Fruit flies are probably the main pests of fruit growing worldwide. Far beyond the guava bug joke, this insect is responsible for a huge amount of annual losses. With the awakening of a new class of consumers, concerned about the health of the products they consume, there has been a need to reduce the use of industrialized chemical pesticides. Biological control has become an important tool in integrated pest and disease management programs. For the control of fruit flies, native parasitoids have not shown the efficiency that would be appropriate in Brazilian orchards, especially in Rio Grande do Sul. One alternative has been to import and release the exotic species Diachasmimorpha longicaudata. This book is the culmination of 12 years of studies on fruit flies. It is the result of a doctoral thesis that presents data on the first releases of this braconid in southern Brazil. We hope it will be useful to students and researchers in the field. Happy reading.