The objective of the study was to evaluate the systemic acquired resistance (SAR) material, Messenger, on emergence, plant height, boll number and lint yields of cotton (Gossypium hirsutum L.). In 1997, boll number and lint yields of 'Deltapine 5690 RR' were higher after application of Messenger at first true leaf, pre-bloom, and early bloom compared to the control and higher than the growth regulator, Early Harvest, alone. Plants were significantly shorter after application of Messenger with the growth regulator, Pix, applied at first true leaf, pre-bloom, and early bloom than control. There was no significant difference between treatments for 1998 lint yield, number of bolls per plant, emergence, or plant height of 'Deltapine 458 BR'. However, there was a tendency for higher lint yields from the seed treated with Messenger compared to control. In 1999, the emergence and number bolls per plant were not significantly different. Plants for treatments with Pix application were significantly shorter than plants from other treatments. Significantly higher lint yields were obtained from treatment with Pix applied alone as compared to other treatments and lower from treatment with Actigard. Higher yields of cotton were obtained from treatments with three applications of Messenger at 4.4 oz/A and 2.2 oz/A and treatments with Early Harvest TST treated seeds and sprayed with Early Harvest TST as compared to the check. Generally, Messenger increased the boll number and lint yields in 1997 and had a tendency to increase lint yields of cotton in 1998 and 1999 as compared to control.