 2.02-times (F0) to 1.41 (F 6) in MNF-strain and from 2.0-times (F o) to 1.21-times (F 6) in KFR-strain, compared to that of susceptible strain. On the other hand, analysis of esterases by native polyacrylamide gel electrophoresis

Archives Of Phytopathology And Plant Protection, 1991

Anzeiger für Schädlingskunde Pflanzenschutz Umweltschutz, 1992

Studies on the application of a nuclear polyhedrosis virus to control population of the Egyptian ... more Studies on the application of a nuclear polyhedrosis virus to control population of the Egyptian cotton worm, Spodoptera littoralis.

Iranian Journal of Fisheries Sciences, 2020

Fish have been widely documented as useful bioindicator model for ecotoxicological studies becaus... more Fish have been widely documented as useful bioindicator model for ecotoxicological studies because of their differential sensitivity to pollution. Thus, the present study was carried out to determine the sublethal effects of commercial herbicide thiobencarb (Saturn®, 50 EC) on the African catfish (Clarias gariepinus). Fish females were exposed to sublethal concentration of thiobencarb (½ LC50, 0.72 ppm) for 3, 9 and 15 days. Severe abnormality in swimming behavior was observed in fish groups exposed for 9 and 15 days. Biometric parameters, e.g. condition factor, gonadosomatic index and hepatosomatic index were analyzed. An adverse effects on the ovary and liver weights were observed. A significant decrease in absolute fecundity was remarked after exposure to thiobencarb at all three periods. Thiobencarb significantly decreased the activities of serum aspartate aminotransferase and alanine aminotransferase as well as protein and glucose levels. Histopathological changes in the live...

Advanced Journal of Toxicology: Current Research, 2020

The Neonicotinoid insecticides are presently used in great amounts, but this can be a problem whe... more The Neonicotinoid insecticides are presently used in great amounts, but this can be a problem when the possible risks of occupational and environmental contamination are considered. The objective of this study was to investigate the potential adverse effects of sublethal doses of Thiamethoxam insecticide on serum biochemical, oxidative stress and histological alterations in male albino mice via 28-day repeated-dose oral toxicity study. The possible ameliorative effect of selenium plus vitamin E against the harmful effects of Thiamethoxam was also investigated. Mice in Thiamethoxam-treated groups received three sublethal doses (6, 12, and 30 mg/kg b.w./day). Animals in another group were orally co-administered selenium + vitamin E with the higher dose of insecticide. The results showed that Thiamethoxam significantly (p < 0.05) increased cholesterol levels and liver enzyme activities, in dose-dependent manner, compared to those of the control group. Levels of creatinine were not s...

Environmental science and pollution research international, Jan 18, 2018

The aim of this research is to investigate the teratogenic effects of chitosan oligosaccharide in... more The aim of this research is to investigate the teratogenic effects of chitosan oligosaccharide in Wistar female rats (Rattus norvegicus). Chitosan LD50 value was calculated by probit analysis. High dose, 1/10 LD50 which equal to 150 mg/kg body weight, and low dose, 1/30 LD50 which equal to 50 mg/kg body weight, were administrated orally to Wistar female rats to examine the teratogenic effect during organogenesis period from 6th day to 15th day of gestation. Treated and control rats were sacrificed and their foetuses were examined for external, skeletal and visceral anomalies, number and length of foetuses and their weights. Obtained results showed toxicity and teratogenic effects of chitosan on treated rats and their progenies, i.e. high fetal mortality, offspring's weight and length reduction, and high incidence of fetal external, skeletal and visceral abnormalities. This suggested that chitosan is a teratogenic compound, restricted to current results from orally treated Wistar...

Pest Management Science, 2010

Pediculosis is the most prevalent parasitic infestation of humans. Resistance to pyrethrin- and p... more Pediculosis is the most prevalent parasitic infestation of humans. Resistance to pyrethrin- and pyrethroid-based pediculicides is due to knockdown (kdr)-type point mutations in the voltage-sensitive sodium channel alpha-subunit gene. Early detection of resistance is crucial for the selection of effective management strategies. Kdr allele frequencies of lice from 14 countries were determined using the serial invasive signal amplification reaction. Lice collected from Uruguay, the United Kingdom and Australia had kdr allele frequencies of 100%, while lice from Ecuador, Papua New Guinea, South Korea and Thailand had kdr allele frequencies of 0%. The remaining seven countries investigated, including seven US populations, two Argentinian populations and populations from Brazil, Denmark, Czech Republic, Egypt and Israel, displayed variable kdr allele frequencies, ranging from 11 to 97%. The newly developed and validated SISAR method is suitable for accurate monitoring of kdr allele frequencies in head lice. Proactive management is needed where kdr-type resistance is not yet saturated. Based on sodium channel insensitivity and its occurrence in louse populations resistant to pyrethrin- and pyrethroid-based pediculicides, the T917I mutation appears to be a key marker for resistance. Results from the Egyptian population, however, indicate that phenotypic resistance of lice with single or double mutations (M815I and/or L920F) should also be determined.

Journal of cutaneous medicine and surgery

Most people in the United States and Canada with pediculosis will be treated with neurotoxic pedi... more Most people in the United States and Canada with pediculosis will be treated with neurotoxic pediculicides containing pyrethrins or pyrethroids. Their widespread use led to significant resistance reported from various countries. Although treatment failures are frequently observed in Canada, the resistance frequency to pyrethroid pediculicide of human head lice (Pediculus humanus capitis) has not been determined. To determine the knockdown resistance (kdr) allele frequency in human head louse populations in Canada. Patients infested with Pediculus humanus capitis, aged 4 to 65 years, residents of Ontario, Quebec, and British Columbia, were participants. Head lice were collected by combing and picking the enrolled subjects' hair. Lice were analyzed by serial invasive signal amplification reaction (SISAR) for genotyping the T917I mutation of lice indicating permethrin resistance. The permethrin-resistant kdr allele (R allele) frequency could then be evaluated in the head lice colle...

Journal of Plant Protection Research, 2013

Abamectin (Avermectin B1a), is a natural fermentation product derived from the soil bacterium Str... more Abamectin (Avermectin B1a), is a natural fermentation product derived from the soil bacterium Streptomyces avermitilis. Abamectin (Avermectin B1a) is widely used as an insecticide, acaricide, and anthelmintic. The present study assessed the effects of repeated subacute and subchronic exposure to the commercial formulation of abamectin (Vertemic, 1.8% EC) in albino male rats. The toxic effects of abamectin were studied. The various biochemical parameters and histopathological changes were noted. A stomach tube was used to orally administer sublethal doses of abamectin suspended in corn oil to the rats. The animals were divided into four groups. Rats of the group T1 were orally administered a sublethal dose of 30 mg/kg body weight (b.wt.) (1/10 LD50) three times a week for 30 days and the animals in group T2 were exposed to 10 mg/kg b.wt. (1/30 LD50) for 210 days, once a week. Two control groups (C1 and C2) were used in parallel studies, where animals were administered a corn oil vehi...

Journal of Plant Protection Research, 2013

The effects of sublethal concentrations of spinosad (Tracer®) on development, fecundity, and food... more The effects of sublethal concentrations of spinosad (Tracer®) on development, fecundity, and food utilization, in the cotton leafworm, Spodoptera littoralis (Boisd.) were investigated. The fourth-instar larvae were fed on castor bean leaves treated with LC25 (13.9 ppm) or LC50 (57.8 ppm) of spinosad. Pupation and pupal weight were significantly reduced in both LC25 and LC50 treatments, compared with those of the controls. The fecundity rates of females in either LC25 or LC50 treatment were also reduced, compared with the controls. The residual activity of spinosad, applied on cotton at labeled field- and subfield-rates (200 and 70 g active substance (a.s.)/ 200 l water, respectively), was examined against the fifth-instar larvae of S. littoralis. Feeding deterrent effects were significantly demonstrated in larvae that fed on leaves collected from field plots with residual deposits of spinosad at 3 and 7 days old after application (DAA). The residual activity of spinosad on feeding a...

Pesticide Biochemistry and Physiology, 2003

The rapid wide-scale spread of fall armyworm (Spodoptera frugiperda) has caused serious crop loss... more The rapid wide-scale spread of fall armyworm (Spodoptera frugiperda) has caused serious crop losses globally. However, differences in the genetic background of subpopulations and the mechanisms of rapid adaptation behind the invasion are still not well understood. Here we report a 393.25-M chromosome-level genome assembly of fall armyworm with scaffold N50 of 13.3 M consisting of 23281 annotated protein-coding genes. Genome-wide resequencing of 105 samples from 16 provinces in China revealed that the fall armyworm population comprises a complex inter-strain hybrid, mainly with the corn-strain genetic background and less of the rice-strain genetic background, which highlights the inaccuracy of strain identification using mitochondrial or Tpi genes. An analysis of genes related to pesticide-and Bt-resistance showed that the risk of fall armyworm developing resistance to conventional pesticides is very high, while remaining currently susceptible to Bt toxins. Laboratory bioassay results showed that insects invading China carry resistance to organophosphate and pyrethroid pesticides, which is consistent with the results of molecular scanning of resistance-related genes, but are sensitive to genetically modified maize expressing Cry1Ab in field experiments. Additionally, we found that two mitochondrial fragments are inserted into the nuclear genome, and the insertion event occurred after the differentiation of the two strains. This study represents a valuable advancement toward the analysis of genetic differences among subpopulations and improving management strategies for fall armyworm.

Pesticide Biochemistry and Physiology, 2000

Glutathione S-transferases (GSTs) isolated from larval midguts of the fall armyworm, Spodoptera f... more Glutathione S-transferases (GSTs) isolated from larval midguts of the fall armyworm, Spodoptera frugiperda, were used to study their sensitivity to inhibition by 44 chemicals, most of which were plant allelochemicals. Many flavonoids, other phenols, and ␣,␤-unsaturated carbonyl compounds were potent inhibitors of the enzymes. For the flavonoids, apigenin was the best inhibitor among those studied, showing an I 50 value of 8.2 ϫ 10 Ϫ7 M. In general, flavonols exhibited higher inhibitory potencies than flavones; flavonoid glycosides were less inhibitory than their corresponding aglycones. In the case of phenols, tannic acid was the best inhibitor among those tested, showing an I 50 value of 2.0ϫ 10 Ϫ7 M. The organotin compound chlorotriphenyltin was an potent as tannic acid in inhibiting the transferases. For the ␣␤-unsaturated carbonyl compounds, ethacrynic acid was the most potent inhibitor among those examined, showing an I 50 value of 1.5 ϫ 10 Ϫ7 M. However, the isothiocyanates were found to be marginal inhibitors of GSTs. GSTs isolated from larval fat bodies showed differential sensitivity to inhibition by some selected inhibitors compared with midgut GSTs. Kinetic studies of midgut GSTs revealed that ellagic acid exhibited a noncompetitive inhibition toward 1-chloro-2, 4-dinitrobenzene (CDNB) but a competitive inhibition toward glutathione (GSH). In contrast, inhibition by tannic acid and ethacrynic acid were noncompetitive toward both CDNB and GSH. Diethyl maleate did not affect GSH levels in midguts when larvae were topically treated with this compound for up to 24 h.

Pest Management Science, 2003

Three insect growth regulators (IGR), the chitin synthesis inhibitors (CSI) teflubenzuron and hex... more Three insect growth regulators (IGR), the chitin synthesis inhibitors (CSI) teflubenzuron and hexaflumuron and the juvenile hormone mimic (JHM) pyriproxyfen, as well as the organophosphate (OP) pirimiphos-methyl, were evaluated for their activity against the cowpea weevil, Callosobruchus maculatus (F), in cowpea seeds stored for up to 8 months post-treatment. The initial activity data showed that, based on LC50 level, teflubenzuron had strong ovicidal activity (LC50 = 0.056 mg kg −1) followed by pirimiphos-methyl (1.82 mg kg −1) and pyriproxyfen (91.9 mg kg −1). The residual activity data showed that none of the IGRs tested had strong activity when applied at 200 mg kg −1 in reducing the oviposition rates of C maculatus at various storage intervals up to 8 months post-treatment. However, teflubenzuron reduced adult emergence (F1 progeny), achieving control ranging from 96.2% at 1 month to 94.3% at 8 months. Hexaflumuron showed a similar trend in its residual activity, ranging between 93.8% control at 1 month to 88.2% control at 8 months post-treatment. However, pyriproxyfen was more active than the CSIs tested and caused complete suppression (100% control) of adult emergence at all storage intervals. Unlike the IGRs tested, pirimiphos-methyl applied at 25 mg kg −1 was more effective in reducing oviposition rates of C maculatusup to 8 months post-treatment. A strong reduction of adult emergence was also observed at various bimonthly intervals (98.6% control at 1 month to 91.6% control at 8 months post-treatment). The persistence of hexaflumuron and pirimiphos-methyl in cowpea seeds was also studied over a period of 8 months. The loss of hexaflumuron residue in treated cowpeas (200 mg kg −1) was very slow during the first month post-treatment (4.43%). At the end of 8 months, the residue level had declined significantly to 46.4% of the initial applied rate. The loss of pirimiphos-methyl residue in treated cowpeas (25 mg kg −1) was relatively high during the first month post-treatment (36.7%) and increased to 81.6% after 8 months.

Insect Biochemistry and Molecular Biology, 2004

Diflubenzuron (DIMILIN 1) is a powerful insecticidal chemical which has been known for many years... more Diflubenzuron (DIMILIN 1) is a powerful insecticidal chemical which has been known for many years to inhibit chitin synthesis in vivo in insects and related arthropod species. However, its action mechanism has remained unresolved partly because of its inaction on any of the enzymes involved in chitin synthesis in vitro. Based on our previous work (Diflubenzuron affects gamma-thioGTP stimulated Ca 2+ transport in vitro in intracellular vesicles from the integument of the newly molted American cockroach, Periplaneta americana L. Insect Biochem. Mol. Biol. 24 (1994) 1009) showing that diflubenzuron inhibits Ca 2+ uptake by vesicles obtained from the integument of American cockroach, Periplaneta americana (L.), in vitro, we tested the hypothesis that the action site of diflubenzuron is an ABC (ATP binding cassette) transporter, probably a sulfonylurea-sensitive transporter. Glibenclamide, one of the most commonly used sulfonylureas for type II diabetes treatment, was the positive control. When given to immature insects, glibenclamide clearly caused toxicity, with symptoms indicating molting abnormality comparable to diflubenzuron. Its LD 50 (0.472 lg/nymph) was approximately 2.8 times the value obtained for diflubenzuron (0.17 lg/nymph, topical) in German cockroach, Blattella germanica (L.). However, in terms of the inhibitory activities on chitin synthesis, in isolated integuments glibenclamide showed an identical potency to diflubenzuron in B. germanica nymphs. A competitive binding assay with [ 3 H]-glibenclamide and unlabeled diflubenzuron clearly established that the latter is capable of competitively displacing the former radioligand. The K D values observed for vesicles prepared from fruit fly larvae, Drosophila melanogaster M., were 44.9 nM for glibenclamide and 65.0 nM for diflubenzuron, respectively. Furthermore, glibenclamide was found to affect Ca 2+ uptake by isolated cuticular vesicles from B. germanica in a manner very similar to diflubenzuron. These results support our conclusion that the sulfonylurea receptor (SUR) is the target of diflubenzuron in inhibition of chitin synthesis in these two insect species.

Anzeiger für Schädlingskunde Pflanzenschutz Umweltschutz, 1994

The deterrent effects of nine herbicides on feeding and growth of cotton leafworm, Spodoptera lit... more The deterrent effects of nine herbicides on feeding and growth of cotton leafworm, Spodoptera littoralis (Boisd.), larvae were investigated. Fourth-instar larvae were fed on castor-bean leaves treated with recommended field rates of selected herbicides. Nutritional indices were measured regularly throughout the feeding tests until pupation. The food consumed by larvae in most herbicide-treatments was below that of control. Fluazifop [500 active ingredient (AI)], bentazon (250 AI), ametryne (800, 1600 AI), flamprop (130 AI), and isoxynil (187.5 AI) treatments seemed to be the best feeding deterrents. Relative growth rates of larvae fed on leaves treated with bentazon (250 AI), ametryne (1600 AI), gluphosate (1440 AI), glufosinate (800 AI), and bromoxynil (120 AI) were significantly reduced compared to that in control. Likewise, both the efficiency of conversion of ingested food to body substance (ECI) and the efficiency of conversion of digested food to body substance (ECD) were reduced with herbicide treatments below that in control. Approximate digestibility (AD), however, was significantly increased with most herbicide treatments. Moreover, feeding on herbicide-treated leaves resulted in a significant reduction in both pupation and adult emergence compared to that in control.

Pesticide Science, 1992

Five insecticides were tested in the laboratory for their selective activities between the cabbag... more Five insecticides were tested in the laboratory for their selective activities between the cabbage aphid, Brevicoryne brussicae (L.), and its associated parasitoid, Diaeretiella r a p e (M'Intosh). Based on the concentration/mortality regressions, the synthetic pyrethroids tralomethrin and cypermethrin were the most active insecticides against both the cabbage aphid and the parasitoids within the mummified aphids, whereas the carbamate methomyl was the least active. Selectivity ratios, at LC,,, for B. brassicae vs. D. r a p e in the mummified aphids showed that all insecticides tested were more active against E. brassicae than against the parasitoids. All insecticides used at the recommended field rates reduced the emergence of adult parasitoids from mummified aphids by 55-97 O h of that of control. Survival and longevity of emerged D. r a p e were significantly reduced by all insecticides and rates used. Consequently, the latent effects of these insecticides applied at and below the recommended field rates were estimated on the parasitoids through two successive generations. The recommended rates used for both methomyl and cypermethrin reduced fecundity of D. rapae recorded at the F,-generation by 75% of that of control. The emergence of F,-progeny D. rapae was not significantly affected in any treatment, whereas the survival and longevity of adult parasitoids were reduced by most treatments. At the F,-generation, the fecundity of parasitoid females was still lower than in the untreated control. Emergence and survival of adult parasitoids seemed to be slightly affected, whereas the adult longevity was highly affected in all treatments. Methomyl, tralomethrin and cypermethrin might be preferred because they had minimal adverse effects on emergence of parasitoids from the mummified aphids and their subsequent survival, longevity and fecundity, when applied at rates little below the recommended field rates.

Archives Of Phytopathology And Plant Protection, 1994

... GAMAL ES ABO EL-GHAR, ABD EL-GHANY M. EL-SAYED*, ANWAR E. EL-SHIEKH and HOSNY SA RADWAN ... D... more ... GAMAL ES ABO EL-GHAR, ABD EL-GHANY M. EL-SAYED*, ANWAR E. EL-SHIEKH and HOSNY SA RADWAN ... Dr. Gamal ES Abo El-Ghar, Department of Pesticides, Faculty of Agriculture, Minufiya University, Shibin El-Kom, Egypt 531 Page 2. ...

The effectiveness of two synthetic pyrethroids, cypermethrin and fenvalerate, and of methomyl app... more The effectiveness of two synthetic pyrethroids, cypermethrin and fenvalerate, and of methomyl applied to cabbage plants was tested against the cabbage aphid, Brevicoryne brassicae (L.), and its parasitoid, Diaeretiella rapae (M 'Zntosh). Dosage rates chosen were equivalent to the manufacturer'.s maximum and minimum recommendations. Methomyl was considerably more toxic to B. brassicae adults than the two synthetic pyrethroids used. Fenvalerate, at the lowest rate used (71 g h a-') , showed satisfactory effectiveness in reducing aphid adult population on treated plants by c. 77% below that of the control. All insecticides and rates used significantly reduced the emergence of parasitoid adult D. rapae f o m mumm$ed aphids compared to the control. Fenvalerate clearly had less impact on emergence than cypermethrin or methomyl at any dosage used, while methomy1 has appeared to be the most toxic compound in this respect. Longevity of parasitoid adults was highly affected by insecticide application, particularly those adults emerging from mummified aphids exposed to methomyl or cypermethrin. However, only a slight difference in longevity was seen at the lower rate of 71 g ha-' of fenvalerate. At the lowest dosage rates used, methomyl and cypermethrin reduced the F,-progeny of adult parasitoid females by 70,5% and 58.3%, respectively, of the control, whereas fenvalerate reduced the progeny by only 36,4%.