Syngonium plants are generally easy to care for and relatively pest and disease-resistant. However, like all plants, they can still fall victim to various pests and diseases. Here's a detailed guide on common Syngonium diseases and pests to look out for:

1. Spider mites Spider mites are tiny pests that suck sap from the leaves of Syngonium plants, causing them to yellow and eventually fall off. They can be identified by the fine webbing they leave behind. To prevent and treat spider mites, keep the humidity high and mist the leaves regularly. You can also use a miticide to kill the pests.

2. Mealybugs Mealybugs are another common pest that can infest Syngonium plants. They look like white, cottony masses and feed on the plant's sap, causing stunted growth and leaf drop. To prevent and treat mealybugs, remove the affected parts of the plant and use a horticultural oil or insecticidal soap to kill the pests.

3. Scale insects Scale insects are small, hard-shelled pests that attach themselves to the plant's leaves and stems, feeding on sap and causing yellowing and leaf drop. To prevent and treat scale insects, use a horticultural oil or insecticidal soap to kill the pests.

4. Root rot Root rot is a common disease that affects Syngonium plants that are overwatered or planted in soil that doesn't drain well. It causes the roots to rot, and the leaves to turn yellow and fall off. To prevent and treat root rot, ensure that the soil has adequate drainage and don't overwater the plant. You can also repot the plant in fresh, well-draining soil.

5. Leaf spot Leaf spot is a fungal disease that causes circular, brown spots on the plant's leaves. It's caused by high humidity and poor air circulation. To prevent and treat leaf spot, increase air circulation around the plant, reduce humidity, and remove the affected leaves. You can also use a fungicide to treat the disease.

6. Bacterial blight Bacterial blight is a bacterial disease that causes brown, water-soaked spots on the plant's leaves, eventually causing them to turn yellow and fall off. It's caused by overwatering and poor sanitation. To prevent and treat bacterial blight, ensure that the soil has adequate drainage, don't overwater the plant, and remove the affected leaves. You can also use a bactericide to treat the disease.

In summary, Syngonium plants can fall victim to various pests and diseases, including spider mites, mealybugs, scale insects, root rot, leaf spot, and bacterial blight. By identifying the signs of these pests and diseases early and taking appropriate measures to prevent and treat them, you can keep your Syngonium plants healthy and beautiful.