Read the latest information on Fall armyworm findings in the 2023/24 season.
Key points:
- FAW has been found at two locations of the West Coast Region. The Early population is small, larvae have only recently hatched and are mostly 1st instar.
- There have been 31 confirmed findings of fall armyworm (FAW) in the 2023/24 season to date in Northland and Westland (vs 45 finds nationwide, including Northland, Auckland, Waikato, Taranaki and Westland at this time last year).
- The majority of recent observations have been of late instar larvae and pupa. Where larvae are not present, but frass and signs of feeding damage are, it is likely that FAW are present in the pupal stage of the life cycle.
- It can be anticipated that the 2nd generation adults will begin to emerge resulting in a moth flight. Pheromone traps may indicator the presence of this new generation of moths; however crop scouting is key!
- Observations of parasitisation of FAW by the parasitic wasp, Cotesia sp have been extremely encouraging. Small infestations appear to be kept in check by Cotesia.
- Cosmopolitan armyworm, greasy cutworm, tropical armyworm and corn earworm have also been observed across the country.
- FAW populations appear to be small and localised, and well below economic thresholds. Keep crop scouting and liaise with your advisor to seek advice.
- Continuing observations are important, the earlier FAW is identified the better the chance of effective management.
- Please remember to record and inform us of any finds.
- The insecticide Sparta® is on label for aerial and ground applications for controlling fall armyworm on maize and sweetcorn crops. Consult with your advisor and avoid the use of insecticides that are ineffective on fall armyworm and potentially harmful to beneficial insects such as parasitic wasp Cotesia sp. which will help contain the numbers.
Photo above (top): FAW damage on the leaves and whorl, with some frass on the leaves.
Photo above (bottom): Late instar larva surrounded by frass within the whorl of the same plant.
Investigating damage on crops and identifying the pest is vital to understand FAW distribution and the correct method of control
Findings compared with last year
At this date last year there had been 45 fall armyworm finds nationwide, including Northland, Auckland, Waikato, Taranaki and Westland.
- Average winter and spring temperatures were considerably lower in regions this year than last year.
- Marginal areas may have seen FAW populations unable to overwinter and depend on migration from more favourable areas.
- If you are scouting your crops inform us even if you do not find FAW, THIS POPULATION DATA IS USEFUL. The data provided has been fantastic, enabling constant development of the modelling and has been extremely helpful for ongoing research aiming to develop predictive tools.
Photo above (top): Larvae drop to the ground and burrow around 25mm below the surface to pupate. Some will also be found as pupa in the whorl or cobs. See our identification resource here.
Photo above (bottom): Current FAW distributions in Northland. FAW can travel over 400 kilometers in a night when assisted by the wind, so growers anywhere in the North Island should now be checking crops and reporting any finds as the 2nd generation adult flight is predicted shortly.
What to do if you think you find fall armyworm
Photograph it: It can be easily mistaken for other species, so if you suspect Fall armyworm, take a good quality photo, and be sure to include the head, body and rear of the larvae. This can be in multiple photos if necessary. This great guide from the Queensland Department of Agriculture and Fisheries will help How to take a photo of FAW_24Mar20 (thebeatsheet.com.au)
Catch it: Samples will be welcomed and are important for positive identification and testing.
Contact us: Contact the Foundation for Arable Research at FAR@far.or.nz or Biosecurity Officer Ash Mills at ashley.mills@far.org.nz
- Trap network and active scouting and reporting have been fantastic throughout the winter and spring and are much appreciated.
- All data recorded (even zero finds) are valuable for the validation of modelling platforms and for understanding the pest in New Zealand.
- If you are keen to monitor a trap and share scouting information please get in touch
- Data and observations of parasitism as well as potential relationships with other pest species would also be welcomed.
Consult the FAR website for the latest resources and identification guides
FAR Research | Welcome to the Foundation for Arable Research
Listed below are useful updates, tools and guides on detection and identification
FAR Research | Fall armyworm identification and background
For advice around Sparta, FAW information and requesting a great FAW glovebox guide - Fall Armyworm (corteva.co.nz)
Thresholds of economic damage
Plant Health Australia provides useful guidance for this:
Useful insight from over the ditch - https://www.planthealthaustralia.com.au/fall-armyworm/
SGRR Davis Scale Guide - 86d44eb4-7d19-5ce5-befe-4dd32eeca38c.pdf (far.org.nz)
A farm Biosecurity Register is a great way of reducing the risk of unwanted weeds, pests and diseases arriving on your doorstep. Do you have one? Find out more here FAR Research | Arable Biosecurity Risk Register