Leaf by Leaf: An improved method of describing apple scab infections in field trials using MS Excel

An improved method for the evaluation of Venturia inaequalis infections of apple trees in field trials is proposed. The method takes into account the position of infected leaves on long shoots. A MS Excel worksheet was developed to facilitate the processing of these data. This can be downloaded at http://www.oeon.de/downloads/venturia.zip. We use this worksheet in our field trials and also for our consultancy service to compare different onfarm control strategies

Regulation of Cydia pomonella in the Northern German climate

Population control of the codling moth (Cydia pomonella) is of great importance in ecological fruit-growing. In the work described here we attempted (1) to determine the efficacy of plant protection preparations certified for organic fruit production, and (2) to develop a suitable application strategy. We found that a Granulovirus (Madex3), Bacillus thuringiensis (Xentari) and Neem Azal were able to provide effective control of C. pomonella. The reduced efficacy of Madex 3 as reported e.g. from some Southern German orchards could not be observed in our trials

Economics of Hot Water Dipping

Hot water dipping is an appropriate method to protect apples against spoilage caused by gloeosporium rot. Tests on the varieties Topaz and Ingrid Marie at the OVB Jork (Germany) have demonstrated an effective reduction of spoilage from between 80% and 92% in charges by an infection rate of 40%. The result of an intensive R&D process between 2002 and 2003 is the development of a praxis-tested big box (300 kg) dipping station. With the first Bio Dipping systems now on the market it has now been possible to analyse the economics of this process. The costs of the systems per apple farm have been calculated from the fixed capital costs for the system itself (including maintenance costs) and from the variable costs based on an average crop of 250 t gloeosporium-sensitive varieties, which would be treated with this process every season. The Return on Investment depends largely on the effectiveness of the process in reducing spoilage and on the level of infection within the crop, assuming that losses occur in storage. Based on an average effectivity of 85% and an infection rate of 10% it has been possible to calculate an amortisation within eight years. Higher levels of infection and a consistent effectivity of 85% shorten this time span significantly. The attractions of the hot water dipping process are in the opinion of the research team at the OVB Jork not merely economically convincing in terms of ROI. By reducing the levels of spoilage throughout the entire supply chain, it is for the first time possible to make a significant development in the sustainable quality management of organic apples, providing clear benefits for both consumer, trade and the grower

Efficacy of Quassia extract on the apple sawfly Hoplocampa testudinea Klug

The efficacy of Quassia extract with a standardized content of Quassin was proved in various field trials in different regions during three years. The amount of Quassin of 6 g/ha/m tree height will be recommended to practice. It is not important to have a contact effect on the eggs. The larvae must feed on the product before they enter the fruit. There is a very good efficacy on primaray infestation. Furthermore, there is even an efficacy on secondary infestation. Thus, even if due to difficult conditions during application or not optimal termination of the treatment the efficacy on the primary infestation is not entirely sufficient, the secondary infestation will be controlled better

Control of the apple sawfly Hoplocampa testudinea Klug in organic fruit growing

The best application technique and application data for the treatments with Quassia extract against the apple sawfly Hoplocampa testudinea Klug were tested. The spraying solution was distributed best on the receptacle of the blossom – the place where the sawfly larvae feed before the enter the blossom – when the treatment was effecttuated at fading blossom with a high amount of water (about 500 l/ha/mTh). The addition of T/S forte, a wetting agent, could also improve the efficacy of Quassia treatments in a lower dose. Thus, it is recommended to apply in fading blossom with addi-tion of T/S forte and high amounts of water to obtain the best effect. If the conditions for applica-tions are good and the infestation is not too high, the normally recommended dose of 6 g/ha/mTh can even be reduced

Wirkung von Quassiaextrakt auf die Apfelsägewespe Hoplocampa testudinea Klug

The efficacy of Quassia extract with a standardized content of Quassin was proved in various field trials in different regions during three years. The amount of Quassin of 6 g/ha/m tree height will be recommended to practice. It is not important to have a contact effect on the eggs. The larvae must feed on the product before they enter the fruit. There is a very good efficacy on primaray infestation. Furthermore, there is even an effi-cacy on secondary infestation. Thus, even if due to difficult conditions during application or not optimal ter-mination of the treatment the efficacy on the primary infestation is not entirely sufficient, the secondary in-festation will be controlled better

Control of the apple sawfly Hoplocampa testudinea Klug in organic fruit growing and possible side effects of control strategies on Aphelinus mali Haldeman and other beneficial insects

The effect of Quassia extract on eggs and larvae of the apple sawfly Hoplocampa testudinea was studied. The efficacy of this extract is mainly due to an oral toxicity to the neonate sawfly larvae. The main active ingredients, Quassin and Neoquassin, were tested separately. Wheras Quassin has a considerable efficacy also on older larvae, Neoquassin is less efficient in this case. While Quassin and Neoquassin are found in different Quassia sources in varying relations to each other and have different efficacy, they have to be considered separately in the definition of extract quality by the content of active ingredients. These findings mean, that the “egg maturity” is not important for application date. Nevertheless, the application must take place before the larvae hatch. It was shown that low rates of Quassin (4-6 g/ha) can show very good results in the field, in other cases the rates necessary for good efficacy are much higher. This corresponds to farmers experience. Several factors as application technique and the condition of the blossom must be taken in consideration and will be object of further studies. The side effects of Quassin, Neoquassin and Quassia extract on Aphelinus mali and other beneficial arthropods were tested. Quassia is harmless to all organisms tested

Untersuchungen und Prozessbegleitung zur Praxiseinführung von Heißwassertauchanlagen im ökologischen Kernobstanbau

In general, organic grown apples (Malus x domestica Borkh.) are not treated with chemical fungicides to prevent storage decay and these fruits may suffer up to 30% decay during storage. Preliminary experiments had shown that hot water dipping of apples may be an alternative. To inhibit Gloeosporium rot (Pezicula alba, P. malicortis) water temperature may be of about 50°C and dipping time from 60 sec up to 180 sec. The present investigation was conducted to test different ranges of temperatures and dipping time periods in different apple cultivars over a three year investigation. The objective was to determinate the suitable hot water treatment that prevents decay incidence and maintains fruit quality (firmness, scale symptoms). For the reduction of post harvest decay the treatment 53°C and 180 sec is recommended; that was found suitable for `Topaz`. For cultivars with a sensitivity to skin disorders dips for 120 sec or 180 sec are recommended; that was found best for ´Elstar´(51°C), ´Ingrid Marie` (49°C), ´Holsteiner Cox´(51°C) und ´Boskoop´(51°C). A big box dipping machine was invented in northern Germany to improve the situation on the farms. The parameters we found in the trails were used as standards on the developing side. Today’s ma-chine runs with a precision temperature range of one K inside the box

Arbeitsnetz zur Weiterentwicklung der Anbaukonzepte im Ökologischen Obstbau

Im Rahmen des Projektes ist eine Schwachstellenanalyse der Anbaukonzepte des ökologischen Obstbaus gefolgt von einer Erarbeitung von kurz- und langfristig umsetzbaren fundierten und praxisnahen Strategieansätzen zur Optimierung dieser Konzepte in enger Vernetzung von Praxisbetrieben, Beratung, angewandter Forschung und Grundlagenforschung sowie fachspezifischer Experten erfolgt. Das bundesweite Diskussionsforum aus Praktikern, Berater und Forschern, das zur laufenden Weiterentwicklung der Anbaumethoden geschaffen wurde, ist inzwischen eingespielt, arbeitet effizient und richtungsweisend. Dadurch werden laufenden Arbeiten zu verschiedenen Fragen optimal begleitet. Neu auftretende Fragen können rasch aufgegriffen und bearbeitet werden. Diese Form der Weiterentwicklung entspricht der ursprünglichen Struktur, die den Ökologischen Landbau hervorgebracht hat. Für die wichtigsten ungelösten Problembereiche (Apfelwickler, Schorf, Regenflecken, Feuerbrand) konnten sehr effizient aus der Praxis heraus Strategien für Lösungsansätze erarbeitet und in Form von Projekten umgesetzt werden. Stein- und Beerenobst waren vor Beginn des Arbeitsnetzes stark vernachlässigte Bereiche. Durch die Aktivitäten im Arbeitsnetz wurden hier erstmals Schwachstellen erkannt und Handlungsbedarf formuliert. Aus dieser Arbeit sind Projektanträge sowohl im Stein- als auch im Beerenobst hervorgegangen, die die ermittelten Schwachstellen bearbeiten und in Zusammenarbeit mit der Praxis umsetzen sollen. In beiden Kulturen haben sich außerdem Aktivitäten etabliert, die in Zusammenarbeit mit den Versuchsanstalten und Züchtern eine Prüfung neuer Sorten unter ökologischen Anbaubedingungen in den Betrieben ermöglichen sollen. Für Kernobst wurde im Jahr 2005 ein Sorteninformationsnetz gegründet. Strategieansätze wurden aber nicht nur für eine Optimierung der Wirtschaftlichkeit sondern auch der Nachhaltigkeit der Anbaukonzepte erarbeitet. So wurden erste Konzepte für eine ökologische Aufwertung von Obstanlagen angedacht, die derzeit in einigen Praxisbetrieben getestet werden. Durch die Diskussion der Strategieansätze der einzelnen AKs im Rahmen der jährlichen Veranstaltung mit den Praktikern ergibt sich die Möglichkeit zur interdisziplinären Verknüpfung einzelner Projektergebnisse zu einem praxistauglichen Gesamtkonzept. Die Arbeit im Arbeitsnetz hat daher entscheidend dazu beigetragen, den ökologischen Obstbau sicherer, wirtschaftlicher und nachhaltiger zu gestalten

Regulierung der Apfelsägewespe im Ökologischen Obstbau und Nebenwirkungen der Strategien auf die Blutlauszehrwespe

The effects of Quassia extract on eggs and larvae of the apple sawfly Hoplocampa testudinea were studied in the laboratory. The efficacy of this extract was mainly due to an oral toxicity to neonate sawfly larvae. The main active ingredients, Quassin and Neoquassin, were tested sepa-rately as pure substances. While Quassin had a considerable efficacy also on older larvae, Neo-quassin was less efficient in this case. Since Quassin and Neoquassin were found in different Quassia sources in varying relations to each other and had different efficacy, they have to be considered separately in the definition of extract quality by the content of active ingredients. This requires the application of Quassia extracts before larval hatch. It was shown that low concentra-tions of Quassin (4-6 g/ha) can achieve very good control in the field, in other cases the concentra-tions for good efficacy are much higher. These varying results seem to be connected with applica-tion technique and application date. Trials in 2004 showed that the best way of application is with plenty of water (500 to 1000 l/ha) and the best date is during the stage when blossom is fading. The side effects of Quassin, Neoquassin and Quassia extract on Aphelinus mali and other benefi-cial arthropods were tested. Quassia is harmless to all organisms tested