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BAY OF PLENTY REGIONAL COUNCIL TOI MOANA

Home > Our region and environment > Pest management > Case study - Pest alert saves maize growers

Case study - Pest alert saves maize growers

Good spotting by Waihau Bay (near Te Kaha) cropping contractor Joe Rua back in 2006 helped stop the spread of one of the real nasties of the weed world – horsenettle. It’s toxic, thorny, hardy and incredibly invasive – and it probably piggybacked a trip to New Zealand from the United States in contaminated maize seed.

HorsenettleDue to the unpleasant characteristics of horsenettle, it is listed as an ‘Eradication Pest’ in the Regional Pest Management Plan, which means that the Regional Council is responsible for the weed’s control and control costs.

Horsenettle is incredibly hard to kill due to its underground rhizomes, which can sprout hundreds of new plants even when it appears to be dead above ground. Cultivation can aid the spread of the surviving rhizomes. Control work has been slow and painstaking and, despite not being required to help, contractor Joe and the landowners have been incredibly supportive, assisting council staff.

Many hours have been spent walking up and down the maize rows seeking out and destroying horsenettle plants, repeated several times each year. One area of the farm, covering 1.5 hectares, is too densely infested for the ‘seek and destroy’ method of control. Instead, the landowners have left the paddock fallow and contractor Joe regularly boom sprays the area.

Council staff, Joe and the landowners are happy with the progress, albeit very slow, towards eradicating horsenettle at Waihau Bay and all are appreciative of the collaborative approach.