Juniper (Juniperus) is occasionally affected by the so-called needle blight, which is manifested by brown branches and needle drop. It can be caused by irregular watering (waterlogging or drought) or also by an infestation of the juniper leaf miner moth. The moths of this moth fly in the months of May/June. They then immediately begin to lay their eggs. The young, very small caterpillars bore into the tips of the shoots and eat out the pith from the inside. They overwinter in the browned shoot tips as a pupa. The infestation can be recognized by small holes on the shoot tips. Control is only possible during the flight season. Use a pyrethrum preparation, such as Spruzit or Parexan. The preparations are not dangerous to bees.
Browning of junipers can also occur due to damage to the roots. Pests such as voles or beetle larvae are responsible for this. Also look at the condition of the roots. To do this, carefully dig a small “peephole” next to the roots and check the root ball for pests or dry or rotten fibers. If pests such as beetle larvae have crept in, you can use plant protection sticks (available at drugstores and garden centers). These are applied directly to the root stem and reapplied several times.
The juniper may also be in the wrong location. It could be that the soil is too calcareous, such as when construction debris has been buried. Or you have limed your lawn or soil and the juniper has gotten a bit of it. In this case, apply lime only at a distance of 5 meters from the juniper.
There is also a disease called pear lattice rust. The juniper serves as an intermediate host for the dangerous fungus. The spores show up as orange-brown coatings on the juniper.
So what do you end up doing with the brown branches? Cut off the infested areas down to the old wood. Junipers can regenerate again. Only if the browning has progressed too far would we recommend replacing the woody plant.
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