I have a Ficus Benjamina which has always been indoors and receives a good amount of light (southern exposure). For several months it has been dropping leaves.
Many of the leaves look as though they have dust on them. The underside of the leaves have what appears to be dots of dust – some also have white dots stuck to the leaves. Many leaves are beginning to go brown while still on the branches and then drop off and others drop off while still green.
Any suggestions on what to do to turn around this situation would be appreciated.
It sounds like your Ficus benjamina has been infested with scale, which appear as small flattened round lumps on the leaf surface. These insect pests are common on indoor plants which have become stressed. If you haven’t changed the plants environment recently (light conditions, temperature, watering routine) then it may be root bound, causing the plant distress. Repot your tree in a larger pot with a good quality indoor plant potting mixture, if you think your tree has outgrown its pot.
To remove the scale, gently wipe the leaf surface with gloved hands or a soft cloth. They come off quite easily. It is a labour of love, but kinder than harsh chemical pest sprays. You could also try an insecticidal soap. Spray on plants, misting both sides of the leaves and stems. The soap dehydrates any residual adult scale, and their eggs, and they die.
Remove any dead leaves or branches and discard into the garbage. Disinfect any tools that you use, to prevent cross infection of your other houseplants. Check that your Ficus pot isn’t being exposed to cold draughts or temperature extremes. Overnight lows should be no less than 10 degrees celsius. While you are nursing your Ficus back to health, keep it away from other plants until you have the scale under control. If the scale return, repeat this process as necessary. If your plant is well nourished and happy in its location it will be less susceptible to future infestations.
Have a look at this site to see if these images look like your pest problem. https://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/insects/scale/scale-indoors.aspx