Sprayer boom movements let in blight

Relatively small movements of the sprayer boom can result in significant variations in late season potato blight control, according to new Dutch research.

Bumps in the field, wet patches or minor steering adjustments resulted in boom movements of up to 50cm in either plane (horizontal swing and vertical pitch and yaw), the results from Plant Research International in the Netherlands showed.

This resulted in significant under and over-dosing, with some parts of the crop receiving 40% of the full dose and other parts being oversprayed by 60%. This meant that some treated areas had 80% of the late season blight infection that they would have had if they had not been treated.

“Over and under-dosing occurs in the same places in the field during a season, which means there is a cumulative effect,” said researcher, Jan van de Zande. “The work has highlighted the importance of sprayer application technology and the value of a skilled operator.”

Growers need to ensure beds and tramlines are as even, smooth and straight as possible, he said. Varying the direction you travel your tramlines can help reduce the cumulative effect through the season, he added.