Assessing the potential of Yersinia entomophaga to control plantain moth in a laboratory assay

The recent increased use of the high-quality drought-tolerant forage plant plantain (Plantago lanceolata) (Plantaginaceae) has been associated with outbreaks of native geometrid caterpillars, such as Scopula rubraria. The outbreaks most often occur under warm climatic conditions and within plantain monocrops. Pest populations can reach 11,500 larvae/m2. Stands can be severely damaged with 90% of plants destroyed and stand life expectancy reduced by 2-3 years. This study assessed the efficacy of the insecticidal bacterium Yersinia entomophaga against S. rubraria under laboratory conditions using a leaf dip bioassay. A LD50 of 2.26 ± 0.33×105 cells per larva was determined with an LT50 defined as 3.1 days when treated with 4.8×106 cells per larva. These data combined with the life history of S. rubraria and the pathobiology of Y. entomophaga suggest the bacterium could be developed as a biopesticide for use against S. rubraria