Effect of fenvalerate on oxidative stress biomarkers in the brackish water prawn Penaeus monodon

The toxicity of fenvalerate to the prawn Penaeus monodon was evaluated using biomarkers of stress. In a preliminary bioassay test, P. monodon was exposed to a series of fenvalerate concentrations, which showed 4, 6.5 and 8.5 μg L⁻¹ to be sublethal, median lethal and lethal, respectively. Sublethal effect of fenvalerate was further evaluated in hepatopancreas, muscle and gills of prawns with reference to oxidative stress biomarkers. Significant induction of lipid peroxidation and glutathione-S-transferase activity was found in hepatopancreas, muscle and gills of prawns exposed to fenvalerate when compared to control (P < 0.001, P < 0.05 and P < 0.05). On the contrary, the activities of Superoxide dismutase, catalase, glutathione peroxidase, vitamin C, vitamin E and glutathione were found to be reduced in the experimental group of prawns when compared to control. The results suggest that the animals were under oxidative stress when exposed to sublethal concentration of fenvalerate.     

加州新小绥螨对朱砂叶螨的控制作用

为明确加州新小绥螨Neoseiulus californicus（McGregor）国内种群对朱砂叶螨Tetranychus cinnabarinus（Boisduval）的控制潜力,应用功能反应、数值反应及实验种群生命表参数评价了该捕食螨对朱砂叶螨的控制能力。加州新小绥螨对朱砂叶螨的功能反应能很好地拟合Holling Ⅱ方程。在25℃,加州新小绥螨雌成螨对朱砂叶螨卵、幼螨、若螨和成螨的功能反应参数a/T_h值分别为42.4195、81.6275、54.3044和17.9399,对朱砂叶螨幼螨、若螨和卵的控制力高于成螨。在19~31℃,加州新小绥螨对朱砂叶螨雌成螨日均捕食量和对猎物的控制能力a/T_h随温度升高而增大,在31℃时达最大值,分别为10.80头和29.5364。在28℃时,加州新小绥螨的净增殖率和内禀增长率分别为26.1522和0.2213。表明加州新小绥螨国内种群表现出重要的生物防治潜能。     

Biochemical alteration induced by monocrotophos in the blood plasma of fish, Channa punctatus (Bloch)

Monocrotophos (MCP), commonly known as azodrin, is one of the organophosphate (OP) pesticides extensively used in agricultural practices throughout the world. Channa punctatus were exposed to sublethal concentrations (0.96 and 1.86 mg/L) of monocrotophos for 15 and 60 days to assess the alterations in the level of some biochemical parameters in blood plasma. Significant alterations in all the biochemical parameters were found to be dose dependent. Hypoglycemia and hypocholesteremia were observed in plasma of fish at both exposure periods (15 and 60 days). Increased activities of glutamate-oxalacetate transaminase (GOT), glutamate-pyruvate transaminase (GPT), acid and alkaline phosphatase of blood plasma indicated hepatic tissue damage. Decrease in lactate dehydrogenase (LDH) content in plasma further indicated lower metabolic rate after 60 days of exposure. Significant decline in triglycerides content was observed in fish exposed to both sublethal concentrations of monocrotophos. We suggest that analysis of biochemical parameters in the fish blood may be useful in environmental biomonitoring.     

Biochemical studies on sheep body louse Bovicola ovis (Schrank) (Phthiraptera: Trichodectidae): comparison of pyrethroid and organophosphate resistant and susceptible strains

Strains of sheep louse Bovicola ovis (Schrank) with various levels of resistance to pyrethroid and one strain with high degree of resistance to organophosphate (OP) insecticides were used to investigate the biochemical mechanisms of insecticide resistance, i.e., enhanced levels of general esterases, specific acetylcholinesterases (AChE), glutathione S-transferase (GST), and mixed function oxidases. Native gel electrophoresis combined with quantitative enzyme assays showed analogous expression profiles of several esterase isozymes in all the strains tested. The determination of the sensitivity of each esterase isozyme to five inhibitors (acetylthiocholine iodide, butyrylthiocholine iodide, paraoxon eserine sulfate, and pCMB) led to the identification of nine esterases in the B. ovis strain. Gel electrophoresis results are supported by enzyme assay studies where, except for the OP resistant strain, no differences in esterase activities were detected in all the pyrethroid resistant and susceptible strains assayed. Statistical analyses demonstrated that some strains have elevated GST activities compared to the susceptible reference strain.     

Biological activity of the essential oil from the leaves of Piper sarmentosum Roxb. (Piperaceae) and its chemical constituents on Brontispa longissima (Gestro) (Coleoptera: Hispidae)

The results showed that the essential oil from Piper sarmentosum has strong antifeedant and toxicity effects on Brontispa longissima. The best antifeedant and contact toxicity effects were observed in the 1st-2nd instar larvae. The essential oil also displayed a notable fumigation effect on the eggs and pupae of B. longissima. It took the control-treated insects 43.34 d to complete one generation, while the insects treated with 2000 mg/L essential oil needed 73.58 d. The essential oil was analyzed by gas chromatography/mass spectrometry and 41 components were identified. Myristicin (65.22%) and trans-caryophyllene (13.89%) were the major components. Myristicin exhibited strong antifeedant and contact toxicity effects on both the 3rd instar larvae and the imagoes of B. longissima, when it showed a significant fumigation effect on the eggs and pupae of B. longissima. Another P. sarmentosum essential oil and myristicin all showed a strong inhibiting effect on the growth and development of B. longissima along with the activity of AChE, CarE, GSTs and Na⁺, K⁺-ATPase in B. longissima larvae.     

The effects of Artemisia annua L. and Achillea millefolium L. crude leaf extracts on the toxicity, development, feeding efficiency and chemical activities of small cabbage Pieris rapae L. (Lepidoptera: Pieridae)

The biological effects of two important medicinal plants, Artemisia annua L. and Achillea millefolium (L.) (viz, mortality, growth, and feeding indices as well as enzyme and non-enzymatic activities) were studied on small white Pieris rapae L a deleterious pest of cruciferous plants under controlled conditions (16:8 h L:D at 25 ± 1 °C and 65 ± 5% RH). The LC₅₀ and LC₂₅ values were 9.387% and 3.645% for A. annua L. and 4.19% and 1.69% for A. millefolium (L.), respectively. At the lowest concentration (0.625%), the deterrency was 29.826% and 44.185% for A. annua L. and A. millefolium (L.), respectively. Feeding indices were variously affected with changes in a number of parameters and an increase in larval and pupal duration. The activity level of alkaline phosphatase increased sharply while alanin and aspartate aminotransferases showed a sharp decrease. For non-enzymatic compounds, the amount of glucose and uric acid increased, but total protein and cholesterol decreased. These results indicate that these two medicinal plants might possess potential secondary metabolites that may be useful for controlling potential insect pests.     

Investigation of acute toxicity of (2,4-dichlorophenoxy)acetic acid (2,4-D) herbicide on crayfish (Astacus leptodactylus Esch. 1823)

The acute 96 h LC₅₀ of (2,4-dichlorophenoxy)acetic acid (2,4-D), a widely used agricultural herbicide, was determined on crayfish (Astacus leptodactylus Esch. 1823). Crayfish of 23.5 ± 1.49 g mean weight and 9.6 ± 0.21 cm mean length were selected for the bioassay experiments. The experiments were repeated three times, in 10 L tap water. The data obtained were statistically evaluated by the use of the E.P.A computer program based on Finney’s probit analysis method and the 96 h LC₅₀ value for crayfish was calculated to be 32.6 mg/L in a static bioassay test system. 95% lower and upper confidence limits for the LC₅₀ were 15.10-327.16. In conclusion, 2,4-D is highly toxic to crayfish, a non-target organism in the ecosystem. Water temperature was 23 ± 1 °C. Behavioral changes of crayfish were recorded for all herbicide concentrations.     

灭蚊幼球形芽孢杆菌漂浮颗粒剂研制与应用

根据蚊虫的生活习性和球形芽孢杆菌BS-10灭蚊特点,以玉米棒芯颗粒为载体、以球型芽胞杆菌BS-10为杀虫活性物质,加工制成生物灭蚊漂浮颗粒剂新剂型,经试验与示范应用,该颗粒剂具有高效,毒力效价达106.5 IU／mg,每平方米水面使用颗粒剂2 g,对蚊幼虫(孑孓)杀灭效果达95%以上;持效期长,药后12 d,灭蚊效果达96.8%;性质稳定,室内常温储存1 a,药效无变化;生产工艺简单,药剂使用方便,与环境相容性好。     

Effect of Basudin, Selecron and the phytoalkaloid Colchicine (pesticides) on biological and molecular parameters of Biomphalaria alexandrina snails

The results showed that survival rates of Biomphalaria alexandrina snails, reproductive potential and hatchability of eggs were evaluated post exposure to Basudin, Selecron and Colchicine. As well, DNA and RNA changes in the cells of ovotestis-digestive gland complex of treated snails were estimated. The current molluscicide Bayluscide was used as a reference compound.The pesticide Selecron proved to be more toxic to B. alexandrina snails than Basudin and Colchicine. Juvenile snails were dead post 3 weeks of exposure to the sublethal concentration LC₀ of either Selecron or Basudin, while 26.75% of snails still alive at Bayluscide treatment. In addition, exposure of adult snails to LC₀ of Selecron for 24 h/week for 4 weeks markedly reduced their reproductive rate (R₀) by 89.9%. Moreover, snails’ eggs failed to hatch post 24 h of exposure to LC₉₀ of either Selecron, Basudin or Bayluscide. Electrophoretic analysis indicated a decrease in the molecular weight of intact DNA in the ovotestis-digestive gland complex of snails treated with 250 ppm of Colchicine and LC₂₅ of Selecron, as it scored 1.2 and 76 bp, respectively, compared to 166.46 bp for control group, while the vice versa was recorded for RNA intensity. It was concluded that the tested pesticides have deleterious effects on snails’ reproductive rate, their eggs and the intensities of DNA and RNA in their ovotestis-digestive gland complex. Therefore, it is expected that reaching of such pesticides to snails’ habitats in water courses during plant pests control could minimize the population density of the snails intermediate hosts of schistosomiasis, hence probably interrupt and reduce the transmission of this parasite.     

Effects of Artemisia annua L. (Asteracea) on nutritional physiology and enzyme activities of elm leaf beetle, Xanthogaleruca luteola Mull. (Coleoptera: Chrysomellidae)

Methanolic extract of Artemisia annua L., a weed collected around paddy fields in north of Iran, was investigated for its toxic effects on: feeding, growth, fecundity, fertility including the biochemical characteristics of elm leaf beetle Xanthogaleruca luteola Mull. The toxicity tests indicate that insecticidal effect was 2.4-fold higher in 3rd instar larvae than in adults. The LC₅₀ was 48% and 43.77% of a methanolic leaf extract at 24 and 48 h, respectively. The feeding deterrence was highest at 10% concentration and lowest at 0.625% for 3rd instar larvae and adults during the first 24 h and decreased thereafter. Larval duration significantly increased at higher concentrations. Larval treatment with 10% methanolic extract resulted in deformed adults (adultoids) with drastic changes in gross morphology of female reproductive system. Food digestion and assimilation significantly decreased in adults. Larval duration and adult fecundity and fertility were also significantly reduced. Twenty-four hours after treating 3rd instar larva with the extract the levels of glucose, protein, urea, uric acid, α-amylase, alkaline phosphatase, alanine amino transferase and aspartate amino transferase significantly changed. However, at 48 h the extract lost its potency. The extract did not effect the level of cholesterol in treated larva. These results indicate that Artemisia annua L. extract contains inhibitors of key metabolic pathways that may be useful in future control of the elm leaf beetle.     

高、低温处理对斜纹夜蛾生长发育、存活及耐寒性的影响

为探究短期高、低温对斜纹夜蛾的影响,将其3龄幼虫于35 ℃高温和13 ℃低温分别处理8、16、24、32 h后观察生长发育和存活情况,并比较其于-5 ℃胁迫下的耐寒性变化。结果表明,与对照温度相比,高温处理8 h的斜纹夜蛾3龄幼虫,其4～6龄各龄发育历期显著延长;处理24 h和32 h的幼虫其3、4、6龄发育历期缩短;各处理的预蛹期均缩短,3～5龄幼虫存活率显著降低。低温处理后3～6龄各龄发育历期显著延长,存活率显著降低。高、低温处理后幼虫化蛹率均降低,蛹重减小,且低温的伤害作用大于高温。高、低温处理8 h的3龄幼虫-5 ℃胁迫后耐寒性显著提高,存活率分别为对照的1.15和1.29倍;处理24 h和32 h的幼虫耐寒性及存活率均较对照显著下降。表明短期高、低温处理对斜纹夜蛾的生长发育和存活会产生不利影响,但一定程度上可提高其耐寒性。     

Potentiation/antagonism of deltamethrin and cypermethrins with organophosphate insecticides in the cotton bollworm, Helicoverpa armigera (Lepidoptera: Noctuidae)

The joint action of pyrethroids deltamethrin and cypermethrins in combination with organophosphates ethion, profenofos, chlorpyrifos, quinalphos, and triazophos was studied on putatively resistant field populations of Helicoverpa armigera from Pakistan by using a leaf-dip method. Ethion produced a good potentiation with deltamethrin, cypermethrin, alphacypermethrin, and zetacypermethrin, whereas profenofos, chlorpyrifos, quinalphos, and triazophos exhibited an antagonism with deltamethrin as well as cypermethrins. Implications of using mixtures for counteracting insecticide resistance are discussed.     

暗黑赤眼蜂对梨小食心虫卵的寄生作用

为检验暗黑赤眼蜂Trichogramma pintoi Voegele对梨小食心虫Grapholita molesta(Busck)卵的寄生效果,在室内条件下,以松毛虫赤眼蜂Trichogramma dendrolimi Matsumura为对照,比较暗黑赤眼蜂对其自然寄主棉铃虫Helicoverpa armigera(Hübner)和非自然寄主梨小食心虫的寄生效果。暗黑赤眼蜂与松毛虫赤眼蜂对梨小食心虫卵的寄生率和在被寄生卵中的羽化率差异均不显著。暗黑赤眼蜂对梨小食心虫卵的寄生率显著高于对棉铃虫卵的寄生率;在15、45、60和75粒卵/管条件下,暗黑赤眼蜂寄生梨小食心虫和棉铃虫卵后羽化率差异不显著,但在30和90粒卵/管条件下,羽化率差异显著。拟合分析显示,暗黑赤眼蜂和松毛虫赤眼蜂对梨小食心虫卵的寄生符合Holling-Ⅱ型功能反应圆盘方程,说明暗黑赤眼蜂是一种防治梨小食心虫的潜在寄生蜂。     

Oxidative stress and locomotor behaviour response as biomarkers for assessing recovery status of mosquito fish, Gambusia affinis after lethal effect of an organophosphate pesticide, monocrotophos

Recovery study was performed at regular intervals to establish the time course of 50% and 100% recovery in neurotransmitter enzyme (acetylcholinesterase, AChE, EC 3.1.1.7) and locomotor behaviour response of mosquito fish, Gambusia affinis exposed to lethal concentration (20.49 mg L⁻¹) of an organophosphorous pesticide, monocrotophos (MCP) for 96 h. In vitro AChE activity studies indicated that MCP could cause 50% inhibition (I₅₀) at 10.2 × 10⁻⁵ M. A positive correlation was observed between brain AChE activity and swimming speed during the recovery study. Also, the recovery response of the antioxidant enzymes superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6) and glutathione reductase (GR, EC 1.6.4.2) as well as lipid peroxidation (LPO) as biomarkers of oxidative stress were assessed in viscera of G. affinis. The results showed that the MCP besides its inhibitory effect on target enzyme AChE activity and induction in antioxidant enzyme activities as a characteristic of oxidative stress, which can be used as biomarkers in the pesticide contaminated aquatic streams.     

Interaction of Cry1Ac toxin (Bacillus thuringiensis) and proteinase inhibitors on the growth, development, and midgut proteinase activities of the bollworm, Helicoverpa zea

Potential resistance development to Bt cotton in certain lepidopterans has prompted research to develop strategies that will preserve this environmental-friendly biotechnology. Proteinase inhibitors are potential candidates for enhancing Bt toxicity against lepidopteran pests and for expanding the spectrum of control for other insects. Interactions of Bt toxin from Bacillus thuringiensis and proteinase inhibitors were investigated by monitoring growth, development, and gut proteinase activities of the bollworm, Helicoverpa zea. Several proteinase inhibitors were combined with Bt protoxin Cry1Ac in artificial diet and fed to newly molted 3rd-instar bollworm larvae to determine effects on larval body weight and length, pupation progress, and mortality rate. Major midgut proteinase activities, including caseinase, tryptic, and chymotrypsin activities, were examined after treatment. A concentration of Bt at a level causing minimal mortality (<10%), was mixed with the following proteinase inhibitors: benzamidine, phenylmethylsulfonyl fluoride (PMSF), and N-α-tosyl-l-lysine chloromethyl ketone (TLCK). When compared with controls, the synergistic effect of Bt toxin and proteinase inhibitors caused significant decreases in mean larval weight and length over time. Midgut samples tested against the substrates azocasein, α-benzoyl-dl-arginine-p-nitroanilide (BApNA), and N-succinyl-alanine-alanine-proline-phenylalanine-p-nitroanilide (SAAPFpNA) showed significant decreases in the protease activity of larvae fed Bt plus inhibitor versus control. Interaction of Bt and proteinase inhibitors significantly retarded larval growth and resulted in developmental delay and up to 20% mortality.     

温度对悬铃木方翅网蝽生长发育、存活和繁殖的影响

在室内研究不同温度下悬铃木方翅网蝽各虫态的发育历期、存活率及雌成虫的产卵量,组建不同温度下的实验种群生命表。结果显示,在15~33 ℃范围内,随温度升高悬铃木方翅网蝽的发育速率加快,并符合Logistic模型。悬铃木方翅网蝽卵、1龄、2龄、3龄、4龄、5龄若虫、产卵前期和全世代的发育起点温度分别为10.42、9.49、7.89、10.12、8.82、7.80、9.69和10.42 ℃,有效积温分别为153.9、38.8、41.4、31.8、42.0、69.5、101.9和479.3日·度。悬铃木方翅网蝽世代存活率和单雌产卵量在测定温度范围内均表现为先升高后降低的抛物线关系,在25 ℃时最高,分别为57.81%和87.71粒/雌。成虫寿命和雌成虫产卵期均随温度的升高而缩短。25 ℃时,种群内禀增长率和种群趋势指数最大,分别为0.0388和22.46。25~30 ℃是该虫生长发育的最适温区。     

单种或多种寄主植物混合共存对B型烟粉虱成虫的影响

为探究B型烟粉虱Bemisia tabaci(Gennadius)成虫对寄主植物多样性的适应性,采用生态测定和生化方法,比较了油菜、棉花、番茄、黄瓜4种寄主植物同时存在与单种寄主植物存在时对B型烟粉虱存活率、产卵量、总蛋白、海藻糖、超氧化物歧化酶(superoxide dismutases, SOD)、碱性磷酸酶(alkaline phosphatase, AKP)、海藻糖酶、蔗糖酶、淀粉酶等指标的影响.同时,利用“Y”型嗅觉仪,测定了B型烟粉虱雌成虫对4种寄主混合共存和单独存在时的行为反应.结果表明,与单种寄主植物相比,4种寄主植物混合共存时,烟粉虱9 d时存活率显著降低,为(64.0±3.8)%,总产卵量为907±52.5粒,大于棉花,小于油菜、黄瓜,与番茄无显著差异;海藻糖含量及SOD、AKP、海藻糖酶、蔗糖酶、淀粉酶活性相对增大;行为研究表明4种寄主植物混合共存与单种植物存在时相比,除油菜外,B型烟粉虱雌虫对单种植物选择趋性较强.     

常用杀虫剂对异色瓢虫的毒力及其保护酶的影响

为明确杀虫剂对异色瓢虫Harmonia axyridis(Pallas)幼虫、成虫的毒力及其体内保护酶的影响,采用喷雾法测定了7种杀虫剂对异色瓢虫3龄幼虫和成虫的毒力,同时测定了3种杀虫剂对3龄幼虫和成虫体内超氧化物歧化酶(superoxide dismutase)、过氧化物酶(peroxidase)和过氧化氢酶(catalase)活性的影响。结果显示:7种杀虫剂对3龄幼虫的毒力大小为阿维菌素、啶虫脒吡虫啉、虫酰肼哒螨灵噻嗪酮吡蚜酮,对成虫的毒力大小为阿维菌素、啶虫脒虫酰肼、吡虫啉哒螨灵噻嗪酮吡蚜酮,吡蚜酮对异色瓢虫最安全。亚致死浓度LC10药剂可促进保护酶活性的提高,但随着浓度提高和处理时间增长,3种酶的活性总体呈逐渐下降趋势,表明低浓度的杀虫剂对异色瓢虫体内酶活性存在一定的不利影响。     

Toxicity and neurophysiological effects of selected insecticides on the mole cricket, Scapteriscus vicinus (Orthoptera: Gryllotalpidae)

Mole crickets (Scapteriscus spp.) are severe subterranean pests of turfgrasses, commonly targeted with neurotoxic insecticides. Ideally insecticides used against mole crickets should induce quick knockdown or mortality to minimize damage caused by their tunneling. However, neurophysiological effects of insecticides on mole crickets are mostly unknown. The aims of this study were to investigate neurophysiological and toxic effects of several insecticides on tawny mole cricket (Scapteriscus vicinus Scudder) adults and nymphs, and potential synergy between pyrethroid and neonicotinoid insecticides. Bifenthrin, fipronil, and the combination of bifenthrin + imidacloprid provided the fastest median mortality when injected. The combination of bifenthrin + imidacloprid elicited faster toxicity than either active ingredient alone. Imidacloprid, bifenthrin, and bifenthrin + imidacloprid caused immediate knockdown, whereas fipronil immobilized mole crickets within 1-2 h. Acephate, bifenthrin, fipronil, imidacloprid, and bifenthrin + imidacloprid caused significant neuroexcitation. Bifenthrin + imidacloprid resulted in greater increases of spontaneous neural activity than the additive effects of imidacloprid and bifenthrin alone. Excitatory compounds acting at sodium and chloride channels (bifenthrin and fipronil) were the most toxic against S. vicinus. Combining a sodium channel toxin (bifenthrin) and a synaptic toxin (imidacloprid) led to greater than additive neurophysiological and toxic effects, which to our knowledge provides the first documented evidence of synergistic neurological “potentiation”.