The latest update on fall armyworm for the 2023-2024 season shows the pest has spread further but the overall count for the season is down 26 on the same time last year.
Over the past three weeks there have been two new confirmed finds of the crop pest, both from Northland, bringing the 2023-24 growing season count to 113 confirmed reports from Northland, Westland, Tasman, Bay of Plenty, Auckland, Waikato, Marlborough and Canterbury.
This time last year there were 139 fall armyworm (FAW) finds nationwide, including Northland, Auckland, Waikato, Taranaki and Canterbury.
Westland, Tasman and Bay of Plenty are new regions with FAW finds this year.
Northland FAW moth flights are still being consistently observed in pheromone traps, however moth numbers are falling.
Adult FAW have the potential to travel significant distances in one flight and in the absence of maize they may travel inter-regionally to seek suitable locations to mate and initiate the next generation.
The Foundation for Arable Research (FAR) urges farmers who have been monitoring traps to keep checking them even after crops have been harvested.
While many susceptible crops around the country have been harvested, or are close to harvest, meaning a reduction in FAW’s preferred food source, maize grain crops are still at risk.
FAW larvae will typically enter the cob through the side and observations of population dynamics and kernel damage will be beneficial to help develop New Zealand-specific economic damage thresholds.
FAR reports that as temperatures decrease, the life cycle has begun to slow, but along with a reduction in surveillance, it is important to stay vigilant and scout harvested and any neighbouring paddocks as FAW will predate a large variety of crops.
In NZ they have been observed on ryegrass and clover in a harvested maize paddock.
Crop residues should not be overlooked, nor should any volunteer maize that may emerge in the coming weeks or months.
FAW will feed on a large variety of crops in the absence of maize and sweetcorn. Research has shown they will happily travel to an acceptable alternate host.
