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PubMed1991

Experimental hut trials of bednets impregnated with synthetic pyrethroid or organophosphate insecticide for mosquito control in The Gambia.

1. Nylon bednets impregnated with different insecticides were evaluated in 1988 against wild adult mosquito populations, mostly Mansonia africana (Theobald) and Anopheles gambiae Giles sensu lato, entering experimental verandah-trap huts in The Gambia. Each bednet had six 10 x 10 cm holes made in the walls to simulate torn conditions and permit female mosquitoes to enter and feed on sleepers. 2. Individual net treatments, determined by gas chromatography of net samples from before and after 12 weeks use of the bednets, were: permethrin 670 +/- 159 and 405 +/- 190 mg/m2 (40% loss), cypermethrin 37 +/- 8 and 16 +/- 9 mg/m2 (57% loss), deltamethrin 10 +/- 7 and 10 +/- 8 mg/m2 (no loss), lambda-cyhalothrin 2.6 +/- 0.9 and 1.6 +/- 0.5 mg/m2 (38% loss), pirimiphos-methyl 4017 +/- 117 and 1160 +/- 319 mg/m2 (71% loss). 3. Washing three times in the traditional manner with local cow-fat soap reduced the initial dosages by about 85% of cypermethrin and lambda-cyhalothrin, 99.8% of pirimiphos-methyl and left no detectable residues of deltamethrin or permethrin. 4. The unwashed permethrin-treated bednet reduced the number of mosquitoes entering a hut by 60% of An.gambiae s.l. and 68% of Mansonia spp. This deterrency was less pronounced with the other insecticides and was lost by washing the bednets. 5. Each insecticide, especially lambda-cyhalothrin and pirimiphosmethyl, caused significant mortality rates of mosquitoes that entered huts with impregnated bednets, and prevented the majority of An. gambiae s.l. and Mansonia females from bloodfeeding. Washing completely removed the efficacy of deltamethrin and permethrin treated bednets, whereas nets treated with cypermethrin, lambda-cyhalothrin or pirimiphos-methyl remained significantly insecticidal after washing. 6. Aerial toxicity from the pirimiphos-methyl treated bednet killed 80% of An.gambiae s.l. confined overnight in the hut at the end of the trial, whereas the pyrethroid-treated bednets gave negligible mortality rates of mosquitoes. 7. Sleepers using the bednets had no medical symptoms significantly associated with any of the treatments. On the contrary, from 216 interviews, 4/10 complaints were associated with the use of untreated nets (P approximately 0.05), perhaps because sleepers were kept awake by mosquitoes and became more aware of any ailments. 8. It is concluded that permethrin tends mainly to deter mosquitoes from house-entry, enhancing personal protection, whereas the other insecticides kill higher proportions of the endophilic mosquitoes, which would give better community protection against malaria transmission.

Analysis of Variance↗
PubMed1996

Neuronal ion channels as the target sites of insecticides.

Certain types of neuronal ions channels have been demonstrated to be the major target sites of insecticides. The insecticide-channel interactions that have been studied most extensively are pyrethroid actions on the voltage-gated sodium channel and cyclodiene/lindane actions on the GABAA receptor chloride channel complex. With the exception of organophosphate and carbamate insecticides which inhibit acetylcholinesterases, most insecticide commercially developed act on the sodium channel and the GABA system. Pyrethroids show the kinetics of both activation and inactivation gates of sodium channels resulting in prolonged openings of individual channels. This causes membrane depolarization, repetitive discharges and synaptic disturbances leading to hyperexcitatory symptoms of poisoning in animals. Only a very small fraction (approximately 1%) of sodium channel population is required to be modified by pyrethroids to produce severe hyperexcitatory symptoms. This toxicity amplification theory applies to pharmacological and toxicological action of other drugs that go through a threshold phenomenon. Selective toxicity of pyrethroids between invertebrates and mammals can be explained based largely on the responses of sodium channels and partly on metabolic degradation. The pyrethroid-sodium channel interaction is also supported by Na+ uptake and batrachotoxin binding experiments. Cyclodienes and lindane exert a dual action on the GABAA system, the initial transient stimulation being followed by a suppression. The stimulation requires the presence of the gamma 2 subunit. The suppression of the GABA system is also documented by Cl- flux and ligand binding experiments. It appears that the sodium channel and the GABA system merit continuing efforts for development of newer and better insecticides. Nitromethylene heterocycles including imidacloprid act on nicotinic acetylcholine receptors. Insect receptors are more sensitive to these compounds than mammalian receptors. Single-channel analyses of the nicotinic acetylcholine receptor of PC12 cells have shown that imidacloprid increases the activity of subconductance state currents and decreases that of main conductance state currents. This may explain the imidacloprid suppression of acetylcholine responses.

Animals↗
PubMed1995

Settling of insecticide from dip wash mixed with dam water and zinc sulphate and used to control sheep lice (Bovicola ovis).

Insecticidal dipping fluid emulsions, mixed in vitro in dam water containing suspended clay particles and 1% w/v zinc sulphate, were analysed to determine rates of settling of diazinon, cyhalothrin and cypermethrin. Fifteen minutes after mixing, the concentration of the insecticides 5 cm below the surface had declined by 72.5%, 72.8% and 89.4%, respectively. On remixing, the concentration of insecticide in suspension was close to or greater than the initial concentration. In 2 trials, lice were eradicated from sheep showered with dip wash mixed in cloudy dam water to which 1% w/v of zinc sulphate was added. In 12 flock treatments in which 1000 to 2000 sheep were dipped with added zinc sulphate, the concentration of insecticide remained above the minimum lethal for susceptible strains of lice. However, lice were still present 6 months later in 8 of these flocks. When zinc sulphate is added to dip wash, agitation is needed to maintain the insecticide in suspension.

Animals↗
PubMed1970

Effect of four organophosphorus insecticides on microbial activities in soil.

Laboratory tests were conducted with four organophosphorus insecticides, Bay 37289 (O-ethyl O-2,4,5-trichlorophenyl ethylphosphonothioate), diazinon [O,O-diethyl O-(2-isopropyl-4-methyl-6-pyrimidinyl) phosphorothioate], Dursban (O,O-diethyl O-3,5,6-trichloro-2-pyridyl phosphorothioate), and Zinophos (O,O-diethyl O-2-pyrazinyl phosphorothioate), applied to a sandy loam at rates of 10 and 100 mug/g to determine whether these materials caused any serious effects on microbial activities related to soil fertility. All insecticides showed an effect on fungi and bacteria for the first and second week of incubation, but, subsequently, the populations returned to levels similar to those obtained in the controls. All insecticide applications increased ammonium production, but, in some instances, there appeared to be a slight depression of nitrification. Sulfur oxidation was equal to or better than that obtained with untreated soil in most cases. There was no significant effect on phosphorus mineralization. Oxygen consumption indicated that microbial respiration increased in proportion to the concentration of insecticides, suggesting the possibilities of microbial degradation of the insecticides or their degradation products and of uncoupling oxidative phosphorylation.

Actinomyces↗
PubMed1993

Evolution of Drosophila insecticide resistance.

The impact of insecticide resistance is well documented. It includes the toxic effects of pesticides on the environment and the cost of the increased amounts of insecticides required to effectively control resistant insects. Resistance evolves by the selection of genes that confer tolerance to insecticides. Several resistance genes have been identified and cloned in Drosophila, including genes for mutant target molecules and genes that increase insecticide degradation. Drosophila is a useful system to understand the evolution of quantitative traits in general as well as the population genetics of insecticide resistance. Through it, we may hope to understand the relationship between discrete genetic change and continuously varying characters. In addition, molecular genetic techniques developed using Drosophila can eventually be transferred to other insects in order to help control pest populations.

Acetylcholinesterase↗
PubMed1976

Degradation of [14C]photodieldrin by Trichoderma viride as affected by other insecticides.

Various soil fungi were tested for their capacity to degrade the insecticide [14C]photodieldrin. Of nine species investigated, Trichoderma viride was the only one which degraded the insecticide to an appreciable extent into water-soluble, non-insecticidal compounds within 4-5 weeks. These products amounted to 32-41% of the radiocarbon applied to the culture media. The degradation was a function of live mycelia, which metabolized the insecticide and excreted water-soluble compounds into the culture media. Since soils usually contain a mixture of pesticide residues, the effects of several chlorinated hydrocarbon insecticides on the capacity of the fungus to degrade [14C]photodieldrin were studied. Thus, in fungal cultures treated with compounds structurally similar to photodieldrin, such as aldrin and dieldrin, only 4-17% of the applied radiocarbon was water-soluble and more photodieldrin remained. In controls, however, 35% of the applied radiocarbon was in the form of water-soluble products and less photodieldrin remained. The degradation of [14C]photodieldrin by T. viride, with time, was associated with a continuous decline of hexane-soluble radiocarbon and a steady increase of water-soluble metabolites, which appeared in the fungal media. The amount of hexane-soluble radiocarbon in mycelia was directly related to the fungal mass.

Biodegradation, Environmental↗
PubMed1984

The metabolism of insecticides: the role of monooxygenase enzymes.

In summary, it can be said that advances have been made in understanding the range and significance of monooxygenase reactions involving insecticides in both target and non-target species and that some specific aspects emerge that should command the attention of insecticide toxicologists and others in the immediate future. The role of co-oxidation of insecticides during prostaglandin synthesis has just emerged as an issue but, if we can extrapolate from other xenobiotics (126), we can predict with some confidence that it will assume major proportions. It is also apparent that both activation and detoxication reactions are catalyzed by the FAD-containing monooxygenase and that many of these reactions were formerly attributed to the cytochrome P-450-dependent monooxygenase system. Since any particular substrate may be oxidized by either or both of these two routes, it is essential that studies be conducted to define their relative contributions to xenobiotic oxidation in microsomal preparations and ultimately in vivo. The area of interactions and the mechanisms behind them is also of importance, from the public health point of view in the case of multiple exposures, and from the practical viewpoint in the case of insecticide synergists. While the above aspects are not the only ones of future importance, they should contribute to the ultimate goal of insecticide toxicology: practical, safe use of chemicals for the control of insect pests.

Amines↗
PubMed2000

Organic insecticides.

Organic insecticide poisoning continues to be a major health problem not only in the developing communities but also in the Western population. The insecticides commonly used are the organophosphates, organocarbamates, organochlorides and pyrethroids. Patients with organic insecticide poisoning present with a spectrum of manifestations ranging from gastrointestinal symptoms of nausea, vomiting and diarrhoea to severe neurological manifestations of fasciculations, seizures and neuromuscular weakness and paralysis or cardiac manifestations of arrhythmias and conduction disturbances. A strong clinical suspicion is necessary to make an early diagnosis of insecticide poisoning. Treatment is primarily supportive and includes decontamination, protection of airways and cardiac and respiratory monitoring. Specific therapy for organophosphates and organocarbamates includes the use of anticholinergics. The use of oximes, especially high dose, is controversial and may be associated with a higher mortality rate. Low-dose oximes given early in the course of the illness may be beneficial. This paper reviews the literature on organic insecticide poisoning worldwide.

Carbamates↗
PubMed2004

Tents pre-treated with insecticide for malaria control in refugee camps: an entomological evaluation.

BACKGROUND: A refugee shelter that is treated with insecticide during manufacture would be useful for malaria control at the acute stage of an emergency, when logistic problems, poor co-ordination and insecurity limit the options for malaria control. METHODS: Tents made of untreated canvas with deltamethrin-treated polyethylene threads interwoven through the canvas during manufacture, 'pre-treated tents', were tested in Pakistan for their impact on malaria vectors. Fixed-time contact bioassays tested the insecticidal activity of the material over 3 months of outdoor weathering. Unweathered tents were erected under large trap-nets on outdoor platforms and tested using wild-caught, host-seeking mosquitoes and insectary-reared mosquitoes released during the night into the trap-nets. RESULTS: The insecticide-treated tents were effective both in killing mosquitoes and reducing blood-feeding. Mean 24 hour mortality was 25.7% on untreated tents and 50.8% on treated tents (P = 0.001) in wild anophelines and 5.2% on untreated tents and 80.9% on treated tents (P < 0.001) in insectary-reared Anopheles stephensi. Blood-feeding of wild anophelines was reduced from 46% in the presence of an untreated tent to 9.2% (P < 0.001) in the presence of treated tents and from 51.1% to 22.2% (P < 0.001) for insectary-reared An. stephensi. In contact bioassays on tents weathered for three months there was 91.3% mortality after 10-minute exposure and a 24 h holding period and 83.0% mortality after 3-minute exposure and a 24 h holding period. CONCLUSION: The results demonstrate the potential of these pre-treated canvas-polyethylene tents for malaria control. Further information on the persistence of the insecticide over an extended period of weathering should be gathered. Because the epidemiological evidence for the effectiveness of pyrethroid-treated tents for malaria control already exists, this technology could be readily adopted as an option for malaria control in refugee camps, provided the insecticidal effect is shown to be sufficiently persistent.

Animals↗
PubMed2006

An intervention to reduce residential insecticide exposure during pregnancy among an inner-city cohort.

BACKGROUND: We previously reported widespread insecticide exposure during pregnancy among inner-city women from New York City. Here we report on a pilot intervention using integrated pest management (IPM) to reduce pest infestations and residential insecticide exposures among pregnant New York City African-American and Latina women (25 intervention and 27 control homes). METHODS: The IPM consisted of professional cleaning, sealing of pest entry points, application of low-toxicity pesticides, and education. Cockroach infestation levels and 2-week integrated indoor air samples were collected at baseline and one month postintervention. The insecticides detected in the indoor air samples were also measured in maternal and umbilical cord blood collected at delivery. RESULTS: Cockroach infestations decreased significantly (p = 0.016) after the intervention among intervention cases but not control households. Among the intervention group, levels of piperonyl butoxide (a pyrethroid synergist) were significantly lower in indoor air samples after the intervention (p = 0.016). Insecticides were detected in maternal blood samples collected at delivery from controls but not from the intervention group. The difference was significant for trans-permethrin (p = 0.008) and of borderline significance (p = 0.1) for cis-permethrin and 2-isopropoxyphenol (a propoxur metabolite). CONCLUSION: To our knowledge, this is the first study to use biologic dosimeters of prenatal pesticide exposure for assessing effectiveness of IPM. These pilot data suggest that IPM is an effective strategy for reducing pest infestation levels and the internal dose of insecticides during pregnancy.

Adolescent↗
PubMedDate not supplied

Cytogenetic effects of the insecticide methamidophos in mouse bone marrow and cultured mouse spleen cells.

The cytogenetic effect of the insecticide methamidophos (0,S-dimethylphosphoroamidothiolate) was studied in mouse bone marrow and mouse spleen cells in culture. In vivo the ability of methamidophos to induce micronuclei and sisterchromatid exchange in mouse bone marrow was investigated. In vitro mouse spleen cells in culture were used to assess the ability of the insecticide to induce chromosomal aberrations and sister chromatid exchange. Three different routes of application for the pure insecticide were tested so as to cover the different possibilities for human exposure to the insecticide. Intraperitoneal, oral and dermal treatment with methamidophos caused toxicity to marrow as indicated by a significant increase in the percentage of polychromatic erythrocytes (PEs) over that of the control. Methamidophos showed mutagenic potential as evidenced by a positive response in the micronucleus and chromosomal aberrations assays. Thus, single and multiple i.p. injections at 6 and 4.5 mg methamidophos/kg body wt., oral administration of the insecticide for 14 consecutive days at a dietary level of 100 ppm and multiple dermal treatments (total 4) with 24 mg/kg body wt. induced a statistically significant increase in the frequency of PEs with micronuclei in mouse bone marrow. Moreover, the tested concentrations of methamidophos as low as 0.25 microgram/ml induced a high percentage of metaphases with chromosomal aberrations in cultured mouse spleen cells. Methamidophos is a weak inducer of SCEs in mouse bone marrow and cultured mouse spleen cells.

Animals↗
PubMed1999

Insecticidal paint and fumigant canisters for Chagas' disease control: community acceptance in Honduras.

This study assessed public acceptance for two new vectorial control techniques for Chagas' disease: insecticidal paint and fumigant canisters. The study compared the two with traditional fenitrothion insecticide spraying. An experimental field study was performed in an endemic area of central Honduras from August to November 1992, a year after the initial application of the treatments. The objectives of the study were to determine the acceptability of the tools on the part of the population whose homes were treated, and on the part of the personnel applying the treatments. The sample size was drawn up according to a uniform protocol applied in six Latin American countries. For this study a total of 651 persons were surveyed in 15 rural communities. Along with the surveys, focus groups were used to collect information to learn the reasons for accepting or rejecting particular treatments. The survey was done with heads of households. Focus groups were done with heads of households and also with the field operators who applied the treatments. The research showed that insecticidal paint had a low level of community acceptance (28.8%). Field operators strongly disliked the paint because of problems with its transport, application, unpleasant smell, and very low effectiveness against triatomines and pest insects. The traditional insecticide was more acceptable to the community (93.9%) and to the field operators, especially for its strong effect against the triatomines and pest insects. The results showed that in order to increase the public acceptance for insecticidal paint, it would be necessary to make the paint easier to transport and apply and to increase its effectiveness. Because of their very low effectiveness, fumigant canisters did not represent an acceptable alternative for triatomine vector control. A public educational effort should be a component of any new control method developed.

Chagas Disease↗
PubMed2000

Potential for integrating eleven agricultural insecticides with the predatory bug Pristhesancus plagipennis (Hemiptera: Reduviidae).

A problem for growers attempting to implement integrated pest management programs is the lack of information regarding the compatibility of insecticides with natural enemies. To provide information about this problem, we evaluated the acute and residual effects of 11 commonly used insecticides on nymphs of Pristhesancus plagipennis (Walker) under both laboratory and field conditions. For each insecticide, the length of time that weathering residues caused > 50% mortality was evaluated and compared against the LC50 (acute-toxicity) divided by the recommended field rate. Plots thus combined the acute and residual toxicity of each insecticide. Results suggested that carbaryl, esfenvalerate, endosulfan, and deltamethrin had low residual and acute toxicity to P. plagipennis, whereas chlorpyrifos, methomyl, and monocrotophos were highly toxic at low concentrations and left persistent harmful residues. Cypermethrin, methidathion, malathion, and dimethoate were moderately toxic. The potential use of these insecticides to supplement the control activity of P. plagipennis is discussed.

Animals↗
PubMed2001

Baseline monitoring of codling moth (Lepidoptera: Tortricidae) larval response to benzoylhydrazine insecticides.

A diet-incorporation larval bioassay was developed to measure the response of codling moth, Cydia pomonella (L.), to the benzoylhydrazine insecticides tebufenozide and methoxyfenozide. The bioassay tested neonates and third, fourth, and fifth instars from a laboratory colony and neonates and fourth instars from a pooled population collected from five certified-organic apple orchards. Bioassays were scored after 6 and 14 d. No differences between the laboratory and field population were found for either insecticide. Significant differences were found in the response of third and fifth instars between the 6 and 14 d bioassays, primarily due to a high proportion of moribund larvae in the shorter assay. Larval age had a significant effect in bioassays and was more pronounced in 6- versus 14-d tests. Fifth instars were significantly less susceptible to both insecticides than other stages, while responses of third and fourth instars were similar. The response of neonates was significantly different from third and fourth instars to tebufenozide but not with methoxyfenozide in the 14-d test. Field bioassays excluded the use of fifth instars and were scored after 14 d. LC50s estimated for 18 field-collected populations varied five- and ninefold for tebufenozide and methoxyfenozide, respectively. The responses of all but six field-collected populations were significantly different from the laboratory strain. Five of these six populations were collected from orchards with no history of organophosphate insecticide use. The LC50 for methoxyfenozide of one field-collected population reared in the laboratory for three generations declined fourfold, but was still significantly different from the laboratory population. These data suggest that transforming current codling moth management programs in Washington from a reliance on organophosphate insecticides to benzoylhydrazines may be difficult.

Animals↗
PubMed2001

Method of insecticide delivery affects horizontal transfer of fipronil in the German cockroach (Dictyoptera: Blattellidae).

Horizontal transmission of insecticide occurs when foragers contact or ingest an insecticide, return to the aggregation or nest, and translocate the insecticide to the shelter and its vicinity. Relatively more sedentary members of the population then contact or eat the translocated insecticide and die. We evaluated three different methods of delivering fipronil to adult male German cockroaches, Blattella germanica (L.), for their potential to cause such secondary mortality in various developmental stages of the cockroach. Adult males topically treated with 5 ng of fipronil (approximately LD99) caused low mortality in untreated nymphs and no mortality in untreated adults within the same aggregation. Males exposed to residual fipronil on a glass surface translocated more insecticide, resulting in higher mortality of cockroaches they contacted, but only early instars were affected and no adult mortality was observed. Ingested fipronil bait, however, was most effectively translocated, and caused high mortality of untreated adults and nymphs. Ingestion of fipronil also caused greater secondary kill compared with a topical application of 25 ng, approximately the same amount recovered from the exterior of males that ingested 1 mg of 0.05% fipronil bait. Secondary mortality in the untreated population was significantly affected by the duration of contact between the treated and untreated cockroaches, the quantity and freshness of excretions from the treated insects, and the accessibility of the secretions to untreated cockroaches. The mechanisms that cause secondary kill may include ingestion of excreted fipronil residues, cannibalism of bait-fed cockroaches, as well as contact with fipronil-contaminated substrates.

Animals↗
PubMed2001

Effects of various insecticides on the development of the egg parasitoid Trichogramma dendrolimi (Hymenoptera: Trichogrammatidae).

The toxicity of six insecticides, acephate, methomyl, ethofenprox, cartap, chlorfluazuron, and Bacillus thuringiensis (Bt) was tested on different developmental stages of the egg parasitoid, Trichogramma dendrolimi (Matsumura). Each of the insecticides tested showed different degrees of toxicity to the parasitoid, Ethofenprox showed the highest toxicity and cartap showed relatively higher toxicity compared with the other insecticides. The development of the parasitoids treated with these two insecticides was normal, similar to that of the control group. Only the emergence of adult wasps from host eggs was disturbed. Emergence of the host, Mamestra brassicae larva was reduced following treatment with ethofenprox, cartap and methomyl. However, adult female wasps, which emerged from host eggs treated with the insecticides had the ability to oviposit normally.

Animals↗
PubMed2002

Hazards of insecticides to the bumble bees Bombus impatiens (Hymenoptera: Apidae) foraging on flowering white clover in turf.

Insecticides used on turf are sometimes applied to areas with flowering weeds that attract honey bees and native pollinators. We tested residual effects of such treatments on colony vitality and behavior of the bumble bees Bombus impatiens Cresson foraging on turf containingwhite clover, Trifolium repens L. Imidacloprid, a syst emic chloronicotinyl used for preventive control of root-feeding grubs, was applied as granules, followed by irrigation, or sprayed as a wettable powder, with or without irrigation. Hives were confined on the plots in large field cages after residues had dried and colony vitality (i.e., numbers of brood, workers, and honey pots, and weights of queens, workers, and whole colonies with hives) was evaluated after 28-30 d. Workers' foraging activity and defensive response to an aggressive stimulus also were evaluated. In another test, weedy turf was sprayed with chlorpyrifos, carbaryl, or cyfluthrin at labeled rates for surface-feeding pests. Bee colonies were confined on the plots after residues had dried, with effects on colony vitality evaluated after 14 d. Finally, foraging activity of wild bumble bees was monitored on open plots to determine if insecticide-treated areas were avoided. Imidacloprid granules, and imidacloprid sprays applied with posttreatment irrigation, had no effect on colony vitality or workers' behavior, suggesting that such treatments pose little systemic or residual hazard to bumble bees. In contrast, exposure to dry nonirrigated residues of all of the aforementioned insecticides had severe impact on colony vitality. Foraging workers did not avoid insecticide-treated areas. Means by which turf managers can reduce hazards of insecticide applications to pollinators are discussed.

Agriculture↗
PubMed2006

Potential of selective insecticides for managing Uraba lugens (Lepidoptera: Nolidae) on Eucalypts.

The leaf skeletonizer Uraba lugens Walker (Lepidoptera: Nolidae), an Australian species, locally known as "gumleaf skeletonizer", is well established in New Zealand. This insect has the potential to become a serious pest of forestry and amenity eucalypts (Eucalyptus spp.) and is the focus of a long-term management program. The use of synthetic chemical or biological insecticides is one possible control method within an integrated control program. A series of dose-response trials were conducted using laboratory bioassays to test the efficacy of several insecticides against U. lugens: pyrethroids, spinosad, Bacillus thuringiensis kurstaki Berliner (Btk) and an insect growth regulator, Mimic. Pyrethroids and spinosad proved highly effective against U. lugens larvae, achieving 100% mortality after 3-6-d exposure. The performance of Btk was lower against gregarious skeletonizing larvae compared with solitary chewing larvae. When good coverage of the target foliage is achieved, >90% mortality is possible with Btk. Mimic performed poorly against U. lugens compared with other insecticides tested (<60% mortality). The Eucalyptus species on which larvae were feeding significantly altered insecticide efficacy. Treatments applied to Eucalyptus nitens (Deane & Maiden) Maiden had reduced efficacy compared with E. cinerea F. Muell. ex Benth. or E. fastigata Deane & Maiden. Cooler temperatures also reduced insecticide efficacy, presumably by decreasing movement and food consumption by U. lugens. Recommendations on spray applications to control U. lugens in New Zealand are given.

Animals↗