Der GARDENA Gartenexperte
Dear Mr. G., by the time the pear tree drops its infested leaves, the fungi has mainly already distributed its spores. However, it is still expedient to collect all these leaves and dispose of them. If you conduct reliable thermal rotting in your compost, then you can add the leaves to it. If not, it is better to go to municipal green waste plant.
Then you will have done all you can do during the autumn. In winter, you then have time to search your juniper plant for gelatinous infestation on the branches. That is the same fungi, but it acts as an intermediate host on your juniper berry. It then distributes its pores in March/April and attacks the pear tree leaves, becoming visible in early May in the form of orange-red pustules. Cut back infested juniper plants to the healthy wood.
With regard to this, it is repeatedly recommended to ban juniper plants from the garden completely. Of course it is possible to do this as a preventative action, but the spores distribute themselves so widely that it will hardly have a substantial effect. However, cutting back or, if applicable, clearance is perfectly suitable as a method of containment.
The only other thing you can do is to spray the tree, leaves, bark and surroundings at the start of the infection time period as a preventative measure. You have already mentioned the Neudorff preparation; other possibilities are the Compo Duaxo Universal Pilz-frei fungicide and preparations suitable for combatting scab, such as the Pilzfrei Ectivo. In order to achieve lasting success with such spraying measures, you must change the active ingredient each time you spray (see packaging) – otherwise the fungi may become resistant to the effects.
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