Journal of Economic Entomology (2019) 112, 691-698

Jian Chen, Tahir Rashid, Guolei Feng, Yan Feng, Aijun Zhang and Michael J. Grodowitz (2019)
Insecticidal activity of methyl benzoate analogs against red imported fire ants, Solenopsis invicta (Hymenoptera: Formicidae)
Journal of Economic Entomology 112 (2), 691-698
Abstract: Although insecticidal properties of certain benzoates have been investigated for pest insects and mites, toxicity of benzoates to the red imported fire ants, Solenopsis invicta Buren, has never been reported. In this study, 15 commercially available benzoates were assessed for their contact and fumigation toxicity to S. invicta workers and their chemical structure–activity relationships. Among tested benzoates, benzylbenzoate, n-pentybenzoate, and n-hexylbenzoate were three most potent contact toxins against S. invicta workers (mean LD₅₀ value = 23.31, 35.26, 35.99 µg per ant, respectively) and methyl-3-methoxybenzoate, methyl-3-methylbenzoate, and methylbenzoate were the three most potent fumigants (mean LC₅₀ value = 0.61, 0.62, 0.75 µg/ml, respectively). For nonsubstituted alkyl benzoates (esters of benzoic acid and C1–C6 linear alcohols), the contact toxicity was positively correlated to the alkyl chain length (r = 0.89), while the fumigation toxicity was negatively correlated (r = 0.90). Presence of a methoxyl group at either the ortho or meta position of methylbenzoate significantly increased its contact toxicity, so did a methyl group at meta position. However, presence of a methyl group at ortho position reduced the contact toxicity. Presence of methyl or methoxyl group at the meta position did not have significant effect on the fumigation toxicity; however, methyl, methoxyl, chloro, or nitro groups at the ortho position significantly reduced fumigation toxicity. Hexylbenzoate has neither known Occupational Safety and Health Administration hazards nor aquatic toxicity, and methyl 3-methoxybenzoate is not considered a hazardous substance, indicating a great potential for their application in fire ant management.
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Database assignments for author(s): Aijun Zhang, Michael J. Grodowitz

Research topic(s) for pests/diseases/weeds:
control - general

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Solenopsis invicta