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The fiddle leaf fig typically has no serious insect pests or diseases. As a houseplant, monitor for scale, aphids, mealy bugs, thrips, and spider mites. Potential diseases include bacterial or fungal diseases. Leaf scorch can occur if the plant is receiving too much direct sunlight. Brown spots may occur if there is a fluctuation in room temperatures for heating or cooling vents. Leaf drop may occur from too much or too little water.  If the roots are circling around the outside of the soil ball. Repot in a larger pot, something about 5-7 inches bigger in diameter, adding fresh potting soil. Do not bury the stem deeper than it is now. Cold air from air-conditioning can cause leaf spots. Figs prefer their leaves to be dusted and misted regularly, about once per week. Check the bottom of the leaves and the stems for any bumps or insects- if you find some please take pictures and attach them to this question. Potted fig needs light, regular fertilization.

You could also send a photo to <personal data hidden> for an opinion or to submit a sample.

Insect Pests of Houseplants | Mississippi State University Extension Service (msstate.edu)
Fig | Diseases and Pests, Description, Uses, Propagation (psu.edu)

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