My Dwarf Key Lime Tree Is Losing Its Leaves and They Are Turning Yellow & Falling Off

Salt Burn

• If your whole key lime leaf turns yellow, with a bit of browning at the tip, the key lime tree could be experiencing salt burn. Caused by excess salt in the soil, salt burn gradually affects more tissue. If your key lime is in a container without drainage holes, more salts will build up. Fertilizer also carries salt into the soil. Flush out salt buildup twice a year by flooding the soil with water, using a hose set to low.

Root Rot

• If the key lime tree gets too much water, it could rot the roots. While early symptoms occur underground, leaves can yellow and drop in a more advanced stage. If the lime tree gets root rot, it will eventually die as the roots continue to rot. There's nothing you can do.

Citrus Canker

• If the leaves develop yellow blotches with brown lesions inside, rather than an all-over yellow hue, they might have citrus canker. Leaves and fruit turn yellow, then leaves fall. Trees with serious infections may bear no fruit. This disease affects all types of citrus and can be spread from plant contact, rain or human contact with infected plants. If you think your key lime has citrus canker, ask your county extension agent to come out and view the plant. He can help you decide on a treatment. Do not send the plant material anywhere, since you could spread disease.

Citrus Greening

• One of the more serious citrus problems affecting key limes, citrus greening is a deadly disease with no cure. Carried by insect pests, this disease's symptoms include yellowing of leaves and leaf drop. If you see dead twigs and yellowed or fallen leaves, find a county extension agent to help you diagnose the disease. Other insects can cause yellowing and leaf dieback too, so the professional can help you determine which insect pests you have.