Biological control of Trialeurodes vaporariorum (Westwood) by Encarsia formosa Gahan was tested during three consecutive production cycles (16-28 weeks) on a beef tomato (Solanum lycopersicum L.) crop in a glasshouse and a plastic greenhouse on the Bogota Plateau in Colombia. During the course of this study over the period 1997-1999, the mean temperature was around 16° C in the plastic greenhouse and around 17° C in the glasshouse. E. formosa was introduced at a rate of 3 adults per m2 per week in the 1997
