Publications by authors named "Dong-Hwan Choe"

Solenopsis invicta Buren (Hymenoptera: Formicidae), also known as the red imported fire ant (RIFA), is currently established in many Southern and Central Californian regions. RIFA can be managed using various insecticides, but in recent decades, granular baits have become a standard and effective management tool. To improve and maintain effective RIFA management programs, researchers and pest control experts need to perform careful population monitoring before and after treatments.

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  • Western drywood termites cause a lot of damage to wooden structures in places like California.
  • Local insecticide injections can help control them, but sometimes the termites are hard to reach because of where they live in the wood.
  • Scientists found that certain chemicals (like α-pinene and β-pinene) can attract termites to the treated areas, making it easier for insecticides to work better.
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  • Isocycloseram, a novel insecticide from the isoxazoline class, effectively targets GABA-gated chloride channels in insects, showing promising results against various strains of German cockroaches.
  • In laboratory tests, a gel bait formulation with 1% isocycloseram demonstrated rapid lethality, with average survival times of just 0.9 to 5.4 days across different cockroach strains.
  • Resistance testing indicated no significant resistance in most strains, though some showed varying levels of resistance; additionally, combining isocycloseram with piperonyl butoxide enhanced its effectiveness against resistant strains.
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We investigated the expression of 4 cytochrome P450 genes (CYP4G19, CYP6J1, CYP6K1, and CYP4C21) in 4 field-collected strains (WM, RG386, CDR, and Ryan) of the German cockroach, Blattella germanica (L.), collected from California. The UCR susceptible strain was used as a comparison.

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Artificial or non-nutritive sweeteners are indigestible by most animals. Some sweeteners are orally toxic to insects and have received recent interest as potential safe insecticides due to their low mammalian toxicity. In this study, we investigated the oral toxicity of sucralose on insecticide-susceptible and resistant German cockroaches, Blattella germanica (L.

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  • Histamine, a compound involved in immune responses, is found in large amounts in bed bug feces, which contributes to indoor contamination.
  • This study aimed to determine if other common indoor arthropods also excrete histamine, particularly looking at different blood-feeding insects and members of the Hemiptera order.
  • The findings revealed that histamine excretion is mainly observed in hematophagous hemipterans like bed bugs and related species, indicating they are the primary source of histamine contamination in U.S. homes.
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Selenium, a naturally occurring metalloid, is an essential trace element for many higher organisms, including humans. Humans primarily become exposed to selenium by ingesting food products containing trace amounts of selenium compounds. Although essential in these small amounts, selenium exhibits toxic effects at higher doses.

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The western yellowjacket, (Saussure), is an important seasonal pest of recreational and outdoor venues in the western United States. Its propensity to scavenge food increases the likelihood of stinging incidences. Control measures are limited to intensive trapping and treating subterranean nests.

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Due to their mutualistic relationship with plant pests, the Argentine ant is considered a major pest in subtropical fruit orchards and vineyards. Besides insecticide sprays, liquid baiting has been demonstrated as an effective method to suppress the Argentine ant populations. To improve the economic feasibility of liquid baiting, hydrogel materials have been recently tested as a carrier for liquid baits containing various insecticidal active ingredients.

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The use of the entomopathogenic fungus Beauveria bassiana (Bals. - Criv.) Vuill.

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Pyrethroids are frequently detected in urban wastewater. Even though treatment facilities remove most pyrethroids (> 90 %) in wastewater, residual concentrations can exceed thresholds that are acutely toxic to sensitive aquatic species. Total release foggers (also known as "bug bombs") are widely used by the general public for insect control.

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New infestations of the Formosan subterranean termite, Coptotermes formosanus Shiraki (Blattodea: Rhinotermitidae), were discovered in southern California, namely in Rancho Santa Fe and La Mesa (San Diego County) and Highland Park (Los Angeles County) in 2021. We investigated whether these new infestations were related to the previous infestations in La Mesa (2018) and Canyon Lake, Riverside County (2020). We used two mitochondrial genes (COI and COII) and seven polymorphic microsatellite markers to infer the genetic relationship between southern California colonies and their breeding systems.

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  • German cockroach populations have shown significant resistance to pyrethroids and fipronil due to physiological mechanisms like metabolic detoxification and target-site insensitivity.
  • Testing revealed that even high doses of insecticides resulted in low mortality rates (less than 53%), confirming their ineffectiveness against resistant strains.
  • Genetic mutations associated with resistance were found in most field populations, indicating that standard spray formulations are likely unsuccessful in controlling these cockroaches in real-world settings.
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Gel bait insecticides have been extensively used to manage the German cockroach, Blattella germanica (L.) (Blattodea: Ectobiidae), but issues with reduced effectiveness of such formulations are becoming increasingly common. We collected five field strains of German cockroaches in California and evaluated them against five commercial bait products [Maxforce FC Magnum (0.

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The western mosquitofish, Gambusia affinis (Baird & Girard), has been used worldwide for the control of larval mosquitoes for more than 100 yr. We found that the western encephalitis mosquito, Culex tarsalis Coquillett (Diptera: Culicidae), can detect the presence of G. affinis in oviposition sites based on associated chemicals, leading to a decrease in the number of egg rafts laid.

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Argentine ants are one of the most common nuisance pest ants treated by pest management professionals (PMPs) in southern and western urban residential areas of the United States. Two new technologies (spraying with a pheromone adjuvant and using a biodegradable hydrogel bait delivery method) were used to develop a unique low-impact integrated pest management (IPM) protocol for Argentine ants in urban residential settings. The IPM protocol included a one-time perimeter spray treatment with 0.

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A new infestation of the Formosan subterranean termite, Coptotermes formosanus Shiraki (Blattodea: Rhinotermitidae), was discovered in Canyon Lake, Riverside County, California. We used three mitochondrial DNA (COI, COII, and 16S) and seven polymorphic microsatellite markers to characterize the genetic relationship of the colony with two other colonies that were collected in 1992 and 2018 in La Mesa, San Diego County. Maximum likelihood phylogeny of C.

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Bed bugs produce volatile aldehydes that have alarm and aggregation functions. Using two synanthropic bed bug species, L. and (Fabricius), developmental changes were examined for ()-2-hexenal, 4-oxo-()-2-hexenal, ()-2-octenal, and 4-oxo-()-2-octenal, the four most abundant aldehydes shared between the two species.

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Artificial sweeteners are sweet-tasting additives found in consumable products as substitutes for naturally occurring sugars. They are derived from plant extracts or manufactured by chemical synthesis. Ingestion of sweeteners by insects can lead to significant physiological effects, such as mortality, decreased fecundity, and behavioral change.

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Colonies of western drywood termites, Incisitermes minor (Hagen) (Blattodea: Kalotermitidae), are difficult to detect and treat due to their cryptic nature. The use of heated air to create lethal temperatures within infested wood serves as a nonchemical treatment option targeting whole structure or large portions of the structure. However, the presence of hard-to-heat areas and potential risk of damage for heat-sensitive items are recognized as important challenges.

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Here, we review the literature on the development and application of hydrogel compounds for insect pest management. Researchers have used hydrogel compounds for the past few decades to achieve the controlled release of various contact insecticides, but in recent years, hydrogel compounds have also been used to absorb and deliver targeted concentrations of toxicants within a liquid bait to manage insect pests. The highly absorbent hydrogel acts as a controlled-release formulation that keeps the liquid bait available and palatable to the target pests.

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Lateral flow strip tests are a cost-effective method for detecting specific proteins in biological samples, which can be performed in the field without specialized expertise. While most recognizable in the pregnancy tests, there are many other applications for lateral flow strip technology. The pest control industry has increasingly emphasized the importance of pest monitoring to reduce unnecessary applications, focus interventions into locations with active pest infestations, and to develop records of pest infestation.

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Use of heated air to create lethal temperatures within infested wood serves as a nonchemical treatment option against western drywood termites, Incisitermes minor (Hagen). When treating a whole or large portion of the structure, however, the presence of hard-to-heat areas (structural heat sinks) and potential risk of damaging heat-sensitive items are recognized as important challenges. To address these challenges, we tested if the incorporation of a volatile essential oil would increase the overall efficacy of heat treatments against the drywood termites.

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Baiting is an effective method to manage Vespula spp. yellowjacket (Hymenoptera: Vespidae) populations without having to locate and treat nests. Here, we assessed the utility of a commercially available polyacrylamide hydrogel as an alternative bait material for yellowjacket baiting.

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The invasive Argentine ant (Linepithema humile) has become established worldwide in regions with Mediterranean or subtropical climates. The species typically disrupts the balance of natural ecosystems by competitively displacing some native ant species via strong exploitation and interference competition. Here we report that Argentine ants utilize glandular secretions for inter and intra-specific communications during aggressive interactions with a heterospecific competitor, California harvester ant (Pogonomyrmex californicus).

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