Image top: Kumara, upper row, grown without alligator weed while the lower row is kumara grown with alligator weed present. Image bottom: alligator weed and the distinctive white paper flower head on a stalk.

One of the world’s most invasive plant species is threatening New Zealand’s productive landscapes - including kiwifruit orchards.

Recent research led by AgResearch and supported by KVH, regional councils, and the Ministry for Primary Industries (MPI) is shedding new light on how to manage alligator weed, a persistent pest.

A new publication has been created covering its impacts, eradication, mitigation and management – including tips for what to do on-orchard.

Originally a problem in Northland’s kumara plantations, alligator weed has spread to the Bay of Plenty, including within kiwifruit orchards, and has also appeared across other regions of the North Island. Its spread is largely attributed to the movement of contaminated machinery and equipment. Because the plant reproduces vegetatively, even the smallest fragment can establish a new infestation, highlighting the need to clean machinery and equipment between orchards.

It poses a risk to kiwifruit growers as the weed’s dense mats compete with crops for light, nutrients, and space, reducing yields and complicating orchard management. Its underground rhizomes are notoriously resistant to herbicides, making eradication difficult once established.

If you see alligator weed on your orchard, contact KVH or your regional council.