The silverleaf whitefly Bemisia argentifolii Bellows and Perring, become a serious cotton pest in Mexico early in the 1990xs. Insect pest management strategies implemented at the regional level were effective to reduce the high populations observed at that time. Special attention on cultural practices such as planting dates and crop residue destruction were key to the strategy. However, once the problem was solved in 1997, the order and discipline established on planting dates, and pest management actions were relaxed. This 2005 cotton season whiteflies resurged and produced dramatic crop losses on cotton, reducing more than 50% seed cotton yield. This is an indication that whiteflies are a potential pest problem in cotton areas if IPM strategies are not maintained.