Pflanzenschutz im Wandel – Zwischen Europ?ischer Gesetzgebung und innovativer Forschung

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Pflanzenschutz im Wandel – Zwischen Europ?ischer Gesetzgebung und innovativer Forschung     

Eignen sich die Mauerbienen Osmia bicornis und Osmia cornuta als Best?uber im Obstbau?

Mason bees have been successfully managed as orchard pollinators in Japan and USA for many decades. Recently, the European species Osmia bicornis (L.) and Osmia cornuta (Latr.) attract more interest as pollinators in fruit orchards in Germany. Several studies indicate the potential of these mason bees as pollinators of pome and stone fruit. Here, we investigated the composition of the pollen loads in the brood cells of these two mason bees in fruit orchards different in habitat characteristics. At eight study sites, trap nests and cocoons of O. bicornis and O. cornuta were installed. During fruit tree blossom, pollen was sampled every two weeks and the percentage of Rosaceae pollen was identified. Landscape characteristics were assessed in a radius of 250 m from the trap nests. At all eight study sites, O. bicornis and O. cornuta collected pollen of Rosaceae. The percentage of Rosaceae pollen in the samples and the local habitat quality of the foraging sites were negatively correlated. In fruit orchards with a low diversity of suitable foraging habitats, brood cells contained a relatively high percentage of fruit tree pollen. These results indicate the potential of O. bicornis and O. cornuta as efficient pollinators in intensively managed fruit orchards. However, intensive fruit orchards appear less suitable as habitats for these mason bees to establish an endogenous pollinator population. Hence, the introduction and management of mason bees in orchards will improve pollination.     

Betrachtung möglicher Auswirkungen des Klimawandels auf Schadpilze im Obstbau am Beispiel von Fruchtfäuleerregern an Äpfeln

Whereas the rise in temperature during the past 30–40 years has already had clear impacts on the phenology of fruit trees and pathogenic insects, there is a lack of such correlations for fungal pathogens. An examination of fruit rots indicates that pathogenic fungi react differentially to climate change due to their complex infection biology. The appearance of the black rot fungus Diplodia seriata in Northwestern Europe is best explained by rising temperatures during the vegetation period. An increase in fruit rot caused by Nectria galligena is anticipated when milder and more humid winter months favour canker formation on twigs and branches, thereby increasing inoculum for fruit infections. An increasing importance of Neofabraea alba and Glomerella cingulata and/or G.??acutata as storage rots of apples in Northern Germany cannot be safely correlated with the climate change at present. Research on fungi is currently being expanded at the OVB Jork in order to ensure a faster identification of new pathogens and a more thorough investigation of relevant features of their infection biology.     

Vergleich von Anbausystemen beim Apfel in Abhängigkeit von Sorte und Unterlage: Schlanke Spindel und Güttinger-V-System

To the 11th leaf the influence of two planting systems on yield and fruit size of apple cultivars ‘Golden Delicious, Weinsberg’ and ‘Jonagold, Rubinstar’ grafted on the dwarfed rootstocks M 9 and P 16 was investigated. The planting systems “Slender Spindle” (3.25 × 1.25 m) and “Güttinger-V-System” (3.50 × 0.60 m) were compared. In average of both cultivars and rootstocks the “Güttinger-V-System” let to significantly higher yields than the planting system “Slender Spindle”. The difference between the planting systems amounted to 121.7 t/ha from the 3rd to the 11th leaf. In this period the annual per-hectare yield of the “Güttinger-V-System” was in average 13.5 t higher than the yield of the “Slender Spindle”. The simple fruit weight of the 3rd to the 11th leaf was affected by the planting system. For both rootstocks and cultivars the simple fruit weight of the “Slender Spindle” was significantly higher than that of the “Güttinger-V-System”. However the fruit size sorting showed for both cultivars no mentioning differences between the planting systems. To the additional yield of the “Güttinger-V-System” face additional costs for the installation of the orchard and for the formation of crown. Thus the decision for this planting system will be influenced in a high measure from the producer price.     

Einfluss von Unterlagen im Vergleich zu selbstbewurzelten Birnenbäumen auf vegetative und generative Parameter unter biologischen Anbaubedingungen in Ostösterreich

In spring 2006, in the research center of the University of Natural Resources and Life Sciences in Vienna, the pear cultivars ‘Bosc’s’, ‘Williams’ Christ’ and ‘Uta’ were planted on the rootstocks Kirchensaller Mostbirne (Seedling), Pyrodwarf, Farold 69, Quince Adams (with intercropping ‘Conference’) and own-rooted from in vitro culture, trained as spindles and tested for eight years under organic production rules. The own-rooted ‘Williams’- and ‘Bosc’s’-trees had many tree losses in the first year, they grew medium and started with fruiting later than the grafted trees. The trees on rootstock Quince Adams were growing very weakly in the high lime containing soil at the site, with the consequence of chlorosis, tree losses and small fruits, but also a higher brix-, vitamin C- and apple acid-content in the fruits. ‘Bosc’s’ showed low yields on all rootstocks in the observing period. ‘Williams’ on Farold 69 and Seedling had good yield and fruit quality, while the weakly growing cultivar ‘Uta’ showed low tree losses and high yields on Seedling. Pyrodwarf had very few tree losses and was similar in growth and yield compared to Farold 69 and Seedling, however the fruits of ‘Williams’ and ‘Bosc’s’ were smaller.     

Mechanische Fruchtbehangsregulierung bei Apfel verbessert Fruchtgröße,Fruchtfestigkeit, Fruchtausfärbung und die Source: Sink – Verhältnisse mit mehr Einzelfruchtständen (Singlets) bei ‘Gala’

The objective of the MSc project was to improve fruit quality, i.e. fruit firmness, colour and size, by mechanical blossom thinning. Ten-year-old slender spindle apple cv. ‘Gala, Mondial’ trees at Campus Klein-Altendorf near Bonn, Germany with an intense flowering of 7–8 on the 0–9 scale were blossom-thinned on 21 April 2009; unthinned trees served as control. Rotor speeds were 360 rpm or 420 rpm at 5 or 7.5 km/h tractor speed using the new mechanical thinning device developed at the University of Bonn in 2004–2006. Therein, a vertical mast supports three horizontal rotors, whose vertically rotating tines remove excessive flowers; the device was mounted on the front three point hitch of the tractor with the following results:

1. Mechanical thinning reduced the number of apple fruit from 18 per branch section in the un-thinned control, 12–13 in the medium to 8 fruit in the strongest thinning (420 rpm, 5 km/h).
2. Similarly, the number of singlets (one fruitlet/flower cluster) nearly doubled from ca. 2 per branch in the control to 3–4 after mechanical thinning, as intended.
3. The natural June drop after mechanical thinning resembled that in the un-thinned control.
4. Mechanical thinning increased fruit mass by 20 g—48 g relative to the un-thinned control.
5. Mechanical thinning with 420 rpm increased the portion of premium fruit >?70 mm (class I) by 43?% (7.5 km/h) and 63?% (5 km/h); combined mechanical and hand-thinning yielded the largest portion of fruit >?70 mm (70?%), but with a dramatic loss in yield (55?%).
6. Mechanical and manual thinning improved the portion of well coloured fruit (75–100?% coloured) (78–98?%) when compared to the un-thinned control fruits with 55?%, probably due to selective removal of shaded fruits from the inner tree canopy.
7. Overall, mechanical thinning alone gave better results than hand thinning alone or its combination with hand-thinning in cv. ‘Gala’; mechanical thinning waived the need for hand thinning in this experiment.
8. Mechanical thinning improved fruit firmness from 9.4 kg/cm² in the un-thinned control to 10.4 kg/cm².
9. Neither vegetative growth nor subsequent fruit drop were stimulated by this type of mechanical thinning.
10. The risk of both alternate bearing and over-sized fruit was waived due to the variety employed.
11. An economic evaluation showed a net profit of € 220/ha in the weak (420 rpm—7.5 km/h) aνô € 1,844/ha in the intermediate (360 rpm—5 km/h), but a net loss of € 1,120/ha (420 rpm—5 km/h) for the strongest thinning treatment, assuming a cost of € 120/ha for the mechanical treatment and a saving of € 200 for reduced hand thinning.

Overall, the positive results of a better fruit quality (size, colour and firmness) offer the potential of mechanical blossom thinning in cv. ‘Gala’, which is difficult to blossom-thin chemically.