Growers are urged to continue scouting maize and sweet corn crops across New Zealand. Last week’s Otago find has been shown not to be fall armyworm, while in Northland, trap numbers suggest the emergence of a third generation of moths is imminent.
Key Points:
- Last week’s find in Central Otago has now been shown NOT to be fall armyworm. Closer scrutiny of the specimen at MPI proved it was actually an early instar larvae of diamond back moth, Plutella xylostella, commonly found in brassicas and other broad leaf crops.
- Since 1st September 2022 there have been 107 confirmed fall armyworm finds (this is the number of properties where the pest has been found, not the number of insects found).
- Numbers of moths in Northland traps have dropped significantly in the past week, marking the beginning of a third generation.
- ALL maize and sweet corn crops should be scouted nationwide.
- There are no signs of fall armyworm yet in Canterbury, but some damage from other established noctuids was noted.
- The insecticide Sparta is on label for use on maize and sweetcorn crops.
- We are still in a response. All finds must be reported here or call 0800 80 99 66
- There are no negative consequences to growers for reporting, as this pest will not be controlled by removing crops.
Photo: Fall armyworm life cycle, courtesy of MPI. Find it here.
Please contact your local advisor for details on the safe use of this or any other insecticides on maize or sweetcorn.
Thresholds of economic damage:
Plant Health Australia provides useful guidance for this:
For useful tools and guides on detection and identification consult FAR website for the latest identification guides here and MPI Website here or contact Ivan Lawrie ivan.lawrie@far.org.nz