P.S.Karunanayake says. Reply. Botrytis blight spores enter orange trees through wounded bark and cover the injury with fuzzy, grayish mold. Affected twigs develop discolored, curled leaves. The satsuma mandarin (Citrus reticulata or Citrus unshiu Marc.) I have a washington navel, valencia orange, and taracco blood orange tree and all three are experiencing upward curling leaves and yellowing. March 25, 2019 at 1:39 am. Wilted Leaves on Satsuma Trees. The leaves curl, wither and fall from the tree. When you know the symptoms you can quickly diagnose and manage a particular disease. Curled leaves disease on lemon plants like limes, lemon and orange trees are a matter of concern as it may indicate significant problems. This insect will cause the new leaves on the trees to curl. Greasy spot – Greasy spot is fungal infection that causes dark, greasy-looking spots on leaves, leaf drop, and reduced tree vigor. have curling leaves or limp leaves and how to fix it. Leaf Curl on a Citrus Tree. and the fruit of tree always has black on them. Fruits may have black specks. Keep a close eye on your trees and look for the characteristic signs that you have sick orange trees. Hello, I'm in Northern California, zone 9. These had dark green leaves about a month-two months ago. Leaf Curl on Citrus Trees (WHY). I also have meyer lemons, but those are fine. This year there was prolonged periods of high temperatures and rain so the tree suffered a few diseases. Leaf-Curling Diseases. Bacterial blast disease — aka citrus blast — surfaces with black lesions girdling the leaves’ stems. the leaf on the orange tree is curled up a little and it has these brown marks as if a worm was crawling in it. The Fixes The most likely reason why your citrus trees (lemon, orange, etc.) Watch out for the citrus leaf miner infesting your Satsuma mandarin orange trees. Growing citrus trees provide a fresh supply of sweet, tart and delicious fruit from your own backyard. is a relatively cold-hardy citrus tree believed to have originated in Japan. my orange tree is 2y old and have the same problem as the Pamela need a solution .