Technical Abstract: The incidence of spider mites was evaluated· in four locations of south Texas between Progreso (Hidalgo Co.) to Bishop (Nueces Co.). This is an area with a south to north transect of 125 miles from south Progreso to north Bishop (respectively).The other two intermediate sampled locations were Harlingen (Cameron Co,), and Raymondville (Willacy Co.). Spider mite evaluations surveys were made conducted from 12 April to 25 July, 2011. In each location, the percentages of plants infested by spider mites were determined by sampling 50 leaves in each border and interior of 10 plants (10 leaves/plant). Spider mites appeared early in the season in Progreso, Harlingen and Raymondville compared with Bishop. Similar trends were found in the percentages of plants infested by spider mites and their presence through the growing season for Harlingen and Raymondville. The Progreso cotton field was isolated and surrounded by the Rio Grande River and onion fields; whereas the rest of the remainder of surveyed fields were associated with large acreages of sorghum or corn nearby that which may have contributed to early season initial spider mite populations within the cotton. A mixed population of Tetranychus urticae, the two spider mites and an unidentified 'reddish' unidentified spider mite species were found in Bishop. It is also possible, but yet to be confirmed by further taxanomic support, that the reddish spider mite species might be more than one species (i.e. T. cinnabarinus, T. tumidus or T. urticae). From all other sites sampled, the unidentified species spider mite was the most frequently encountered.