Management of early-instar Japanese beetle (Coleoptera: Searabaeidae) in field-grown nursery crops.

Numerous field studies were conducted in commercial nurseries in Tennessee from 1996 through 1999 to evaluate chemical and biological treatments, application timing and rates, and method of application for control of early instars of Japanese beetle, Popillia japonica Newman. Insecticide treatments included bifenthrin, bendiocarb, chlorpyrifos, carbaryl, fipronil, halofenozide, imidacloprid, permethrin, tefluthrin, thiamethoxam, and trichlorfon. Biological treatments included entomopathogenic nematodes (Heterorhabditis bacteriophora HP88 or H. marelatus, Bacillus thuringiensis Berliner subspecies japonensis Buibui strain, and Beauveria bassiana (Balsamo) Vuillemin. All treatments were applied on the soil surface or injected into the soil around the base of each tree. Tree type and size varied among and within tests, however, the sampling unit (61-cm-diameter root ball) remained the same throughout all tests. The biological treatments provided poor-to-moderate control (0-75%) of Japanese beetle larvae. Imidacloprid was the most frequently evaluated insecticide and achieved 91-100, 87-100, 83-100, and 41-100% control with applications in May, June, July, and August, respectively. Halofenozide treatments were not significantly different from imidacloprid treatments with one exception. Halofenozide provided 60-87, 85-100, and 82-92 control with applications made in June, July, and August, respectively. Fipronil and thiamethoxam were evaluated to a lesser extent but both performed similarly to imidacloprid. Most other insecticide treatments were less successful in reducing numbers of Japanese beetle larvae and with few exceptions achieved <50% control.     

Baseline toxicity and field efficacy of metaflumizone on Colorado potato beetle (Coleoptera: Chrysomelidae)

Baseline toxicity levels to a novel semicarbazone insecticide, metaflumizone were established for 25 field populations of Colorado potato beetle, Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae),from North America. Excluding the susceptible laboratory strain, 50% lethal concentrations of metaflumizone ranged from 0.57 to 1.31 ppm, while response slopes ranged from 1.92 to 4.24 (average = 2.93), and were unrelated to the 50% lethal concentration (r = 0.06; P = 0.76). Beetle populations with known resistance to the neonicotinoid imidacloprid also exhibited the highest LC50 levels to metaflumizone suggesting at least the possibility of cross-resistance. Additional experiments using a potato leaf-dip bioassay as well as field efficacy evaluations confirmed the high level of toxicity of metaflumizone to L. decemlineata and demonstrated a potential benefit of tank mixing a low rate of the pyrethroid esfenvalerate with metaflumizone at one-tenth the recommended field rate. These research findings confirm that metaflumizone is highly active against L. decemlineata larvae and adults and could provide an effective alternative insecticide for potato pest management.     

山东省五个棉花产区绿盲蝽对药剂的敏感性检测（英文）

利用闪烁管药膜法测定了2009年山东省德州、滨州、梁山、曲阜和聊城5个棉花产区绿盲蝽Lygus lucorum Meyer-Dür对硫丹、马拉硫磷、毒死蜱、灭多威、丁硫克百威、吡虫啉、联苯菊酯和氟虫腈8种杀虫剂的敏感性,筛选出适合各地区的高效防治药剂。结果表明：5个地区绿盲蝽种群对马拉硫磷、毒死蜱、丁硫克百威、联苯菊酯和吡虫啉处于敏感性阶段。不同种群之间对灭多威、硫丹和氟虫腈的敏感性差异较大,其中聊城种群为最敏感种群,滨州种群对灭多威、 硫丹和氟虫腈的LC₅₀值分别为聊城种群的5.12,6.04和39.80倍;曲阜种群对灭多威、硫丹和氟虫腈的LC₅₀值分别为聊城种群的22.12,5.48和22.80倍。两种群对此3种药剂的敏感性下降,而其余种群仍处于较敏感阶段。8种药剂对绿盲蝽成虫的毒力按大小依次排序为：氟虫腈＞灭多威、联苯菊酯、硫丹＞马拉硫磷、毒死蜱＞丁硫克百威＞吡虫啉。2009年7-10月间德州夏津绿盲蝽种群对8种杀虫剂的敏感性变化极微。     

Effect of irrigation on the efficacy of insecticides for controlling two species of mole crickets (Orthoptera: Gryllotalpidae) on golf courses

Effects of irrigation regimen, quantity, and timing on the efficacy of three insecticides for controlling nymphs of the southern mole cricket, Scapteriscus borellii Giglio-Tos, and the tawny mole cricket, Scapteriscus vicinus Scudder, were studied on golf courses in 1997, 1998, and 1999. Two irrigation regimen tests using two rates of bifenthrin and lambda-cyhalothrin produced inconclusive results. Mole cricket damage ratings after the applications of bifenthrin (60 g [AI]/ha) and lambda-cyhalothrin (76 g [AI]/ha) were not significantly different among the four irrigation regimens (non-irrigation, irrigation before treatment, irrigation after treatment, and irrigation before and after treatment). Mole cricket damage rating after the application of bifenthrin (120 g [AI]/ha) under irrigation before and after irrigation was significantly better than those under other irrigation regimens at 14 and 21 d after treatment (DAT). Different irrigation quantity and irrigation timing (after insecticide treatment) did not significantly affect the performance of imidacloprid (434 g [AI]/ha) in the 1998 tests. However, the results from the 1999 test indicated that mole cricket damage ratings from the imidacloprid-treated plots were significantly different between 2 and 0.5 cm irrigation water after treatment at 21 and 28 DAT. Application of bifenthrin at a rate of 120 g (AI)/ha with 0.5 cm of irrigation water after treatment resulted in significantly lower mole cricket damage ratings than those of 1.0 and 2.0 cm of irrigation water after treatment at 30 DAT only in the 1998 test. Bifenthrin with irrigation at 1 h after insecticide treatment provided better mole cricket control than that of irrigation at 5 min after treatment at 30 DAT only in the 1998 test. Mole cricket damage ratings after application of bifenthrin were not significantly different between either irrigation quantity treatment or irrigation timing treatment in the 1999 tests. Possible effects of application timing, environmental conditions, irrigation practice, and insecticide physical properties on the results are discussed.     

Impact of whole-canopy and systemic insecticidal treatments on Callirhytis cornigera (Hymenoptera: Cynipidae) and associated parasitoids on pin oak

The gall wasp Callirhytis cornigera (Osten Sacken) is a cynipid with alternating generations that produce large, woody stem galls and tiny blister-like leaf galls on pin oak, Quercus palustris Muenchhausen, in the United States. We tested 3 approaches to control the leaf-galling generation, and determined their impact on associated parasitoids and effectiveness in reducing numbers of new stem galls. First, trees were sprayed with bifenthrin or chlorpyrifos in late March to kill females emerging from stem galls before they oviposited into buds. Second, concentrated solutions of abamectin, imidacloprid, or bidrin were injected from pressurized containers into tree sapwood to control larvae developing in young leaf galls. Finally, systemic insecticides (acephate, abamectin, dimethoate, or imidacloprid) were sprayed at early leaf expansion (2 May) or to young, expanded leaves (17 May) to target larvae in leaf galls. Parasitoids, mostly eulophids, accounted for approximately 70% mortality of leaf-galling C. cornigera larvae on untreated trees. Whole-canopy sprays during C. cornigera emergence from stem galls reduced overall numbers of galled leaves and leaf galls. Trunk injections of bidrin or abamectin resulted in significant mortality of gall inhabitants, including parasitoids. However, neither of the aforementioned approaches significantly reduced numbers of new stem galls. Sprays of abamectin, dimethoate, or imidacloprid applied on 2 May caused high mortality of all gall inhabitants. There was no net benefit, however, because parasitism caused a similar reduction in C. cornigera survival on unsprayed shoots. Sprays applied later in leaf expansion had little impact on gall inhabitants. Of the treatments tested, bifenthrin sprays at bud break provided the greatest reduction in new leaf galls, whereas bidrin injections provided the greatest reduction in gall wasps emerging from galled leaves. This study suggests that gall wasp outbreaks are unlikely to be controlled by a single treatment, regardless of application method.     

Effect of insecticides on Tiphia vernalis (Hymenoptera: Tiphiidae) oviposition and survival of progeny to cocoon stage when parasitizing Popillia japonica (Coleoptera: Scarabaeidae) larvae

The effect of insecticides on oviposition of Tiphia vernalis Rohwer and subsequent survival of parasitoid progeny to the cocoon stage was determined in the laboratory by using larval Japanese beetle, Popillia japonica Newman, as the host. Insecticides tested were imidacloprid, thiamethoxam, halofenozide, chlorpyrifos, and carbaryl at labeled rates. Female T. vernalis were allowed 2 d to parasitize P. japonica larvae after the parasitoids had received a 4-d exposure to insecticide-treated soil. Another group of female T. vernalis were allowed 2 d to parasitize P. japonica larvae that had been exposed to insecticide-treated soil for 3-4 d. Percentage of parasitism of P. japonica larvae in these trials after exposure of adult parasitoids to carbaryl, chlorpyrifos, halofenozide, or imidacloprid-treated soil (23.3-50.0%) or adult parasitoids to chlorpyrifos, halofenozide, or imidacloprid-treated grubs (33.0-56.7%) was not negatively affected relative to the control treatment (21.7-54.2%). A third group of adult T. vernalis and P. japonica larvae were simultaneously exposed to chlorpyrifos or carbaryl treatments. Percentage parasitism in these trials was lower for T. vernalis adults exposed to the chlorpyrifos and carbaryl (15.0-25.0%) relative to the control (57.5-62.5%) with the exception of one trial with carbaryl (40.0%). However, exposure of the parasitoid and P. japonica to chlorpyrifos 0.5X, carbaryl 0.5X, imidacloprid, halofenozide, or thiamethoxam in several trials resulted in parasitism that was equivalent or greater than (45.0-80.0%) the untreated control (57.5-62.5%). Japanese beetle larval mortality in these trials was greater in the insecticide and parasitoid combination (97.5-100.0%) than with insecticides alone (45.0-100.0%). Percentage of survival of T. vernalis progeny to the cocoon stage was not negatively affected by a 4-d adult parasitoid exposure to carbaryl and chlorpyrifos treated soil (11.7-16.7% versus 18.3% control) or a 2-d exposure to P. japonica-treated larvae (16.7-18.3% versus 28.3% control). However, simultaneous exposure of T. vernalis progeny and P. japonica larvae to chlorpyrifos- and carbaryl-treated soil resulted in no parasitoids surviving to the cocoon stage. Between neonicotinoids, thiamethoxam had more adverse impact on percentage parasitism (52.5%) and survival to the cocoon stage (10.0%) than imidacloprid (80.0 and 32.5%, respectively). Results of this study indicate soil incorporation of imidacloprid and halofenozide had minimal effect on the number of P. japonica larvae parasitized by T. vernalis or survival of T. vernalis progeny to the cocoon stage; therefore, they are more suitable for use with T. vernalis. In contrast, chlorpyrifos, carbaryl, and thiamethoxam lowered the number of T. vernalis progeny surviving to the cocoon stage, and carbaryl and chlorpyrifos reduced the number of P. japonica larvae parasitized. The soil incorporation of insecticides is discussed as one explanation for the minimal effects of some insecticides on T. vernalis.     

Susceptibility of the summer fruit tortrix moth, Adoxophyes orana (Lepidoptera: Tortricidae), to chlorpyrifos and strategies for insecticidal control in orchards

The susceptibility of populations of the summer fruit tortrix moth, Adoxophyes orana, from apple orchards in Kent, England, to chlorpyrifos was determined in 1992, 1994 and 1995, by topically dosing larvae feeding on leaves or adults adhered to pheromone trap sticky bases. LD₅₀ values (range 6.3 to 23.2 ng chlorpyrifos per individual) for first or second generation males, second generation females or for first generation fourth instar larvae collected in the field were significantly greater (2–3 fold) for populations from orchards with a long history of treatment with broad-spectrum organophosphorous and other insecticides than for those from untreated orchards (range 1.6 to 8.1 ng chlorpyrifos per individual), though there was considerable variation between sites and years. Twelve replicated orchard experiments between 1993 and 1995 were used to examine a range of different strategies for insecticidal control. Applications of chlorpyrifos against overwintered larvae feeding in trusses in spring gave, at best, a 75% reduction in larval numbers, insufficient to prevent damage by the subsequent generation in summer. However, two applications of fenoxycarb (one immediately pre-and one immediately post-blossom of apple cv. Cox) completely prevented successful subsequent development of the pest, and a single (post-blossom) spray nearly so. The timing of application of chlorpyrifos against first generation larvae hatching from eggs in June was shown to be critical and currently used methods of spray-timing were unreliable. The effective persistence of chlorpyrifos was short (< 7 days). Though good control could be achieved with a single spray, a better strategy was to apply a series of sprays at 7-day intervals to cover the egg hatch period. Sprays of Bacillus thuringiensis at the same timing intervals gave, maximally, an 80% reduction in larval numbers, but usually less: improved control was not achieved by applying a programme of sprays compared to a single spray, though a novel, more potent, formulation was significantly more active. Triazophos was also effective as an egg hatch spray. Sprays of chlorpyrifos or tebufenozide between late September and mid-October 1995 against second or third instar larvae migrating to overwintering sites before diapause, failed to reduce significantly the numbers of subsequent overwintering larvae or the numbers that emerged to feed on blossom trusses in spring.     

Assessment of Potential Sublethal Effects of Various Insecticides on Key Biological Traits of The Tobacco Whitefly,Bemisia tabaci

The tobacco whitefly Bemisia tabaci is one of the most devastating pests worldwide. Current management of B. tabaci relies upon the frequent applications of insecticides. In addition to direct mortality by typical acute toxicity (lethal effect), insecticides may also impair various key biological traits of the exposed insects through physiological and behavioral sublethal effects. Identifying and characterizing such effects could be crucial for understanding the global effects of insecticides on the pest and therefore for optimizing its management in the crops. We assessed the effects of sublethal and low-lethal concentrations of four widely used insecticides on the fecundity, honeydew excretion and feeding behavior of B. tabaci adults. The probing activity of the whiteflies feeding on treated cotton seedlings was recorded by an Electrical Penetration Graph (EPG). The results showed that imidacloprid and bifenthrin caused a reduction in phloem feeding even at sublethal concentrations. In addition, the honeydew excretions and fecundity levels of adults feeding on leaf discs treated with these concentrations were significantly lower than the untreated ones. While, sublethal concentrations of chlorpyrifos and carbosulfan did not affect feeding behavior, honeydew excretion and fecundity of the whitefly. We demonstrated an antifeedant effect of the imidacloprid and bifenthrin on B. tabaci, whereas behavioral changes in adults feeding on leaves treated with chlorpyrifos and carbosulfan were more likely caused by the direct effects of the insecticides on the insects'' nervous system itself. Our results show that aside from the lethal effect, the sublethal concentration of imidacloprid and bifenthrin impairs the phloem feeding, i.e. the most important feeding trait in a plant protection perspective. Indeed, this antifeedant property would give these insecticides potential to control insect pests indirectly. Therefore, the behavioral effects of sublethal concentrations of imidacloprid and bifenthrin may play an important role in the control of whitefly pests by increasing the toxicity persistence in treated crops.     

Persistence and efficacy of termiticides used in preconstruction treatments to soil in Mississippi

Laboratory and field studies were conducted to determine the persistence and efficacy of termiticides used as preconstruction treatments against subterranean termites. Bifenthrin (0.067%), chlorpyrifos (0.75%), and imidacloprid (0.05%) ([AI]; wt:wt) were applied to soil beneath a monolithic concrete slab at their minimum labeled rates. Soil samples were taken from three depths (0-2.5, 2.6-7.6, and 7.7-15.2 cm) at six sampling times (0, 3, 6, 9, 12 and 48 mo) from sites in Harrison and Oktibbeha counties in Mississippi. Residue analyses were conducted on the 0-2.5- and 2.6-7.5-cm depths, and bioassays were conducted using all three depths. In field studies, significant termiticide degradation occurred between sampling times 0 and 48 mo for all termiticides. At all sampling times, the top 2.5 cm of soil contained more termiticide than the other depths. Time to 50% dissipation of termiticide in the 0-2.5-cm depth was 9, 6, and 2 mo for bifenthrin, chlorpyrifos, and imidacloprid, respectively. Termite mortalities in contact bioassays remained high for bifenthrin and chlorpyrifos throughout the 48-mo sampling period; however, mortality of termites exposed to imidacloprid-treated soil dropped after the initial sampling. Termites readily penetrated all termiticide-treated soil in bioassays of 52-mm soil cores at 48 mo. Percentage of mortality in these bioassays was 15, 43, and 13 for bifenthrin, chlorpyrifos, and imidacloprid respectively.     

Comparative efficacy of different pesticides against mango bark beetle Hypocryphalus mangiferae Stebbing (Coleoptera: Scolytidae)

Hypocryphalus mangiferae Stebbing is one of the most destructive insect pests of mango trees and is found to be associated with the transmission of causal organisms of mango sudden death disease. The present study was carried out to evaluate the toxicity of deltamethrin, bifenthrin, chlorpyrifos, emamectin benzoate, imidacloprid and spinosad in laboratory and field trials. Bioassay results showed that the toxicity of chlorpyrifos was significantly higher than deltamethrin but similar to bifenthrin. Deltamethrin and bifenthrin toxicity, however, increased significantly (P < 0.01) from day 1 to day 3. Spinosad was the least toxic compound while emamectin was the most toxic among new chemical insecticides tested, but its toxicity increased significantly from day 1 to day 5. Comparison of the efficacies of the insecticides using lethal times to produce 50% mortality (LT₅₀) and 90% mortality (LT₉₀) showed that the relative potencies of chlorpyrifos, emamectin, imidacloprid and spinosad were greater than bifenthrin and deltamethrin. The results of field trials showed the highest number of beetles emerged from the control twigs while significantly fewer beetles emerged from the twigs treated with bifenthrin (P < 0.05), which accounted for 12% for bifenthrin compared to that of the control. The present study demonstrated increased toxicities of systemic insecticides and chlorpyrifos compared to toxicities of deltamethrin and bifenthrin, suggesting these insecticides could be an alternative tool in a comprehensive H. mangiferae management program to eradicate the beetles from mango orchards.     

Prevalence and stability of insecticide resistances in field population of Spodoptera litura (Lepidoptera: Noctuidae) from Huizhou,Guangdong Province,China

The field population of Spodoptera litura from Huizhou, Guangdong Province, China was evaluated for resistance to 21 insecticides, including conventional and new chemistry insecticides. Extreme levels of resistance were observed to metaflumizone and emamectin benzoate with resistance factors of 234.1 and 183.3, respectively. Resistance to abamectin was also high (perhaps extremely high) and over 71.9-fold. The Huizhou population of S. litura possessed high resistance to deltamethrin (96.5-fold) and moderate resistance to beta cyfluthrin and lambda cyhalothrin but remained susceptible to bifenthrin. Moderate resistance to chlorantraniliprole (22.3-fold), endosulfan (22.2-fold), tebufenozide (10.7-fold) and thiodicarb (14.3-fold), and low-level resistance to fipronil, indoxacarb and spinosad were also reported in this population. This field population remained susceptible to acetamiprid, chlorfenapyr, chlorfluazuron, hexaflumuron, chlorpyrifos, pyridalyl and spinetoram. The stabilities of resistance to metaflumizone, emamectin benzoate, deltamethrin, chlorantraniliprole and endosulfan were evaluated, the resistance level decreased when the insecticide stress was removed, suggesting stop of the application of insecticides with high level resistance could be implemented into the resistance management. Because S. litura from Huizhou developed resistance to multiple insecticides, integration of different control practices, especially the rotation of insecticides with biocontrol agents, should be performed in the management of this pest. The results suggested the suspension of the application of insecticide to which S. litura had developed high level of resistance in order to mitigate the resistance status, and the use of the insecticides to which this pest remained sensitive, including spinetoram, pyridalyl, indoxacarb, hexaflumuron, chlorfluazuron, chlorfenapyr and bifenthrin, could be incorporated into the alternating application for resistance management.     

A field study investigating the insecticidal efficacy against Diaphorina citri Kuwayama on Kinnow mandarin,Citrus reticulata Blanco trees

Asian citrus psyllid is a most damaging insect pest of citrus. In this field study, the efficacy of seven insecticides (emamectin benzoate, bifenthrin, chlorfenapyr, fipronil, imidacloprid, pyriproxyfen and thiamethoxam) was evaluated against Diaphorina citri Kuwayama in the citrus orchard of Kinnow mandarin, Citrus reticulata Blanco. The insecticides revealed a differential and substantial relative efficacy against D. citri compared to the untreated plants. The insecticidal effect attributed as percent reduction in insect population was more prominent after three days of spray: highest reduction values were recorded with thiamethoxam (50.89%), imidacloprid (44.27%) and bifenthrin (42.94%) after first spray, and thiamethoxam (83.36%), imidacloprid (73.20%) and bifenthrin (72.66%) after second spray. Thus, neonicotinoids (thiamethoxam and imidacloprid) and pyrethroid (bifenthrin) resulted as highly effective against D. citri at three days after both sprays. At seven days, imidacloprid (63.53%) and fipronil (62.47%) presented relatively higher population reduction after first spray, and thiamethoxam (92.66%) and chlorfenapyr (89.59%) after second spray. At 12 days, the insecticidal effect on insect population became significantly at par after each spray except chlorfenapyr that reflected high population reduction (93.17%) only after second spray. It is also obvious from the data that there is need of regular monitoring to suppress the psyllids population below threshold level by timely application of the second insecticidal spray.     

Establishment of baseline susceptibility data to various insecticides for Homalodisca coagulata (Homoptera: Cicadellidae) by comparative bioassay techniques

Homalodisca coagulata Say, adults from three locations in California were subjected to insecticide bioassays to establish baseline toxicity. Initially, two bioassay techniques, petri dish and leaf dip, were compared to determine the most useful method to establish baseline susceptibility data under laboratory and greenhouse conditions. Comparative dose-response data were determined by both techniques to endosulfan, dimethoate, cyfluthrin, and acetamiprid. Toxic values were similar to some insecticides with both techniques but not for all insecticides, revealing susceptibility differences among the three populations of H. coagulata. In subsequent tests, the petri dish technique was selected to establish baseline susceptibility data to various contact insecticides. A systemic uptake bioassay was adapted to estimate dose-mortality responses to a systemic insecticide, imidacloprid. A 2-yr comparison of toxicological responses showed all three populations of H. coagulata to be highly susceptible to 10 insecticides, including chlorpyrifos, dimethoate, endosulfan, bifenthrin, cyfluthrin, esfenvalerate, fenpropathrin, acetamiprid, imidacloprid, and thiamethoxam. In general, two pyrethroids, bifenthrin and esfenvalerate, were the most toxic compounds, followed by two neonicotinoids, acetamiprid and imidacloprid. The LC50 values for all insecticides tested were lower than concentrations used as recommended field rates. Baseline data varied for the three geographically distinct H. coagulata populations with the petri dish technique. Adult H. coagulata collected from San Bernardino County were significantly more susceptible to select pyrethroids compared with adults from Riverside or Kern counties. Adults from San Bernardino County also were more sensitive to two neonicotinoids, acetamiprid and imidacloprid. The highest LC50 values were to endosulfan, which nonetheless proved highly toxic to H. coagulata from all three regions. In the majority of the tests, mortality increased over time resulting in increased susceptibility at 48 h compared with 24 h. These results indicate a wide selection of highly effective insecticides that could aid in managing H. coagulata populations in California.     

两种盲蝽的抗药性监测

本文从2009到2011年连续3年用马拉硫磷、毒死蜱、灭多威、三氟氯氰菊酯、吡虫啉、硫丹6种杀虫药剂诊断剂量监测了河北、河南、山东、安徽等重要棉产区绿盲蝽Apolygus lucorum(Meyer-Dür)田间种群的抗药性。2010年马拉硫磷诊断剂量处理河北邱县、安徽望江田间种群死亡率95%以上;毒死蜱诊断剂量河南郑州、山东滨州,安徽地区的田间绿盲蝽死亡率大于80%;三氟氯氰菊酯诊断剂量死亡率接近95%以上;2010年安徽望江、2011年河北邱县、山东滨州、安徽无为田间种群在吡虫啉诊断剂量下的死亡率在78%～90%。点滴法对2011年各地绿盲蝽种群抗药性监测表明,各地绿盲蝽对毒死蜱、灭多威、吡虫啉均处于敏感阶段,对于马拉硫磷、三氟氯氰菊酯、硫丹大多处于低抗水平阶段。在对中黑盲蝽Adelphocoris suturalis Jakovlev3年的抗性监测中,作者发现种群抗性个体频率的出现更为普遍。     

Comparative acaricidal efficacy of the topically applied combinations fipronil/(S)-methoprene, permethrin/imidacloprid and metaflumizone/ amitraz against Dermacentor reticulatus, the European dog tick (ornate dog tick, Fabricius, 1794) in dogs

The acaricidal efficacy against Dermacentor reticulatus in dogs of the commercial topical combinations fipronil/(S)-methoprene (FRONTLINE Combo spot-on dog), imidacloprid/permethrin (Advantix) and metaflumizone/amitraz (ProMeris Duo) was evaluated and compared. Three treatment groups and one untreated control group of six adult Beagle dogs each were randomly formed. Each treatment was administered topically once on Day-0, according to the recommended label dose and instructions for use. All dogs were infested weekly with approximately 50 adult unfed D. reticulatus over a period of seven weeks. Ticks were removed and counted approximately 48 hours after each infestation. The percent reduction in numbers of ticks for fipronil/(S)-methoprene was > or = 97% compared to untreated controls for all seven weekly infestations. The percent reductions for imidacloprid/permethrin and metaflumizone/amitraz were satisfactory initially but fell and stayed below 90 % after three weeks. From the third week onwards, fipronil/(S)-methoprene treated dogs had significantly fewer ticks than imidacloprid/permethrin or metaflumizone/amitraz treated dogs (p < 0.05).     

Rapid degradation of termiticides under field conditions

Abstract  Soil testing is used by regulatory agencies to determine the adequacy of termiticide application by pest controllers. Because tests may be carried out years after treatment, an accurate knowledge of termiticide degradation rates is crucial if determinations are to be valid. Degradation of exposed residues of bifenthrin, chlorfenapyr, chlorpyrifos, fipronil and imidacloprid was investigated in a field trial conducted near Narrandera (inland New South Wales) and in Sydney. Samples of soil 75 mm deep were collected immediately after treatment and after 12 months from plots treated with termiticides to a minimum depth of 350 mm and analysed for termiticide residues. Bifenthrin and chlorfenapyr were the most persistent termiticides. Losses of chlorpyrifos exceeded 99% at both locations. Losses of fipronil and imidacloprid were 96% and 94%, respectively, at Narrandera and 67% and 50%, respectively, in Sydney. To explore the fate of chlorpyrifos, fipronil and imidacloprid in the soil profile at Narrandera, samples were collected 15 months after treatment to a depth of 450 mm, in 150 mm increments, from plots treated to a depth of 700 mm. In soil below 150 mm, chlorpyrifos and fipronil content was little changed from time of application whereas major losses of imidacloprid had occurred at all depths. These findings have implications for termite treatment regulation in Australia. Regulatory agencies have relied upon degradation rates observed in laboratory experiments to determine in situ treatment adequacy. Results of this field study suggest that termiticides can degrade more rapidly in situ than indicated by laboratory experiments.     

Survival of adult Tiphia vernalis (Hymenoptera: Tiphiidae) after insecticide, fungicide, and herbicide exposure in laboratory bioassays

Tiphia vernalis Rohwer is a hymenopteran ectoparasitoid of Japanese beetle, Popillia japonica Newman, larvae. The adult wasps feed on nectar or honeydew between mid-April and late June. Adults may contact pesticides when landing on foliage or when females hunt for grubs in the soil. The lethal effect of nursery, turf, and landscape pesticides was determined by exposing wasps to treated foliage in the laboratory. Pesticides tested at labeled rates were the insecticides bifenthrin, carbaryl, chlorpyrifos, halofenozide, and imidacloprid; the herbicides oryzalin, pendimethalin, and a combination product with 2,4-D, dicamba, and mecoprop (multiherbicide); and the fungicides chlorothalonil and thiophanate-methyl. During 2001 and 2002, male and female T. vernalis were exposed to pesticides by using turf cores. For both years, bifenthrin, chlorpyrifos, and imidacloprid treatments lowered adult survival relative to the control, but halofenozide had minimal effect on mortality of males and females. More males than females died after exposure to carbaryl treatments. Survival of females was not reduced by exposure to herbicides or fungicides. Females were apparently more tolerant of pesticides than males. Mortality of males in response to herbicides and fungicides was more variable than for females; in 2002 trials, male mortality was higher after exposure to multiherbicide, oryzalin, pendimethalin, and thiophanate-methyl than the control. The fungicide chlorothalonil did not increase mortality of males or females in either year. Sublethal effects were not evaluated. The study indicates the choice of pesticide may be important for conserving T. vernalis in nursery, landscape, and turf settings.     

Ultralow rates of spinosad in phagostimulant granules provide control of Spodoptera frugiperda (Lepidoptera: Noctuidae) in maize

Field trails in 2002 and 2003 were performed to determine the efficacy of maize flour-based granular formulations with ultralow rates of the naturally derived insecticide spinosad (0.1, 0.3, and 1.0 g [AI]/ha), for control of Spodoptera frugiperda (J.E. Smith) in maize, Zea mays L., in southern Mexico. Spinosad formulations were compared with a chemical standard, a commercial granular formulation of chlorpyrifos (150 g [AI]/ha). In both years, application of spinosad resulted in excellent levels of control, indicated by the number of living S. frugiperda larvae recovered from experimental plots. The efficacy of spinosad applied at 0.3 and 1.0 g (AI)/ha was very similar to that of chlorpyrifos. Natural reinfestation caused S. frugiperda numbers in insecticide treated plots to return to values similar to the control treatmentby 10-15d postapplication. Many spinosad-intoxicated larvae collected in the field died later in the laboratory in 2002, but not in 2003. Percentage mortality due to parasitoid emergence did not differ in any treatment in either field trial. The number of parasitoids that emerged from S. frugiperda collected in each treatment was significantly reduced after application of spinosad (all rates) or chlorpyrifos due to a reduction in the number of host larvae. Parasitoid numbers returned to control values by 9-15 d postapplication in all treatments. The most prevalent parasitoid was the braconid Chelonus insularis Cresson, which represented approximately 80% of emerging parasitoids in both years. We conclude that appropriate formulation technology can greatly enhance the performance of this naturally derived, biorational insecticide.     

Effect of neonicotinoid synergists on entomopathogenic nematode fitness

In previous greenhouse and field studies, the neonicotinoid insecticide imidacloprid interacted synergistically with five entomopathogenic nematode species against five scarab species. Two other neonicotinoids, thiamethoxam and acetamiprid, showed a weaker interaction with nematodes in scarab larvae. Entomopathogenic nematodes have the potential to recycle in hosts after inundative applications, thereby increasing the persistence of nematodes and insect control. Thus we investigated the effect of neonicotinoids on nematode fitness after tank mixing and after combined applications. Tank mixing only had a negative effect on nematode survival and infectivity in a few nematode–insecticide combinations and only if both insecticide concentration and exposure time were several times higher than typical for field applications. Combined application of nematodes with imidacloprid generally had no negative effect on the percentage of scarab cadavers producing progeny or the number of nematode progeny emerging per cadaver. In experiments with a synergistic increase in scarab mortality, the total number of progeny in combination treatments was up to four times higher than in nematodes only treatments. Similarly, nematode populations in soil from combination treatments were 13.2 times greater than for nematodes only treatments at 28 days after treatment. Combined imidacloprid–nematode applications did not affect the pathogenicity or infectivity of the nematode progeny. Combining thiamethoxam with nematodes had no negative effects on nematode reproduction in the majority of treatments. However, due to the weaker interaction of thiamethoxam and nematodes on scarab mortality, the total number of nematode progeny per treatment generally did not increase compared with nematodes only treatments. The demonstrated tank mix compatibility of imidacloprid and nematodes improves the feasibility of combining these agents for curative white grub control. The positive effect of imidacloprid on nematode reproduction after combined application may increase the likelihood of infection of white grubs by subsequent generations of nematodes, thereby improving their field persistence and biological control potential.     

Susceptibility of immature stages of Homalodisca coagulata (Hemiptera: Cicadellidae) to selected insecticides

Susceptibility of immatures of the glassy-winged sharpshooter, Homalodisca coagulata (Say) (Hemiptera: Cicadellidae), to 10 insecticides that included chlorpyrifos, dimethoate, endosulfan, bifenthrin, cyfluthrin, esfenvalerate, fenpropathrin, acetamiprid, imidacloprid, and thiamethoxam was evaluated in the laboratory. All five instars were exposed to different doses of each foliar insecticide by the petri dish technique, whereas a systemic uptake method was used to assess the toxicity to imidacloprid and thiamethoxam. All test insecticides exhibited high toxicity to all immature stages of H. coagulata at concentrations below the field recommended rates of each insecticide. Although all five instars were susceptible to test insecticides, mortality was significantly higher in first instars than in the older immatures based on low LC50 values (ranging from 0.017 to 5.75 ng(AI)/ml) with susceptibility decreasing with each successive stage. Fifth instars were generally the least sensitive (LC50 values ranging from 0.325 to 216.63 ng (AI)/ml). These results show that mortality was directly related to age of the insect and suggest that chemical treatment at early stages is more effective than at late stages. Acetamiprid (neonicotinoid) and bifenthrin (pyrethroid) were the most toxic to all five instars, inducing most mortality within 24 h and showing lower LC50 values ranging from 0.017 to 0.686 ng/ml compared with other insecticides (LC50 values ranging from 0.191 to 216.63 ng(AI)/ml). Our data suggest that a diverse group of very effective insecticides are available to growers for controlling all stages of H. coagulata. Knowledge on toxicity of select insecticides to H. coagulata immatures may contribute to our understanding of resistance management in future for this pest by targeting specific life stages instead of the adult stage alone.