Toxic effects of novel organophosphorus insecticide (RPR-V) on certain biochemical parameters of euryhaline fish, Oreochromis mossambicus

The euryhaline fish, Oreochromis mossambicus was exposed to sub-lethal concentration (0.017 mg L⁻¹) of a novel phosphorothionate, 2-butenoic acid-3-(diethoxy phosphinothionyl) ethyl ester (RPR-V) for 30 days and allowed to recover for 7 days. Important biomarker enzymes were assayed in plasma, brain, gill, liver, kidney, and muscle during exposure tenures of day-3, -7, -15, -30, and also at 7 days (withdrawal) after stopping treatment. Acetylcholinesterase (AChE) activities of brain, gill, and muscle were strongly inhibited by 67, 75, and 66%, respectively, on day-30. Exposure (time) dependent increases in alanine aminotransferase (ALAT), and aspartate aminotransferase (ASAT), acid phosphatase (AcP), and alkaline phosphatase (AkP), activities in plasma and kidney; AcP and AkP activities in gill were noticed. However, significant decrease in ALAT, ASAT, AcP, and AkP activities in liver was observed. The depletion of glycogen was observed in liver, brain, and gill tissues, an indication of typical stress related response of the fish with pesticide. A significant increase in lactate dehydrogenase (LDH) activity in gill and brain was observed and decreased in liver and muscle, indicating tissue damage and muscular harm. Depletion of glutathione (GSH) was observed in the above tissues, there by enhancing the lipid peroxidation resulting in cell damage. The induction in hepatic glutathione-S-transferase (GST) levels indicates the protection against the toxicity of xenobiotic-induced lipid peroxidation. There was a significant recovery in all the above biochemical parameters, in all the tissues of fish after a recovery period of 7 days. These results revealed that RPR-V affects the intermediary metabolism of O. mossambicus and the increase of biomarker enzymes in plasma, might be due to the necrosis of liver.     

Adaptive changes in the patterns of carbohydrate metabolites in blood,liver, muscle and heart tissues of Sarotherodon mossambicus (Peters) exposed to the carbamate fungicide ziram

Adaptive changes in the levels of carbohydrate metabolites, glucose, glycogen and lactic acid, were studied in a freshwater edible fish, Sarotherodon mossambicus exposed to a carbamate fungicide, ziram. Based on the results obtained, it was concluded that the fish showed (i) adaptive utilization of stored glycogen, particularly in liver tissue; (ii) adaptive accumulation of glycogen in muscle and heart tissues, probably by glyconeogenesis and (iii) adaptive mechanism of operation of ‘diving syndrome’, to meet the stress of the pollutant under sub-lethal exposure. © 1998 SCI.     

Effect of fenvalerate on protein and amino acid contents and enzyme activities in the ostracod Chrissia halyi

The short-term effect of fenvalerate on some metabolites and enzymes of protein metabolism in the ostracod Chrissia halyi was studied. The ostracods were subjected to two different concentrations of fenvaierate and the alterations in total proteins, total free amino acids, transaminases i.e. aspartate amino transferase (AAT)/glutamate oxaloacetate transaminase (GOT) and alanine amino transferase (ALAT)/glutamate pyruvate transaminase (GPT) and glutamate dehydrogenase (GDH) after one and three days were noted. Total protein and free amino acid contents in the organisms were found to be depleted, whereas both the transaminases and GDH levels were elevated. The results indicate that exposure of C. halyi to fenvalerate leads to metabolic adaptations to suit the functional need of the animal.     

Insecticidal activity of surfactants and oils against silverleaf whitefly (Bemisia argentifolii) nymphs (Homoptera: Aleyrodidae) on collards and tomato

The insecticidal activities of four surfactants (Cide‐kick, Silwet L‐77, M‐Pede and APSA‐80), a dishwashing detergent (New Day), a mineral oil (Sunspray oil), a cotton seed oil and a vegetable oil, alone or in combination, were tested against nymphs of Bemisia argentifolii Bellows & Perring on collards and tomato. Silwet L‐77 was more effective (>95% mortality) than Cide‐Kick or APSA‐80 at rates from 0.25–1.00 g AI litre⁻¹ but caused severe phytotoxicity to tender tomato leaves at all but the lowest rate. New Day dish detergent at 2.0 ml litre⁻¹ caused mortality (95%) comparable to M‐Pede insecticide soap at 10‐fold greater concentration. A New Day ingredient, cocamide DEA, was considerably more active than the other ingredients or the commercial mixture. Additional surfactants added to Sunspray oil increased efficacy in some treatments, but not others. Toxic responses of 2nd‐ and 3rd‐ instar whiteflies to vegetable oil and cotton seed oil at 5.0 and 10.0 ml litre⁻¹ plus 0.4 g AI litre⁻¹ APSA‐80 ranged from 22.1 to 79.9% and 66.3–88.7% mortality, respectively. Whitefly mortality was greater on tomato than on collard in six of seven instances when differences between host plants were significant. Our results indicate that the these surfactants and oils have good potential for controlling B argentifolii. © 2000 Society of Chemical Industry     

Effect of temperature on the toxicity of low concentrations of methyl bromide to diapausing larvae of the warehouse moth Ephestia elutella (Hübner)

The performance of low concentrations of methyl bromide against diapausing larvae of Ephestia elutella at 15 and 25°C was assessed in extended exposure periods. At concentrations of 1.9 mg litre^?1 and below, test batches required higher concentration-time (ct) products for 100% kill at 25°C than at 15°C. The minimum concentration at which the concentration: time relationship still applied was between 1.3 and 1.9 mg litre^?1 at 15°C, whereas at 25°C it was between 2.7 and 4.0 mg litre^?1. For many individuals within each population sample, however, lower concentrations at moderate dosage levels remained lethal. At 25°C, a ct product of about 90 mg litre^?1 h gave between 53 and 77% kill at 6.1, 4.0, 2.7 and 1.9 mg litre^?1. The trends observed suggest that the most tolerant members of the population have an enhanced ability to detoxify methyl bromide at the higher temperature. The implications of the results for the build-up of resistance and for practical control measures are discussed.     

Pesticidal properties of parthenin (from Parthenium hysterophorus) and related compounds

Eleven sesquiterpene lactone derivatives of parthenin ( 1 ), obtained from wild feverfew, Parthenium hysterophorus, were prepared by chemical and photochemical transformations. The compounds tested were a pyrazoline adduct ( 2 ) of parthenin, its cyclopropyl ( 3 ) and propenyl ( 4 ) derivatives, anhydroparthenin ( 5 ), a dihydro‐deoxygenated product ( 6 ), a formate ( 7 ) and its corresponding alcohol ( 8 ) and acetate ( 9 ), a rearranged product ( 10 ), lactone ( 11 ) and hemiacetal ( 12 ). All these derivatives, along with parthenin, were tried for their antifeedant action against sixth‐instar larvae of Spodoptera litura, for insecticidal activity against the adults of store grain pest Callosobruchus maculatus, for phytotoxic activity against Cassia tora, and for nematicidal activity against the juvenile stage‐II (J₂) of the root knot nematode Meloidogyne incognita. Antifeedent bioassay revealed that parthenin is moderately antifeedant. Among the derivatives, the saturated lactone ( 11 ) was found to be about 2.25 times more active than parthenin. The pyrazoline adduct ( 2 ) was found to be the most effective as an insecticide, with LC₅₀ values after 24, 48 and 72 h of 96, 43 and 32 mg litre⁻¹, respectively, which are comparable with neem extract. Compound 4 was found to be the most effective inhibitor of germination and seedling growth of C tora, with ID₅₀ values for germination, plumule length and radicle length of 136, 326 and 172 compared with 364, 738 and 427 mg litre⁻¹, respectively, for parthenin. Compound 10 was found to be the most effective in terms of nematicidal activity. The LC₅₀ values for this compound were 273 and 104 mg litre⁻¹, respectively, after 48 and 72 h compared with 862 and 512 mg litre⁻¹ observed for parthenin after 48 and 72 h. © 2001 Society of Chemical Industry     

Disposition kinetics,cytotoxicity and residues of fenvalerate in tissues following oral administration to goats

Disposition kinetics in goats of fenvalerate [(RS)-α-cyano-3-phenoxybenzyl (RS)-2-(4-chlorophenyl)-3-methylbutyrate] were studied after oral administration at 5 mg kg^?1. The insecticide persisted in blood for up to 48 h. The V_d(area), t_1/2(β), and t_1/2(Ka), of fenvalerate were 12.14 (±0.39) litre kg^?1, 12.25 (±0.25) h and 0.63 (±0.11)h, while the AUC and Cl_B values were respectively 7.35 (±0.39) μg h ml^?1 and 0.68 (±0.04) litre kg^?1 h^?1. The residues in tissues reached a peak four days after insecticide administration and then started to decline. Maximum residue was found in the adrenal gland, followed by liver, kidney and intestine. Both GOT and GPT activities in kidney tissue, but only GPT activities in liver tissue had decreased significantly 4, 8 and 22 days post-administration. The fenvalerate did not produce any significant effects on serum acetylcholinesterase, cholesterol or protein levels in goats. Histopathological examination showed fatty changes in the periphery of lobule, congestion in sinusoid, haemolysis in central vein, necrosis and periportal fibrosis around the central vein of liver, and necrosis in kidney of fenvalerate-treated goats.     

Effect of short term exposure of fenvalerate on biochemical and haematological responses in Labeo rohita (Hamilton) fingerlings

Experiment was carried out to determine the median lethal concentration (LC₅₀) of fenvalerate to Labeo rohita fingerlings. After determining the LC₅₀ value of fenvalerate, a sub-lethal concentration (1/3rd of LC₅₀) of fenvalerate was exposed for 15 days. Significant alterations in SOD (P < 0.05) activity of liver and gill was observed due to fenvalerate. Catalase activity in gills of fishes was also affected significantly (P < 0.05). WBC, NBT and Hct values were reduced significantly in fenvalerate exposed fishes as compared to control group, whereas blood glucose level showed higher values in fenvalerate exposed group. Serum total protein and albumin were also reduced significantly as a result of fenvalerate exposure. Significant increase in the serum GOT, serum GPT, creatinine, triglyceride and serum ACP was noticed after 15 days of fenvalerate exposure. Results indicated that short term exposure of fenvalerate can induce biochemical and haematological alterations causing stress to L. rohita fingerlings.     

Correction: Pestic. Sci. 53, 201–208 (1998)

In the paper ‘Proinsecticides effective against insecticide-resistant peach-potato aphid (Myzus persicae (Sulzer)),’ by D. Hedley et al., in Table 3 the units of both columns headed LC₅₀ should be (mg litre⁻¹)     

The response of pyriproxyfen-resistant and susceptible Bemisia tabaci Genn (Homoptera: Aleyrodidae) to pyriproxyfen and fenoxycarb alone and in combination with piperonyl butoxide

Pyriproxyfen was effective against susceptible Bemisia tabaci eggs at a LC₅₀ of 0.003 mg litre⁻¹ and against nymphs at 0.02 mg litre⁻¹. In comparison, eggs of a laboratory selected, pyriproxyfen-resistant B tabaci strain, originating in an Israeli greenhouse, exhibited 6500-fold resistance and nymphs exhibited 1100-fold resistance. Eggs and nymphs of a strain from an Israeli sunflower field exhibited 450 and 210-fold resistance in comparison to the susceptible standard. Fenoxycarb was generally less effective than pyriproxyfen against B tabaci eggs and nymphs but was unaffected by pyriproxyfen resistance. Piperonyl butoxide (PB) was antagonistic to pyriproxyfen, and this increased with increasing pyriproxyfen resistance. PB had no effect on the toxicity of fenoxycarb. Collectively, these data imply that the modes of action of pyriproxyfen and fenoxycarb are distinct, despite the structural similarities of these molecules. Possible reasons for the antagonism of PB against pyriproxyfen are discussed. © 1999 Society of Chemical Industry     

Impact of malathion stress on lipid metabolism in Limnonectus limnocharis

Despite mounting concerns about amphibian population declines, information on impact of pesticides on physiological changes is meager. The present study deals the influence of an organophosphate pesticide—malathion on the lipid metabolism of Limnonectus limnocharis under laboratory conditions. Changes in the lipid metabolism were analyzed in the liver, muscle, ovary, and testis of frogs exposed to lethal (10.67 mg L⁻¹ for 1, 2, 3, and 4 days) and sub-lethal (2.13 mg L⁻¹ for 1, 5, 10, 15, 20, and 25 days) concentrations of malathion. Upon lethal concentration treatment, against the increase of fatty acids, glycerol, and lipase activities in all tested tissues, there was decrease in the total lipids content over different durations. On the other hand, exposure to sub-lethal concentration, the amount of total lipids content, free fatty acids, glycerol and lipase activity increased. Changes in the lipid metabolism due to lethal concentration of malathion exposure could depict the negative impact on the reproductive success, which would result in decline of amphibian population.     

Laboratory Evaluation of the Novel Naturally Derived Compound Spinosad against Ceratitiscapitata

Laboratory studies were conducted to determine the effect of the naturally derived compound spinosad on Ceratitis capitata Wied. (Diptera, Tephritidae). The organophosphate fenthion was used as a standard. Direct dose-dependent mortality and reduced fecundity were observed in oral treatment of adults with spinosad. The LC₉₀ values 14 h and seven days after treatment were 19·50 and 0·49 mg litre⁻¹ respectively. Fenthion was less active (the LC₅₀ eight days after treatment was 1·17 mg litre⁻¹) and did not affect the fecundity of the fly. Adults were also very susceptible to spinosad and fenthion via residual contact. For spinosad, 100% mortality was recorded 48 h after treatment for a dose of 10 mg litre⁻¹. Spinosad was more effective than fenthion in suppressing larval development when neonate larvae were reared on treated diet supplemented with a range of concentrations from 0·02 to 0·83 mg kg⁻¹ diet. Last-instar larvae were much less susceptible to spinosad or fenthion when exposed via dipping or when they pupated in treated medium and both products had similar performance. A lack of ovicidal activity was observed in direct egg-treatments with spinosad but significant reductions from 1 mg litre⁻¹ onwards were recorded for fenthion.     

Intoxication effects of lindane (γ-BHC) on the activities of aspartate and alanine aminotransferases of Anabas testudineus (Bloch)

Two transaminases, viz., aspartate aminotransferase and alanine aminotransferase, in six tissues of Anabas testudineus (Bloch) exposed to 0.075 mg/liter (120 hr LC₀) and 0.59 mg/liter (24 hr LC₁₀₀) of lindane were studied. An increase in the transaminase activity levels was observed in all the tissues except liver and muscle. Elevations observed in the later periods of exposure were higher than those observed in the initial periods of exposure in all the tissues except liver which showed an inverse trend. The significance of the results is discussed.     

In-vitro and in-vivo nematicidal activities of the cyclic dodecapeptide omphalotin A

Omphalotin A, a cyclic dodecapeptide produced by submerged cultures of the basidiomycete Omphalotus olearius, exhibited in-vitro and in-vivo nematicidal activity. Meloidogyne incognita was the most sensitive nematode. At 2.0 mg litre⁻¹, 50% of the nematodes were dead after one hour. Heterodera schachtii, Radopholus similis and Pratylenchus penetrans were affected at higher concentrations. Incorporated into agar, the compound prevented infection of cucumber seedlings by M. incognita at concentrations of 1 mg litre⁻¹ and higher. In glasshouse tests, complete protection of cucumbers and lettuce was achieved between 2.5 and 10 mg litre⁻¹. No insecticidal activity was observed when Plutella xylostella, Phaedon cochleariae or Spodoptera frugiperda were fed material containing 4 g kg⁻¹ of omphalotin A. © 1999 Society of Chemical Industry     

Effect of fipronil seed treatments on the germination and early growth of rice

Fipronil seed treatments were evaluated to determine whether they directly influence germination and subsequent seedling growth in rice (Oryza sativa L). Continuous seed exposure to fipronil (four days) at 2 000 mg litre⁻¹ significantly impaired germination (P < 0.001). When exposure was restricted to a 1-h period 48 h after the initiation of germination, early post-germination growth was also impaired (assessment two days after exposure, P < 0.05). The proportion of seeds satisfying our criteria for normal germination fell by 2.3 and 2.6% respectively across 17 cultivars. Cultivar effects were highly significant (P < 0.001). When exposure to fipronil (2 000 mg litre⁻¹) was restricted to 2 h at initial seed wetting no significant growth impairment occurred. No significant differences (P > 0.05) were found between shoot lengths or root system dry weights of control plants and plants developing from seed exposed continuously (two days) to fipronil at rates of up to 2 000 mg litre⁻¹ during germination and harvested nine days after sowing. Treating germinated seed with fipronil for 1 h immediately prior to sowing at rates of up to 4 000 mg litre⁻¹ did not result in significant changes (P < 0.05) in plant growth parameters at either nine or 25 days after sowing. No evidence of fipronil having a direct phytostimulatory effect on rice was obtained. © 1999 Society of Chemical Industry     

Individual and combined effects of dimecron-ziram on the levels of serum prolactin and selected minerals of an edible freshwater fish, Oreochromis mossambicus (Peters)

The individual and combined effects of dimecron (an organophosphate pesticide) and ziram (a carbamate fungicide) on the levels of serum prolactin and selected minerals (Ca, P, and Mg) are studied in an edible freshwater fish, Oreochromis mossambicus (Peters) exposed to sub-lethal concentrations of individual dimecron (0.002 mL L⁻¹) and ziram (0.008 mL L⁻¹) and combined 1:4 mixture of dimecron-ziram (0.01 mL L⁻¹) for 24, 48, and 72 h. Exposure of fish to sub-lethal concentration of individual and mixture of dimecron and ziram caused changes in the levels of serum prolactin and minerals studied compared to control fishes. Based on the results obtained, it was concluded that the individual exposures of dimecron and ziram comparatively manifested higher toxic effects (than the combined exposure) by reducing prolactin levels and loss of mineral contents. These changes may result in a severe osmoregulatory problem.     

Hormone profile of an edible, freshwater teleost, Sarotherodon mossambicus (Peters) under endosulfan toxicity

The hormone profile of Sarotherodon mossambicus (Peters) under endosulfan (an organochlorine pesticide) toxicity was investigated by estimating the serum levels of T₃ (triiodothyronine), T₄ (thyroxine), cortisol, prolactin and insulin in control and sub-lethal (0.001 mg L⁻¹) endosulfan-exposed fish for 1, 6, 12, 24 h and 5 days. Exposure of fish to sub-lethal concentration of endosulfan caused varying changes in the levels of serum hormones studied. Based on the results obtained, it was concluded that (i) the fish registered an increased metabolic activity during the initial period followed by an adaptive lowering of metabolic rate as indicated by changes in the serum T₃ and T₄ levels, (ii) the fish showed an adaptive stress response as indicated by the reduced cortisol level which could be probably due to severe interrenal exhaustion, (iii) the increased serum prolactin levels in the fish under endosulfan exposure is indicative of a possible action of prolactin on gills and kidney towards hydromineral regulation in the fish body under pesticide stress, (iv) the fish adaptively increases its serum insulin level thereby registering a possible adaptive hypoglycemic role of the hormone to favour the transport of glucose to different tissues besides a possible lipogenic activity of the higher insulin level in fish tissue under pesticide toxicity and (v) the fish appears to exhibit a possible adaptive recovery response in its hormone profile following prolonged exposure for 24 h and 5 days.     

Post-harvest disinfestation of lightbrown apple moth,Epiphyas postvittana Walker (Lepidoptera: Tortricidae), with an alkane

Lightbrown apple moth (LBAM), Epiphyas postvittana Walker was used as a test insect to evaluate a post-harvest oil, C15 Ampol CPD, and a spray oil, C23 Ampol DC-Tron NR, both applied as dips. CPD was much more efficacious than C23 DC-Tron NR against exposed third-instar larvae. Higher oil concentrations were required to penetrate and kill larvae sheltering under the calyx of oranges. LBAM eggs were more susceptible to CPD oil than larval stages. LBAM larvae dipped in sub-lethal doses of oil continued to develop, but the fecundity of both males and females was reduced. DC-Tron had a significant effect on egglaying. CPD and C23 DC-Tron NR affected the fertility of eggs laid. CPD oil sprayed at 50 ml litre⁻¹ on adult LBAM moths reduced their fertility. Factors contributing to the higher efficacy of CPD and its potential use as a post-harvest treatment are discussed. © 1999 Society of Chemical Industry     

Impact of sodium cyanide on catalase activity in the freshwater exotic carp, Cyprinus carpio (Linnaeus)

The Cyprinus carpio fingerlings on exposure to lethal (1 mg/L) and sub lethal concentrations (0.066 mg/L) of sodium cyanide showed inhibition in the activity of catalase. The disruption of catalase activity in freshwater fish, C. carpio is demonstrated in the present study using UV–visible spectrophotometer at 240 nm using hydrogen peroxide as a substrate. It suggests toxic effects of sodium cyanide and consequent accumulation of hydrogen peroxide in the functionally different tissues namely, liver, gill, muscle and brain. This might lead to cellular damages, and create widespread physiological disturbance. The results suggest that catalase activity can be a good diagnostic tool for sodium cyanide toxicity in biomonitoring programme.     

Susceptibility pattern and development of resistance in the diamondback moth,Plutella xylostella L,to Bacillus thuringiensis Berl var kurstaki in India

Base‐line susceptibility for six‐day‐old larvae of the diamondback moth, Plutella xylostella, against Bacillus thuringiensis var kurstaki (Biobit^®) was studied by a cabbage leaf disc dip bioassay technique. Diamondback moth from 13 locations in seven different states spread over a distance of about 3000 km longitudinally was used for these studies. Forty‐eight‐hour LC₅₀ values varied from 1.0 to 10.97 mg AI litre⁻¹. Further investigations on the development of resistance under laboratory conditions showed an increase in LC₅₀ from 2.76 (for unselected F₁ generation) to 5.28 mg AI litre⁻¹ (for selected F₉ generation), using a selection concentration of 6.4 mg AI litre⁻¹. This suggested a possibility of the development of resistance under field conditions if there were to be extensive and indiscriminate use of B thuringiensis. These findings are discussed in relation to integrated pest management and the mechanisms of resistance in resistance management tactics. © 2000 Society of Chemical Industry