What Causes White Marks on Plant Leaves

Hi Judy, i have attached 3 pics in the hopes you might be able to tell me the problem. Thanks in advance.
Barbara Cramer

Hi Barbara,

scaleSoft Brown Scale is the most common scale that attacks indoor houseplants especially ficus, ivy, spider plants, ferns, aralia, and schefflera. It appears as small bumpy brown spots that appear to move. As the scale sucks on the sap of the plant it secretes a sticky substance called honeydew. The honeydew attracts black mildew. Because of the shell-like exterior, sprays are only partially effective against scale. Wipe off the lines of brown oval bumps with your finger, a cloth, or a child’s toothbrush then spray the plant with Neem Oil. Use the Green Solution to clean off the black mildew.d.jpg 1920w" sizes="(max-width: 225px) 100vw, 225px" />scaleSoft Brown Scale is the most common scale that attacks indoor houseplants especially ficus, ivy, spider plants, ferns, aralia, and schefflera. It appears as small bumpy brown spots that appear to move. As the scale sucks on the sap of the plant it secretes a sticky substance called honeydew. The honeydew attracts black mildew. Because of the shell-like exterior, sprays are only partially effective against scale. Wipe off the lines of brown oval bumps with your finger, a cloth, or a child’s toothbrush then spray the plant with Neem Oil. Use the Green Solution to clean off the black mildew.d.jpg 1920w" sizes="(max-width: 225px) 100vw, 225px" />

From the picture it looks like your croton is getting burned by being in the direct sun. The plant likes very bright lightVery few houseplants should be placed in direct sun. High light refers only to bright indirect light since direct sun often burns the leaves of indoor houseplants. An area that is too hot and dry encourages Spider Mites and causes blooms to quickly fade. A northern exposure really doesn't provide enough light for high light plants. These plants need to be placed directly in front of an east-facing window, within 1-3 feet of a west-facing window, and within 5 ft. of a south facing window. A high light area has over 300 ft. candles of light., but not any direct sun. If you think that this could not be the cause, please let me know and I’ll suggest some other possible reasons. You can read all my care tips for a croton in the Popular Houseplant section of the website.

https://www.houseplant411.com/houseplant/croton-plant-how-to-grow-care-guide