A mechanical harvester with nylon arms is being tested by the US-based orange growers. The machine gently shakes ripe fruit off the tree. The growers are using the technique originally developed for picking blackberries. If the machine is found successful, it would help orange growers in the US to compete with lower labour costs. Donald Peterson, an engineer at the US Department of Agriculture, has designed the machine. The designer says that during tests on two Florida groves, the machine was able to remove up to 95 per cent of the mature fruit from trees. Peterson had earlier developed a similar shaking machine to harvest blackberries at the Department of Agriculture's Appalachian Fruit Research Station in Kearneysville, West Virginia, USA. The engineer says that the machine can harvest nearly nine trees per minute. Whereas the product can be nearly 15 times more efficient than hand labour, which would depend on the size and yield of the tree ( New Scientist , Vol 157, No 2124).