Dicyphus tamaninii Wagner and Macrolophus caliginosus Wagner (Heteroptera: Miridae) are 2 native generalist predatory bugs being successfully used for management of greenhouse whitefly, Trialeurodes vaporariorum (Westwood), in outdoor tomato crops in Catalonia, Spain. However D. tamaninii also is phytophagous and occasionally feeds on tomato fruits. Damage to fruits can be related to a shortage of alternative insect prey. This hypothesis was the basis for a decision chart which allows the conservation of D. tamaninii to a level where ii may excessively control whiteflies and start damaging the fruit. Here we report on the results of a 4-yr evaluation of the decision chart. The implications of zoophytophagous behaviour in IPM are discussed.