Neolema ogloblini exploring a new option for the control of tradescantia (Tradescantia fluminensis)

Abstract

The leaf beetle Neolema ogloblini was released in 2011 as a biological control agent for Tradescantia fluminensis a major warm temperate forest environmental weed in New Zealand To assess whether N ogloblini can suppress T fluminensis and improve native seedling growth and survival a glasshouse experiment was established Kawakawa (Macropiper excelsum) and mahoe (Melicytus ramiflorus) seedlings were planted underneath uncontrolled T fluminensis and compared with seedlings (1) under T fluminensis damaged by N ogloblini (2) under T fluminensis sprayed with herbicide (triclopyr) and (3) released from competition by manually removing T fluminensis Seedlings did not grow faster in response to reduced T fluminensis biomass and increased light levels following feeding by N ogloblini over the 12 week experiment However seedling survival rates were higher (kawakawa 87 and mahoe 93) with N ogloblini feeding than herbicidetreatment (kawakawa 17 and mahoe 3) T fluminensis Survival in uncontrolled T fluminensis (kawakawa 90 and mahoe 57) varied for the two species This experiment suggests that regeneration of native plants may benefit from damage to T fluminensis caused by N ogloblini feeding in the field