5 yrs ago, my sisters best friend died suddenly and she was given her desert roses. 2 have been stolen from her decorated mailbox area and 1 remains on her lanai. my sister doesn't have a nack with plants so I try to help. I was researching what to do about a pest problem and before I could get back to her, she believed a label and sprayed it with Garden Safe. She called me frantic because the leaves are turning yellow and dropping as are the flowers. It had just begun a very beautiful showy time with lots of buds/blooms too!!! Please advise IF you are experienced with this. Googling has produced a plethora of contradicting advice! needless to say, I am desperate to help her save this plant as its so precious to her! FYI, the pest/pests were leaving sticky white "webish" spots on the leaves and there was sticky liquid drops on stems. I had removed the infected leaves but wanted to research before doing anything else. she lives in FL.