The silverleaf whitefly (SLWF) Bemisia argentifolii is a serious cotton pest in the cotton growing area of Mexico. Control measures are difficult, because the population increases quickly and the immatures develop on the undersides of the leaves. Our studies during 1992-1995 indicate that only mixtures of insecticides control these insects.

In order to confirm these findings at the commercial level with growers, we performed a trial in the Mexicali Valley, Mexico. Two pyrethroids were validated; Karate (lambda cyhalothrin) and Herald or Danitol (fenpropathrin) + the organophosphates Orthene (acephate) and Hostathion (triazophos). All treatments had good control of SLWF during 15 days, when applied at an economic threshold of 10 to 13 adults/leaf. These insecticide mixtures are good choices for controlling SLWF, but if another pest is present, it is better to choose the appropriate mixture and apply it accurately.