Effect of Delayed Toxicity of Chemical Barriers to Control Argentine Ants (Hymenoptera: Formicidae)

Abstract

Brief exposures of Argentine ants to four different insecticide treatments, bifenthrin, beta-cyfluthrin, bifenthrin + beta-cyfluthrin, and fipronil, were conducted to determine Kaplan-Meier product limit survivorship percentiles (SPs) at 21-23 and 27-29 degrees C. Bifenthrin, beta-cyfluthrin, and bifenthrin + beta-cyfluthrin provided rapid kill at 21-23 degrees C with SP10 values ranging from 11.2 to 33.7 min. Fipronil provided delayed toxicity at 21-23 degrees C with SP10 values ranging from 270 to 960 min. At 27-29 degrees C, all of the SP10 values significantly decreased. Field tests in which Argentine ants were induced to forage across insecticide-treated surfaces were used to determine the effect that speed of action has on foraging and recruitment ability, and whether these insecticides are repellent. The slower-acting fipronil allowed a greater amount of foraging and consequently a greater fraction of the colony to be exposed, whereas fast-acting bifenthrin, beta-cyfluthrin, and bifenthrin + beta-cyfluthrin inhibited recruitment, resulting in fewer ants being exposed and killed. Implications for controlling ants by using perimeter barrier treatments are discussed.

Activity of Bifenthrin, Chlorfenapyr, Fipronil, and Thiamethoxam Against Argentine Ants (Hymenoptera: Formicidae)

“…Spraying Argentine ant trails with bifenthrin kills foraging ants quickly, thus most die before they can return to the nest. In a Þeld study, there was little recruitment to food sources surrounded by bifenthrintreated sand (Soeprono and Rust 2004a). When the sand was treated with one of the fast-acting pyrethroids, there were not only fewer live ants present on test panels, but fewer dead ants as well.…”

“…In our study, bifenthrin was faster acting than the other chemicals when applied topically, immobilizing 100% of the ants within 30 min. Likewise, brief exposure to sand treated with bifenthrin or another pyrethroid, ␤-cyßuthrin, resulted in shorter survival times than exposure to Þpronil-treated sand (Soeprono and Rust 2004a). Spraying Argentine ant trails with bifenthrin kills foraging ants quickly, thus most die before they can return to the nest.…”

“…Because pots were initially infested, they concluded that Þre ant exclusion from the pots was due to mortality, not repellency. When Argentine ants were placed directly on treated sand, Soeprono and Rust (2004a) found that for Þpronil, bifenthrin, and cyßuthrin, higher doses resulted in a shorter survival time. In addition, increasing the dose reduced recruitment of Þeld colonies across the treated sand, thereby reducing the number of dead ants on treated sand.…”

Toxicity, Repellency, and Transfer of Chlorfenapyr Against Western Subterranean Termites (Isoptera: Rhinotermitidae)

“…The delay in toxicity permits movement of workers and social activities such as grooming and trophallaxis to occur. For example, exposure to Þpronil barriers permitted L. humile to recruit nestmates for nearly 2 h, exposing greater numbers of ants (Soeprono and Rust 2004). In contrast, Su et al (1982) reported that termites avoided dead and decaying termites that had been killed by fast-acting toxicants by sealing them off in tunnels.…”

Evaluation of Liquid Baits Against Field Populations of the Longlegged Ant (Hymenoptera: Formicidae)

“…Fipronil has been shown as an effective insecticide against many structural insect pests, including ants, termites, and cockroaches (Tingle et al, 2000). It is a nonrepellent insecticide that can act as both a stomach and contact poison (Soeprono andRust 2004, Klotz et al 2007). In laboratory studies, colonies of Tapinoma melanocephalum (F.) that fed on 0.05% Þpronil in 10% sugar (2000) showed with L. humile that as low as 1 ϫ 10 Ϫ5 Þpronil in 25% sucrose water killed 100% of workers and queens in 14 d.…”