Laboratory Evaluation of Vairimorpha necatrix (Microspora: Microsporidia) as a Control Agent for the Black Cutworm (Lepidoptera: Noctuidae)

The microsporidium, Vairimorpha necatrix (Kramer), was evaluated for potential use as a biological control agent for black cutworm, Agrotis ipsilon (Hufnagel), larvae. The LC50 of V. necatrix was determined for third, fourth, and fifth instars. LC50 values increased ca. 10-fold between instars. A grape pomace bait that incorporated V. necatrix spores was also bioassayed. LC50 values for this formulation increased with instars; a 17-fold difference occurred between third- and fifth-instar black cutworms.