It's known with 100% certainty that household cleaners like Dawn, Ivory, Palmolive, et al, damage/dissolve cutin, cutan, suberin, lipids, waxes, and other hydrophobic (water-repellent) substances that are synthesized by the plant and provide a protective coating. The function of these water repellent compounds is to A) limit water loss from the aerial parts of all terrestrial plants, B) block the entry of pathogenic fungi and bacteria, and C) they cause water to bead up on the plant's leaf surface and run off, which effectively removes light-blocking dust and debris from leaves. Even in the face of overwhelming evidence of the damage caused by these household cleaners, you'll still have a vocal group of naysayers suggesting that because they are unable to immediately discern the damage these products cause, they must surely be completely safe, and all should follow the clarion call that "It works for me"! As long as your plant is healthy and you're providing cultural (growing) conditions that aren't at or beyond what the plant is genetically programmed to tolerate, you'll be pleasantly surprised by its resiliency. Your plant has internal chemical messengers that will signal 'plant central' when a leaf becomes a deficit instead of an asset. When the plant gets the message it's to its advantage to shed the offending leaf, the plant will begin to remove any mobile nutrients and biocompounds from the spoiled foliage, then shed it. If you can tolerate the blemished leaves, leave them on the tree until they are all brown or shed. It might be helpful to take the plant into the shower and allow room temp water (will feel quite cool to the skin) to spray on the leaves for several minutes. If you have a hand-held spray device in the shower, use it to thoroughly spray the leaves' undersides. While you have it in the shower, slowly pour a volume of room temp water equal to about 10X the volume of the pot the plant is in through the soil. This will remove any accumulation of salts that might have occurred. Beyond that, make sure you're monitoring moisture levels so you're watering on an 'as needed' basis instead of according to the calendar. If you offer appropriate light levels, temperatures, and start a well-considered nutritional supplementation program, your plant should fare very well. If you use an appropriate soil (one you can water to beyond the point of saturation w/o the need to worry that your plant's root system will suffer from prolonged soil saturation), and can keep the watering intervals, and light/temperature levels close to the 'sweet spot', your plant will fare well. If you can be patient until a more appropriate time to work on the tree (June in the Northern Hemisphere) we can fix things by forcing your tree to grow a brand new flush of growth. The new leaves will be pristine in appearance and perfectly attuned to light levels where the plant is sited. Plants have natural rhythms. Working with those rhythms instead of at cross-purposes with them makes things much easier on the plant, and satisfies the itch you have to nurture much more effectively than simply forging ahead w/o a plan that benefits the plant. You should find this useful. Al

Looks like mealy bugs to me too. To find out, get a q-tip; moisten with rubbing alcohol and apply to 'white fuzzy blob'. If mealy, the white fuzz will dissapear, and you should see tiny bug of darker color. Rubbing alcohol will kill it. If there are too many, maybe you should get rid of infected plant, as Morgan suggested. Small infestation could be eradicated by spraying with rubbing alcohol, but you said it looks like it spread to couple of plants - it would be difficult to get rid of them. Problem is that they hide very well, in spots that are difficult to see and treat. Mealy bugs spread easily to other nearby plants. There are some chemicals/systemic sprays that could be used, but I am not sure which ones as I never used any.

That looks like natural variegation to me. There are many forms of variegated pothos, so nothing to get worried about :-)

Powdery mildew is my diagnosis, too. Cool nights, hot days and little/no rainfall or overhead watering favors the spread of this tough to control fungus. It's even harder than black spot to control here in W. PA, but not quite as destructive, and it is seasonal here, occurring mostly in spring and fall when hot days and cool nights are the norm and pretty much skipping summer, thank G-d! Good control can be achieved by regular spraying with Bayer Advanced Disease Control for Roses, Flowers and Shrubs. Immunox is reported to be a better control for PM, but I have not yet tried it. I would not remove any damaged foliage, just a regular spray of fungicide is my advice. In CA, weather conditions that favor PM, cool nights, warm days and no rain or overhead watering, may be an ever present challenge. Can't change the weather! I heard of a W. PA rose gardener who controlled our seasonal PM here very effectively with regular, daily overhead watering of the bushes, just plain tap water from the garden hose. Of course, the dreaded black spot fungus would be stimulated to proliferate under such management. Moses