Determination of the tree row volume in stone-fruit orchards as a tool for adapting the spray dosage

The tree row volume model is a method for adapting dosage and spray volumes to tree crops. The method can potentially facilitate the comparison of field efficacy trials and can contribute to fanners’effective and rational use of plant protection products. It has been developed and applied in pome fruit but not yet in stone fruit. Stone-fruit orchards vary considerably in tree size, tree shape and distance between tree rows. Based on 700 detailed measurements of stone-fruit trees in south-eastern France, in southern Germany and in Switzerland, a multiple linear regression was computed that allows the calculation of tree row volume from the height and maximum width of the tree crown, and the distance between tree rows. Seasonal increases of tree row volumes in stone-fruit orchards were most pronounced in May and June, and the increase was usually greater in young orchards than in older ones.