3 years ago . The leaves have developed dark blotches that appear to begin on the underside and spread through to the top, along with some yellowing. Meyer Lemon Leaf Spots. Lemon trees prefer a warm subtropical climate, but grow in cooler climates if sheltered from cold winds and cold winter conditions. Messages: 826 Likes Received: 10 Location: Pensacola, USA. Shelter lemons from cold winds with plastic, a screen or a hedge. Greasy spot is a fungus, known as Mycosphaerella citri, that affects the leaves of citrus trees and thrives in tropical and subtropical climates. Michael. Can you diagnose my potted Meyer lemon tree, which is now indoors over winter? This year the tree has black leaves and a few black lemons. Even citrus trees aren't immune to disease. Over the last couple weeks, it has gone from developing yellow spots on some of the leaves to dropping leaves. If you notice huge chunks missing at a time, it could very well be a rodent or animal like a deer. When the tree is cold its roots are unable to absorb enough nutrients to keep the leaves green so they turn yellow. You probably have sooty mold--keep the leaf litter cleaned up and spray with a copper fungicide. Citrus trees are absolutely beautiful and one of the most popular is the Meyer lemon tree. What happened and what should I do? Greasy spot fungal spores germinate on the lower leaf surfaces and create blisters in the spots where they attack the leaf tissue. Discover some of the most common Meyer lemon tree diseases below. Aphids consume the Meyer and leave behind honeydew (sticky, black soot) which then feed the ants. Meyer Lemon Yellow Spots/Blotches on Leaves, Dropping. Asked January 19, 2018, 4:47 PM EST. Skeet skeeterbug, May 27, … As the fungus develops, the spots become visible on the leaf top. The leaves die and fall from the tree, which increases the tree's chances of being damaged by cold or attacked by other pests or diseases. The tree grew well and we had many big & juicy lemons. They chew up entire branches of leaves and can leave your Meyer tree bare. This is why you may encounter pairs. They work together to feast on your tree. Hello, I have a several year old potted Meyer Lemon that has developed some sort of ailment. HOPELR, May 27, 2007 #1. skeeterbug Active Member. There stood a small, sad looking tree that was pretty hard to spot as being a Lemon tree, because it was absolutely covered in a thick, black, sticky coating on all of it’s leaves. The fungus appears as yellow, dark brown, or black lesions that initially occur on the underside of mature citrus leaves. If you currently have or are looking to add lemon trees to your garden or landscaping, you want to make sure that you know how to properly care for and protect them. On the upper leaf surface, yellow spots turn into greasy-looking, raised dark brown blisters. (There is also a fungus gnat problem—not sure if that’s related.) Some leaves have dropped.