Hi Ccarroll, I believe what the gardener was referring to is Sooty Canker, a fungal pathogen that affects stressed plants and usually invades the host at sites of pruning, sunburn, freeze damage, etc. The fungal spores can be transmitted from plant to plant on tools or can be airborne. This disease is not new. Healthy plants are rarely affected. Take care to maintain optimum plant health by watering properly, not overpruning, avoiding freeze damage (if possible) and disinfecting tools. Your tree (citrus?) may or may not have Sooty Canker. To be sure I've included a link to the U of A Extension Plant Pathology web site. You can also take samples or send photos to the U of A Cooperative Extension office in Phoenix. Here is a link that might be useful: Diseases of Citrus in Arizona

It could still be deficient in Macro/Micro nutrients. Have you checked the pH of your soil? If the pH is too High or too low, it can affect nutrient absorption. You can give it lots of micronutrients but it may be too difficult for the roots to take up the nutrients if the pH is out of wack. Another thing it could be is overwatering. You should let potted citrus dry out slightly before the next watering otherwise you can encourage root rot. Next time, before you water your citrus, tip the pot on its side and check the drainage holes and feel if the soil on the bottom is wet. If its still wet, do not water. Your plants actually look pretty healthy to me but I do notice that in the pictures you posted that they are in some shade. citrus loves sunlight and you should put them in the sunniest location you can find. There is lots of talk in the citrus forum about Gritty Mix and 5-1-1 mix. I believe these are mixes that are fast draining and can be beneficial to citrus. There is a good chance that your trees are simply dropping old leaves before new ones come in. Please keep us updated. Simon

Check the Pest Notes at UC IPM http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn74137.html Here is a link that might be useful: Univ of CA re citrus leafminer

My potted citrus tree is 12 years old and until recently has thrived indoors. It was started from seed and I don't know if it is a lemon or orange tree as it has never flowered. This year, new leaf growth has been stunted and the tree has strange looking spikey shoots (see photo). Is my potted citrus tree sick? Any advice would be much appreciated.