The insecticide Sparta™ (spinetoram) has now been approved for aerial application for the control of fall armyworm.
Key Points:
- The insecticide Sparta™ is now on label for both aerial and ground application for controlling fall armyworm on maize and sweetcorn crops. Consult with your advisor.
- Avoid using insecticides that are ineffective on fall armyworm and potentially harmful to beneficial insects.
- We have received questions on thresholds for economic damage. While we work on New Zealand specific information, international (Australian) guidelines suggest, that at whorl stage and above, economic damage will occur when at least 20% of plants have larvae present and/or signs of damage on 75% of plants. Scout crops (if safe) by using a “W” pattern; fall armyworm tends to feed along rows.
- The total number of finds for the 2022-23 season has now reached 127, with two of the eight properties this week located on the South Island’s West Coast.
- Only one moth was found in Northland traps this week, with very low numbers of larvae found in the region.
- The main concern has been the wet condition of many crops, hence scouting and reporting may not be thorough, which is fully understandable.
- There continue to be reports of fall armyworm larvae being parasitised by the parasitic wasp Cotesia sp., which will help contain the numbers.
- Maize and sweet corn crops in areas affected by floods should only be scouted where possible and when safe to do so.
- We are still in a response. All finds must be reported to MPI here or by calling 0800 80 99 66
- There are no negative consequences to growers for reporting, as this pest will not be controlled by removing crops.
Thresholds of economic damage:
For the latest identification guides click here and MPI Website here, or contact Ivan Lawrie ivan.lawrie@far.org.nz or Ash Mills ashley.mills@far.org.nz
For other useful tools and guides on detection and identification, consult the FAR website.