1. The temperature is too low: the money-sucking tree is not cold-tolerant. If the curing temperature is too low, the leaves will turn black and fall off when touched. It is suggested to cut off the blackened leaves, move them indoors for maintenance in time, adjust the indoor temperature, and properly contact with the sun can promote the recovery.
2. Soil discomfort: wealth-absorbing trees are suitable for growing in fertile and breathable acid soil. If the soil is uncomfortable, it will cause the leaves to turn black and fall off at the touch. It is suggested to change the soil in time and use soft, breathable and slightly acidic soil for maintenance.
3. Insufficient light: the wealth-absorbing trees need to receive sufficient light to grow normally. If the light is insufficient, the leaves will turn black and fall off when touched. It is suggested that the wealth-absorbing trees should be maintained in sunny places, but direct sunlight should be avoided to avoid burning the leaves.
4. Infected with pests and diseases: If the money-sucking tree is infected with pests and diseases, it will also cause the leaves to turn black and fall off when touched. It is suggested to check whether plants are infected with pests and diseases in time and take corresponding control measures, such as spraying pesticides and fungicides.
5. Root damage: the root system of the wealth-absorbing tree is relatively fragile. If you water too much or fertilize too thick, it will damage the root system and cause the black leaves to fall off as soon as they touch. It is suggested to control the amount of watering and fertilization to avoid excessive watering or fertilization.
According to the information you provided, I can't determine the specific reason. I suggest you investigate one by one according to the above reasons and take corresponding measures to prevent and control them. If the problem is serious or cannot be solved by itself, please contact a professional botanist or horticulturist for consultation and treatment.