7 Apr 2017

Cover Story

From Country Life, 9:14 pm on 7 April 2017

For the first time, New Zealand potatoes are getting the mesh test.

Charles Merfield

Photo: RNZ/Cosmo Kentish-Barnes

Mesh crop covers are already extensively used in Europe to control insect and vertebrate pests on a wide range of crops, but now they are being trialled on spuds in New Zealand.

Potatoes are susceptible to a wide range of pests and diseases and are often dosed with agri-chemicals to control them, so a scientist at Lincoln University's Future Farming Centre is testing a non-chemical method to protect potatoes.

Dr Charles Merfield's mesh crop cover field trial is proving effective in controlling tomato potato psyllid as well as reducing potato blight.

However he has found that aphids are slipping through the holes in the mesh and through small rips.

"The aphid nymphs are unbelievably tiny and they are able to penetrate the mesh and once inside they can reproduce in the absence of beneficial insects," he says.

Mesh crop cover

Photo: RNZ/Cosmo Kentish-Barnes

The focus is now on developing a finer mesh and finding a suitable bio-control agent that can be under the cover in case any aphids slip in.

For Dr Merfield, this is what his research is all about.

"We didn't get blight and psyllids but we got aphids under the mesh, so that's the whole point of agricultural scientists. We make all the dumb mistakes so farmers don't have to!"

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