Q.My 2 Y/o Meyer Lemon Tree Is Covered With A Sticky Substance. Is This A Disease & What Can I Use To Treat It?
The entire plant has branches that are bumpy & very sticky. Some branches are brown & look dead further out on the branch. But on the same branch closer to the trunk it is green. The lemon on the tree is also very sticky and even the pot it is planted in is sticky.

Certified GKH Gardening Expert
Unfortunately your photos did not come through.
It is a symptom of a problem. Actually, it is pretty much the defense mechanism to all problems that can affect citrus.
In order to know where to begin treatment, you must first find out what is causing sap. There are many pests and problems that can cause damage to citrus trees, so without detailed photos there will be no way to tell what is causing the damage.
If it happens to be something like spider mites or scale, then treatment will need to be done quickly.
If it is an aphid infestation, then it can be treated pretty easily.
If it is fungal or bacterial, then you may have a battle ahead. These types of infections can be caused by overwatering, or by pests sucking sap, making them among the most common problems.
Here are some articles that will help in the meantime:
https://www.gardeningknowhow.com/special/organic/what-are-organic-pesticides.htm
https://www.gardeningknowhow.com/garden-how-to/info/using-fungicides-in-garden.htm
https://www.gardeningknowhow.com/garden-how-to/info/applying-bactericide-to-plants.htm