Mechanical distribution of natural enemies in the open field

For experimental trials in strawberry open field, two different applications of a new version of a prototype, built for mechanical distribution of natural enemies, were used: one mounted on a bar carried by an operator with a shoulder strap and lateral handle; the other mounted on a carrying bar connected to three linkage points to a tractor. In this case, three prototypes were attached to three support rods and connected electrically to one another in parallel, powered by a single battery and commanded by a single switch, positioned near the tractor driver. In this configuration, laboratory trials to evaluate the throw direction, the spatial distribution, the quantity distributed, the uniformity of throw in time were carried out. Previous laboratory trials were carried out to assess the performance of the new version of the prototype and to set the suitable flow rate for the distribution in open field with reference to the forward velocity of the tractor. With these applications of the new version of prototype, the maneuverability has been much improved and consequently better results can be obtained in terms of both work capacity and uniformity of distribution. The high values of the Uniformity Index and Similarity Index confirm that the application of the prototype mounted on the carrying bar could represent a suitable solution for the distribution of natural enemies in strawberry crops. Also the work capacities show the advantage using the machine tested as opposed to the manual distribution generally adopted for biological and integrated crops.