Field evaluation of Amdro® granular baits in targeted control of Owyhee harvester ant colonies (Pogonomyrmex salinus, Hymenoptera: Formicidae

Publication Type:

Journal Article

Authors:

Robertson, Ian C.; Clark, William H.; Baun, Charles W.; Warner, Kevin S.

Source:

Journal of the Idaho Academy of Science and Engineering, Volume 53, Issue 2, p.1-8 (2017)

Call Number:

A17ROB01IDUS

Keywords:

hydramethylnon, Lepidium papilliferum, pesticides, Pogonomyrmex salinus

Abstract:

Harvester ants (Pogonomyrmex spp.) are considered agricultural pests in many areas of western North America because of their nesting and foraging activities in crops and rangeland. We conducted a field test of Amdro® granular ant baits (active ingredient: hydramethylnon) for the targeted removal of Owyhee harvester ant, Pogonomyrmex salinus Olsen, colonies in southwestern Idaho sagebrush-steppe. We found that a single application of two tablespoons of the pesticide was sufficient to kill colonies. Ants rapidly collected the insecticide granules and delivered them below ground into their nests. Within 24 h many ants on the surface of treated nests were either dead or impaired. Most treated colonies were completely inactive when observations were repeated two weeks after application and again the following year. We discuss targeted control of P. salinus colonies for use in recovery efforts of slickspot peppergrass, Lepidium papilliferum, a threatened mustard endemic to southwest Idaho. Populations of L. papilliferum overlap extensively with P. salinus colonies, and its seeds are vulnerable to predation by these ants.