Wild hosts of Bemisia argentifolii (Homoptera : Aleyrodidae) Bellows & Perring in semiarid northwest Mexico.

Field sampling and laboratory analysis were performed on 24 plants species from 15 families to determine wild hosts of the silverleaf whitefly Bemisia argentifolii Bellows & Perring (also known as B. tabaci Strain B). Plants were collected from undisturbed vegetation surrounding horticultural plots in the La Paz-Carrizal B.C.S. (Mexico) agricultural valley. Of the 24 plant s studied, 17 carried fourth-stage nymphs or pupae, of B. argentifolii, dem ostrating that this pest has a,vide range of wild hosts in semiarid lands. Plant species with the greatest number of B. argentifolii pupae were Croton californicus L., Viguiera deltoidea Blake, and Tribulus terrestris L. in t he families Euphorbiaceae, Compositae and Zygophyllaceae, respectively. Pop ulation densities observed in the wild plants were similar to those observe d on cantaloupe, which is considered to be the horticultural crop most pref erred by B. argentifolii in agricultural areas of semiarid northern Mexico.