Repellency and Toxicity of Mint Oil Granules to Red Imported Fire Ants (Hymenoptera: Formicidae)

• Published in: Journal of economic entomology 2004-04, Vol.97 (2), p.575-580
• Main Authors: Appel, A G, Gehret, MJ, Tanley, MJ
• Format: Article
• Language: English
• Subjects: Formicidae; Solenopsis invicta
• ISSN: 0022-0493
• DOI: 10.1043/0022-0493(2004)097(0575:RATOMO)2.0.CO;2

Repellency and toxicity of 2% mint oil granules were evaluated against worker red imported fire ants, Solenopsis invicta Buren, in a series of laboratory and field experiments. In continuous exposure experiments, LT50 values ranged from 1.2 h with 164.8 mg/cm2 of 2% mint oil granules to 15.3 h with 1.65 mg/cm2 of granules. LT50 values declined exponentially with increasing rate of mint oil granules. Limited exposure to 164.8 mg/cm2 mint oil granules resulted in >50% knock down (KD) after 30 min; however, there was no KD at 15 min. Twenty-four hour mortality increased linearly with increasing exposure time. Mean repellency of worker red imported fire ants ranged from 49.2 plus or minus 5.4% for 0 mg/cm2 (untreated control) of mint oil granules at 30 min to 100% for 147.8 mg/cm2 of mint oil granules at 3 h. Repellency increased with increasing milligrams per square centimeter of mint oil granules and exposure time. In field tests, 100% of mounds opened and treated with mint oil granules were abandoned 5 d after treatment and ants had relocated or formed satellite mounds by 2 d after treatment. Unopened mounds treated topically with mint oil granules were not abandoned, but ants formed satellite mounds 2 d after treatment. Mint oil granules could provide another tool for red imported fire ant integrated pest management, particularly in situations in which conventional insecticides would be inappropriate.