Epiblema minutana (Lepidoptera, Tortricidae) in Israel: Promise or Peril?

Abstract

Parthenium weed (Parthenium hysterophorus L.) is a noxious weed and a flagship invasive that has been spreading throughout Israel and the Palestinian Authority since 1980. In other regions affected by this invader, parthenium weed has been managed through classical biological control releases of Epiblema strenuana, a stem-galling tortricid moth native to North America. More recently, a congeneric moth, Epiblema minutana has been identified from Israel. To better understand the implications of E. minutana for controlling parthenium weed, we investigated the spread of E. minutana within Israel and the Palestinian Authority from 2012 to 2019 and explored its host range. We used a series of no-choice experiments in field cages to evaluate damage on naturalized Ambrosia spp., Xanthium italicum and parthenium weed as well as potential non-target, commercial cultivars of sunflower (Helianthus annuus L.) and niger (Guizotia abysinnica (L. f.) Cassini). We also evaluated damage in the field, where we found substantial gall formation on Ambrosia spp., but none on P. hysterophorus or other genera. The geographical distribution increased from an estimated 424 km² in 2017 to 1671 km² in 2019. While E. minutana shows promise as a biological control agent of Ambrosia spp. and does not attack the oil crops sunflower and niger, it is not a suitable biological control agent of parthenium weed.