Lemon tree

Question

Why has the tree (2 years old), which was growing and healthy, now lost its leaves and its branches are going brown?

• 

Answer 1

Frost damage, wind damage, phytophthora root rot, bacterial blast, and several other diseases can all cause specific branches on a citrus tree to die and lose their leaves. Please see these articles for more information and links:

http://ipm.ucanr.edu/PMG/C107/m107bpleaftwigdis.html
https://cals.arizona.edu/pubs/diseases/az1154/

Diseases vary by region, so you might want to consult a local extension agent or other expert.