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

Stanley, you don't say where you live, which helps, but it appears to me to be gummosis (phytophthora). If you Google "gummosis citrus", you'll come up with several link for treatment. I've provided one below for you. Patty S. Here is a link that might be useful: UC IPM: CItrus Gummosis

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

How old are the trees? Are they grafted or were they grown from seeds? They need a large number of leaf nodes before fruiting. Grafted trees bloom/fruit at young ages, because they were made from mature trees. I have lots of Citrus that are under 3' tall, that are loaded with fruits. My trees also bloom over extended periods, starting in late winter, so a few storms don't seem to do any damage overall to the blooms. Are your trees exposed, in a large open area? I wouldn't think that would be detrimental. Maybe the issue is lack of pollinators? Do you see lots of bees around your Citrus when they flower? The petals do of course all fall off after they open, but if pollinated, fruits should take their places. Do the trees look otherwise healthy? Where do you live? This problem has me very puzzled. I've never heard it mentioned on the Citrus Forum either. Sorry, I have no idea how to make flowers stay on, other than by having healthy, trees that are mature enough to hold fruits. Tell us more please. What kinds of Citrus do you have? Most Lemons/Limes bloom off and on most of the year. Lisa