Farm Table says:
The take home messages from this GRDC funded research are below. Please access the full paper via the link below for methodology, references, acknowledgements and discussion.
Since its arrival in Australia, Fall armyworm (FAW) has been active in the tropics, impacting maize and sweetcorn crops. FAW infestation of maize in North Qld (Burdekin, Bowen regions) has been continuous, from emergence to maturity. Consequently, crop growth rates and yield potential are significantly impacted. Infestations during cob-fill result in significant reductions in yield and grain quality, as a result of secondary infections entering the cobs.
FAW larvae have proved extremely difficult to control with insecticides. The frequency of egg lays, and the hidden feeding sites of larvae (in the whorl, under wrapper leaves, in leaf axils, in silks and cobs) makes chemical control only partially effective.
FAW has been observed feeding in other crops (sorghum, millet, summer pulses), but to date these crops have experienced only minor feeding damage.
It is very clear that affected industries cannot rely on insecticides alone to manage FAW. To date, little effective natural enemy activity has been observed. Whilst selective insecticides have been used preferentially, in maize these are limited to 2 applications per crop, and the broad-spectrum options are highly disruptive to natural enemies.
In maize, FAW has been managed effectively in other countries for many years with transgenic Bt crops a primary means of controlling FAW. Bt provides continuous control of larvae through the vegetative stages (in particular), and in feeding in sites where they cannot be easily contacted with conventional insecticides.
Managing FAW without transgenic crops will be a major challenge for Australian growers, particularly in tropical regions where FAW are attacking crops from emergence to maturity.
In regions where crops are infested by FAW for only part of the growing season, or sporadically in outbreak years, the challenges are less, but not insignificant.