Cotton Boll Weevil and Thurberia Bollworm Problem in Arizona

Abstract

The cotton growing valleys of southern Arizona, particularly those about Tucson are of great interest to southwestern entomologists because of the presence in the near-by mountain ranges of certain potential cotton pests which occur on a native plant, the so-called wild cotton, Thurberia thespesioides . These insects are a native variety of the boll weevil, Phytonomus grandis thurberiae Pierce, and a noctuid moth, Thurberiphaga diffusa Barnes, the larva of which is a bollworm. The native weevil is shown to have habits distinct from the Mexican boll weevil. Both it and the bollworm are well adapted in their life histories to the normal late fruiting habit of the wild cotton. It is believed that either or both might, if proper opportunity were afforded become pests of domestic cotton. A problem is created by the fact that in the district cultivated about Tucson the wild cotton, harboring both insects, grows quite close to areas on which domestic cotton may be grown. Incipient infestations of the weevil, but thus far none of bollworm, have already occurred in the past few years but have been stamped out. At present there is a controversy to be settled by the courts between the Arizona Commission of Agriculture and Horticulture and the cotton growers of this district regarding the maintenance of a non-cotton area near the natural habitat of Thurberia.