Efficacy Of Imidacloprid Research Articles

Antiparasitic effect of imidacloprid on the copepodite and adult stages of Caligus rogercresseyi

In Chile, there are currently eight authorized pharmaceutical chemical compounds for the control of sea lice (Caligus rogercresseyi), namely emamectin benzoate, diflubenzuron, lufenuron, hexaflumuron, hydrogen peroxide, deltamethrin, cypermethrin and azamethiphos; however, being this range of tools considered scarce, moreover, loss of sensitivity to some of these compounds have been described in previous studies. Imidacloprid is a neonicotinoid synthetic insecticide that was authorized in Norway in 2021 and has revealed good efficacy in controlling Lepeophtheirus salmonis on salmon farms; however, it has not been authorized for use in Chile. Therefore, in this study, we investigated the efficacy of imidacloprid on the copepodite and adult stages of C. rogercresseyi, which, to our knowledge, has not been investigated in previous studies. We observed that imidacloprid immobilized the parasite at both stages; however, adults were able to recover after the exposure, with 50 % of the adults exposed to concentrations <40 ppm for 24 h recovering, suggesting that a concentration > 20 ppm is required for 100 % mortality of this parasite. In contrast, the copepodite stage was immobilized at 20 ppm, suggesting that copepodites are more sensitive to imidacloprid than the adults. Further studies are required to understand the biological responses of the different stages of C. rogercresseyi to design effective control strategies, improve our understanding of the mechanisms of imidacloprid, and determine the optimal concentrations for control of the parasite.

Investigating the spatial associations between thatch and white grub populations in imidacloprid‐treated turfgrass

AbstractField surveys were conducted on golf courses reporting the inability of imidacloprid to control white grubs (Coleoptera: Scarabaeidae) when applied preventively. Surveys of five sites with significant past imidacloprid use (&gt;10 years) revealed significantly greater white grub populations in rough‐mown turf following imidacloprid treatment than that of adjacent short‐mown fairways. Additionally, spatial analysis by distance indicEs (SADIE) analyses demonstrated a positive correlation between white grub and thatch spatial patterns. To investigate the impact of thatch on imidacloprid efficacy and translocation throughout the turfgrass plant, greenhouse experiments were conducted using turf with differing thatch levels. Imidacloprid concentrations in soil and plant tissues were measured with high‐performance liquid chromatography (HPLC) and compared to values obtained through an enzyme‐linked immunosorbent assay (ELISA) kit to determine if the latter could be a cost‐effective alternative in future studies. ELISA provided reliable estimates of concentrations of imidacloprid compared to HPLC, with only minor discrepancies noted across different types of treatments and assessment timings. Despite finding higher imidacloprid levels in leaf tissues compared to roots and some differences in concentration across thatch treatments, there was no clear pattern showing that thatch thickness significantly affects imidacloprid penetration or accumulation in plant tissues or soil over time. These findings suggest that factors other than thatch thickness may contribute to the observed field failures of imidacloprid in controlling white grubs. Further research is necessary to identify these factors and optimize the use of imidacloprid in turfgrass pest management strategies.

Impact of a worker bee thoracic ganglion RIC-3 variant on the actions of acetylcholine and neonicotinoids on nicotinic receptors in Apis mellifera.

A transmembrane thioredoxin (TMX3) enables the functional expression of insect nicotinic acetylcholine receptors (nAChRs) in Xenopus laevis oocytes, while co-factors RIC-3 and UNC-50 regulate the receptor expression level. RIC-3 (resistant to inhibitors of cholinesterase 3) has been shown to diversify by its differential mRNA splicing patterns. How such diversity influences neonicotinoid sensitivity of nAChRs of beneficial insect species remains poorly understood. We have identified a RIC-3 variant expressed most abundantly in the thoracic ganglia of honeybee (Apis mellifera) workers and investigated its effects on the functional expression and pharmacology of Amα1/Amα8/Amβ1 and Amα1/Amα2/Amα8/Amβ1 nAChRs expressed in X. laevis oocytes. The AmRIC-3 enhanced the response amplitude to the acetylcholine (ACh) of these A. mellifera nAChRs when its cRNAwas injected into oocytes at low concentrations but suppressed the ACh response amplitude at high concentrations. Co-expression of the AmRIC-3 had a minimal impact on the affinity of ACh, but changed the efficacy of imidacloprid and clothianidin, suggesting that the presence and the level of RIC-3 expression can affect the nAChR responses to ACh and neonicotinoids, depending on nAChR subunit composition in honeybees. © 2024 Society of Chemical Industry.

Use of double-stranded RNA targeting β2 divergent nicotinic acetylcholine receptor subunit to control pea aphid Acyrthosiphon pisum at larval and adult stages.

In recent years, the use of the RNA interference technology (RNAi) has emerged as one of the new strategies for species-specific control of insect pests. Its specificity depends on the distinctiveness of the target gene sequence for a given species. In this work, we assessed in the pea aphid Acyrthosiphon pisum (A. pisum) the use of a double-stranded RNA (dsRNA) that targets the β2 divergent nicotinic acetylcholine receptor (nAChR) subunit (dsRNA-β2), which shares low sequence identity with other subunits, to control populations of this pest at different developmental stages. Because nAChRs are targeted by neonicotinoid insecticides such as imidacloprid, we also assessed the effect of dsRNA-β2 coupled to this insecticide on aphid survival. Finally, because the effect of a control agent on beneficial insect must be considered before any use of new pest management strategies, the acute toxicity of dsRNA-β2 combined with imidacloprid was evaluated on honeybee Apis mellifera. In this work, we demonstrated that dsRNA-β2 alone has an insecticidal effect on aphid larvae and adults. Moreover, dsRNA-β2 and imidacloprid effects on aphid larvae and adults were additive, meaning that dsRNA-β2 did not alter the efficacy of imidacloprid on these two developmental stages. Also, no obvious acute toxicity on Apis mellifera was reported. Using RNAi that targets β2 divergent nAChR subunit is effective alone or combined with imidacloprid to control A. pisum at larval and adult stages. Because no obvious Apis mellifera mortality has been reported, this RNAi-based pest management strategy should be considered to control insect pest. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Imidacloprid-resistant Aphis gossypii populations are more common in cotton-dominated landscapes.

Widespread reports of reduced efficacy of imidacloprid for managing cotton aphids (Aphis gossypii Glover) in cotton (Gossypium hirsutum L.) prompted an investigation to characterize the susceptibility of 43 populations over a 2-year period. The susceptibility of A. gossypii populations to imidacloprid was examined by calculating LC50 values. Further analyses related resistance assay results to a gradient of cotton production intensity. Concentration-mortality bioassays documencted populations that were 4.26-607.16 times more resistant than the susceptible laboratory population. There was a significant positive relationship between LC50 values and percentage of cotton within 2.5- and 5-km buffers surrounding collection sites. No significant relationship was detected between LC50 values and the percentage of alternative crop and noncrop hosts. Variable and high levels of resistance were detected in A. gossypii populations, and this variation was positively associated with cotton production intensity. Cotton is a host that may receive multiple applications of neonicotinoids (via seed treatment and foliar sprays) annually for seedling and mid-season pests. Rotating modes of action and limiting insecticide use should be implemented to delay the evolution of insecticide resistance in A. gossypii populations. © 2022 Society of Chemical Industry.

Evaluation of Imidacloprid 6%+ Lambda cyhalothrin 4% SL Against Sucking Pests of Cotton

Two field experiments were conducted to evaluate the efficacy of imidacloprid 6%+ lambda cyhalothrin 4% SL against sucking insects viz., aphid Aphis gossypii Glover, leafhopper Amrasca biguttula biguttula (Ishida), thrips Thrips tabaci L. and whitefly Bemisia tabaci (Gennadius) on cotton during kharif, 2018-19 and 2019-20 at the Agricultural Research Station, Dharwad farm, UAS, Dharwad, Karnataka. Results showed that the higher dose of imidacloprid 6%+ lambda cyhalothrin 4%SL @ 500 ml ha-1 resulted in 89.02, 88.52, 91.91 and 90.17% reduction of aphids, thrips, leafhoppers and whitefly, respectively in first season and 93.03, 87.15, 97.01 and 89.65% in second season compared to the untreated check. It was on par with its lower dose @ 450 ml ha-1. There was no significant difference in the counts of grubs and adults of coccinellids and number of chrysopids. Thus, imidacloprid 6%+ lambda cyhalothrin 4% SL could be used for the management of sucking pests without any effect on non-target insects.

Evaluation the efficacy of Insecticides Spinosad and Imidacloprid in olive trees infested by termite Microcerotermes diversus (Silvestri) (Isoptera: Termitidae)

Termites reason deep commercial fatalities international. Microcerotermes diversus (Silvestri) reasons marvelous indemnities to timber effort in the constructions and woodland plants. Diverse kinds of fly spray have been utilized to dominate this underground termite. In the present research, efficacy of imidacloprid and Spinosad against Microcerotermes diversus (Silvestri) was studied. The results showed that the direct spray of different concentration (200, 400 and 600 ppm) for both Spinosad and imidacloprid on the stems of Olive trees and soil surrounding a diameter of 20 cm was high impactive in termite infestation reduction which decreasing the tunnels length and the quantity of workforces gradually and absence the termite infestation after the time. The duration of absence of termite infestation refinish on concentrations of the both termiticides. It is noted in concentrations 200 and 400 ppm for the pesticide imidacloprid, the infestation was continuous during the year and the termite infestation did not stop, as for the concentration of 600 ppm, it prevented the infestation for a period of 3 months, and then the infestation resumed in the months of April, May and June, after which the infestation was stopped. As for the pesticide Spinosad at all its concentrations, it prevented the infestation with different periods, the best and most efficient, the concentration of 600 ppm, the infestation was prevented after two months of spraying, and the infestation continued for all concentrations until the assumption of the investigate period, besides the impact of spinosad reduced and prevent the quantity of workforces visiting the stem of Olive trees gradually till the infestation was absence.

Effects of Two Adjuvants (Scorch and Torpedo п) on Efficacy of Imidacloprid and Flonicamid to Control the Aphis gossypii Aphid in Greenhouse Cucumber

Effects of Two Adjuvants (Scorch and Torpedo п) on Efficacy of Imidacloprid and Flonicamid to Control the Aphis gossypii Aphid in Greenhouse Cucumber

Measurement of biorational effect of imidacloprid on some aphids spp. as well as on wheat (Triticum aestivum L.) using biochemical parameters and ISSR-PCR.

Aphid species are the most common insect pest infesting wheat plants. The LC values of imidacloprid against aphid spp., ISSR-PCR molecular markers and biochemical parameters in wheat plant in the present study were carried out. The LC50 of imidacloprid on Rhopalosiphum maidis, Rhopalosiphum padi, Sitobion avenae, and Schzaphis graminum were 71.626, 85.853, 91.05, and 115.806, respectively. While, the biochemical parameters in treated wheat plants including; total protein, RNA, and DNA contents increased in all experimental groups. Moreover, total carbohydrates and soluble sugar also increased in treated wheat seedlings. Also, the genetic diversity studies revealed that among six ISSR primers produced 36 amplified DNA fragments in a molecular weight range of (480-1545bp). About 28 fragments were monomorphic, and 8 fragments were polymorphic. It can be concluded that the effectiveness of imidacloprid against sucking insects in treated wheat plants may due to few genetic variations and some metabolic changes in the Triticum. aestivum. PRACTICAL APPLICATIONS: The current study indicated that the potent efficacy of imidacloprid against different aphid spp. which were the most insect pest in wheat plants. As well as the application of imidacloprid as seed dressing insecticide, significantly increase carbohydrate, protein, amino acids, and RNA content in T. aestivum plants. While there was no significant increase in DNA in treated one. The recorded increase in these biochemical parameters may due to the increase in the gene expressions as a result of the application of such pesticides. These results explain the extra mechanism of the effect of imidacloprid against sucking insects. Also, the conducted results explain the effect of imidacloprid as a seed dressing insecticide in wheat crop protection from sucking insects and increasing seed germination, increasing seed wheat and number of seeds/spike.

Modulation by neonicotinoids of honeybee α1/chicken β2 hybrid nicotinic acetylcholine receptors expressed in Xenopus laevis oocytes

Neonicotinoids targeting insect nicotinic acetylcholine (ACh) receptors (insect nAChRs) are used for crop protection, but there is a concern about adverse effects on pollinators such as honeybees (Apis mellifera). Thus, we investigated the agonist actions of neonicotinoids (imidacloprid, thiacloprid and clothianidin) on A. mellifera α1 (Amα1)/chicken β2 hybrid nAChRs in Xenopus laevis oocytes according to the subunit stoichiometry of (Amα1)3(β2)2 and (Amα1)2(β2)3 using voltage-clamp electrophysiology. ACh activated (Amα1)3(β2)2 and (Amα1)2(β2)3 nAChRs with similar current amplitude. We investigated the agonist activity of imidacloprid, thiacloprid and clothianidin for the two hybrid nAChRs and found that: 1) imidacloprid showed higher affinity than clothianidin, whereas clothianidin showed higher efficacy than imidacloprid for the nAChRs; 2) Thiacloprid showed the highest agonist affinity and the lowest efficacy for the nAChRs. The Amα1/β2 subunit ratio influenced the efficacy of imidacloprid and thiacloprid, but hardly affected that of clothianidin. Hydrogen bond formation by the NH group in clothianidin with the main chain carbonyl of the loop B may account, at least in part, for the unique agonist actions of clothianidin on the hybrid nAChRs tested.

Efficacy of imidacloprid 10%/moxidectin 1% spot-on formulation (Advocate\xae) in the prevention and treatment of feline aelurostrongylosis

BackgroundIn three randomized, controlled laboratory efficacy studies, the efficacy in the prevention of patent infections of a topical combination of imidacloprid 10%/moxidectin 1% (Advocate® spot-on formulation for cats, Bayer Animal Health GmbH) against larval stages and immature adults of Aelurostrongylus abstrusus, as well as the treatment efficacy of a single or three monthly treatments against adult A. abstrusus, were evaluated.MethodsCats were experimentally inoculated with 300–800 third-stage larvae (L3). Each group comprised 8 animals and the treatment dose was 10 mg/kg bodyweight (bw) imidacloprid and 1 mg/kg bw moxidectin in each study. Prevention of the establishment of patent infections was evaluated by two treatments at a monthly interval at three different time points before and after challenge infection. Curative efficacy was tested by one or three treatments after the onset of patency. Worm counts at necropsy were used for efficacy calculations.ResultsIn Study 1, the control group had a geometric mean (GM) of 28.8 adult nematodes and the single treatment group had a GM of 3.4 (efficacy 88.3%). In Study 2, the control group had a GM of 14.3, the prevention group had a GM of 0 (efficacy 100%), while the treatment group had a GM of 0.1 (efficacy 99.4%). In Study 3, the GM worm burden in the control group was 32.6 compared to 0 in all three prevention groups (efficacy 100% for all of those groups).ConclusionsThe monthly administration of Advocate® reliably eliminated early larval stages and thereby prevented lung damage from and patent infections with A. abstrusus in cats. Regarding treatment, a single application of Advocate® reduced the worm burden, but it did not sufficiently clear the infection. In contrast, three monthly treatments were safe and highly efficacious against A. abstrusus.

Imidacloprid Efficacy against Brown Planthopper, &lt;i&gt;Nilaparvata lugens&lt;/i&gt; under Elevated Carbon Dioxide and Temperature

Influence of elevated CO 2 and temperature (elevated condition (EC)) vis-a-vis ambient CO2 and tempera-ture (ambient condition (AC)) on plant (rice) growth, insect Nilaparvata lugens (brown planthopper (BPH)) population and insecticide (Imidacloprid) efficacy was evaluated under open top chamber conditions. EC had a positive effect on rice crop through increase in tillers numbers (18.4%), reproductive tillers (20.5%) but in-flicted negative effect on 1000-grain weight (11.7%) and grain yield (11.9%). Likewise, higher canopy cover of the plant was noticed under EC (16.1 cm) when compared to AC (12.9 cm). With respect to BPH population during 2013 and 2014, EC exhibited posi-tive effect by enhancing its mean population to 66.1 and 49.4 hoppers hill –1 respectively, compared to cor-responding 36.8 and 29.5 hoppers hill –1 under AC. With respect to Imidacloprid efficacy against BPH, LC50 was significantly lower under EC (0.044%) in comparison to AC (0.065). Similarly, in 2013 under AC, 500, 600, 700 l ha –1 spray volume caused >50% BPH mortality than 400 l ha –1 at 5 day after spray. However, during the same exposure period under EC, only 700 and 600 l ha –1 produced more than 50% mortality compared to 500 and 400 l ha –1 . Positive in-fluence of EC on BPH population resulted in signifi-cantly higher yield loss (41.1%) compared to ambient (26.5%) in untreated check. Though LC50 under EC was less, higher canopy size and more BPH population resulted in increase in spray volume to cause similar mortality as of AC. The present results indicated that spray volumes of 400 and 500 l ha –1 was found insuffi-cient to manage BPH population under EC; hence the current management strategies for BPH needs to be redefined under changing climatic conditions.

Comparative Efficacy of Imidacloprid as Seed Treatment Insecticide against Sucking Insects and their Predators in the Wheat Crop

Sucking insects are the most serious insect pests in wheat crops; the harmful effect of aphid in wheat plants is due to sucking of plant sap, honeydew excretion and causing many diseases by transport of plant viruses. The experiment was carried out at Sakha Agric. Res. Station farm during 2017-2018 on wheat Giza 171 growing season. The insecticide used is Imidacloprid (Nofedor 600 FS.) The present study was designed to evaluate comparative efficacy of imidacloprid as seed dressing formulation against sucking insects (Schizaphis graminum, Nezara viridula, Empoasca spp.) as well as their predators; Chrysoperla carena, Labidura riparia, Scymunus spp. and true spiders in two types of wheat sowing (Drill and Broadcast) in the wheat crop field. The results according to analysis of variance showed that there was a significant variation among the insect’s reduction in all-season periods as a result of treatment of the wheat seeds before sowing with imidacloprid in the Broadcast and drill sowing. Whereas there is no significant effect of the treatment when comparing S. graminum in different sowing methods, also there was a non-significant effect of the treatment on S. graminum in broadcast method versus N. viridula, Empoasca spp. and predators. While, the number of seeds/spikes, Weight of 100 seeds (gm) and the Germination increasing % in Broadcast sowing were more than that in Drill sowing by 1.31,1.11 and 1.11 respectively. Thus, it could be concluded that the broadcast sowing is suitable economically for farmers than drill sowing methods when using imidacloprid as seed dressing before cultivation for sucking insect control as well as its predators.

Piperonyl Butoxide Enhances the Insecticidal Toxicity of Nanoformulation of Imidacloprid on Culex pipiens (Diptera: Culicidae) Mosquito.

The use of conventional pesticides becomes a complicated issue as more species of insect pests become resistant to them. Nanopesticides suit new approaches in pest control. Herein, we tested the toxicological efficacy of imidacloprid compared with three of its nanoformulations (IMD01, IMD02, and IMD03) on second and fourth instar of Culex pipiens larvae. Furthermore, we assessed the synergistic actions of piperonyl butoxide (PBO) on imidacloprid and its nanoformulations against second and fourth instar of C. pipiens. The nanoformulation (IMD03) was the most potent insecticide (LC50 = 14, 6, and 2 ng/mL after 24, 48, and 72 h of exposure, respectively), whereas the lowest toxic nanoformulation was IMD01. However, imidacloprid had the lowest toxicity among the tested compounds (LC50 = 1015, 705, and 621 ng/mL after 24, 48, and 72 h of exposure, respectively). PBO significantly synergized imidacloprid and its nanoformulations. However, the most synergistic effects were on IMD03 and the lowest was imidacloprid itself. Based on our results, nanopesticides are currently the most promising tool to control C. pipiens mosquitoes. However, further semifield and field studies should be done to illustrate the efficacy of imidacloprid and its nanoformulations on C. pipiens mosquitoes.

Comparative Efficacy of Varied Concentrations Imidacloprid in the Laboratory Management of Termites (Microtermes natalensis)

Imidacloprid is a termiticide that is slow-acting timber and soil applied but can be transferred in termite workers. The objective of this study was to determine efficacy of imidacloprid to control of termites on sand. Termiticides were tested at Imidacloprid 200 g/L concentrations (2 mL/L, 4 mL/L, 6 mL/L and 8 m/L) were tested. Descriptive analysis presented the mean weight loss for wood blocks under treated sand as follows E. grandis 0.003 (Std: 0.02) and G. robusta 0.013 (Std: 0.04) whereby only woodblocks under treated sand with 2 mL/L were attacked, while the mean weight loss for untreated woods under untreated sand were as follows E. grandis was 0.1 (std: 0.06) and G. robusta was 0.216 (std: 0.147). However, termites attacked all untreated wood blocks regardless of wood species. It was concluded that Imidacloprid at concentration of 4 mL/L serves as the best concentration threshold required in the control of termites on sand in the management of termites. It was recommended that soil is effective mode of applying imidacloprid termiticide integratedly given that the right concentration levels are utilized.

Efficacy of imidacloprid 10%/moxidectin 2.5% spot on (Advocate®, Advantage Multi®) and doxycycline for the treatment of natural Dirofilaria immitis infections in dogs

Heartworm infection (also known as dirofilariosis due to Dirofilaria immitis) in dogs causes chronic pulmonary disease that, if left untreated, can lead to right-side congestive heart failure. Currently, the only registered drug for adulticide therapy in dogs with heartworm disease (HWD) is melarsomine dihydrochloride. The recent targeting of the bacterial endosymbiont Wolbachia, through antibiotic therapy of the infected host, has offered an interesting alternative for the treatment of HWD. Recent reports of the adulticide activity of an ivermectin/doxycycline combination protocol has lead the American Heartworm Society (AHS) to include in its guidelines that, in cases where arsenical therapy is not possible or is contraindicated, a monthly heartworm preventive along with doxycycline for a 4-week period might be considered. In the present study, 20 dogs with confirmed natural D. immitis infection were included following owner consent. Fourteen dogs were treated with a topical formulation containing 10% w/v imidacloprid and 2.5% w/v moxidectin (Advocate®, Advantage Multi®, Bayer), monthly for nine months, associated to doxycycline (10 mg/kg/BID) for the first 30 days. Six dogs were treated with melarsomine (Immiticide®, Merial) (2.5 mg/kg) at enrollment, followed one month later by two injections 24 h apart.The presence of circulating antigens and the number of microfilariae (mf) were evaluated at the moment of enrollment and then at 1, 2, 3, 4, 5, 6, 7, 8, 12, 18, 24 months post enrollment. Echocardiogram and radiographs were performed at month 0, 6, 12, 18, 24.Monthly moxidectin combined with 30 days of doxycycline eliminated circulating microfilariae within one month, thus breaking the transmission cycle very quickly. Furthermore, dogs treated with the combination protocol started to become negative for circulating antigens at 4 months from the beginning of treatment and all except one were antigen negative at 9 months. All dogs treated with melarsomine were antigen negative by 5 months from the beginning of the treatment. No dogs showed worsening of pulmonary patterns or criteria indicative of pulmonary hypertension 12 to 24 months after. For the criteria mf concentration, antigen concentration, radiography and echocardiography at 12, 18 and 24 months the non-inferiority for the moxidectin group could be proven for a non-inferiority margin of 15% for the rate difference. Dogs treated with moxidectin and doxycycline became negative for microfilariae and antigens sooner when compared to melarsomine in the present study and to dogs treated with doxycycline combined with ivermectin in studies previously published.

Residues of imidacloprid insecticide and its efficacy on whitefly, Bemisia tabaci (gennadius) in tomato plants

The present work was conducted to evaluate the efficacy of imidacloprid against the whitefly, Bemisia tabaci infesting tomato plants under field conditions and its residues in leaves and fruits after different periods of application, using root treated seedling, treated seeds and foliar spray techniques. The root treated seedling was more effective than treated seeds in decreasing different stages of whitefly population. The reduction percentages of egg, nymph and adult stages in root treated seedlings and sprayed with half and field rates were more than that in untreated seedlings. The fruit yield was increased in root treated tomato seedlings sprayed with the recommended rate of imidacloprid compared to root untreated seedlings. Residues of imidacloprid in leaves and fruits in root treated seedlings sprayed with field rate were more than root untreated seedlings and sprayed, as well as the residues of imidacloprid were higher in leaves than fruits. The residual level of imidacloprid in fruits was less than maximum residual level (MRL = 1 mg kg−1) which recommended by Codex Alimentarius Commission. Half-life (t 1/2) was 7.27 and 6.37 day for leaves and fruits of root treated seedling and was 7.14 and 4.88 day for untreated seedling and sprayed. Imidacloprid was more more toxic to white fly Bemisia tabaci and also, its residues were under maximum resuidual limits ( MRL) in tomato fruits after one hr (initial residues) of spraying and after different periods of treatment with field recommended rate, it is safe for consumers and effective against white fly, so it could be suggested to use in white fly integrated management.

Insecticides resistance and detoxification enzymes activity changes in brown planthopper, Nilaparvata lugens in Guizhou Province

The brown planthopper (BPH), Nilaparvata lugens (Homoptera: Delphacidae), is a kind of seriously pest of rice crops throughout Asia and effective control is essential for economical crop production. Insecticides Abamectin, Imidacloprid, Chlorantraniliprole, Phoxim and Chlorpyrifos have been broadly used to control the brown planthopper for recent years. To investigate the resistance development of the BPH in Guizhou Province, we collected BPH from 5 sites (Panxian, Jinping, Sandu, Daozhen and Huaxi) in Guizhou Province June–August 2014. Their responses to two diagnostic doses of 5 insecticides (LD50 and detoxification enzyme activity) were examined. The results showed that LD50 value for Chlorantraniliprole in Jinping and Huaxi BPH population were 199.810 and 282.082 μg/g higher than imidacloprid, phoxim and chlorpyrifos. LD50 value for Imidacloprid in Jinping population was 3.957 μg/g lower than other BPH populations for 4 insecticides. The GSTs activity is significantly higher with Abamectin, Chlorpyrifos and Phoxim treatments. AchE activity is higher with Chlorantraniliprole and Imidacloprid, but lowest among three enzymes with Phoxim and Chlorpyrifos. The data demonstrate the development and spread of multiple resistance in N. lugens in Guizhou Province and support reports of reduced field efficacy of imidacloprid.

EFFECT OF APPLICATION METHODS OF TWO NEONICOTINOID PESTICIDES ON SPRAY COVERAGE SPECTRUM AND REDUCTION PERCENT OF WHEAT APHID, RHOPALOSIPHUM PADI AT SHARQIA GOVERNORATE

In the current study, two equipment were used to control wheat Aphid, Rhopalosiphum padi. The first equipment, Knapsack sprayer (3WDB) with battery charge and flat fan nozzle. The second equipment, Knapsack motor sprayer (IE34F) with hydraulic pump and spray gun at New Salhyia city, Sharqia Governorate. The present study aimed to determine the effects of application method on initial and late biological efficacy of imidacloprid and dinotefuran (belong to neonicotinoid) against wheat aphid. Results in two seasons (2016 & 2017) indicated that, IE34F Motor sprayer (as high volume sprayer) showed less initial efficacy compared with 3WDB Power sprayer (as medium sprayer volume). Although the imidacloprid pesticide gives high efficacy compared with dinotefuran pesticide. The main obtained difference was Imidacloprid with 3WDB Power sprayer gave the highest efficacy with a significant difference compared with dinotefuran with IE34F Motor sprayer.

Efficacy of some Novel and Conventional Insecticides against Aphis gossypii Glover and their Side Effects on Non-Targeted Organisms and Plant Defense Enzymes of Cotton Plants

Cotton aphid, Aphis gossypii Glover (Homoptera: Aphididae) is considered a key pest of cotton in Egypt. Hence, field and laboratory studies were conducted at Sakha Agriculture Research Station, Egypt during seasons 2016 and 2017. Efficiency of seven insecticides i.e., flonicamid, imidacloprid, thiamethoxam, emamectin-benzoate, chlorpyrifos, methomyl and deltamethrin against A. gossypii in cotton fields were evaluated. Their side effects on the associated predators, soil fauna and plant defense enzymes also were studied. Flonicamid was the most effective against A. gossypii. The efficacy of imidacloprid and thiamethoxam did not differ significantly from that of chlorpyrifos and methomyl recording from 83.28 – 93.27% reduction in A. gossypii infestation. Flonicamid, emamectin-benzoate, imidacloprid and thiamethoxam were the least harmful to the associated predators causing less than 50% mortality, while the others were highly toxic. Flonicamid exhibited the highest degree of safety to the soil micro-arthropods, followed by emamectin-benzoate, methomyl and deltamethrin. In contrast, chlorpyrifos and imidacloprid were the most toxic to the soil micro-arthropods. The conventional insecticides (chlorpyrifos, methomyl and deltamethrin) increased the activity of catalase and peroxidase causing physiological stress on the treated cotton plants, whereas the other tested insecticides recorded decreases in catalase and peroxidase activities inducing the plant defense response. Only imidacloprid and thiamethoxam increased the activity of polyphenol oxidase. Emamectin-benzoate and deltamethrin decreased the total soluble protein content, while the others tested insecticides caused increases in this criterion comparing to the control.