Oedema. Oedema Oedema is a physiological disorder that can affect all plants. It occurs when the plant takes up more water than it can rid itself of via the process of transpiration. The word itself means 'swelling', which is usually the first symptom, and comes in the form of pale blisters or water-filled bumps on foliage. Under a variety of circumstances/cultural conditions, a plant's internal water pressure (turgidity) can become so high that some leaf cells rupture and leak their contents into inter-cellular spaces in leaf tissue, creating wet or weepy areas. Symptoms vary by plant, but as the malady progresses, areas of the leaf turn yellow, brown, brown with reddish overtones or even black, with older damage appearing as corky/ scaly/ ridged patches, or wart/gall-like bumpy growth. Symptoms are seen more frequently in plants that are fleshy, are usually more pronounced on the underside of leaves, and older/lower leaves are more likely to be affected than younger/upper leaves. Oedema is most common in houseplants during the winter/early spring months, is driven primarily by excessive water retention in the soil, and can be intensified via several additional cultural influences. Cool temperatures, high humidity levels, low light conditions, or partial defoliation can individually or collectively act to intensify the problem, as can anything else that slows transpiration. Nutritional deficiencies of Ca and Mg are also known contributors to the malady. Some things that can help you prevent oedema: * Increase light levels and temperature * Monitor water needs carefully – avoid over-watering. I'd heartily recommend a soil with drainage so sharp (fast) that when you to water to beyond the saturation point you needn't worry about prolonged periods of soil saturation wrecking root health/function. Your soil choice should be a key that unlocks the solutions to many potential problems. * Avoid misting or getting water on foliage. It slows transpiration and increases turgidity. * Water as soon as you get up in the AM. When stomata close in preparation for the dark cycle, turgidity builds. If you water early in the day, it gives the plant an opportunity to remove (for its own needs) some of the excess water in the soil. * Put a fan in the room or otherwise increase air flow/circulation. Avoid over-crowding your plants. Al

What's the bulb's wattage, and is it soft white or bright white? Most plants need a brightness of 100W or brighter, and the light frequency has to be 5000k-6500k. Bright white bulbs are very white, even bluish, while soft white bulbs gives off yellowish light that doesn't do much if anything for plants. The numbers should be on the bulb's box or somewhere on the bulb itself, though you may have to look on the manufacturer's website or even ask them. As for effectiveness, a combination of CFL and LED 100W, 5000k bulbs for about 14 hours a day had had a big impact on my little collection of light-loving plants (I get very little natural light in fall and winter). Some of them had stopped growing and a few really neglected ones were dropping leaves like crazy. Some of the improvement was from getting rid of spider mites, but I credit the supplemental light with the major flush of new growth. Get a cheap grocery store timer for your light so you don't have to think about turning it on and off. Good luck; it looks like a nice little plant!

It does look fungal. Maybe powdery mildew? Many fungal diseases are result of environmental problems. Most of them spread and spores could be 'hiding', so just trimming some visibly infected leaves usually doesn't solve the problem. Maybe you need to change something - you didn't say anything about growing conditions (watering; potting mix and container; light exposure; temperatures and where it is growing...) Plat should bounce back once conditions are improved.

Jades will loose old leaves, they usually dry up to crisp and eventually fall off (or you can take them off). There could be few at the same time, but usually just 1 or 2. Do you have just few or may yellowing at the same time? Black spots could be oedema/edema, that is a disorder, not a disease. Those spots could be raised, like a pimple, often hard and you shouldn't try to take them off (they would have to be scraped, using bit of force, and would leave wound on the leave). Oedema could also look like irregular spots. If the black spots were oval-shaped and quite same in size, it could be scale insect but I do not think that's what you have. Powdery mildew could also have darker spots, but that is a fungal disease and often covers more of the leaf. It could also be 'fuzzy; - doesn't look like you have that either. If the soil was hardened around root ball, it is likely because it is mostly peat that became hydrophobic. Not best for the plant, since hydrophobic peat is quite difficult to re-wet. Hard as it is, it repels water and regardless how much you water, plants roots can't get any. Since you repotted it with that hard soil on, all new soil will get saturated but roots will stay dry. It is better to get rid of old, hard soil and loose some, even lots of roots. Jade will regrow roots in better potting mix quite fast. The mix should be well draining. You can make it so by adding lots of sifted or rinsed perlite (or pumice if available). Mixing it in 1:1 ratio is recommended.