Conference pears; work on system changes to enable better scab control in organic orchards in the Netherlands

Scab control in Conference pears is the bottleneck in organic growing. A group of growers, advisers and researchers in the Netherlands is working on new approaches to organic pear growing. Central to this approach is a reliable and good scab control. Changes in the system of cultivation are sought which will enable this scab control with less fungicide. This has become even more urgent since copper was banned as a fungicide in the Netherlands. First results from trials on vigour control show that there is potency for system changes that will enable a better scab control in organic growing. Scab incidence was reduced in three trials with 34, 58 and 82% respectively. The project, in which also other cultivation measures are being tested, will be continued

Fruit quality of Elstar en Santana in the Netherlands

The growth of the market for Dutch organic apples is disappointing. Especially the large-scale introduction in the supermarket channel is not happening as fast as many hoped. One of the explanations given is that there is a gap between the quality as produced and the quality as expected by the retailers. In a three year project the Louis Bolk Institute together with many other partners in the sector have tried to facilitate talks on apple quality between actual partners in the different chains from producer till retailer. During this period we monitored the quality of Elstar and Santana on many farms and on the shelf in the different outlets. This has given us detailed information about the current quality of Dutch organic apples. Presented here are some preliminary results of the monitoring at the farms. The project will end mid 2004, final results will be published by the end of the year. Progress of the project can be followed through the website www. louisbolk. nl/projects/fruit/’classy apples’

Disease management in organic apple orchards is more than applying the right product at the correct time

The relative importance of diseases on apple is varying with cultivar, management, time, and climate. Many aspects of the cropping system influence the development of diseases. The choice of the variety determines the disease management during the lifetime of the orchard. Cultural practices improve the growth and nutrial status of the tree, and therewith influence the susceptibility of the plant and fruits to diseases directly. Prolonged growth can also have an indirect effect by causing a microclimate and growing pattern that favours infection of tree, leafs and fruits by various diseases. Sanitation measures are common practise for most organic fruit growers and help to make other measures more effective by reducing infection inoculums. Despite all preventive measures, disease control in organic orchards at an economically feasible level still largely depends on the application of fungicides. Measures that allow reduction of fungicidal applications on key diseases, lead to the development of a secondary disease complex that can cause severe losses when not managed effectively and make a well thought-out control strategy necessary. In research, advisory and practical decision making, disease management in organic orchards should always be seen in the perspective of the management of the total growing system. With all factors that contribute to disease management in organic orchards optimized, we are able to successfully implement new materials and methods that may not be as effective as common fungicides in themselves, but add to the effectiveness of the disease management system as a whole. This total system approach makes organic fruit growing what it is

Undergrowth of late summer sowings at the tree strip

The tree strip strategy of a 'late summer cover crop' is evaluated regarding a number of aims: soil improvement, frost control, weed control, growth regulation and regulation of nitrogen availability

Calcium uptake and Fruit Quality Improving calcium uptake in an 'organic' way

Die positive Korrelation zwischen einem hohen Kalziumgehalt in den Früchten und guter Qualität wird von der Literatur zusammengefasst. Die traditionellen Kalziumspritzungen sind nicht ideal (Synthetische Ursprung, Schalenberostung, Sonnebrand). Wir forschen nach Möglichkeiten für Obstbauern weniger abhängig zu sein von Kalziumchlorid und doch qualitatives Obst zu bekommen. Bei unserer Beurteilung der Kulturmaßnahmen in Bio Obstbau ist der Kalziumgehalt der Früchte eines der Kriterien. Positiv in diesem Rahmen haben sich gezeigt: ein lebendiger Boden, Begrünung, besonders Klee, Begrenzung des Wuchsniveaus, gute Qualität Rosettenblätter, Früchte an der Basis des Triebes und Früchte mit viele Samen

Scab prevention: reduction of ascospores through increased decomposition of fallen leaves (BIOFRUITNET Video)

In this video, Gerjan Brouwer, advisor at Delphy and organic fruit grower Pieter Jans Jansonius present complementary approaches on how to enhance leaf degradation during winter

Slaked lime against european fruit tree canker: efficacy and introduction into practice

European fruit tree canker, caused by Nectria galligena, is a major disease in organic apple cultivation. No copper can be used in Denmark and the Netherlands to control the disease. Removal of cankers is the only remaining method to control the disease. Slaked lime (calcium hydroxide) was applied at 50 or 100 kg/ha three times during the leaf fall period to protect apple trees against the disease. Experiments under high inoculum pressure showed a reduction in newly formed cankers of 57, 35 and 60 % with respect to untreated for 3 years respectively. The chemical standard thiophanate-methyl further reduced the number of newly formed cankers by 99, 60 and 89 % with respect to untreated for these 3 years respectively in these experiments. These results showed that slaked lime was less efficacious than the chemical standard under these high inoculum pressure circumstances. Demonstration experiments showed an efficacy of 70 and 68 % for slaked lime and 62 and 62 % for the conventional standard (carbendazim and captan) with respect to untreated controls in 2 years respectively. The demonstration experiments, done in commercial orchards and under normal inoculum pressure, showed a similar efficacy as the conventional standard. It is concluded that the use of slaked lime to control European fruit tree canker can contribute to a more economic organic apple and pear production in temperate climate zones