James Frederic Walter

Assessment ofBeauveria bassiana Nov. EO-1 strain, which produces a red pigment for microbial control

A new strain of the fungusBeauveria bassiana Nov. EO-1 (ATCC 74037), which produces a red pigment in solid and liquid culture, has been isolated from an infected whitefly. The red pigment was extracted and has been identified by mass spectrometry as oosporein, a potent dibenzoquinone mycotoxin.In order to assess the potential of this entomogenous fungi for microbial control purposes, a mycelium bead formulation was developed as a source for pathogenic conidial spores and oosporein production. The mycelium bead preparation was found to be a stable fungal carrier. Conidiation and germination studies have revealed the mycelium bead viability is 100% over a 1-yr period when stored at 4°C. Conidial spore production from the mycelium beads has been falling substantially per time from an initial value of 1.5 × 108 spores per bead to 3 × 105 spores per bead after a year storage at 4°C. However, the mycelium bead formulation continues to produce oosporein on agar media, at the same intensity throughout the 1 yr period.In in vitro and in vivo small scale greenhouse experimentsBeauveria bassiana Nov. EO-1 were compared with known entomogenous fungi,Beauveria sp. andPaceilomyces sp. Beauveria bassiana Nov. EO-1 was found to have a high pathogenicity against foliage insect pests (e.g., whiteflies and mealy bugs), and against soil insects (e.g., citrus root weevils). The utilization of a mycelium bead based on this strain,Beauveria bassiana Nov. EO-1, as a source of conidial spores and oosporein may have broad applications for the control of various insect pests.