Pre-Pupae and Pupae of Anticarsia gemmatalis as Suitable Alternative Hosts for Tetrastichus howardi Mass Rearing

Optimizing mass-rearing systems using alternative hosts is essential for successful biological control programs. This study evaluated the effect of foundress density on the biological parameters of Tetrastichus howardi (Olliff) (Hymenoptera: Eulophidae) reared on pre-pupae and pupae of Anticarsia gemmatalis Hübner (Lepidoptera: Erebidae). Hosts were individually exposed to six parasitoid densities (1, 5, 10, 15, 20, and 25 females/host) for 24 h under laboratory conditions. Tetrastichus howardi successfully parasitized both developmental stages across all densities. Parasitism and emergence rates reached 100% at densities ≥ 10 females/host. The egg-to-adult development period decreased as foundress density increased, indicating intraspecific competition. Total progeny peaked at the 25:1 density, yielding 389.4 individuals per pre-pupa and 414.0 individuals per pupa. Conversely, individual female productivity was inversely proportional to density. The sex ratio remained highly female-biased (~0.80) across all treatments, and female longevity (~9 days) was not compromised. In conclusion, A. gemmatalis pre-pupae and pupae are highly suitable alternative hosts for T. howardi multiplication. For optimized mass production, a foundress density of 5 to 10 females per host is recommended to maximize high-quality progeny yield.