The excess white crusty, salt-like layer is a salt buildup in the soil. To correct this condition leach out the excess salts by watering thoroughly and water a second time in 30 minutes to wash the salts out the drainage hole. Pour off the excess drainage water. I have found white, cottony masses on the stems of my plants, and there is a sticky sap-like liquid. The white, cottony masses are most likely egg masses of a Mealybug species.
Mealybugs attack all parts of plants.
Their damage is often similar to that of aphids. Depending on how severe the infestation of your plant is, the cottony masses may be spot treated by dabbing a cotton swab of rubbing alcohol on individual insects. If your plant is covered with white masses everywhere, you may need to decide if the plant may need replacing. For more information on how to get rid of Mealybugs, see Plant Insect, Mealybugs. Your plant is probably suffering from being chilled, in addition to looking wilted it may drop some of its foliage.