The state of Tamaulipas in Mexico has 2.4 million acres of cultivated agricultural land and cotton has been planted on 500,000 of these acres in northern and southern Tamaulipas. Cotton is planted in the subtropical northern area in March and in the tropical southern area in June. Locations are separated by 550 km. The tobacco budworm is a major pest in both of these areas. A slight trend for increased resistance by methyl parathion in 1992 was shown in both northern and southern Tamaulipas when compared with 1991 data. Response to cypermethrin by the tobacco budworm in northern Tamaulipas was variable but one high LD(50) was shown. Trap captures of tobacco budworm moths were about 100 times greater in northern Tamaulipas than southern Tamaulipas.