satsuma pruning & disease control
Last year my satsuma tree developed a black fungus. What and when should I spray it this year? Before pruning or after?
Newton County Texas plant health
There are several fungal issues that can occur on citrus (incl. satsuma). Can you elaborate further on the symptoms that you are describing as black fungus? (Are you talking sooty mold or melanose? Photographs and more information would be helpful in understanding what you are dealing with and will allow for a more reliable recommendation.
I can describe it. It was a black scale on the bark, leaves and fruit. I could was it off the fruit with no noticeable difference in the taste of the fruit.
The information you provided saying that have scaly appearance on plant parts as well as these can be washed off would suggest it might be sooty mold.
I would recommend consulting your local Texas A&M AgriLIfe Extension county office for ascertain the nature of the problem so that proper advice can be given.
Based on the information provided, I think this is an insect problem that resulted in the growth of sooty mold fungus. It would be critical to know which insect you are dealing with so that proper treatments can be used to suppress that insect population hence reducing sooty mold problems in future.
IF possible, please post photo of the black fungus.
Thank you for sharing the photo. It does appear to be sooty mold.
Check out this factsheet by the Extension folks in Galveston County: