Hydrogel baits with low‐dose thiamethoxam for sustainable Argentine ant management in commercial orchards

Abstract

Argentine ants, Linepithema humile (Mayr) (Hymenoptera: Formicidae), are a significant pest in various agricultural systems around the world, and are often associated with outbreaks of phloem‐feeding hemipteran insects. Previous research has evaluated a number of active ingredients and management approaches for controlling Argentine ant populations in agricultural systems, but various regulatory and economic issues have limited the development of effective management tools. Current chemical controls rely on residual sprays or toxic baits, each one posing unique disadvantages that limit their usefulness and efficacy. This study evaluated the potential of water‐storing crystals to effectively deliver liquid baits to Argentine ants. The efficacy of bait crystals containing 0.007% thiamethoxam was first evaluated in laboratory colonies. In addition, field studies were performed in a commercial plum orchard to determine the efficacy of the bait crystals. Protein marking was used within the orchard to examine the distribution of the bait in Argentine ant populations when delivered via water‐storing crystals. Results of laboratory tests showed that water‐storing crystals containing 0.007% thiamethoxam are highly attractive and effective against Argentine ants and require ca. 3–5 days to kill all castes and life stages. Results of the protein‐marking study demonstrated that the percentage of ants carrying protein‐labeled sugar water decreases sharply with increasing distance from the bait station. Bait movement was limited to within 17 m of the bait dispenser. Furthermore, bait efficacy tests in the field showed that Argentine ants can be effectively controlled using liquid thiamethoxam baits deployed via water‐storing crystals. The bait was highly effective and ant densities throughout the baited plots declined by 94 ± 2% within 14 days. The results of this study demonstrate that (1) thiamethoxam is highly effective for Argentine ant control in fruit orchards when used in low concentrations (0.007%), and (2) water‐storing crystals are an effective tool for delivering liquid baits to Argentine ants in agricultural settings.

Trap–treat–release: horizontal transfer of fipronil in field colonies of black carpenter ants, Camponotus pennsylvanicus

“…One of the most important goals is to develop effective ant control strategies while minimizing negative environmental impact. Recent developments in this area include hydrogel baits, prey‐baiting based on the use of poisoned prey, and pheromone‐assisted baiting . The current study evaluated a novel, target‐specific approach for managing pest ants based on a three‐step method of trap–treat–release.…”

Development of an alginate hydrogel to deliver aqueous bait for pest ant management

“…To overcome the limitations of conventional liquid baiting, a hydrogel matrix has been recently studied as a method to deliver liquid baits to ants without using bait stations . A synthetic hydrogel composed of polyacrylamide has been tested to deliver sucrose liquid baits targeting Argentine ants . The use of hydrogel matrices makes it possible to apply liquid baits directly on the ground where ants are foraging.…”

“…The use of hydrogel matrices makes it possible to apply liquid baits directly on the ground where ants are foraging. The highly absorbent hydrogel matrices act as a controlled‐release vehicle as they keep the liquid bait palatable for an extended period by retaining water . Polyacrylamide hydrogel, however, slowly degrades into its monomer, acrylamide, upon exposure to a temperature of 35 °C .…”

Association between ants (Hymenoptera: Formicidae) and the vine mealybug (Hemiptera: Pseudococcidae) in table‐grape vineyards in Eastern Spain

“…In vineyards, ant control is usually advocated as part of IPM programs to enhance the activity of mealybug natural enemies . The most commonly used strategies for ant management are based on chemical control by means of spray applications, or the use of liquid toxic baits . Physical exclusion methods have been developed as well, banding the stem of the vines with sticky tape .…”