Hornet sting could cripple rural NZ

The hornet (Vespa velutina) was discovered on Auckland’s North Shore late last year, and Biosecurity New Zealand is using advanced radio tracking technology to track it. At the time of writing, it was still contained in Auckland, but Farmlands Horticulture summer intern Henry Crawford warns that rural people still need to keep an eye out.

Henry researched the hornet as part of his internship, after a discussion with Bay of Plenty beekeeper and a Farmlands shareholder about the potential damage it could cause. “Not only is it a predatory pest that preys on honeybees, but if they're present near a bee colony, then it can actually stop them from foraging and pollinating because they just hide in the hive,” Henry says. “This can be disastrous for industries that depend on bee pollination.

It also kills moths and beneficial insects.” Although kiwifruit growers have other methods of pollination available to them, Henry says they aren’t viable for a lot of other growers. “New Zealand produces 60% of the world's radish seed and 50% of the world's white clover seed in the Canterbury Plains, so the introduction of the pest into the South Island could be disastrous on a global scale.” “It even affects pastoral based systems. Reduced honeybee activity could lower clover pollination and persistence over time, which may then reduce biological nitrogen fixation in pastures and increase reliance on synthetic nitrogen inputs.”

Henry says the most important things for rural dwellers to be aware of regarding the yellow-legged hornet are what it looks like and where it likes to hang out. People can make their own homemade traps to catch them (see below). “They’re huge – 2-3cm – over twice the size, if not three times the size of a normal honeybee and they've got different features. They look like they're wearing socks,” he says. “They like to nest in trees and in places like boat covers, so it’s a good idea to check your boat for them if you’re taking it away for a fishing weekend.”

How to build a homemade hornet trap

• Cut the top third off a plastic soft drink bottle.
• Turn the top cut part upside down and put it neck downwards into the bottom part of the bottle to create a funnel.
• Punch holes through the side so you can hang it up with string. 4. Mix together 400g of sugar, 10g of yeast, vinegar, and 1 litre of water (you can also add 100 ml of beer). You’ll have enough to fill several traps.
• Add the bait to the bottle, making sure to leave about 5cm above the liquid for hornets to enter the bottle and be trapped.
• Hang your trap from trees or other garden structures well away from your house, under shelter to prevent rain entering.