From early summer onwards, some pear leaves get rusty spots. At first they are hardly noticeable, but that changes. They are getting bigger and more numerous. Ultimately, it can lead to there being hardly any pure green leaves left on the tree. What caused this?
What causes rust spots on the pear tree?
The “rust spots” are yellow-orange leaf spots caused by the disease pear rust. The fungal pathogen Gymnosporangium sabinae overwinters on junipers within a radius of 0.5 km, which makes it difficult to control. Strengthen your pear tree with pesticides so that it can survive an infestation better.
What are those rusty spots on the leaves of the pear tree?
The “rusty leaf spots” on the pear tree are not rust spots in the traditional sense. What makes the spots appear as rust spots is their yellow-orange color. In fact, these are leaf changes caused by the fungal pathogen Gymnosporangium sabinae. It belongs to the so-called rust fungi. The disease caused by this fungal pathogen is called pear rust. It begins in spring, around the beginning of flowering, and ends with leaf fall in autumn. The fungal pathogen overwinters on juniper (Juniperus).
What other symptoms occur with pear gridiron?
Yellow-reddish spots are the main feature of this disease and also the most visible symptom. Because they are placed on the upper side of the leaves, they become larger over time and appear in large numbers when there is a severe infestation. Other symptoms are present, but are somewhat obscured:
- Spore storage on the underside of leaves
- look like wart-like nodules
- when torn open they leave a grid pattern
If there is a severe infestation, fruits can also be affected:
- Pear tree loses a lot of fruit
- Development of remaining fruits is disrupted
- deformations occur
- Fruits can no longer be stored
- remain edible
Can I successfully combat pear rust?
Since the rust fungus uses two host plants, it is difficult to control it on the pear tree alone. Only if all junipers within a radius of around 500 m are removed can reinfection not occur. Such a fight is practically impossible. But don't worry, most pear trees survive minor infestations well. Additionally strengthen your tree with field horsetail broth and good fertilizer. Collect and dispose of the infected leaves.
Tip
Plant a less susceptible pear tree variety
There are no varieties that are resistant to pear rust. But 'Clapp's favorite', 'Trevoux', 'Gellerts' and some other varieties are less susceptible. Ask specifically about this when purchasing.
