Italy: Replant diseases a focus at Interpoma
The first speakers were Robert Wiedmer, from the Alto Adige Consultancy Service for Fruit and Wine Growing, and Martin Thalheimer, from the Laimburg Research Centre for Agriculture and Forestry. They illustrated practical experiences and the results of tests carried out on land hit by fruit growing replant diseases in Alto Adige.
The speakers described the problem of exhaustion of cultivated land and then illustrated how the influence of tired soil on the growth of plants varies significantly from one area to another and often even in different areas of the same orchard.
Overall the tests carried out have revealed that chemical treatments of the soil have a significant affect on all the areas treated in this way; alternative measures on the other hand have resulted effective only in specific circumstances.
The second speaker, Luisa Manici from the Agricultural Research Council (CRA/CIN) of Bologna, presented the results of tests on soil fungal communities as indicator of soil health in fruit orchards.
Rot complex caused by fungi is in fact the main biotic cause of the decline in yield that has characterised the European intensive cultivation systems. To back this Luisa Manici also illustrated that the average growth increase of plants on disinfected soils compared to replant soils is 42% as shown by the recent biological essay on 9 different apple orchards.
Root response to crop residues was the topic of the speech by Davide Neri from the Università Politecnica delle Marche, Ancona, while Mark Mazzola, from Washington State University, Wenatchee (USA) illustrated some biologically-based strategies for the management of apple replant disease; the latter explained that non-fumigant measures for replant disease control are based on the knowledge of the process and that the level of efficiency and persistence of the biologic effects may depend on the rootstock.
Gerhard Baab, from the DLR Kompetenzzentrum Gartenbau, Kleinaltendorf (D) described some experiences with replant diseases in apple orchards in Germany, and added that there are different causes, many of which have not yet been fully understood. According to Gerhard Baab, who illustrated some examples of treatments with organic products, dead roots and their residues probably cause an accumulation of bacteria and fungi that attack new roots.
Terence Robinson from the Cornell University, Geneva (USA), illustrated some examples of rootstock resistant to replant disease, such as fire blight. Robinson explained that the keys to the success of new apple orchard systems are the high density (about three thousand trees per hectare) and the high yield equal to about 150 tons per hectare in the first five years.
In addition to the above these systems offer rapid growth of the plants, high yield of mature trees (over 60 tons per hectare) and high quality fruit.
Finally, Walter Rass from the Alto Adige Consultancy Service for Fruit and Wine Growing, presented the prototype of a new machine for exchanging soil in the planting row which – despite its cost which is still too high – has given satisfying results.
For more information:
Francesco Reggiani and Giorgia Marchetti
International press office of Interpoma c/o Fruitecom
Tel: +39-059-7863894
www.interpoma.it