Quality check of the parasitoid Metagonystilum minense (Diptera: tachinidae), mass reared for the control of Diatraea Spp. (Lepidoptera: cambridae)

In the Sugar cane growing area of the Cauca river valley, two borer species have been registered: Diatraea saccharalis and Diatraea indigenella, and have been managed by means of two tachinid parasitoids: Metagonystilum minense and Paratheresia claripalpis. An unusual increase of borer damage was detected in 2005, the areas with high levels of incidence were diagnosed. The factors that may have influenced this outbreak were analyzed on the quality of parasitoids commercially reared. In relation to the quality of mass reared M. minense, it was not possible to capture adequate numbers of wild individuals to the compared with mass reared individuals. Using pupae obtained from commercial suppliers, several biological parameters were evaluated to forecast their efficiency in the field. These are pupal weight, emergency, sex proportion, abnormal adults, mortality, total and active progeny, it was determined among suppliers, and that pupal weight is related to progeny numbers and their activity, which are the most important parameters to forecast their activity in the field. In addition, limit values for each parameter were proposed to measure the quality of mass reared individuals of M. minense.