Efficacy of Isaria fumosorosea (= Paecilomyces fumosorosea) and horticultural oils on ornamentals infested with the Madeira mealybug, Phenacoccus madeirensis Green

Phenacoccus madeirensis Green, also known as the Madeira mealybug, is an invasive cosmopolitan ornamental pest known to cause extensive feeding damage and facilitate sooty mold growth through honeydew excretion on host plants. To prevent further dissemination via ornamental propagation transportation, cuttings infested with the Madeira mealybug were dipped into various concentrations of Isaria fumosorosea (PFR 97®) and horticultural oils individually and in combination in a randomized complete block experimental design. Collected data were used to determine if there are synergistic combinations. Phytotoxicity tests for each ornamental cutting and pathogenicity tests for all mealybug life stages were conducted under greenhouse, laboratory, and simulated shipment conditions, respectively.  This research may lead to further studies in utilizing PFR 97®, horticultural oil, or possible synergistic combinations for establishing a national treatment model for transporting pre-clearance ornamental cuttings.