Leaf Rot

Also known as Petiole Rot

Description

Unlike Crown Rot or Root Rot, Leaf Rot is not caused by a fungus but by too much fertilizer. Symptoms of Leaf Rot tend to manifest on the outer, lower leaves and stems. This is the part of the African Violet that rests on the rim of the pot, where high concentrations of fertilizer salts will accumulate. (Also see Too Much Fertilizer.)

Distinguishing Symptoms

• Leaves have lesions where they rest on the rim of the pot.
• Stems have lesions where they rest on the rim of the pot.

If your African Violet exhibits these symptoms, it probably has Leaf Rot.

Other Symptoms

• Leaves wilt. They may appear translucent brown with a soft, jelly-like consistency. This symptom will begin and be most noticeable where the leaves rest on the rim of the pot.
• Leaves have orange crystals clinging to the plant hairs. This symptom will be most visible on the crown.
• Leaves darken on the tip (necrosis). This is called Leaf Tip Burn, and it is brown in color.
• Leaves darken. They appear brown or black in color.
• Plant growth is slow.

Treatment

Remove any rotting leaves or stems.

Rinse the plant and pot with lukewarm water. If you see orange crystals on the leaves or other concentrations of fertilizer salts, rinse long enough to dissolve and wash away these crystals.

Drench the soil with lukewarm water to leach out any additional concentrations of fertilizers salts. To do this, water from the top until about of cup (8 oz.) of water has drained from the pot. Allow any excess water to drain.

Wait one week before fertilizing, again. After that, use a fertilizer that has been specifically formulated for African Violets. A good Violet Food should be fully-dissolving and contain approximately equal amounts of the primary nutrients, nitrogen (N), phosphorus (P) and potassium (K). Also, your Violet Food should not contain urea nitrogen, since urea causes Root Burn. For standard-sized African Violets (in 3-inch pots or larger), look for a Violet Food with an NPK of 14-12-14. For Miniature Violets, look for a fertilizer that has somewhat lower percentages, though with a slightly higher proportion of phosphorus. A good plant food for Miniature Violets will have an NPK of 7-9-5.

Also see Too Much Fertilizer.

Prevention

About every three months, drench soil with lukewarm water leach out any unwanted concentrations of fertilizer salts. To do this, water from the top until about a cup (8 oz.) of water has drained from the pot. Allow any excess water to drain.

Routinely examine the rim of the pot. Concentrations of fertilizer salts on the rim are an early sign of over-fertilizing.

Finally, only use a fertilizer which has been specifically formulated for African Violets. For specifications, see above, under Treatment.

Also see Too Much Fertilizer.

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