FOOT ROT GUMMOSIS - CITRUS

This is a well known disease in fruit trees. I am sharing with you my limited experience with gummosis on one of our Satsuma trees and how I am treating it.

In simple terms, foot rot gummosis in citrus occurs when zoospores splash into wound or bark crack around the trunk base. Zoospores travel thru rain and/or irrigation, contact the roots, germinate and cause root rot. They can affect other parts of tree but this discussion is limited to disease on citrus trunk bases.

Upon initial inspection I thought deer had damaged the trunk (and they may very well have wounded the tree) but excessive rains are probably more of a factor, encouraging zoospore travel. Once I noticed orangey sap oozing from the base I knew this needed further attention. It is a contagious disease so prompt attention is important.

Here are two pics of what the base of my Satsuma looked like:

Here are my tools, a scraper, thoroughly washed with Clorox and dried; and a copper fungicide, available at HD.

The hardest part (not really hard) was to sit as close as possible to the base of the trunk so I could scrape all the soft and dead tissue, as well as any sap. I scraped until I felt firm tissue. In my case, there was not much scraping to do. After scraping, I thoroughly sprayed the area with the fungicide. Here are two pics of how the trunk looked post scraping

This message was edited Jul 20, 2016 2:44 PM

I will post an update on the success of my treatment of choice. My tree is under 10 years old and I saw no evidence of damage in foliage, branches, fruit--just the base of the trunk.

Here are two links I found useful when researching gummosis:

http://www.idtools.org/id/citrus/diseases/factsheet.php?name=Phytophthora

http://aggie-horticulture.tamu.edu/citrus/l2313.htm

A final pic shows some of the sap removed from the trunk. It was hard are resin! I have lost the tag on my Satsuma, it could be Seto or Owari, not sure