Efficacy Of Imidacloprid Research Articles

Neonicotinoid resistance in rice brown planthopper, Nilaparvata lugens

Rice brown planthopper, Nilaparvata lugens Stål, is a primary insect pest of cultivated rice, and effective control is essential for economical crop production. Resistance to neonicotinoid insecticides, in particular imidacloprid, has been reported as an increasing constraint in recent years. In order to investigate the extent of resistance, 24 samples of N. lugens were collected from China, India, Indonesia, Malaysia, Thailand and Vietnam during 2005 and 2006. Their responses to two diagnostic doses of imidacloprid (corresponding approximately to the LC(95) and 5 x LC(95) of a susceptible strain) were examined. Ten of the 12 samples collected during 2005 were found to be susceptible to imidacloprid, but two late-season samples from India showed reduced mortality at both diagnostic doses. All 13 strains collected in 2006 showed reduced mortality at both doses when compared with the susceptible strain. Dose-response lines showed resistance in one of the most resistant field strains to be approximately 100-fold compared with the susceptible standard. The data demonstrate the development and spread of neonicotinoid resistance in N. lugens in Asia and support reports of reduced field efficacy of imidacloprid.

Combined roles of loops C and D in the interactions of a neonicotinoid insecticide imidacloprid with the α4β2 nicotinic acetylcholine receptor

Neonicotinoid insecticides are widely used for crop protection based on their selective actions on insect nicotinic acetylcholine receptors (insect nAChRs). Loops C and D in insect nAChRs have been shown to possess structural features favorable for neonicotinoid–nAChR interactions. However, it remains to be resolved whether such features serve either co-operatively, or independently, to enhance neonicotinoid sensitivity of nAChRs. We therefore examined using voltage-clamp electrophysiology the effects on the response to imidacloprid of combinatorial substitutions of residues in loops C and D of the chicken α4β2 nAChR by those present in insect nAChRs. The E219P mutation in loop C of the α4 subunit resulted in enhanced responses to imidacloprid of α4β2, whereas E219S and E219T mutations barely influenced its actions. On the other hand, mutations in loop D (T77R; E79V and T77N; E79R) alone shifted the imidacloprid concentration–response curve to the left (lower concentrations). Interestingly, all three mutations did, however, further enhance the agonist efficacy of imidacloprid when combined with the mutations in loop D. Such synergistic effects of the two loops on the interactions with imidaclprid were observed irrespective of subunit stoichiometry. Computational modeling of the ligand binding domain of the wild-type and mutant α4β2 nAChRs using the crystal structure of the acetylcholine binding protein from Lymnaea stagnalis also indicated that interactions with loop F of loops C and D may contribute to determining the response to imidacloprid.

Drip Chemigation with Imidacloprid and Nematodes for Control of Scarab Larvae in Nursery Crops

Abstract Larvae of scarabs, also known as white grubs, are subterranean insects that damage ornamental nursery crops when they feed on roots. Management is generally based on application of chemical insecticides to the soil surface, followed by supplemental water to leach the toxicants into the soil. Drip irrigation systems have the potential to deliver insecticides and insect pathogens to the root zones of crops to control subterranean insects. From 2004 through 2006, we tested the efficacy of imidacloprid (2004–2006), clothianidin (2006), or entomopathogenic nematodes (EPN) + imidacloprid (2005) applied through drip irrigation to control white grubs in an ornamental nursery. Insecticides (imidacloprid or clothianidin) or EPN + imidacloprid were injected into drip irrigation lines at the upstream end of rows in a commercial nursery. EPN + imidacloprid was also injected into the root zone of trees or applied as a surface drench. In 2004 and 2005, imidacloprid applied at a preventive timing through drip irrigation lines significantly reduced the numbers of white grubs in the root zones of Kousa dogwood (Cornus kousa Hance) trees. In 2006, variation in the data resulted in no significant differences at the P = 0.05 level, although, the percentage reductions of grubs by imidacloprid and clothianidin applied through drip irrigation were similar to trials in 2004 and 2005. EPN + imidacloprid applied through drip irrigation, injected into the soil, and surface drenched at a curative timing all significantly reduced the numbers of grubs compared to untreated trees. These data indicate drip irrigation is a viable delivery system for controls of white grubs in nursery crops.

Efficacy of imidacloprid 10%/moxidectin 1% (Advocate®/Advantage Multi™) against fleas (Ctenocephalides felis felis) on ferrets (Mustela putorius furo)

Ferrets (Mustela putorius furo) are becoming increasingly popular as pets and are kept in households with other pet animals such as dogs and cats, from which they may catch flea infestations with the predominant flea species Ctenocephalides felis. In this study, the efficacy of imidacloprid/moxidectin spot-on (Advocate/Advantage Multi) was investigated in the therapy and prevention of flea infestation in ferrets. Sixteen adult ferrets of varying weights and ages and of both sexes were included. Ferrets were infested with 50 fleas each on days -7, -1, 7, 14, 21, and 28. On study day -6, the animals were randomized into two groups based on body weight and flea count. Each ferret allocated to group 1 was treated with 0.4 ml of imidacloprid 10%/moxidectin 1% (Advocate/Advantage Multi). The ferrets in group 2 remained untreated. Flea counts were performed by combing 24 to 48 h after infestation. The primary efficacy criterion was the reduction in the number of fleas at each time point post treatment compared to the ferrets in the untreated control group. On day 1, the therapeutic efficacy was 100%. The preventative efficacy was 100% at 1 and 2 weeks post treatment, and it was >97% and >90% at 3 and 4 weeks post treatment. No local or systemic side effects were observed in any of the ferrets treated.

Effect of imidacloprid foliar treatment and banana leaf age on Pentalonia nigronervosa (Hemiptera, Aphididae) survival

Pentalonia nigronervosa, the banana aphid, is the vector of Banana bunchy top virus to banana. This virus is the etiological agent of banana bunchy top disease, a limiting factor in many banana growing regions, including Hawaii, United States. Laboratory bioassays on banana plants were conducted to evaluate the efficacy of imidacloprid (Provado®), to control P. nigronervosa by comparing insect mortality at four different insecticide concentrations (120,60,24, and 12 ppm) over 1 month, and compared effects on the aphids on new emerging, and old leaf material. We found significant differences between treatments and time after treatment. Aphids survived poorly on newer plant growth, regardless of presence or absence of imidacloprid, or time after treatment. Examining the insecticidal effect on old leaves only, we found that the three highest concentration treatments resulted in high mortality over the 4‐week‐long period of testing. Our results confirm that imidacloprid foliar application on bananas results in effective control of aphids and does not become systemic within the plant. From these results, it is likely that management of banana aphid using imidacloprid under field conditions will be effective on old leaves and new leaves that are sprayed, but leaves emerging after sprays will not be completely protected from aphids. Regular scouting for aphids should be implemented in support of imidacloprid applications.

Efficacy of Imidacloprid 10% and Imidacloprid 10% plus Moxidectin 2.5% against Natural Lice (Trichodectes canis) Infestations in Dogs

Two negative controlled GCP studies of identical design were conducted in adult mixed-breed dogs to evaluate the efficacy of imidacloprid-containing formulations when used at the minimum therapeutic dose to treat an existing natural infestation of dog lice (Trichodectes canis), and to control lice infestation for five weeks, following a single topical administration.

Efficacy of a combination of 10% imidacloprid/50% permethrin for the prevention of leishmaniasis in kennelled dogs in an endemic area

The efficacy of imidacloprid 10% and permethrin 50% (Advantix ®; Bayer AG, Germany) in a spot-on formulation was evaluated in the field as a control measure to prevent canine leishmaniasis (CanL) in dogs in an endemic area of southern Italy. In February 2005, out of 845 dogs initially tested for CanL, 631 dogs which tested negative (315 from a kennel in Bari (KB) and 316 from a kennel in Ginosa (KG)) in a serological and a parasitological examination were allocated to one of three groups: Group A—treated with imidacloprid 10% and permethrin 50% once a month; Group B—treated every 2 weeks; and Group C—untreated control animals. All the dogs were examined serologically and parasitologically for CanL prior to the start of the study, in November 2005 (end of the sandfly season) and in March 2006 (end of the study). An initial CanL seroprevalence of 24.7% (209 dogs) was detected in KB and KG. In KB Leishmania infection, inferred by positivity in at least one of the three tests performed at the interim or final follow-up, was found in one animal from Group A and in nine from Group C. No positive animals were detected in Group B, thus giving a final protection efficacy of 88.9% in Group A and 100% in Group B. In KG Leishmania infection was identified in one animal from Groups A and B, respectively, and 11 from Group C (protection efficacy of 90.36% in Group A and 90.73% in Group B). The incidence density rates (IDRs) of infection in both Groups A and B at each kennel were statistically significantly lower than that registered in Group C (KB p < 0.05 and KG p < 0.01). The results clearly show that a combination of imidacloprid 10% and permethrin 50%, by virtue of its repellent activity against sandflies, is effective under both application regimes in preventing CanL in the field in endemic areas.

Evaluation of the efficacy of a topically administered combination of imidacloprid and permethrin against Phlebotomus perniciosus in dog

The phlebotomine sand fly Phlebotomus perniciosus is one of the main vectors of Leishmania infantum, responsible for human and canine leishmaniasis in the Mediterranean Basin. The objective of this study was to evaluate the repellent and insecticidal efficacy of imidacloprid 10% (w/v)/permethrin 50% (w/v) spot-on against sand flies ( P. perniciosus) on dogs. The dogs used in this trial were laboratory-bred beagles: eight were impregnated with the solution (treated group), while the other eight were left untreated (control group). On day 0 the animals in the treatment group received 0.1 ml/kg body weight of the combination imidacloprid/permethrin spot-on. Dogs were exposed for 1 h to about 100 female sand flies at weekly intervals for a period of 4 weeks, on day 1, 7, 14, 21, and 28 after applying the product. The repellency criterion was based on the feeding rate of sand flies in the treated compared to the untreated group. The insecticidal efficacy criterion was based on comparison of the survival rate of sand flies between the two groups. The product had an insecticidal efficacy on female sand flies of 53.2% (day 1), 49.4% (day 7), 15.1% (day 14), 13.2% (day 22), and 2.9% (day 29). The product showed a repellent effect of 97.7% (day 1), 96.3% (day 7), 96.5% (day 14), 92.7% (day 22), and 74.0% (day 29). Within the first week of application the insecticidal effect was significant; however it did not surpass 50%. On the other hand, the product showed a potent anti-feeding effect of over 90% during the first 3 weeks of this trial. Therefore, the application of this product every 3 weeks would be a good tool to significantly reduce sand fly bites over the period of transmission of vectorial diseases such as leishmaniasis and several arbovirosis such as Toscana virus.

Comparison of the activity of selamectin, imidacloprid and fipronil for the treatment of cats infested experimentally with Ctenocephalides felis felis and Ctenocephalides felis strongylus

Twenty adult, domestic short hair cats were randomly allocated into four groups of five cats and housed in separated cages. Each cat was infested with 25 fleas Ctenocephalides felis felis and 25 Ctenocephalides felis strongylus and 2 days later (day 0) the cats in group 1, 2 and 3 received a spot on application of selamectin, imidacloprid or fipronil, respectively, while the cats in group four were not treated. The cats were combed 48 h later, the fleas were removed, counted and their subspecies were determined. All the cats were reinfested with the same number of the two subspecies of fleas on days 7, 14, 21, 29 and 35. The efficacy of each treatment was calculated 48 h after each infestation. The mean number of fleas on the control cats was 16.4 C. f. felis and 13.4 C. f. strongylus. The three treatments were effective for the first 31 days for C. f. felis and for the full 37 days for C. f. strongylus. Over the first 31 days, the efficacy of selamectin ranged from 89 to 100% and 85 to 100% against C. f. felis and C. f. strongylus, respectively, the efficacy of imidacloprid ranged from 76 to 100% and 92 to 100% and the efficacy of fipronil ranged from 98 to 100% and 97 to 100% against C. f. felis and C. f. strongylus. There were no significant differences between the control of C. f. felis and C. f. strongylus by the three products.

Efficacy of imidacloprid, imidacloprid/permethrin and phoxim for flea control in the Mustelidae (ferrets, mink)

Farmed mink (Mustela vison), a close relative of the domestic ferret (Mustela putorius furo), naturally infested with the squirrel flea (Ceratophyllus sciurorum) were included in a study to investigate three compounds for flea control. The test products were imidacloprid in a 10% (w/v) solution, an imidacloprid 10% (w/v)/permethrin 50% (w/v) solution, and phoxim; all three are well-known compounds for the control of different ectoparasites in a wide range of animals. Two groups of mink received 0.1 ml per animal of the imidacloprid or the imidacloprid/permethrin combination at days 0 and 28, respectively. Two groups of mink were sprayed with 25 ml of a 0.1% phoxim solution at day 0 and either 1x25 ml or 2x25 ml, respectively, of a 0.05% phoxim solution at day 28. One group of mink served as an untreated control. At assessment on day 56 the efficacy was 91.9% in the imidacloprid group, 89.3% in the imidacloprid/permethrin group, 92.2% in the phoxim 1x25-ml group and 99.3% in the phoxim 2x25 ml group, respectively. In the untreated control group an average of 757 fleas per mink nesting material was recorded.

Efficacy of a combination of imidacloprid 10%/permethrin 50% versus fipronil 10%/( S)-methoprene 12%, against ticks in naturally infected dogs

Preventing tick bites is a fundamental step towards reducing the impact of tick-borne protozoal, bacterial and viral diseases (TBDs) in humans and animals. The aim of this study was to evaluate the efficacy of a combination of imidacloprid 10%/permethrin 50% and of fipronil 10%/ S-methoprene 12% against ticks in naturally infected dogs and to assess methodological parameters to calculate drug efficacy on tick immature stages. From July to August 2004, 45 privately owned dogs of various sexes, ages, breeds, coat length and habits were enrolled in a trial carried out in an area (radius approximately 50 km) in Southern Italy. Three homogeneous groups (both for dog population and tick population) were formed: 15 dogs treated with imidacloprid 10% and permethrin 50% spot-on (group A), 15 dogs treated with fipronil 10% and methoprene 12% spot-on (group B) and 15 untreated dogs (group C). The dogs in each group were then sub-grouped according to their age and weight. Two different treatments were administered (time 0 and +28 days) to groups A and B, and the dogs were checked weekly for tick infestation until day +56 post-treatment (p.t.). Twenty-four areas distributed on the whole body surface were examined for ticks at each follow-up, while only at time 0 and at day +56 p.t., ticks were collected from the dogs and identified. For the immature stages a semi-quantitative method was adopted and the load of immature stages was evaluated and grouped into four classes up to day +56 p.t. when the mean number of immature ticks (MIT) for each infection class was evaluated. All the adult ticks collected were identified as brown dog ticks ( Rhipicephalus sanguineus). Immature stages were first compared at day +28 p.t.. The efficacy of both products used in groups A and B on adult ticks was high and generally very similar. Conversely, the efficacy of imidacloprid 10% and permethrin 50% against immatures was higher than that of fipronil 10% and methoprene 12% throughout the observation period with statistically significant differences ( p < 0.05) at day +28 p.t. (i.e. group A = 98.52%, group B = 72.40%). On the whole, in analysing the efficacy of both products against adult plus immature ticks, it was found that the combination of imidacloprid 10% and permethrin 50% was more effective than fipronil 10% and methoprene 12%, with the differences being statistically significant at day +28 p.t. (group A = 98.43%, group B = 77.56%).

Natural infestation of the chewing lice (Werneckiella equi) on horses and treatment with imidacloprid and phoxim

Infestation with the chewing louse (Werneckiella (Damalinia) equi) can be found on horses world-wide. Louse infestations, including clinical signs of louse-derived dermatitis, are known from Icelandic horses. A clinical field investigation was conducted in Iceland using horses with natural louse infestations to evaluate the efficacy of imidacloprid in a 10% solution in comparison with phoxim in a 0.05% solution. A total of 27 horses received a single imidacloprid treatment using 16 ml of the 10% solution along the mane and on the dorso-lateral trunk. A further 43 horses were treated twice, 14 days apart, with phoxim, using 2 x 50 ml solution applied along the mane and the dorso-lateral trunk. At the final evaluation on day 28, complete control of the lice was obtained for the imidacloprid treated horses and only a single moribund louse was found on two horses treated with phoxim.

Combinatorial mutations in loops D and F strongly influence responses of the α7 nicotinic acetylcholine receptor to imidacloprid

The nitro group of a neonicotinoid, imidacloprid, plays a key role in its selective actions on insect nicotinic acetylcholine receptors (nicotinic AChRs) and is postulated to bind close to residues Q79 in loop D and G189 in loop F of the chicken α7 nicotinic AChR. To evaluate the relative contributions of these residues to interactions with imidacloprid, Q79 and G189 were replaced in tandem by first basic then acidic residues. Changes in the currents evoked by imidacloprid and acetylcholine (ACh) on the α7 wild type and mutant receptors expressed in Xenopus laevis oocytes were investigated using two-electrode voltage clamp electrophysiology. An increase in the efficacy of imidacloprid for the α7 receptor resulting from the Q79K and Q79R mutations was suppressed by a G189E mutation in loop F. However, the increases in efficacy resulting from such Q79 mutations were scarcely influenced by a G189D substitution. Three-dimensional modeling of the α7 nicotinic AChR, based on the acetylcholine-binding protein (AChBP) of Lymnaea stagnalis, suggests that the reduced efficacy of imidacloprid following the G189E mutation is likely to result from carboxylate interference with the electronic interactions between the nitro group of imidacloprid and the basic residues in loop D.

Eastern Hemlock Recovery from Hemlock Wooly Adelgid Damage following Imidacloprid Therapy

Hemlock woolly adelgid (Adelges tsugae) is a serious pest of hemlocks (Tsuga spp.) in the eastern United States. A variety of insecticides are capable of controlling hemlock woolly adelgid. The use of a systemic insecticide, imidacloprid, has gained widespread acceptance and use in the plant care industry. While several studies demonstrate the efficacy of imidacloprid in reducing adelgid populations, none have examined how hemlocks recover following imidacloprid therapy. Using specimen Tsuga canadensis trees in a residential landscape, we found that hemlocks recovered dramatically with new growth once the pressure of the adelgids was reduced following an application of imidacloprid. Most important, the response of trees to imidacloprid therapy differed in relation to their condition at the onset of the experiment. Trees with the healthiest, most foliated canopy improved the least following the reduction in adelgid populations. Trees with little new growth but no dieback recovered the quickest and most densely. Trees in the poorest condition at the onset recovered impressively but more slowly. Trees left untreated remained sparsely foliated, with dieback. These results confirm the value of imidacloprid therapy in improving the quality of hemlocks under attack by the hemlock woolly adelgid in urban forests.

8.エキゾチックペットに寄生した数種外部寄生虫に対するイミダクロプリドの治療効果

8.エキゾチックペットに寄生した数種外部寄生虫に対するイミダクロプリドの治療効果

Effect of application rate and beetle age on efficacy of imidacloprid (Gaucho®) against black maize beetle, Heteronychus arator Fabricius (Coleoptera: Scarabaeidae)

Laboratory trials were conducted to study the effect of application rate and beetle age on damage inflicted by black maize beetle, Heteronychus arator, to maize seedlings treated with imidacloprid. Application rate was evaluated in two trials using young adults during autumn and older adults during spring after hibernation. Three trials evaluating the effect of beetle age were conducted at fortnightly intervals during spring when adults were in a progressively changing reproductive phase. Only females after hibernation were used in the latter trials. In all trials treated and untreated seeds were planted in a greenhouse and maize seedling stems fed to adults in glass vials. Damage to maize seedlings (number of damaged sheaths) was determined and beetle mortalities recorded. Results indicated that with older adults a rate of half the registered rate might be as effective as the registered rate. However, it would be safer to use the higher registered rate until all factors that might affect the efficacy of imidacloprid are known. Females occurring during mid-spring were less affected by the systemic activity of imidacloprid than those occurring later during the season, which might possibly be related to their ovipositional cycle. In the majority of fields in the area where H. arator pest outbreaks traditionally occur, maize seedlings are in a vulnerable growing stage during mid-spring. The systemic component of imidacloprid might therefore not be able to control H. arator effectively in growing seasons when beetle population levels are high, especially when it is used at half the registered rate.

Comparison of the activity of selamectin, imidacloprid and fipronil for the treatment of dogs infested experimentally with Ctenocephalldes canis and Ctenocephalides felis felis

Twenty-four beagles were randomly allocated into four groups of six and housed in separate cages. Each dog was infested with 25 Ctenocephalides canis and 25 Ctenocephalides felis felis and two...

Application technique and irrigation method affect imidacloprid control of silverleaf whiteflies (Homoptera: Aleyrodidae) on poinsettias.

Subirrigation systems are increasingly used to water and fertilize greenhouse crops. They also appear to be well suited for the application of systemic pesticides. We conducted two studies to look at interactive effects ofimidacloprid application technique and irrigation method on plant uptake of imidacloprid and whitefly control. Drench applications of imidacloprid resulted in much higher concentrations in the leaves than applications to the bottom of pots after 14 d. However, imidacloprid efficacy in subirrigated plants was better if the imidacloprid was applied to the bottom of the pot than when an equal amount was applied as a drench. In drip-irrigated plants, imidacloprid efficacy was greater after a drench than after an application to the bottom of the pots. A second study showed that drench applications to drip-irrigated plants result in high imidacloprid concentrations in the bottom of the canopy, whereas bottom applications to subirrigated plants result in a more even distribution of imidacloprid throughout the plant. Surprisingly, the high leaf imidacloprid concentrations in the bottom layer of drip-irrigated plants did not result in improved whitefly control. Imidacloprid efficacy was better in subirrigated, bottom-treated plants than in drip-irrigated, drenched plants. Overall, results from these studies indicate that imidacloprid is very effective when applied to the bottom of subirrigated pots.

Control of immature stages of the flea Ctenocephalides felis(Bouché) in carpets exposed to cats treated with imidacloprid

Fleas cause allergic dermatitis in cats and dogs and therefore warrant control. It has been demonstrated previously that there is marked inhibition of the development of the immature stages of the cat flea Ctenocephalides felis on fleece blankets exposed to cats treated with imidacloprid. This study reports on the efficacy of imidacloprid in suppressing adult flea emergence in carpet exposed to treated cats. Circular discs of carpet pre-seeded with flea eggs and larvae were exposed to 6 untreated control and 6 topically treated (imidacloprid 10% m/v) cats 1 to 2 days after treatment and subsequently fortnightly for 6 weeks. Exposure times on alternate days were either 1 or 6 hours. Adult flea yield from carpets was determined 35 days after exposure. Differences between flea yield on control carpets and those exposed for 1 hour were significant only for days +1 and +14. For the 6-hour exposure, differences were significant at all times except on Day +43. The ability of imidacloprid to suppress the yield of adult fleas on carpets (6-hour exposure) steadily declined from 82 % (Day +2) to 12% (Day +43). For the 1-hour exposure it varied inconsistently between 0 and 83% over the 6-week study period.

Efficacy of Imidacloprid for Control of Cereal Leaf Beetle (Coleoptera: Chrysomelidae) in Barley

The toxicity of imidacloprid to the cereal leaf beetle, Oulema melanopus (L.), was measured under laboratory and field conditions. Insect mortality and plant damage were determined from artificial and natural infestations of O. melanopus applied to various growth stages of barley. All rates of imidacloprid formulated and applied as a seed treatment caused >90% mortality to cereal leaf beetle larvae when barley was infested with eggs at the 4-leaf stage, but were ineffective when barley was infested with eggs at the early tillering or flag-leaf stages of barley. This window of susceptibility influenced results obtained in field trials where peak larval emergence did not occur until the early tillering stage of barley. The resulting mortality in plants from treated seeds never exceeded 40% in the field. Foliar imidacloprid, however, caused >90% mortality in the field, and may be another option in the management of the cereal leaf beetle.