Assessment of centrifugal distribution of natural enemies for the open field

In order to promte the spread of biological plant protection the authors have designed and built a second version of a prototype which can mechanically distribute natural enemies in greenhouses or in open field. This differs from the preceding one as regards the hopper, doser and distributor disc and also materials and size and it can be directly carried by the worker. Three models of this version were installed on a bar tractor for the open field distribution. Several laboratory trials, have been carred out to evaluate: jet direction, spatial distribution, quantity distributed, uniformity of jet in time, vertical distribution, transversal profile of the product distributed. The distribution mechanism of the prototype seem well suited to biological pest control strategies and negligible impact on natural enemies shows technical and economic advantages on manual distribution.