Comparisons of Lygus lineolaris (Hemiptera: Miridae) Populations from Two Distinct Geographical Regions of...

The tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae), is a major pest of cotton (Gossypium hirsutum L.) in the state of Mississippi. Economic data indicate that L. lineolaris is a more serious pest of cotton in the Delta region of Mississippi than in the Hills region; however, little data exist comparing the two populations. Two experiments were undertaken to compare L. lineolaris from these two geographically distinct regions. In the first experiment, colonies of L. lineolaris from each region were reared in the laboratory under controlled conditions and measurements of development time, survivorship, fecundity, and hatch rate were compared. The geographic region of origin had no effect on any of the variables measured; however, the diet used for rearing had a significant effect on all variables except hatch rate. In the second experiment, part of the cox1 gene of the L. lineolaris mitochondrial genome was compared between the two populations to examine possible genetic differences between L. lineolaris from the two regions of Mississippi. Data revealed two cox1 clades in the Delta region and only one cox1 clade in the Hills region. Taken together, the data do not explain the reason for the differences in the severity of damage to cotton in the two regions.