I moved this ficus tree from indoors to my backyard and now it's leaves are infested with something and there's no new growth.

Adding 3 images of complete plant, front of the leaves and back of leaves.

What do I need to do to save it?

Thanks for your suggestions.

Your Weeping Fig (Ficus benjamina) appears to be infected with scale insects; completely soaking the leaves (both top and reverse side) and stems with an insecticidal soap should eradicate them; it may take more than one soaking.

Hi & welcome!

Agree.

The yellowing looks like chlorosis, which can be caused by a number of things like PH out of acceptable range, nutrient deficiency, cold temps, and not enough oxygen in soil when it is moist (AKA overwatering,) and others.

I would suggest adding alcohol to the soapy water to help penetrate the hard outer shell of the scale insects and spray thoroughly as Lin described.

As Tiffany points out, your Ficus is under stress for other reasons and that also need to be corrected. The yellow leaves are a generic symptom of improper watering (too much or too little) and a change in light. If you keep it outside, it may be very potbound. If you recently moved it from inside to outside, the leaves may be adapting to the change in light intensity.

Ficus do not like being moved. I think even mentioning the prospect might cause the Ficus to drop leaves. Gene