Infection with pathogenic fungi is a major threat to the mass production of the parasitoid wasp Habrobracon hebetor: 20 generations under surveillance

• Fungal infection is a major threat for mass rearing of Habrobracon hebetor. • Fungal infected parasitoid population was less effective than the healthy one. • Fungal infection decreased the population growth parameter potential of H. hebetor after 5th generation. • The intrinsic rate of increase ( r ) and finite rate of increase (λ) had no significant differences up to 8th generation. Pathogen infection is one of the most important challenges threatening the success of mass rearing of natural enemies either in insectaries or in augmentative biological control programs. In this investigation, we studied the biological and population growth parameters of a naturally infected colony of the parasitoid wasp Habrobracon hebetor (Say) (Hymenoptera: Braconidae) over 20 generations (G1 inf − G20 inf ) of rearing on Ephestia kuehniella (Zeller) (Pyralidae: Lepidoptera) under laboratory conditions. Based on morphological characteristics and ITS sequences, two types of fungal colonies were isolated from the diseased females and identified as Thermothielavioides terrestris and Aspergillus flavus . The results showed that although no significant differences were found in the female longevity and fecundity of H. hebetor on E. kuehniella up to G15 inf , the duration of the immature period was extended as the number of generations increased. In addition, the intrinsic rate of increase ( r ) and finite rate of increase (λ) had no significant differences up to G8 inf . The net reproductive rate ( R 0 ) of G15 inf had no significant differences with G2 inf , G8 inf , and G10 inf . On the other hand, in G15 inf , R 0 was significantly higher than G4 inf , G6 inf , and G20 inf . The findings underscore the negative impact of fungal infection on population growth parameters compared with uninfected population. This study showed that naturally fungal infection of the parasitoid affected the population growth and life table parameters through mass rearing, compared and discussed with the healthy parasitoid.