I received your envelope of plant parts with all their various ailments. It is hard to be sure but what I think is that you have several problems.
1. You may be overwatering. Cut back on water until the plant is dry to the touch on the surface of the soil. Overwatering can cause your Christmas cactus to go limp, drop leave and get rust spots on the leaves. Christmas Cactus like to get fairly dry. Another sign of water issues is crinkly leaves – this will turn up both from overwatering or underwatering. Over watering will also cause brown tips and brown spots on plant leaves.
2. You may have aphids or some other sucking insects on the Pepperomia (?) plant and they are causing a sooty mold to grow in the leaves.
3. It looks like the mealy bugs may have spread to your rubber tree plant.
I would advise spraying all plants with neem oil, both top and bottom of the leaves and in leaf and stem nooks and crannies. Very badly infest plants should just discarded. Neem will work on the mold and the insect causing it.
Carefully clean the areas where infected plants have resided. Wash any containers from discarded plants with bleach and water. Neem may also get rid of the mealies – just remember to keep spraying every few days to catch new hatchlings mealy bugs are very hard to get rid of and sometimes it is better just to get rid of the plant.
When it comes to water, here are some thoughts:
Fill the watering container and leave it a room temperature.
Water only when the plant s dry and be sure all water is removed from the tray under the plant when it has finished draining.
Let the water run through if you can. Then don’t water again until the soil is dry to a half inch.
At this time of year most plants are resting and require less water than they did during the spring or summer when they are actively growing so don’t fret if they take a couple of weeks to dry out. Small plant containers need water more often that larger plants.
I hope this is helpful to you, Chris.
Very best of luck to you,
Got this beautiful shot in the morning from my window feeder. They are really filling up before their flight south.Linda and Rudy Rosenthal. Dufresne, MB.