Insects face diverse biotic and abiotic stresses that can affect their survival. Many of these st... more Insects face diverse biotic and abiotic stresses that can affect their survival. Many of these stressors impact cellular metabolism, often resulting in increased accumulation of reactive oxygen species (ROS). Consequently, insects will respond to these stressors by increasing antioxidant activity and increased production of heat shock proteins (HSPs). In this study, the effect of heat, cold, starvation, and parasitism by Habroacon hebetor wasps was examined in the carob moth, Ectomyelois ceratoniae, to determine which responses were common to different stresses. For all stressors, malondialdehyde levels increased, indicative of oxidative stress in the insects. The activity of two antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT), increased with each stress, suggesting that these enzymes were serving a protective role for the insects. Heat (46°C for 100 min) and cold (-15°C for 30 min) treatments caused significant mortalities to all developmental stages, but pretrea...
The elm leaf beetle, Xanthogalerucella luteola (Muller) (Col.: Chrysomelidae) is a serious pest o... more The elm leaf beetle, Xanthogalerucella luteola (Muller) (Col.: Chrysomelidae) is a serious pest of elm trees and it has been distributed all over the world. The current study was undertaken to investigate the inhibitory effects of protein extracts of three weed seeds including datura Datura stramonium L., amaranth Amaranthus retroflexus L. and wild oat Avena fatua L. against X. luteola α-amylase using spectrophotometric assay as well as in gel assays. The effects of five concentrations of each seed proteinaceous extracts were tested on α-amylase activity of the larval gut. The results showed a dose dependent manner in inhibition of the insect enzyme. At the highest concentration of protein extracts (12 μg protein) of all three seed extracts including amaranth, wild oat and datura, the inhibition was 71, 79 and 31%, respectively. Whilst, at low concentration (0.75 μg protein), the inhibition observed was 15, 36 and 5%, respectively. Thus, the greatest inhibition percentage was obtain...
Journal of Agricultural Science and Technology, 2011
The experiment was conducted to determine �-amylase activity and the effect of seven plant specie... more The experiment was conducted to determine �-amylase activity and the effect of seven plant species extracts including Punica granatum L. (Punicaceae), Rheum officinale B. (Polygonaceae), Rhus coriaria L. (Anacardiaceae), Artemisia sieberi B. ( Compositae ), Peganum harmala L. (Nitrariaceae) , Datura stramonium L. (Solanaceae) and Thymus vulgaris L. (Lamiaceae) on �-amylase activity of four stored insect pests including Callosobruchus maculatus F. (Coleoptera: Bruchidae), Rhyzopertha dominica F. (Coleoptera: Bostrichidae), Sitophilus granarius L. (Coleoptera: Curculionidae), and Trogoderma granarium E. (Coleoptera : Dermestidae). Also, gut pH and optimum temperature for �-amylase activity of these insects were determined. It was found that � - amylases midgut pH of all four insect species was acidic and optimum temperature was between 30 and 40 °C. Beyond these temperatures, the �-amylases activities sharply decreased. Plant extracts caused inhibitory activity on insect �-amylases va...
The two-spotted spider mite, Tetranychus urticae, is a major pest of crops and ornamental plants ... more The two-spotted spider mite, Tetranychus urticae, is a major pest of crops and ornamental plants worldwide. It is a highly polyphagous pest that has a notorious reputation for its ability to rapidly develop resistance to commonly used pesticides. Thus, in the current study, the contact toxicity of propargite (EC 57%) and chlorpyrifos (EC 40.8%) was investigated against two populations of T. urticae from Iran, Mahallat (MhR) and Karaj (KrS), using a leaf-dip bioassay. Findings showed that the LC50 of propargite against MhR and KrS populations was 5337.90 and 116.81 mg a.i/l, respectively. While the LC50 of the chlorpyrifos against MhR and KrS populations was 2760.83 and 479.25 mg a.i/l, respectively. Based on the median lethal concentrations (LC50), MhR and KrS populations were considered as resistant and susceptible populations to both pesticides, respectively. MhR population was 5.76-fold and 45.70-fold more resistant to chlorpyrifos and propargite than the KrS population, respecti...
Journal of Agricultural Science and Technology, 2012
Beet armyworm ( Spodoptera exigua (Hubner)) (Lepidoptera: Noctuidae) is the most economically imp... more Beet armyworm ( Spodoptera exigua (Hubner)) (Lepidoptera: Noctuidae) is the most economically important sugar beet ( Beta vulgaris ) pest worldwide. The main control method of this pest is insecticides use. Thus, it is important to develop alternative means of controlling this pest, including host plant resistance using plant lectins. In the current study, the effects of GNA ( Galanthus nivalis agglutinin) on the growth and development of beet armyworm were investigated using artificial diet. The presence of GNA in the diet at a level of 0.1, 0.25, 0.5 and 1.0% of the total dietary protein significantly reduced larval and pupal survivability compared with the control insects (P< 0.001). When high doses of GNA (0.5 and 1.0% of dietary protein) were incorporated into the diet, no larvae reached the fourth stadium. Only the lowest dose (0.1% GNA) allowed for larval and pupal development to continue to adult. The lectin retarded larval development in a dose dependent manner. For exam...
A study of insect digestive enzymes makes sense given that the gut is the major interface between... more A study of insect digestive enzymes makes sense given that the gut is the major interface between the insect and its environment. An understanding of gut and digestive enzyme function is essential when advanced methods of insect management such as application of enzyme inhibitors and transgenic plants are developed to control insect pests. The aim of the current research project was to study midgut anatomy, midgut pH and α-glucosidase activity in Sunn pest, Eurygaster integriceps Puton (Hemip: Scutelleridae). Sunn pest midgut is comprised of four distinct regions including first ventriculus (V1), second ventriculus (V2), third ventriculus (V3) and finally fourth ventriculus (V4). The study showed that the first three regions of the Sunn pest midgut are more acidic (pH= 5-5.2), the fourth region moderately acidic (pH= 6.2-6.4), and hindgut slightly acidic (pH= 6.5-6.8). Enzyme assay showed that α-glucosidase activity is present in midgut and salivary glands of adult E. intergriceps. ...
The effect of insect growth regulator (pyriproxyfen) on immature stages (eggs and nymphs) of Sunn... more The effect of insect growth regulator (pyriproxyfen) on immature stages (eggs and nymphs) of Sunn pest, Eurygaster integriceps Puton (Heteroptera: Scutelleridae), which is of great importance in wheat and barley fields as nymphal and adult stages, was determined. When one day old eggs were treated with concentrations of 0.0, 0.1, 10, 100 and 1000 ppm, the egg hatchability were 96.90, 92.38, 98.4, 93.21 and 55.23 %, respectively. Similar results obtained when 3 day-old eggs were treated. However, when 5 day-old eggs were treated, no significant differences in egg hatchability between treatments observed (F = 1.51, P > 0.01). Adult weight was significantly influenced by treatment of nymphal instars. Treatments of first nymphal instars caused significant differences in adult weight between control and treatments (F = 25.63, P 0.1). Adult emergence, sex ratio, nymphal survival rate and adults abnormalities were also affected by pyriproxyfen treatments of nymphs.
... Arash Zibaee, Ali Reza Bandani* and Mehdi Tork ... General esterase (EST) and glutathione S-t... more ... Arash Zibaee, Ali Reza Bandani* and Mehdi Tork ... General esterase (EST) and glutathione S-transferases (GST) are the most commonly involved enzymes in the detoxification of penetrated xenobiotics (Zibaee, Jalali Sendi, Alinia, and Ghadamyari 2008a). ...
Two populations of Aphis gossypii were collected from cotton and melon crops treated with insecti... more Two populations of Aphis gossypii were collected from cotton and melon crops treated with insecticides to control this aphid species. The susceptibility of both aphid populations to pymetrozine, Pirimicarb, Oxydemeton-methyl and Imidacloprid was evaluated using leaf deep bioassays in Laboratory which were commonly used to control this aphid on both crops. Results showed that LC50 values of these insecticides against clones of cotton aphid were 452, 1427, 1810 and 209 ppm, respectively. LC50 values of the above mentioned pesticides against clones of melon aphid were 625, 688, 523 and 125 ppm, respectively. Lc50 data showed that aphids reared on melon was 2.07, 1.6 and 3.4 times more susceptible than cotton aphids to Pirimicarb, Imidaclopride and Oxydemeton-methyl and 1.4 times more resistant to Pymetrozine, respectively. In conclusion, it has been shown that clones of cotton aphid is on average 3.4-fold less susceptible to Oxydemeton- methyl, 2-fold less susceptible to pirimicarb, 1...
The Sun pest, Eurygaster integriceps Puton (Hemiptera: Scutelleridae), is a serious pest of wheat... more The Sun pest, Eurygaster integriceps Puton (Hemiptera: Scutelleridae), is a serious pest of wheat. In addition to wheat, it feeds on variety of graminous plant species including barley and rye as well as many grasses. Aim of the current study was to determine the effect of host plant on body weight, lipid and protein content of the adult Sunn pest. Results showed that host plant affected body weight of the Sunn pest. For example adult produced from nymphs grown on wheat and barley had more weight than those of rye. Also, it was observed that the adult females were produced from nymphs grown on wheat had the highest weight followed by barley and rye. Lipid content also was different based on the type of food the insect received. As can be seen the adult female were produced from nymphs grown on wheat had the highest lipid content weight followed by barley and rye. For example the amount of lipid content of the adult female grown on wheat, barley and rye was 32, 28, and 23 mg, respect...
The sunn pest Eurygaster integriceps Puton (Hemiptera: Scutelleridae) is a major pest of wheat an... more The sunn pest Eurygaster integriceps Puton (Hemiptera: Scutelleridae) is a major pest of wheat and barley in wide areas of the world that cause 100% crop loss when no control measures are taken. The aim of this study was to investigate the effect of the seed proteinous extract of different plant species including Chickpea Cicer arietinum (Fabaceae), bean Phaseolus vulgaris var. naz (Fabaceae), triticale Triticosecale wittmack (Poaceae), Celosia argentea (Amaranthaceae) in artificial diet against the Sunn pest growth and development as well as gut serine proteinase such as trypsin and chymotrypsin activities. The obtained results showed that protease inhibitors present in the seed extract affected nymphal development, adult weight and survivability to some extent. Mean developmental time of third and fourth instar nymphs were not significantly affected by the presence of seed extracts. However, developmental time of the fifth instar nymph was affected by seeds proteinous extracts. Be...
The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) is one of the most i... more The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) is one of the most important agricultural pests of the world. It causes direct and indirect damage on plants which decreases in photosynthesis and crop yield. The effect of sublethal concentrations of Artemisia annua L. (Asteraceae) and Rosmarinus officinalis L. (Lamiaceae) essential oils were assessed on development and reproduction para-meters of two-spotted spider mite T. urticae . Lethal and sublethal concentrations were estimated by fumigant bioassay of essential oils on the adults of T. urticae . The raw life history data of all individuals were analyzed according to the age-stage, two-sex life table theory. LC 30 and LC 50 of A. annua (2.908 and 4.14 µl/80 ml air) and R. officinalis (1.339 and 2.006 µl/80 ml air) showed that rosemary essential oil has higher fumigant toxicity against T. urticae . Sublethal concentration of the two plant oils led to significant decrease in fecundity, generation time a...
Rose aphid, Macrosiphum rosae L. (Hemiptera: Aphididae), is a cosmopolitan pest that can cause se... more Rose aphid, Macrosiphum rosae L. (Hemiptera: Aphididae), is a cosmopolitan pest that can cause severe damage to various members of the Rosaceae family. This pest have various hosts during the year, however, it is most commonly found feeding on roses (Mound & Teulon, 1995).The present study for the first time showed that α-amylase is present in the Macrosiphum rosae L. or rose aphid (Hemiptera: Aphididae). α-Amylases have been found to be active in different insect species (Takagi et al., 1971; Baker, 1991; Kazzazi et al., 2005; Zibaee et al., 2008). Rose aphid α-amylase activity pH was determined to be around 7. Generally, optimal pH is corresponding to the pH prevailing in the midgut from which the enzyme has been extracted so these discrepancies seen in midgut pH are related to the different feeding habits and feeding sources. The optimal temperature for Rose aphid α-amylase activity was 45°C, the enzyme was active over a broad temperature range from 20 to 60°C. Analysis of enzyme...
The tomato leafminer, Tuta absoluta (Meyrich) (Lepidoptera: Gelechiidae) is an important pest of ... more The tomato leafminer, Tuta absoluta (Meyrich) (Lepidoptera: Gelechiidae) is an important pest of tomato crops worldwide. The persistent use of organophosphate insecticide to control this pest has led to resistance. However, there is no report on the susceptibility and resistance mechanism of field population of Tuta absoluta (Meyrik) from Iran. Furthermore, the toxicity and impact of chlorpyrifos on metabolic enzymes in this pest remains unknown. The populations of T. absoluta from Rasht in Iran displayed LC30; 4332, LC50; 5010 and LC90; 7027 μg larva to chlorpyrifos. The toxicity of chlorpyrifos could be synergized more bydiethyl maleate (DEM) and triphenylphosphate (TPP) whereas the synergistic effect of piperonylbutoxide (PBO) was not efficient as well as two other synergists. The synergistic effect ranged from 1.3 to 1.9-fold in 24 h and 1.2 to 1.5-fold in 48 h. The exposure with chlorpyrifos for 24 and 48 h significantly increased the activities of esterase and cytochrome P450-...
Biochemical characterization of -amylase in the midgut and salivary glands of Eurygaster maura ... more Biochemical characterization of -amylase in the midgut and salivary glands of Eurygaster maura was conducted. Results showed that -amylase activities were present in the salivary glands and gut. The activity of -amylase in the midgut and in the salivary glands was 0.098 and 0.057 U/ml, respectively. The pH of salivary glands and the gut was determined to be in the range of 5- 5.5 (for the salivary glands) and in the range of 6-6.5 (for the gut), using staining indicator. The optimum pH and temperature for salivary glands and midgut amylase activity was 6-7 and 35-40oC, respectively. The stability of amylase was highest in the acidic pH (4-5). Ethylenediamine tetraacetic acid (EDTA), urea, sodium dodecyl sulfate (SDS) and Mg 2+ inhibited the enzyme activity but, NaCl and KCl enhanced enzyme activity. Based on linear regression analysis of reciprocal starch concentration versus reciprocal amylase activity K m and V max were 0.11% and 0.04 mM maltose/min for midgut amylase and 0....
Insects face diverse biotic and abiotic stresses that can affect their survival. Many of these st... more Insects face diverse biotic and abiotic stresses that can affect their survival. Many of these stressors impact cellular metabolism, often resulting in increased accumulation of reactive oxygen species (ROS). Consequently, insects will respond to these stressors by increasing antioxidant activity and increased production of heat shock proteins (HSPs). In this study, the effect of heat, cold, starvation, and parasitism by Habroacon hebetor wasps was examined in the carob moth, Ectomyelois ceratoniae, to determine which responses were common to different stresses. For all stressors, malondialdehyde levels increased, indicative of oxidative stress in the insects. The activity of two antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT), increased with each stress, suggesting that these enzymes were serving a protective role for the insects. Heat (46°C for 100 min) and cold (-15°C for 30 min) treatments caused significant mortalities to all developmental stages, but pretrea...
The elm leaf beetle, Xanthogalerucella luteola (Muller) (Col.: Chrysomelidae) is a serious pest o... more The elm leaf beetle, Xanthogalerucella luteola (Muller) (Col.: Chrysomelidae) is a serious pest of elm trees and it has been distributed all over the world. The current study was undertaken to investigate the inhibitory effects of protein extracts of three weed seeds including datura Datura stramonium L., amaranth Amaranthus retroflexus L. and wild oat Avena fatua L. against X. luteola α-amylase using spectrophotometric assay as well as in gel assays. The effects of five concentrations of each seed proteinaceous extracts were tested on α-amylase activity of the larval gut. The results showed a dose dependent manner in inhibition of the insect enzyme. At the highest concentration of protein extracts (12 μg protein) of all three seed extracts including amaranth, wild oat and datura, the inhibition was 71, 79 and 31%, respectively. Whilst, at low concentration (0.75 μg protein), the inhibition observed was 15, 36 and 5%, respectively. Thus, the greatest inhibition percentage was obtain...
Journal of Agricultural Science and Technology, 2011
The experiment was conducted to determine �-amylase activity and the effect of seven plant specie... more The experiment was conducted to determine �-amylase activity and the effect of seven plant species extracts including Punica granatum L. (Punicaceae), Rheum officinale B. (Polygonaceae), Rhus coriaria L. (Anacardiaceae), Artemisia sieberi B. ( Compositae ), Peganum harmala L. (Nitrariaceae) , Datura stramonium L. (Solanaceae) and Thymus vulgaris L. (Lamiaceae) on �-amylase activity of four stored insect pests including Callosobruchus maculatus F. (Coleoptera: Bruchidae), Rhyzopertha dominica F. (Coleoptera: Bostrichidae), Sitophilus granarius L. (Coleoptera: Curculionidae), and Trogoderma granarium E. (Coleoptera : Dermestidae). Also, gut pH and optimum temperature for �-amylase activity of these insects were determined. It was found that � - amylases midgut pH of all four insect species was acidic and optimum temperature was between 30 and 40 °C. Beyond these temperatures, the �-amylases activities sharply decreased. Plant extracts caused inhibitory activity on insect �-amylases va...
The two-spotted spider mite, Tetranychus urticae, is a major pest of crops and ornamental plants ... more The two-spotted spider mite, Tetranychus urticae, is a major pest of crops and ornamental plants worldwide. It is a highly polyphagous pest that has a notorious reputation for its ability to rapidly develop resistance to commonly used pesticides. Thus, in the current study, the contact toxicity of propargite (EC 57%) and chlorpyrifos (EC 40.8%) was investigated against two populations of T. urticae from Iran, Mahallat (MhR) and Karaj (KrS), using a leaf-dip bioassay. Findings showed that the LC50 of propargite against MhR and KrS populations was 5337.90 and 116.81 mg a.i/l, respectively. While the LC50 of the chlorpyrifos against MhR and KrS populations was 2760.83 and 479.25 mg a.i/l, respectively. Based on the median lethal concentrations (LC50), MhR and KrS populations were considered as resistant and susceptible populations to both pesticides, respectively. MhR population was 5.76-fold and 45.70-fold more resistant to chlorpyrifos and propargite than the KrS population, respecti...
Journal of Agricultural Science and Technology, 2012
Beet armyworm ( Spodoptera exigua (Hubner)) (Lepidoptera: Noctuidae) is the most economically imp... more Beet armyworm ( Spodoptera exigua (Hubner)) (Lepidoptera: Noctuidae) is the most economically important sugar beet ( Beta vulgaris ) pest worldwide. The main control method of this pest is insecticides use. Thus, it is important to develop alternative means of controlling this pest, including host plant resistance using plant lectins. In the current study, the effects of GNA ( Galanthus nivalis agglutinin) on the growth and development of beet armyworm were investigated using artificial diet. The presence of GNA in the diet at a level of 0.1, 0.25, 0.5 and 1.0% of the total dietary protein significantly reduced larval and pupal survivability compared with the control insects (P< 0.001). When high doses of GNA (0.5 and 1.0% of dietary protein) were incorporated into the diet, no larvae reached the fourth stadium. Only the lowest dose (0.1% GNA) allowed for larval and pupal development to continue to adult. The lectin retarded larval development in a dose dependent manner. For exam...
A study of insect digestive enzymes makes sense given that the gut is the major interface between... more A study of insect digestive enzymes makes sense given that the gut is the major interface between the insect and its environment. An understanding of gut and digestive enzyme function is essential when advanced methods of insect management such as application of enzyme inhibitors and transgenic plants are developed to control insect pests. The aim of the current research project was to study midgut anatomy, midgut pH and α-glucosidase activity in Sunn pest, Eurygaster integriceps Puton (Hemip: Scutelleridae). Sunn pest midgut is comprised of four distinct regions including first ventriculus (V1), second ventriculus (V2), third ventriculus (V3) and finally fourth ventriculus (V4). The study showed that the first three regions of the Sunn pest midgut are more acidic (pH= 5-5.2), the fourth region moderately acidic (pH= 6.2-6.4), and hindgut slightly acidic (pH= 6.5-6.8). Enzyme assay showed that α-glucosidase activity is present in midgut and salivary glands of adult E. intergriceps. ...
The effect of insect growth regulator (pyriproxyfen) on immature stages (eggs and nymphs) of Sunn... more The effect of insect growth regulator (pyriproxyfen) on immature stages (eggs and nymphs) of Sunn pest, Eurygaster integriceps Puton (Heteroptera: Scutelleridae), which is of great importance in wheat and barley fields as nymphal and adult stages, was determined. When one day old eggs were treated with concentrations of 0.0, 0.1, 10, 100 and 1000 ppm, the egg hatchability were 96.90, 92.38, 98.4, 93.21 and 55.23 %, respectively. Similar results obtained when 3 day-old eggs were treated. However, when 5 day-old eggs were treated, no significant differences in egg hatchability between treatments observed (F = 1.51, P > 0.01). Adult weight was significantly influenced by treatment of nymphal instars. Treatments of first nymphal instars caused significant differences in adult weight between control and treatments (F = 25.63, P 0.1). Adult emergence, sex ratio, nymphal survival rate and adults abnormalities were also affected by pyriproxyfen treatments of nymphs.
... Arash Zibaee, Ali Reza Bandani* and Mehdi Tork ... General esterase (EST) and glutathione S-t... more ... Arash Zibaee, Ali Reza Bandani* and Mehdi Tork ... General esterase (EST) and glutathione S-transferases (GST) are the most commonly involved enzymes in the detoxification of penetrated xenobiotics (Zibaee, Jalali Sendi, Alinia, and Ghadamyari 2008a). ...
Two populations of Aphis gossypii were collected from cotton and melon crops treated with insecti... more Two populations of Aphis gossypii were collected from cotton and melon crops treated with insecticides to control this aphid species. The susceptibility of both aphid populations to pymetrozine, Pirimicarb, Oxydemeton-methyl and Imidacloprid was evaluated using leaf deep bioassays in Laboratory which were commonly used to control this aphid on both crops. Results showed that LC50 values of these insecticides against clones of cotton aphid were 452, 1427, 1810 and 209 ppm, respectively. LC50 values of the above mentioned pesticides against clones of melon aphid were 625, 688, 523 and 125 ppm, respectively. Lc50 data showed that aphids reared on melon was 2.07, 1.6 and 3.4 times more susceptible than cotton aphids to Pirimicarb, Imidaclopride and Oxydemeton-methyl and 1.4 times more resistant to Pymetrozine, respectively. In conclusion, it has been shown that clones of cotton aphid is on average 3.4-fold less susceptible to Oxydemeton- methyl, 2-fold less susceptible to pirimicarb, 1...
The Sun pest, Eurygaster integriceps Puton (Hemiptera: Scutelleridae), is a serious pest of wheat... more The Sun pest, Eurygaster integriceps Puton (Hemiptera: Scutelleridae), is a serious pest of wheat. In addition to wheat, it feeds on variety of graminous plant species including barley and rye as well as many grasses. Aim of the current study was to determine the effect of host plant on body weight, lipid and protein content of the adult Sunn pest. Results showed that host plant affected body weight of the Sunn pest. For example adult produced from nymphs grown on wheat and barley had more weight than those of rye. Also, it was observed that the adult females were produced from nymphs grown on wheat had the highest weight followed by barley and rye. Lipid content also was different based on the type of food the insect received. As can be seen the adult female were produced from nymphs grown on wheat had the highest lipid content weight followed by barley and rye. For example the amount of lipid content of the adult female grown on wheat, barley and rye was 32, 28, and 23 mg, respect...
The sunn pest Eurygaster integriceps Puton (Hemiptera: Scutelleridae) is a major pest of wheat an... more The sunn pest Eurygaster integriceps Puton (Hemiptera: Scutelleridae) is a major pest of wheat and barley in wide areas of the world that cause 100% crop loss when no control measures are taken. The aim of this study was to investigate the effect of the seed proteinous extract of different plant species including Chickpea Cicer arietinum (Fabaceae), bean Phaseolus vulgaris var. naz (Fabaceae), triticale Triticosecale wittmack (Poaceae), Celosia argentea (Amaranthaceae) in artificial diet against the Sunn pest growth and development as well as gut serine proteinase such as trypsin and chymotrypsin activities. The obtained results showed that protease inhibitors present in the seed extract affected nymphal development, adult weight and survivability to some extent. Mean developmental time of third and fourth instar nymphs were not significantly affected by the presence of seed extracts. However, developmental time of the fifth instar nymph was affected by seeds proteinous extracts. Be...
The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) is one of the most i... more The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) is one of the most important agricultural pests of the world. It causes direct and indirect damage on plants which decreases in photosynthesis and crop yield. The effect of sublethal concentrations of Artemisia annua L. (Asteraceae) and Rosmarinus officinalis L. (Lamiaceae) essential oils were assessed on development and reproduction para-meters of two-spotted spider mite T. urticae . Lethal and sublethal concentrations were estimated by fumigant bioassay of essential oils on the adults of T. urticae . The raw life history data of all individuals were analyzed according to the age-stage, two-sex life table theory. LC 30 and LC 50 of A. annua (2.908 and 4.14 µl/80 ml air) and R. officinalis (1.339 and 2.006 µl/80 ml air) showed that rosemary essential oil has higher fumigant toxicity against T. urticae . Sublethal concentration of the two plant oils led to significant decrease in fecundity, generation time a...
Rose aphid, Macrosiphum rosae L. (Hemiptera: Aphididae), is a cosmopolitan pest that can cause se... more Rose aphid, Macrosiphum rosae L. (Hemiptera: Aphididae), is a cosmopolitan pest that can cause severe damage to various members of the Rosaceae family. This pest have various hosts during the year, however, it is most commonly found feeding on roses (Mound & Teulon, 1995).The present study for the first time showed that α-amylase is present in the Macrosiphum rosae L. or rose aphid (Hemiptera: Aphididae). α-Amylases have been found to be active in different insect species (Takagi et al., 1971; Baker, 1991; Kazzazi et al., 2005; Zibaee et al., 2008). Rose aphid α-amylase activity pH was determined to be around 7. Generally, optimal pH is corresponding to the pH prevailing in the midgut from which the enzyme has been extracted so these discrepancies seen in midgut pH are related to the different feeding habits and feeding sources. The optimal temperature for Rose aphid α-amylase activity was 45°C, the enzyme was active over a broad temperature range from 20 to 60°C. Analysis of enzyme...
The tomato leafminer, Tuta absoluta (Meyrich) (Lepidoptera: Gelechiidae) is an important pest of ... more The tomato leafminer, Tuta absoluta (Meyrich) (Lepidoptera: Gelechiidae) is an important pest of tomato crops worldwide. The persistent use of organophosphate insecticide to control this pest has led to resistance. However, there is no report on the susceptibility and resistance mechanism of field population of Tuta absoluta (Meyrik) from Iran. Furthermore, the toxicity and impact of chlorpyrifos on metabolic enzymes in this pest remains unknown. The populations of T. absoluta from Rasht in Iran displayed LC30; 4332, LC50; 5010 and LC90; 7027 μg larva to chlorpyrifos. The toxicity of chlorpyrifos could be synergized more bydiethyl maleate (DEM) and triphenylphosphate (TPP) whereas the synergistic effect of piperonylbutoxide (PBO) was not efficient as well as two other synergists. The synergistic effect ranged from 1.3 to 1.9-fold in 24 h and 1.2 to 1.5-fold in 48 h. The exposure with chlorpyrifos for 24 and 48 h significantly increased the activities of esterase and cytochrome P450-...
Biochemical characterization of -amylase in the midgut and salivary glands of Eurygaster maura ... more Biochemical characterization of -amylase in the midgut and salivary glands of Eurygaster maura was conducted. Results showed that -amylase activities were present in the salivary glands and gut. The activity of -amylase in the midgut and in the salivary glands was 0.098 and 0.057 U/ml, respectively. The pH of salivary glands and the gut was determined to be in the range of 5- 5.5 (for the salivary glands) and in the range of 6-6.5 (for the gut), using staining indicator. The optimum pH and temperature for salivary glands and midgut amylase activity was 6-7 and 35-40oC, respectively. The stability of amylase was highest in the acidic pH (4-5). Ethylenediamine tetraacetic acid (EDTA), urea, sodium dodecyl sulfate (SDS) and Mg 2+ inhibited the enzyme activity but, NaCl and KCl enhanced enzyme activity. Based on linear regression analysis of reciprocal starch concentration versus reciprocal amylase activity K m and V max were 0.11% and 0.04 mM maltose/min for midgut amylase and 0....
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