Improving Liquid Bait Programs for Argentine Ant Control: Bait Station Density

Abstract

Argentine ants, Linepithema humile (Mayr), have a positive effect on populations of mealybugs (Pseudococcus spp.) in California vineyards. Previous studies have shown reductions in both ant activity and mealybug numbers after liquid ant baits were deployed in vineyards at densities of 85-620 bait stations/ha. However, bait station densities may need to be <85 bait stations/ha before bait-based strategies for ant control are economically comparable to spray-based insecticide treatments-a condition that, if met, will encourage the commercial adoption of liquid baits for ant control. This research assessed the effectiveness of baits deployed at lower densities. Two field experiments were conducted in commercial vineyards. In experiment 1, baits were deployed at 54-225 bait stations/ha in 2005 and 2006. In experiment 2, baits were deployed at 34-205 bait stations/ha in 2006 only. In both experiments, ant activity and the density of mealybugs in grape fruit clusters at harvest time declined with increasing bait station density. In 2005 only, European fruit lecanium scale [Parthenolecanium corni (Bouché)] were also present in fruit clusters, and scale densities were negatively related to bait station density. The results indicate that the amount of ant and mealybug control achieved by an incremental increase in the number of bait stations per hectare is constant across a broad range of bait station densities. The results are discussed in the context of commercializing liquid ant baits to provide a more sustainable Argentine ant control strategy.

Liquid baits control Argentine ants sustainably in coastal vineyards

“…Ant control in vineyards has been investigated using granular protein baits for Formica species (Klotz et al 2003;Tollerup et al 2004) and liquid sugar baits for Argentine ants (Daane, Sime, et al 2006;Daane et al 2008;Nelson and Daane 2007 Klotz et al (2002) and described in detail by Daane, Sime, et al (2006).…”

Evaluation of Insecticides for the Control of <I>Linepithema micans</I> (Hymenoptera: Formicidae)

“…In such situations, infestation by Hemiptera is signiÞcantly reduced when the ants are excluded from the plants ). The control of L. humile in vineyards has been mainly carried out by applying insecticides on the ground or the trunks of the vines (Phillips and Sherk 1991, Addison 2002, Klotz et al 2003, Daane et al 2006, or with toxic baits (Nelson and Daane 2007, Daane et al 2008, Nyamukondiwa 2008, Blight et al 2011, Nyamukondiwa and Addison 2011. In these cases, the insecticides that are most often used as chemical barriers are chlorpyrifos, bifenthrin, and Þpronil (Phillips and Sherk 1991, Addison and Samways 2000, Klotz et al 2003, and as toxic baits are boric acid, Þpronil, hydramethylnon, imidacloprid, sulßuramid, and thiamethoxam (Klotz et al 1998;Rust 2000, 2001;Rust et al 2004;Nelson and Daane 2007;Daane et al 2008;Nyamukondiwa 2008;Nyamukondiwa and Addison 2011;Blight et al 2011).…”

Food Preference and Foraging Activity of Ants: Recommendations for Field Applications of Low-Toxicity Baits

“…In this manner, L. humile can easily form supercolonies that can saturate an entire habitat. Nelson and Daane (2007) also found that L. humile is extremely vagile in Californian vineyards, whereas in citrus orchards Markin (1967Markin ( , 1968 and Ripa et al (1999) found that L. humile foraging seldom exceeds 61 m from a nest. Our research was limited to 32 m, as placing baits further apart would probably not result in effective control (see Daane et al 2006).…”

“…We presume that ants forage for shorter distances during this time of the year, since food resources will be highly abundant and in close proximity. Nelson and Daane (2007) hypothesized that ant foraging on 25% sugar water peaks in spring. Rust et al (2000) showed that L. humile foraged 26-60% and 16-40% of available protein in summer and winter respectively, suggesting considerable seasonal differences in activity and bait preferences.…”

“…Preference trials were carried out during austral spring (October 2007), as this is the optimum time for application of baits because ant populations are low (Nelson and Daane 2007). Foraging activity evaluations were carried out during summer (December 2007, January andFebruary 2008) in the Stellenbosch Winelands region.…”