Read the latest Fall armyworm update up to 19 January 2024.
Key Points:
- FAW has been found at three locations of the West Coast Region. Larvae have progressed through to 2nd and 3rd instar stages of their lifecycle.
- The 2023/24 growing season has 44 confirmed reports to date, in Northland and now in Westland. There is one unconfirmed report in the Nelson/Tasman region.
- In general, FAW populations appear to be small and localised, and well below economic thresholds. However, the next generation has been identified in Northland, and has larger populations with the potential for a greater economic threat. Keep crop scouting and liaise with your advisor to seek advice.
- Being observant at this stage is important, the earlier FAW is identified the likelier effective management will be achieved.
- Observations of parasitisation of FAW by the parasitic wasp, Cotesia sp have been extremely encouraging. Small infestations have appeared to be kept in check by the wasp.
- Cosmopolitan armyworm, Greasy Cutworm, Tropical armyworm and Corn earworm have also been observed across the country.
- Observations are important, please record them and inform us.
- 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): Damage on the leaves while scouting this can be observed as multiple plants adjacent to each other with tiny windows/dots or scratches. The small larvae leave the epidermal layer of the plant, which is typically referred to as “windowing” or “window pane” injury.
Photo above (bottom): 1st instar larva feeding (at the end of person's thumb!) Larvae are typically found sheltered from the sun UV, within the folds of the leaves. At 1st instar they are only around 3mm long so can be easily missed.
Investigating damage on crops and identifying the pest is vital to understand FAW distribution and the correct method of control.
At this date last year there were 76 Fall armyworm finds nationwide, including Northland, Auckland, Waikato and Taranaki
- To date, confirmed finds this season are in Northland and now Westland.
- Average temperatures were considerably lower in regions compared to winter and spring 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, it will enable development of the modelling and has been extremely helpful for ongoing research aiming to develop predictive tools.
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)
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
Thresholds of economic damage
Plant Health Australia provides useful guidance for this:
