Heliothis zea larval mortality time from topical and per os dosages of Nomuraea rileyi conidia

Heliothis zea larval mortality time was established for topical applications and per os (feeding) with fungal conidia of Nomuraea rileyi. The 6-to 7-day-old larvae received per os dosages ranging from 6 × 10⁶ to 9 × 10⁹ and a topical dosage of ca. 1 × 10⁹. These spore loads initiated fungal infections in larvae resulting in 1.5–100% accumulated mortality during the 30-day testing periods. The data indicated that regardless of the larval treatment method (topical or per os), or conidial dosage rates, the larval mortality time was never shorter than 5 days post-treatment, nor longer than 22 days. The highest percentage of larval deaths occurred from 7 to 9 days with a maximum mortality at 8 days.