Although the pear rust does not significantly damage the juniper, the fungal spores should be prevented from spreading. The disease can weaken pear trees and result in a smaller harvest. In addition to chemical control, there are alternatives to control and preventive measures.
A generous pruning is often sufficient for pear lattice rust on the juniper
Chemical control
There are few fungicides that can be used specifically against pear rust. They must be used early to prevent further spread of the spores. An injection is only successful if it is carried out as soon as typical symptoms appear. Subsequent applications are useless as the fungus survives in the wood and is not damaged. Scab remedies can also be used to combat the disease.
Alternate Methods
Since the rust fungi are very host-specific, an infection between juniper and pear trees is not always inevitable. Before proceeding to the drastic measure of clearing, you should find out if the rust fungus can actually infect an orchard in the area. If this is not the case, a generous removal of the branches is usually sufficient. However, this measure does not ensure that the fungus has been completely removed. It often sits very deep in the wood.
prevention
To prevent the fungal spores from spreading, the life cycle must be interrupted. This is only possible if the two host plants do not grow in close proximity to each other. The spurs can easily cover distances of 500 meters. To be on the safe side, no juniper should be planted within a kilometer of a pear tree.
Alternatively, you can use robust varieties. The rust fungus colonizes the wood of Pfitzer's juniper, Chinese juniper and the sallow tree. The fungus can survive in the wood of these species for years and develop new fruiting bodies every spring, which form masses of spores.
These species are not attacked:
- Common juniper (Juniperus communis)
- Creeping juniper (Juniperus horizontalis)
- Scale juniper (Juniperus squamata)
plant strengthening
Regular use of horsetail and nettle extracts have proven to be effective measures to prevent infestation. The solution is sprayed weekly over the entire plant. The contained silicic acid strengthens the plants and makes them more robust against infestation by pear rust.