If you see this worm in your garden, take immediate steps to eradicate it – the fall armyworm will decimate your garden.
In the lush gardens of New Zealand, a silent invasion has been taking place – and it is here in the King Country.
The tiny but destructive fall armyworm moths, first thought to have arrived from Australia in February 2022, have now become a widespread garden pest that have defied a programme to eradicate them.
These voracious pests are wreaking havoc, and it was with some dismay my mother let me know we had them in a planter tub which had been filled using a well-known potting mix.
The armyworm, a moth known scientifically as Spodoptera frugiperda, and originally a native to the Americas, is believed to have hitched a ride on imported produce or with eggs in contaminated soil.
With no natural predators in New Zealand, they have quickly multiplied, causing widespread devastation.
Initially, they were a notifiable bug problem, but their presence has escalated so fast that by April this year, the Government had to revert back to a management philosophy rather than an eradication one.
The telltale signs of infestation are skeletonised leaves and chewed stems and if you want a healthy garden to continue, it is vital to get on top of it as soon as possible.
Known to be partial to more than 350 species of plants, they will infest lawns, crops and literally anything in your garden.
The Government has been working with scientists to find strategies such as encouraging natural predators to join the fight.
Flowering plants to attract beneficial insects like ladybugs and lacewings, are known to prey on armyworms and this biological control method proved successful in some cases, as the predators helped keep the population in check. There are three other known species of armyworm, easily mistaken, but it is better to be safe and eradicate all.
Additionally, gardeners can use physical barriers to protect their plants such as netting and fences around vulnerable areas, preventing the armyworm moths from reaching their targets. Regular inspection and manual removal of the pests are also important, as early detection is key to minimising the damage.
Options like neem oil and Bacillus thuringiensis have also proved effective in reducing the pest numbers without harming the environment.
Chemical treatments such as pyrethrum based products can be used, taking care to follow the instructions to minimise any potential risks to beneficial insects.
It is important particularly if reusing old soil in your compost bins, to make sure it does not contain eggs and a good dose of neem oil before you mix it is a good idea.
For our garden, a combination of neem oil and planting herbs and plants such as dill, oregano, cosmos, coreopsis, asters, sweet alyssum, verbena, daisies and other, along with nasturtiums (a good eating plant) sunflowers and roses for aphids for organic control.
The invasion of armyworms in New Zealand gardens has served as a wake-up call for the importance of vigilance and proactive pest management. Its reminded us to remain knowledgeable about potential threats and to adopt sustainable practices to protect our precious plants.
