Armyworms in rice

The common armyworm Leucania convecta (Mythimna convecta) was a localised and sporadic pest of rice until the 2011/12 rice season, but since that time it has become a much more consistent and widespread problem, particularly in the Murray Valley. Major crop damage has occurred, partly as a consequence of inadequate crop monitoring in the period leading up to harvest, and also for logistical reasons in some seasons when shortages of aircraft or poor weather conditions have prevented prompt chemical application.

Agronomists estimated that around 60% of Murray Valley rice crops required spraying for armyworm during the 2012/13 season, with similar proportions of the crop being treated in each subsequent year. 

NSW Department of Primary Industries, Primefact 1316, second edition, July 2016