Syngonium plants can drop leaves for several reasons, including overwatering, underwatering, low humidity, pest infestations, or disease. Here's a detailed guide on why your Syngonium plant is dropping leaves and how to solve it:

1. Overwatering Overwatering is one of the most common reasons why Syngonium plants drop leaves. When the roots are constantly wet, they can't absorb oxygen, and the plant will develop root rot, which can cause the leaves to yellow and drop. To solve this issue, you should water your plant less frequently, allow the soil to dry out partially between watering, and ensure that the pot has adequate drainage.

2. Underwatering Underwatering is another common reason why Syngonium plants drop leaves. When the plant doesn't get enough water, the leaves will start to curl and eventually drop. To solve this issue, you should water your plant more frequently, ensuring that the soil is moist but not waterlogged.

3. Low humidity Syngonium plants require high humidity levels to thrive. Low humidity can cause the leaves to dry out and drop. To solve this issue, you can mist your plant regularly or place a humidifier near the plant to increase the humidity level.

4. Pest infestations Pest infestations can also cause Syngonium plants to drop leaves. Spider mites, mealybugs, and scale insects are common pests that can feed on the plant's leaves, causing them to yellow and drop. To solve this issue, you can use an insecticidal soap or oil to treat the plant or manually remove the pests with a cotton swab dipped in rubbing alcohol.

5. Disease Diseases like bacterial or fungal infections can cause Syngonium plants to drop leaves. To solve this issue, you should remove the affected leaves and treat the plant with a fungicide or bactericide.

6. Environmental stress Syngonium plants can drop leaves in response to environmental stressors like extreme temperatures, drafts, or changes in light levels. To solve this issue, you should ensure that the plant is in an appropriate location with consistent temperature and lighting conditions.

In summary, Syngonium plants can drop leaves due to overwatering, underwatering, low humidity, pest infestations, disease, or environmental stress. To solve this issue, you should identify the underlying cause and take appropriate measures to rectify it. By providing your Syngonium plant with the right conditions, you can prevent leaf drop and keep it healthy and beautiful.