The Jatropha webber (Sciota divisella): a potential biological control agent for Jatropha gossypiifolia (bellyache bush) from India

Abstract

Jatropha gossypiifolia L. (bellyache bush) is a deciduous shrub from tropical America that was introduced into Australia as an ornamental and has since become a serious weed of rangelands and riparian zones in northern Australia. It forms dense thickets that degrade habitat, including suppressing pasture growth and rendering flood plains unproductive. All parts of the plant are toxic and cattle deaths have been attributed to bellyache bush. Opportunistic surveys in India identified the moth Sciota divisella (Duponchel) (Lepidoptera: Pyralidae) as a potential biological control agent for bellyache bush and in December 2014 the insect was imported into the quarantine facility at the Ecosciences Precinct at Dutton Park in Brisbane. The larvae of this moth feed on the leaves and fruits and, in the absence of these, the larvae bore into the stem from the shoot-tip. The moth causes defoliation, fruit loss and shoot die-back. Host testing of the insect has begun with no-choice testing of larvae on 40 species to ascertain whether the agent is specific to bellyache bush. Larval feeding and complete development occurred only on bellyache bush, on the closely related J. curcas (another approved target for biological control) and on Euphorbia grantii a highly toxic, uncommon exotic ornamental). Aside from these two seemingly acceptable non-target hosts, if the agent proves to be host specific then approval to release will be sought through the Australian government.