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Wireworms are primary pests of potatoes in Canada. Presently, the highly toxic organophosphate phorate (i.e., Thimet 20G) is the only effective insecticide in use in Canada. As such, there is an urgent need for novel alternative treatments that provide competitive tuber blemish protection and wireworm reduction with a safer human and environmental portfolio. Herein we evaluated broflanilide, a novel meta-diamide insecticide for both tuber protection and wireworm mortality. When evaluated in field trials in Agassiz, British Columbia over 6 yr, broflanilide applied as a seed piece treatment (SPT) to mother tubers at 1.5–2.0 g AI/100 kg seed (approx. 50 g AI/ha), or as an in-furrow spray (IFS) at 0.23–0.25 g AI/100 m row (approx. 25 g AI/ha) was as effective at reducing blemishes to daughter tubers by wireworms (Agriotes obscurus) as phorate (Thimet 20G at 3230 g AI/ha), bifenthrin (Capture 2EC IFS at 300 g AI/ha) and clothianidin (Titan ST at 312.5 g AI/ha). In addition, broflanilide SPT and IFS applied at the above rates reduced resident wireworms (in the field at the time of planting) by 95.4–99.0% and neonate wireworms (produced from eggs laid during the growing season) by 98.1–100%. Similar results were obtained when broflanilide IFS (nonsystemic) was paired with clothianidin SPT (systemic) for broad-spectrum potato insect pest control. Strategies for the use of broflanilide on wheat (e.g., Teraxxa F4) in rotation with potatoes (Cimegra), both registered in Canada in 2020 are discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two invasive click beetle pest species have established in southwestern British Columbia. • Surveys conducted in 2017–2019 reveal both species have now dispersed widely. • Crop damage, displacement of native species, and continued spread is expected. • Several native, non-pest species are attracted to the pheromone of these pests. Two European click beetle species, Agriotes obscurus L. (AO) and A. lineatus L. (AL) have become serious pests of agriculture in the Fraser Valley and Vancouver Island areas of British Columbia (BC), but prior to the start of this survey (2017) it was unknown if they had established elsewhere in the Province. Pitfall traps baited with sex pheromone of AO and AL were placed throughout BC in 2017–2019 and collected a total of 4,988 AO and 20,103 AL beetles in 150 trap pairs. Both species were found to be distributed throughout southern BC, including high numbers in Creston, Kelowna, Pemberton, and Salmon Arm. Traps placed in northern BC, northern Alberta, northern Idaho, or the Willamette valley in western Oregon did not collect AO or AL. Traps were also deployed for A. sputator L., a related European species that has become a serious pest of potato in eastern Canada, but this species was not collected. AO and AL traps placed in the Pemberton valley of BC also collected 474 A. ferrugineipennis (LeConte), and traps placed in the northern Okanagan valley collected 75 A. oregonensis Becker. Both are native Agriotes species not closely related to AO or AL; this is the first time A. oregonensis was collected in Canada. We discuss the potential implications of the spread of AO and AL to other agricultural areas in BC and beyond. [ABSTRACT FROM AUTHOR]

We present findings of a general survey of pest wireworms in Alberta, Saskatchewan, and Manitoba conducted from 2004 to 2019; the first such survey of the Canadian Prairie provinces since that published by Glen et al. (1943). Samples were collected from 571 farmland locations where crop damage from wireworms was observed or suspected, and a total of 5,704 specimens (3,548 larvae, 2,156 beetles) were identified. Most specimens (96.9%) were identified as Hypnoidus bicolor (3,278), Selatosomus aeripennis destructor (1,280), Limonius californicus (842), and Aeolus mellillus (125). This suggests that H. bicolor has replaced S. a. destructor as the predominant species and that the relative importance of L. californicus as a pest species has increased since earlier reports. Despite the relatively small number of specimens collected per location (approx. 10), H. bicolor and S. a. destructor , and S. a. destructor and L. californicus were frequently collected at or near the same location (within 1 km). We provide species records and incidence of co-occurrence at different spatial scales, discuss potential reasons for and implications of shifts in species composition, implications of species co-occurrence for managing wireworm pests in crop production, and outline pertinent research needs. A path analysis approach used to correlate incidence of the main species with various soil characteristics indicated that organic matter, cation exchange capacity, and water retention capacity all had a significant species-specific influence on wireworm presence. [ABSTRACT FROM AUTHOR]

In North America, monitoring for Agriotes spp. click beetles typically has been done using Vernon beetle traps baited with bubble cap sex pheromone lures. This trap and lure are no longer produced commercially and a new trap, the Vernon pitfall trap, and lure design are used now for both invasive Agriotes and native pest species. Herein we compare the 2 trapping methods for Agriotes sputator (L.) (Coleoptera: Elateridae), and provide a calibration factor between them to allow comparison of survey results using the different methods. When deployed for the entire swarming season, Vernon pitfall traps fitted with the new capsule lures collect 0.7× as many A. sputator as Vernon beetle traps fitted with the bubble cap lures, and Vernon beetle traps fitted with capsule lures collect 0.5× as many beetles as Vernon beetle traps fitted with bubble cap lures. Unlike bubble cap lures, however, capsule-style lures need to be primed (maintained at room temperature for 3 wk) before deployment in the field, or else their initial attractiveness will be limited and trap catches will not be representative of populations present at the time. In addition, results from field studies indicate that these capsule lures deplete over the swarming season, and depending on the trapping objective (e.g., mass trapping) may need to be replaced after 5 to 6 wk of deployment. Increasing the lure load to 2× or 4× the regular 40 µL geranyl butanoate, or the capsule container size from 1.0 to 2.5 mL, did not significantly increase the number of A. sputator collected. [ABSTRACT FROM AUTHOR]

Following the deregistration of lindane, several neonicotinoid insecticides have been registered as seed treatments for controlling wireworms in cereal crops. Unlike lindane, which did both, neonicotinoids provide crop protection but do not reduce wireworm populations. Hence populations of various economic species are growing in key wheat production areas of the United States and Canada, and there is a need for novel seed treatments that match the efficacy of lindane. Herein we evaluated broflanilide, a novel GABA-gated Cl- channel allosteric modulator that differs from the cyclodienes (e.g. lindane) in that it binds to a unique site in the GABA receptor. As such, broflanilide confers a new mode of insecticidal action (Group 30 MOA), and is the first meta-diamide insecticide developed. When evaluated in field trials over 7 yr at various rates, broflanilide at 5.0 g [AI]/100 kg wheat seed was as effective at protecting wheat stand from wireworm (Agriotes obscurus) injury as the current industry standard thiamethoxam at 20–30 g [AI]/100 kg seed. In addition, broflanilide at 5.0 g reduced neonate wireworms (produced from eggs laid in established wheat during the growing season) and resident wireworms (in the field at time of planting) by 73.1 and 81.1%, respectively, which is comparable to that reported for the previous industry standard lindane (75.3 and 57.6%, respectively). These studies show that broflanilide at 5.0 g [AI] will provide consistent wheat stand protection (equal to thiamethoxam at 20–30 g [AI]), and A. obscurus wireworm population reduction (equal to lindane at 59 g [AI]), and will do so at far lower dosages per hectare. [ABSTRACT FROM AUTHOR]

Mark-release-recapture was used to investigate the dispersal of click beetles in spring wheat or fallow fields using edge or centre field releases. Three types of pitfalls were used: gutter traps near field margins, as well as conventional pitfall traps or cross-traps consisting of four gutter trap arms leading to a central pitfall. Capture of naturally occuring beetles was concurrently recorded., In total, 6952 marked Agriotes obscurus (males and females) and Agriotes lineatus (males) were released and 14.74% were recaptured at some time during the present study. Recovery rates ranged from 3.54% to 28.5%., Agriotes obscurus dominated wild populations, with 4011 males and 1672 females trapped compared with 17 males and three females for A. lineatus. Males dominated early in the period, although the sex ratio tended towards equality as the season progressed., Generally, captures of A. obscurus males released in equal numbers at field edges followed a uniform distribution. There were differences for wild beetles caught in the same traps., Spatial trapping patterns of wild and marked beetles across the fields were similar. Within 19 h of release at the field edges A. obscurus males were captured >30 m away., The crop type had a significant interspecific effect on trap counts for males and an intraspecific effect on A. obscurus females, reinforcing the need for caution when using trapping systems to monitor adult stages of these pests., The results of the present study demonstrate that uncropped field margins comprise sources of click beetles. We also conclude that click beetles disperse much further than reported previously. [ABSTRACT FROM AUTHOR]

The efficacy of various insecticides and application methods in protecting potatoes from wireworm (Agriotes obscurus L.) damage as well as reducing wireworm populations was studied over 5 yr in Agassiz, British Columbia. Protection from wireworm damage was measured by the number of blemishes to daughter tubers, and effects on wireworm populations were measured by sampling soil around seed potatoes and/or by bait traps the following spring. Organophosphates registered for wireworm control in the United States and/or Canada (phorate and chlorpyrifos), significantly reduced blemishes to tubers by, respectively, 92.2 and 90.2%, and populations of large (=9 mm long = 'resident') wireworms by 83.4 and 71.0% relative to controls. Similar reductions in smaller (<9 mm long = 'neonate') wireworms were also observed. Neonicotinoids (imidacloprid, clothianidin, and thiamethoxam) tested as seed piece treatments at ~12.5 g active ingredient/100 kg potato seed reduced blemishes by, respectively, 19.1, 71.6, and 90.6%, but resident wireworms were only reduced by, respectively, 22.0, 29.1, and 51.8%. Significant mortality of neonates was not observed with any neonicotinoid treatment. With the possible exception of thiamethoxam, where significant reduction in resident wireworms occurred, it is likely that the blemish protection provided without significant wireworm mortality with imidacloprid and clothianidin treatments was because of long-term wire-worm intoxication followed by population recovery. The phenyl pyrazole, fipronil, applied as an in-furrow spray reduced blemishes by 94.3%, and resident wireworm populations could not be detected in plots the following spring. Neonates were reduced by 93.3%, indicating excellent residual control had occurred with fipronil. These studies indicate that tuber protection by fipronil and currently registered organophosphates is likely because of significant early season mortality of wireworms, whereas neonicotinoids generally provide control through long-term morbidity without high levels of mortality occurring. [ABSTRACT FROM AUTHOR]

The effects of carbon dioxide and the induction of morbidity on aversion learning in larvae of the Pacific Coast wireworm Limonius canus LeConte (Coleoptera: Elateridae) are discussed. Wireworms preconditioned by exposing them one or four times to odour of Tefluthrin 20SC and Dividend XLRTA [Syngenta Crop Protection (Canada), Inc., Canada] during the induction of temporary morbidity subsequently contact tefluthrin-treated wheat seeds in soil bioassays for as long as naïve (i.e. not preconditioned) larvae but are repelled four to five-fold more frequently by Dividend-treated seeds in soil bioassays than naïve wireworms, suggesting that wireworms are capable of associating a novel odour (i.e. Dividend) with morbidity but require a minimum of 10–15 min subsequent contact time with treated seeds before being repelled. Wireworms preconditioned by exposure to peppermint odour during the induction of morbidity are not subsequently repelled by peppermint odour in soil bioassays, suggesting that wireworms are either not capable of aversion learning or that the presence of a CO2 source and/or a suitable host plant may override a negative cue (i.e. peppermint odour). In studies conducted in the absence of soil, a host plant and CO2 production, wireworms are repelled slightly by droplets of 1.0% but not 0.1% peppermint oil. Previous exposure to peppermint odour or contact with peppermint oil-treated filter paper during one induction of morbidity does not increase the repellency of wireworms to 1.0% peppermint oil significantly. Repellency to 1.0% peppermint oil is almost eliminated when morbidity is induced five times in the absence of peppermint odour but is restored when peppermint odour is present during preconditioning. These findings suggest that wireworm sensitivity to repellent compounds decreases when repeatedly made moribund, although the results are not sufficient to conclude that wireworms are capable of associative learning. [ABSTRACT FROM AUTHOR]

Copyright of Phytoprotection is the property of Society for the Protection of Plants and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A bioassay for observing wireworm behavior in soil is described. The bioassay permits analysis of orientation, feeding, repellency, and postcontact toxicity behaviors of wireworms in response to insecticide-treated wheat seeds. Wireworm positions were recorded every 5 mm for 3 h, and the time required to orient to and contact seeds, and the duration of individual feeding events, was calculated. Both avoidance (before contact with seeds) and repellency (after contact) were quantified. A high proportion of Agriotes obscurus (0.95), Limonius canus (1.00), Ctenicera pruinina (0.80), Melanotus communt.s/dietrichi (0.80), and Hypolithus sp. (0.70) larvae contacted untreated wheat seeds and began feeding within 120 mill when seeds were preincubated for 60 mm in soil with 20% moisture. A smaller proportion of A. obscurus contacted seeds if seeds were not incubated in the bioassay before wireworm introduction (0.80) or in soil with 10% moisture (0.65). L. canus larvae required a significantly shorter time (25.3 mm) to contact seeds if seeds were incubated for 60 mm than if seeds were not incubated before wireworm introduction (43.1 mi. Wireworms exposed to untreated seeds and seeds treated with the fungicide Dividend XLRTA fed normally (i.e., sustained feeding for at least 60 mm), but a significant proportion of wireworms exposed to seeds treated with Tefluthrin 20 CS (containing the synthetic pyrethroid tefluthrin) fed for 15 mill or less and were subsequently repelled. Wireworms exposed to Vitavax Dual (containing the organochlorine lindane) were not repelled after feeding and showed symptoms of illness for up to 28 d before making a full recovery'(89%) or dying (11%). [ABSTRACT FROM AUTHOR]

Copyright of Phytoprotection is the property of Society for the Protection of Plants and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)