Is this plum tree sick?

[Crell]

Hi folks. I have a plum tree, not sure what specific variety as it came with the house. It's fruited every 2-3 years for the last several quite nicely, but this year I am finding signs that it may be sick. I am not sure what I'm seeing.

First, some of the plums look like this:

Some have looked like that every year; I've figured it was some fungus or something and just avoided those.

However, this year I am also seeing these odd growths all over the tree, on various branches. Sometimes they have white stuff on them, sometimes not.

This is new this year. It looks almost like animal droppings of some kind, but it's wrapped around the branches like it's a growth on the branch itself. I have no idea what it is.

So, questions:

1) What is causing either of these?
2) How concerned should I be about them, and should I do anything about them?
3) Does it pose any safety concerns for the plums I harvested this year?

Many thanks. I am hoping it's not a fatal problem for the tree.

[told2b]

Search for treatment for Black Knot Tree Diseases

[JONA]

The first picture is a simple case of botrytis following a damaged fruit...wasp bite..etc.
The second though ..,as told2b has said...is probably Black knot.
Trim off the knots that you find ..cutting back to clean wood and sprays of Neem oil will help to keep infections at bay.
Winter oil sprays may help...though they can be a two edged sword as they remove so many ‘ goodies ‘ as spores of disease.
Keep the leaf fall and prunings clear and burn if possible as the spores will over winter in the soil if left..

[Crell]

Hm. From what I'm seeing searching for it, yeah, it looks like Black Knot. Eew.

Some of the deposits are rather low on branches. Does the whole branch need to be removed or can it just be scraped off? I fear losing an awful lot of the tree this way...

Does it infect the fruit at all, or are those safe?

[Crell]

Also, most of the sites I'm finding say to trim branches in early spring. Should I wait until next March to do anything about it, or wait a week until I have more time, or is it imperative at this point to start aggressively cutting now? It's fairly extensive on smaller branches at this point, but so far I haven't seen it on the main trunks.

[JONA]

Any pruning on plums is best carried out while the tree is in full growing mode. This is so that the tree actually weeps sap at the cut site. This is a gooy sticky resin like substance that helps keep the spores of diseases from entering the wound area.
So trimming is fine from now up to once the leaves start to drop.
On branches affected well down their length I would try and cut the growth out ...cutting back to clean wood. Make sure though that you don’t encircle the branch and stop sap flow completely.