Publications by authors named "Shao-Hung Lee"

This study investigated how management strategies influence resistance profiles in German cockroach (Blattella germanica (L.)) populations and their impact on the performance of commercial gel baits containing fipronil, imidacloprid, and indoxacarb. Field populations from premises managed under 3 different strategies: Baiting, random insecticide (RI) used, and insecticide rotation (IR) were tested.

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Article Synopsis
  • 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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We investigated insecticide resistance profiles of field populations of the German cockroach, Blattella germanica (L.), collected from central regions of Thailand. Seven strains (PW, RB, MTH, MTS, TL, AY, and SP) were evaluated with diagnostic doses (DD; 3 × LD95 generated from a susceptible strain) of deltamethrin, fipronil, and imidacloprid using topical assays and compared with a susceptible strain (DMSC).

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Article Synopsis
  • 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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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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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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