The main reason is the spores getting into the apartment and the weakened immunity of the flowers themselves. What can aggravate the development of rust?
1. Lack of drainage. Without a proper drainage system, water stagnates in the soil, oxygen and nutrients are poorly supplied. Thus, the ideal fungus environment develops.
2. Lack of sun. Rust loves to appear in dark environments, so a small amount of sunlight contributes to its reproduction.
3. Ignorance of diseases. If your flower has already suffered from an infection, and you ignored the affected parts, then the rust will attack them much faster.
4. Pests. Needless to say :)
5. Nitrogen fertilizing. If you overfeed your plant with nitrogen, this will help fungus to spread.
6. Overmoistening of the soil. Any fungi loves moisture and rusty ones are no exception. Excess moisture can happen due to frequent watering or poor drainage.
7. Potassium deficiency. Potassium stimulates photosynthesis and metabolism. If there is not enough, these processes are disrupted. Therefore, the plant develops higher exposure to diseases.
8. Non-compliance with the rest regime. In winter, most plants go into a dormant state, they do not need frequent watering and mineral fertilizing. If you do not observe the rest conditions for a plant, fill the flower with water and dressings, while putting it on the battery, you should not be surprised at the appearance of rust.