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Fine plastic mesh covering is proving effective in controlling the tomato/potato psyllid on potato crops.
The mesh covering, used widely in Europe, has been used effectively by organic growers in Canterbury and Hawkes Bay. It was also found to give a high level of control of potato blight.
These findings were presented at the Foundation for Arable Research's CROPS 2014 expo at Chertsey last week.
Dr Charles Merfield, head of the BHU Future Farming Centre, said the mesh crop covers were similar to fly screens on windows, stopping pests reaching the crop.
About 100,000ha of mesh was in use in Europe with hundreds of hectares on individual farms.
The covers were now the only means of controlling root fly on turnips and swedes as there were no legal effective chemicals left, he said.
Mesh covering was designed to have the minimum effect on the plants with just a 1degC average increase in temperature under it.
With mesh size going down to 0.3mm, it could keep out pests as small as thrips.
Jessica Dohmen-Vereijssen, from Plant and Food Research, had some key messages for the management of the psyllid in Canterbury.
These included using clean seed, planting early if possible, using yellow sticky traps to monitor the adult psyllid and aphids, monitoring the crop, using selective insecticides and rotating insecticides with different modes of action.