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PubMed2006

Effect of insecticides on mealybug destroyer (Coleoptera: Coccinellidae) and parasitoid Leptomastix dactylopii (Hymenoptera: Encyrtidae), natural enemies of citrus mealybug (Homoptera: Pseudococcidae).

In this study, we measured, under laboratory conditions, the direct and indirect effects of insecticides on mealybug destroyer, Cryptolaemus montrouzieri Mulsant (Coleoptera: Coccinellidae), and parasitoid Leptomastix dactylopii Howard (Hymenoptera: Encyrtidae), natural enemies of citrus mealybug, Planococcus citri (Risso) (Homoptera: Pseudococcidae). The adult stages of both natural enemies were exposed to sprays of the insecticides buprofezin, pyriproxyfen, flonicamid, acetamiprid, dinotefuran, and clothianidin at label-recommended rates to assess direct mortality after 24, 48, and 72 h, respectively. The effects of the insecticides on L. dactylopii parasitization rate and percentage of parasitoid emergence also were monitored using the label and 4x the recommended label rate. Dinotefuran was extremely detrimental to the adult parasitoid at the label rate with 100% mortality after 24 h. Buprofezin, pyriproxyfen, and flonicamid were not harmful to L. dactylopii when applied at the label rate. At 4x the recommended label rate, dinotefuran, acetamiprid, and clothianidin were all harmful to the parasitoid with 100% mortality 72 h after application. Both buprofezin and flonicamid were not toxic to L. dactylopii with 100% adult survival after 72 h. Pyriproxyfen and flonicamid, at both the label and 4x the recommended label rate, did not negatively affect L. dactylopii parasitization rate or percentage of parasitoid emergence. Acetamiprid, dinotefuran, and clothianidin were toxic to C. montrouzieri adults with 100% mortality after 48 h, whereas buprofezin, pyriproxyfen, and flonicamid demonstrated minimal (10-20% mortality after 48 h) harmful effects to the predator. Based on the results from our study, the indirect effects of the insect growth regulator (IGR) buprofezin were not decisive; however, the IGR pyriproxyfen and the insecticide flonicamid were not directly or indirectly harmful to the predator C. montrouzieri and parastioid L. dactylopii, indicating that these insecticides are compatible with both natural enemies when used together for control of citrus mealybug in greenhouses and conservatories.

Animals↗
PubMed2002

Insecticide susceptibilities of cat fleas (Siphonaptera: Pulicidae) from several regions of the United States.

Eleven cat flea, Ctenocephalides felis (Bouchè), strains, seven field-collected and four laboratory-colonized, were assayed for susceptibilities to five insecticides (carbaryl, chlorpyrifos, malathion, permethrin, and pyrethrin) with an insecticide-treated, horizontally-oriented, Nylon 6,6 disk in a test tube. The pyrethrin was synergized using piperonyl butoxide (PBO). Flea mortality at two doses was recorded after 4 and 24 h exposures. The field strains from Texas and Florida tolerated carbaryl, chlorpyrifos, and malathion; and carbaryl and PBO-synergized pyrethrin, respectively. Tolerance was observed in a field strain from Kansas against malathion. Colonies from California and North Carolina were susceptible to malathion and PBO-synergized pyrethrin, and chlorpyrifos and permethrin, respectively, but three colonies showed tolerance. The insecticidal response of the California colony varied; when exposed to a chlorpyrifos dose of 10 mg (AI)/m2 for 24 h, at various times had mortality of 3-100%. With a PBO-synergized pyrethrin dose of 396 mg (AI)/ m2 for 4 h, the mortality ranged between 4.2 and 97%. Colonized strains were more susceptible than field strains at 4 h exposure to all insecticides except PBO-synergized pyrethrin. Colonized strains survived better in control tubes. The colony strains' susceptibility and variability are of considerable importance because these strains are used for flea product efficacy evaluations and bioassays. The differences in susceptibility between laboratory colonies and the field strains suggested development of both adaptation to colonization, and extensive, multiple cross-resistance to insecticides in field strains. Varying susceptibility of cat fleas may affect control success.

Animals↗
PubMed2006

The sister-chromatid exchange and acetylcholine esterase enzyme levels among patients with insecticide intoxication in the Cukurova region, Turkey.

This study included 45 patients with intentional insecticide intoxication and 21 with accidental intoxication who were treated at the First-Aid and Emergency Department of Balcali Hospital at the Faculty of Medicine in the Cukurova University, Adana, Turkey, while the control group consisted of 25 people selected from university personnel known to be healthy. Patients with a history of X-ray exposure in the last 6 months or of any virus disease as well as continuous drug users and smokers were excluded, leaving a total of 49 patients. Acetylcholine esterase (Pseudocholinesterase) enzyme (AchE), sister-chromatid exchanges (SCE), the mitotic index (MI), and the replication index (RI) were evaluated. Blood samples were cultured for SCE evaluation and sera separated for AchE levels. Insecticide exposure was generally intentional for suicide in adolescents and at older ages, but accidental for children. AchE levels were found to be significantly lower in organophosphorus (OP) and carbamated (CB) insecticide poisoning groups in comparison with the control group (p<0.001), while the pyrethroid (PY) group was not statistically different for the AchE effect (p>0.05). SCE was found to be significantly higher in OP and CB groups (p<0.001), while the PY and control groups were statistically similar for SCE levels (p>0.05). This study showed an increase in SCE in response to orally ingested insecticides. These findings indicate that insecticide exposure results in cell abnormalities, with resulting impediments to the division and replication of cells, as suggested by MI decreases and RI increases, while the speed of the division cycles of stimulated cells increases.

Acetylcholinesterase↗
PubMed1988

A simple screening method for insecticidal substances from actinomycetes.

A simple and selective assay system was developed in the search for new insecticidal substances from Actinomycetales strains propagated on solid culture media. The strains were first tested for their ability to produce antimicrobial compounds. Only strains displaying weak or no activity were retained and screened in the insecticidal bioassay. Microbial solid cultures were given as food to larvae and to adults of Musca domestica to detect insecticide producers. A second phase, after extraction of the active compounds, consisted of an evaluation of the insecticidal potency and a primarily biological identification of the products synthesized by the selected strain. Of 6,280 actinomycete strains which were screened, 47 were active but only 30 of these were finally chosen in the second phase of screening. All these strains, except one, produced known metabolites such as piericidins, avermectins or valinomycin. The one strain, CL307-24, and its insecticide products appeared novel and will be the topic of further study.

Actinomycetales↗
PubMed2000

Toxicity of a Neem (Azadirachta indica) insecticide to certain aquatic organisms.

Neem based insecticides are likely to show a large increase in use in the near future. In the present work, the toxicity of a neem insecticide, Neem-Azal-T/S, was tested against the mosquito larvae, as well as against certain non target organisms occurring in a polluted pond and a shallow stream, located in a cultivated area in Giza, Egypt. Samples of water containing the experimental animals were collected from this area, and toxicity tests were conducted in the laboratory by exposing them to a series of concentrations of the botanical insecticide, using the water of the pond and stream at room temperature (28-31 degrees C). The compound was more or less toxic to all the tested species. The LC50S and mortality rates were determined. The order of tolerance of the organisms to different concentrations of the insecticide was: larvae of Bufo regularis (Amphibia) > Aedes caspius. (Insecta) > Gambusia affinis (Poeciliidae) > Cyclops sp. > Daphnia magna (Crustacea). At a concentration of 20 ppm, all the tadpoles died within 9 days, while all other individuals died within 5 to 8 days after exposure to a concentration of 10 ppm of Neem Azal insecticide.

Aedes↗
PubMed2001

Cabbage root fly control using non-organophosphorus insecticides.

The need to find non-organophosphorus insecticides to control the cabbage root fly has never been so urgent. Of the six non-OP insecticides tested, fipronil was the most effective but spinosad, diflubenzuron and cyromazine also showed considerable promise. As expected, the transplant drenches (34 mg active ingredient (a.i./plant) were more effective than the module drenches (5 mg a.i./plant), which in turn were more effective than the film-coated seed treatments (0.001 mg a.i./plant), simply because of the different amounts of insecticide applied per plant. One remaining major problem is that, even if effective non-OP insecticides can be found, the manufacturers may still not support their insecticides being applied to minor crops such as field vegetables.

Animals↗
PubMed2003

Efficacy of two organophosphorus insecticides, Reldan & Dursban against the larvae of Culex quinquefasciatus.

BACKGROUND & OBJECTIVES: The resistance in vectors to conventional insecticides warrants development of newer insecticides for mosquito control besides use of other counter-measures. The present study was undertaken to test the efficacy of a new and toxicologically safe organophosphorus compound, Reldan (chlorpyrifos-methyl) and compare its efficacy with Dursban (chlorphyrifos-ethyl) against larvae of different mosquito vectors under laboratory conditions and against Culex quinquefasciatus in three larval habitats. METHODS: The susceptibility of larvae of mosquito vector species to Reldan and Dursban was determined by following the standard procedure and the LC50 in mg/l values were calculated by probit analysis. The insecticides were evaluated in the larval habitats of C. quinquefasciatus in and around Pondicherry. The percentage reduction in larval density was calculated using Mulla's formula and duration showing more than 80 per cent reduction was calculated by annotating the graph obtained by plotting percentage reduction in larval density against days of post-treatment. RESULTS: Dursban and Reldan were effective against Anopheles fluviatilis larvae at lower LC50 of 5.90 x 10(-7) and 1.07 x 10(-9) mg/l respectively compared to other species of mosquitoes. Dursban and Reldan were equally effective against Aedes aegypti, An. stephensi and An. culicifacies. Reldan was about nine times more effective than Dursban against C. quinquefasciatus with respective LC50 of 1.17 x 10(-4) and 1.34 x 10(-3) mg/l. Field evaluation of these insecticides against C. quinquefasciatus showed that Reldan and Dursban at the application rate of 500 g (ai)/ha reduced immature density by more than 80 per cent for a mean duration of 4.0 and 4.5 days and 4.6 and 3.7 days in cesspits and cement tanks respectively. In U-drains, at 500 g (ai)/ha, Reldan was effective for a period of 3.6 days whereas, Dursban was not effective. It was effective for 4.0 days only at 1000 g(ai)/ha. There was no significant increase in the residual activity of both Dursban and Reldan with increase in application rates. INTERPRETATION & CONCLUSION: In view of the lack of sustained control with the applications, it is inferred that these insecticides will be of limited use as larvicides against C. quinquefasciatus breeding in polluted habitats.

Animals↗
PubMed2003

[Sublethal effects of insecticides on fecundity of multicolored Asian ladybird Harmonia axyridis].

The effects of sublethal doses of 6 insecticides (imidacloprid, rotenone, fenvalerate, abamectin, pirimicarb and azadirachtin) on the fecundity of multicolored Asian ladybird Harmonia axyridis were determined respectively. The results showed that in all treatments, the daily average number of eggs per female ladybird was about 40-55. Ladybirds pretreated with imidacloprid by contact and feeding methods, and with rotenone by feeding method produced significantly fewer eggs, compared with control. But the accumulative oviposition of ladybirds pretreated with 6 insecticides at sublethal level was no significant differences, compared with untreated ladybirds. The hatching rates of the eggs laid by ladybirds pretreated with 6 insecticides by two methods were all lower than that of control. The accumulative survivals from egg to pupal stage of all treatments decreased significantly. The developmental duration from egg to pupa of those treated with imidacloprid by two methods and with fenvalerate by contact method prolonged significantly, while that of those treated with rotenone by two methods and with fenvalerate, abamectin, pirimicarb, and azadirachtin by feeding method shortened obviously, but that of those treated with rotenone and abamectin by contact method had no differences with control. After the eggs were immersed with sublethal concentrations of imidacloprid, rotenone, fenvalerate and abamectin, the successful hatching rates were all lower than that of control, and the development periods prolonged clearly. The 1st instar larval survival rates of those treated with fenvalerate decreased significantly, and the survivals from 2nd instar larval to pupal stage also reduced to some extent. The total developmental duration of those treated with rotenone and fenvalerate prolonged significantly. These findings suggested that the effects of insecticides at low doses on the fecundity of ladybird were very complicated. The class, action mode, toxicity and exposure route of insecticides could affect the results of experiments.

Animals↗
PubMedDate not supplied

A gas chromatographic determination of residues of eleven insecticides and two metabolites on olive tree leaves.

A gas chromatographic (GC) method was developed and statistically validated for the simultaneous determination of residues of pyrethroid, endosulfan, and organophosphorus insecticides and some of their metabolites on olive tree leaves. Pesticide residues were extracted by static extraction with acetone-dichloromethane. After evaporation of the extract to dryness and redissolution in acetone, the organophosphorus insecticides were determined by GC with nitrogen-phosphorus detection. Another portion of the extract, after solvent change to acetonitrile, was cleaned up on an Alumina-N cartridge and analyzed for insecticides sensitive to electron-capture detection (ECD), i.e., pyrethroids and endosulfan and its metabolite. Recoveries of the organophosphorus insecticides ranged from 80.7 to 93.3% with relative standard deviations (RSDs) of < or = 7.2%; recoveries of the ECD-sensitive insecticides ranged from 71.6 to 89.5% with RSDs of < or = 11.6%. The method was used to analyze 26 samples of olive tree leaves from organic olive groves all over Greece, and the results confirmed the viability of the method for routine analysis. Residues of fenthion and fenthion sulfoxide were found in one and 3 samples, respectively, and their identities were confirmed by GC with mass spectrometry.

Chromatography, Gas↗
PubMed2005

Synergistic efficacy of botanical blends with and without synthetic insecticides against Aedes aegypti and Culex annulirostris mosquitoes.

Increasing insecticide resistance requires strategies to prolong the use of highly effective vector control compounds. The use of combinations of insecticides with other insecticides and phytochemicals is one such strategy that is suitable for mosquito control. In bioassays with Aedes aegypti and Culex annulirostris mosquitoes, binary mixtures of phytochemicals with or without synthetic insecticides produced promising results when each was applied at a LC25 dose. All mixtures resulted in 100% mortality against Cx. annulirostris larvae within 24 h rather than the expected mortality of 50%. All mixtures acted synergistically against Ae. aegypti larvae within the first 24 h except for one mixture that showed an additive effect. We conclude that mixtures are more effective than insecticides or phytochemicals alone and that they enable a reduced dose to be applied for vector control potentially leading to improved resistance management and reduced costs.

Aedes↗
PubMed2005

Effects of sub-lethal concentrations of synthetic insecticides and Callitris glaucophylla extracts on the development of Aedes aegypti.

Synthetic and botanical insecticides can have a profound effect on the developmental period, growth, adult emergence, fecundity, fertility, and egg hatch, resulting in effective control at sub-lethal concentrations. This paper investigated sub-lethal concentrations of fenitrothion, lambda-cyhalothrin, and Callitris glaucophylla Joy Thomps. & L.P. Johnson (Cupressaceae) extract to characterize their effects on the development of Aedes aegypti L. (Diptera: Culicidae) mosquito larvae. The LC25, LC50, and LC75 (four replicates) were used for each synthetic insecticide and the LC25 and LC75 (four replicates) were used for C. glaucophylla. Observations of larval mortality, duration of larval stage, pupal mortality, duration of pupal stage, adult emergence, sex ratio, and malformations were recorded over 14 days. A dose-response effect was observed for all insecticides. Although C. glaucophylla extract doses were higher than synthetic insecticide doses, the LC75 treatment outperformed synthetics by completely prohibiting adult emergence. Consequently, this botanical is recommended for field application either in combination with synthetic or natural insecticides or alone.

Aedes↗
PubMed2006

[Three cases of inhalation of household pyrethroid and metoxadiazone insecticides with remarkable dyspnea].

Household insecticides containing pyrethroids as their active ingredient are widely used in Japan. We encountered three cases of dyspnea caused by insecticides containing pyrethroids and metoxadiazone. The first case was a 52-year-old woman who suffered with dyspnea after breathing interior air following use of a fumigating insecticide. Although bronchoscopy revealed laryngotracheal edema, symptoms improved following administration of hydrocortisone and midazolam. Although the second case was a 63-year-old man who suffered with dyspnea as a result of direct aerosol insecticide inhalation due to missuse, symptoms had dissipated when the patient arrived at the hospital. The third case was a 20-year-old man with allergies who presented with dyspnea due to exposure to an aerosol insecticide three days after use. An allergic mechanism was thought to be involved. Reports of respiratory symptoms and allergic reactions caused by inhalation of pyrethroids are rare. Although the levels of exposure were low in all three cases compared to oral lethal dosage, these cases presented with serious respiratory symptoms, thus suggesting the need for further considerations regarding latent cases and safety.

Adult↗
PubMedDate not supplied

Zinc chloride-diphenylamine reagent for thin layer chromatographic detection of some organophosphorus and carbamate insecticides.

Zinc chloride-diphenylamine reagent, whose use has been reported for the detection of organochlorine insecticides by thin layer chromatography, was further studied for its ability to detect the organophosphorus insecticides phorate, phosphamidon, DDVP, and phosalone and the carbamate insecticide carbaryl and aldicarb. These insecticides give intense blue-green spots with this reagent. The procedure can be applied to the detection of the insecticides in biological materials and thus has a potential use in forensic toxicology.

Carbamates↗
PubMed1989

Organophosphorus insecticide poisoning.

A review of 755 cases of Organophosphorus Insecticide Poisoning, admitted to the department of Intensive Care at the Jinnah Postgraduate Medical Centre between 15th January, 1976 to 31st December 1985, has shown that these insecticides form a majority of the cases of acute poisoning and are associated with a comparatively higher mortality rate. Of 1900 cases, 755 were cases of organophosphorus insecticide poisoning forming 39.7% of the total poisoning cases and 16% of the total admissions to the Unit. Being easily accessible, these insecticides are frequently used as suicidal agents specially by uneducated housewives. They are highly toxic and their management is very complicated. Of 108 deaths from poisoning in the last 10 years 73 (67.6%) were due to Organophosphorus Insecticide Poisoning. This being such a common mode of poisoning in our country, we have presented here our experience of the clinical features and management of these cases.

Adolescent↗
PubMed1989

Inhibition of calmodulin activated adenylate cyclase in rat brain by selected insecticides.

Effect of various insecticides on basal and calmodulin (CaM) activated adenylate cyclase activity was studied in solubilized rat brain nuclear and P2 fractions. Our earlier experiments indicated that plictran, chlordecone and other insecticides affect the calcium transport across cell membranes. The present experiments were designed with the assumption that these compounds might exert their neurotoxic action by interfering with CaM (a calcium receptor protein) regulated processes. We have used detergent solubilized adenylate cyclase for our studies, since membrane bound form is not sensitive to externally added CaM. CaM significantly elevated the adenylate cyclase activity in both the fractions and a maximum stimulation of 97% in nuclear fraction and 50% in P2 fraction was observed with 1 microgram of CaM. All the insecticides studied inhibited both basal and CaM activated adenylate cyclase activity in nuclear and P2 fractions to a different extent. A significant inhibition was observed at 0.05 microM and higher concentrations of plictran. Chlordecone and toxaphene inhibited both basal and CaM activated adenylate cyclase in a concentration dependent manner. Although dieldrin and aldrin inhibited basal adenylate cyclase in a concentration dependent manner, they did not exhibit a similar pattern on CaM activated adenylate cyclase. Of all the insecticides studies, chlordecone is more potent in inhibiting both basal and CaM activated adenylate cyclase which is in agreement with the greater neurotoxic action of this compound. These results indicate that all the insecticides studied are potent inhibitors of detergent solubilized adenylate cyclase, and might exert their neurotoxic differential action by interfering with CaM regulated events in central nervous system.

Adenylyl Cyclase Inhibitors↗
PubMed1979

Assessment of insecticidal impact on the malaria mosquito's vectorial capacity, from data on the man-biting rate and age-composition.

The reduction in average age of a vector population after application of a residual insecticide is commonly interpreted under the implicit assumption that the vector population is uniformly exposed to the insecticide. This assumption maximizes the calculated impact of the insecticide on the vectorial capacity. An alternative assumption, namely that the vector population is composed of two subpopulations, one endophilic and exposed, the other exophilic and not exposed, leads to a much smaller calculated impact of insecticide on the vectorial capacity. This is illustrated with data collected before and after application of propoxur in the Garki District, Kano State, Nigeria. These data were also used to estimate, on the one hand, before spraying, the proportion of blood meals taken by Anopheles gambiae s.l. on man that are followed by rest indoors, and on the other hand, after spraying, the proportion exposed after the first blood meal, according to the model of non-uniform exposure; the two estimates agree fairly well. The discussion compares the models of uniform and non-uniform exposure in terms of plausibility and concludes that the latter is more realistic. It is therefore prudent to take it into account when evaluating the impact of insecticides on the transmission of malaria.

Anopheles↗
PubMed1970

Chlorinated hydrocarbon insecticides: recent animal data of potential significance for man.

The environmental persistence of chlorinated hydrocarbon insecticides is posing a serious threat to the survival of several wildlife species. Sublethal effects, completely unrelated to the insecticidal properties of these chemicals, have contributed markedly to impaired reproduction in many species and to toxicity in neonatal animals. Considering the insecticide levels found in man, are these chemicals potentially dangerous to human infants and adults? Of special concern are the potential long-term, subtle effects of low concentrations of insecticides to which many persons are ordinarily exposed. These agents affect both the peripheral and central nervous systems. They markedly elevate hepatic enzyme levels, enhancing the biotransformation of many pharmacological agents as well as interfering with endogenous steroid biosynthesis and degradation. The DDT-like insecticides are potent estrogenic agents and some have shown teratogenic and carcinogenic activity. These aspects are discussed in relation to present levels found in humans and to possible adverse effects on perinatal and adult individuals.

Animals↗
PubMed1970

Evaluation of ultra-low-volume insecticide dispensing systems for use in single-engined aircraft and their effectiveness against Aedes aegypti populations in South-East Asia.

An evaluation study of ultra-low-volume (ULV) spraying of insecticide from aircraft was carried out in Thailand, to determine if this technique could be used for the emergency control of Aedes aegypti, the major vector of haemorrhagic fever. A small, single-engined aircraft, a Cessna-180, was used in the trials and 2 types of spraying equipment were tested; both were found to be equally effective. The aircraft was fitted with 6 spraying nozzles and flew at an altitude of 150 feet (46 m) at a speed of 100 miles/h (161 km/h). The insecticide used was 95% technical grade malathion and swaths 75 feet wide (22.8 m) were laid down; the rate of application was 3 US fl oz/acre (219 ml/ha).Trials were made in 3 villages near Bangkok and it became apparent that a small aircraft could not produce the required even distribution of insecticide; the rate of application was therefore increased to 6 US fl oz/acre (438 ml/ha). This increased rate appeared to compensate for the narrow width of the swath and produced very satisfactory mortalities in caged mosquitos as well as in natural populations.The size and distribution of droplets was monitored by the use of oil-sensitive red dye cards which showed that there was a good penetration of insecticide into dwellings, etc. Trial results were evaluated by biting counts, bioassays of Aedes and Culex adults and larvae, Culex dips and ovitraps. Biossays indicated that the 6 US fl oz/acre rate of application was almost 100% effective in the open and produced satisfactory mortalities inside markets and dwellings.It was concluded that larger aircraft would be required to treat areas of more than 1000 acres (405 ha) and congested city areas but that the rate of application of insecticide could be considerably lower. Nevertheless, small aircraft can be useful in smaller and less congested areas.

Aedes↗