Shelterbelts need to be free of weeds that cause problems in the orchard.

KVH has regularly alerted orchardists to get rid of weeds such as moth plant, woolly nightshade and pampas, all native to South America and hosts of the Australian insect passion vine hopper, which causes sooty mould to develop on fruit – a significant reject factor reducing kiwifruit orchard returns.

Woolly nightshade is easy to kill. If your orchard is organic, use a tractor and snig chain to pull the entire plant from the ground. Use a spade to dig out seedlings or any broken off roots.

For non-organic properties, a short KVH video of the ‘cut and inject’ method can be seen here. This method is fast, effective, safe, and cheap. Even a large 4m high woolly nightshade can be treated in about a minute – it will be dead two to eight weeks later (two weeks in summer and up to eight weeks in winter).

Use a machete or tomahawk to make downward cuts around the entire circumference of the tree. The cuts do not need to join up, but they do need to go all the way around the trunk and be as close to ground level as possible. Using a stock syringe gun (or oil can), gently squirt 2 to 3mls of undiluted Glyphosate herbicide into the cuts. The herbicide will translocate throughout the tree and in the winter, kill it within two months.

In some valleys adjacent to kiwifruit orchards there are forests of woolly nightshade. Killing them standing up using the cut and inject method is best as you can easily move around the upright dead tree frames to pull seedlings. Providing you pull seedlings at six monthly intervals you will completely remove the woolly nightshade forest. Think about planting the area in native plants or a tree crop to prevent other weeds from establishing.

If you require further advice about killing woolly nightshade or other weeds in or near kiwifruit orchards, contact John Mather at KVH (on 0800 665 825 or info@kvh.org.nz) or your local Regional Council.