Spatial Distribution of Listroderes costirostris and Hypera postica (Curculionidae: Cyclominae, Hyperinae) on a Celery Crop in Mexico's Northwest Region

Celery, Apium graveolens L. (Apiaceae), is an essential salad ingredient in different parts of the world, and production is principally destined for the fresh market. Celery hosts several insect species, including the weevil Listroderes costirostris Schoenher (Coleoptera: Curculionidae). Listroderes costirostris currently is present in the San Quintin Valle, Baja California, Mexico, on commercial celery crops. Hypera postica (Gyllenhal) (Coleoptera: Curculionidae) feeds on several plants of the Fabaceae family and is the principal pest affecting Medicago sativa L. (Fabaceae) alfalfa crops. The purpose of this work was to assess the degree of infestation, spatial distribution, and the association between L. costirostris and H. postica on A. graveolens, in Baja California, Mexico. We established 4 quadrants in 1 ha, and we sampled 100 plants per quadrant in each sample. We collected 22 samplings, counting the larvae and adults of both species. Hypera postica was reported herein for the first time feeding on A. graveolens plants. Between 9.57% and 28.68% of the celery plants served as hosts to both species. Listroderes costirostris had the highest percentage of infested plants. The competitive interaction of these 2 species affected H. postica, which showed lesser abundance. Both species were associated in all the sample quadrants. Listroderes costirostris registered an aggregated distribution pattern, whereas H. postica presented a uniform distribution. The spatial distribution of H. postica is the result of competing for food and space with L. costirostris.