I have white spots on limbs/trunk?

What kind of white spots? Can you please take some pics and post them here so we can have a look in order to give you a more accurate advice.

yes, I just need to figure out to upload pics



see if this works. Tree is in bad shape and use to be a great producer.

Also your location would help.

Florida

That's not a disease, not sure what it is but it is common on citrus. Mold maybe? Dr. Manners should be able to answer that.

Lichen. It grows on anything from trees that are not healthy to the side of your house. It is not the problem but the result of one.

Thanks Hershell.

A quote from the web.

Quote:

Should I scrape off the light colored mossy growth that is growing on the trunk of my citrus tree? Lichen is actually two different organisms, a fungus and an alga living together. It is the fungus that provides the shape with the algal cells growing in a layer near the top of the fungal structure. The algae manufacture food, a process called photosynthesis, for both the fungus and the algae: a symbiotic relationship. Lichen is frequently seen growing on twigs and branches, especially under moist conditions. The lichen structure is usually grayish-green in color, paper-like, and forms small circular to irregular-shaped spots. When lichen is wet from rain or dew it grows actively, but when dry, it stops growing. It doesn’t die but lies dormant until the next rain starts it growing again. Lichens are considered harmless. Although they attach themselves to the tree, they are not pulling vital nutrients from that tree. It is often thought that lichens are injuring a tree because they are growing so well, and the tree looks so bad. This is just an indicator that some other requirements of the plant are not being met. Check and make sure there is no insect infestations (scale, aphids), no old weed- whacker damage and make sure the tree is adequately fertilized.

Lichens will grow on fence post. Cupro or Koicide (copper hydroxide) will control them if they are an eye sore. Also controls citrus scab.