One near-isogenic and two isogenic ‘Texas Marker-1’ (TM-1) cotton,Gossypium hirsutumL., breeder lines differing in alleles for trichome density affected ovipositional behavior and nymphal growth weight ofLygus hesperusKnight. Femalesoviposited 28 and 31% fewer eggs on the normally hirsute and Smooth leaf lines, respectively, than the Pilose line. The leaf petiole was the most preferred oviposition site, with more than 49% of the eggs deposited there on the three lines. The Pilose isoline reduced nymphal weight by 37% compared with the Smooth leaf isoline. Differences in number of eggs laid, nymphal emergence, growth, and survival were not significantly different between the Smooth leaf and normally hirsute lines. Trichome density of 33 cotton genotypes was positively correlated with nymphal emergence. A regression equation was derived to predict nymphs per female based on trichome density