Discolored Pepper Stems: What Causes Black Joints On Pepper Plants

black-pepper-stem
Image by shoelessruth

By Susan Patterson, Master Gardener

Peppers are probably one of the most commonly grown vegetable in the home garden. They’re easy to grow, easy to care for, and are seldom affected by pepper plant problems. However, many people do have issues on occasion with discolored pepper stems or with pepper plants turning black.

Why Pepper Plants Have Black Streaks on Stem

Growing peppers in your garden can be a rewarding and nourishing experience. Peppers are usually easy to grow, generate a lot of fruit and are not bothered by many pests. One commonly reported concern with regards to peppers, however, has to do with a purple-black coloration that occurs on the stems.

For some peppers, purple or black stems are normal and as long as the plant looks healthy, you should not worry about the dark coloration on the stem. While some peppers, such as bell peppers, commonly have purple or black stems that are completely normal, there are some diseases that do cause discolored pepper stems. Proper diagnosis and treatment of disease will help keep your entire crop of peppers from going to waste.

Discolored Pepper Stems

If your pepper plant has a dark black ring that encircles the stem, it may have a disease known as phytophthora blight. Besides your pepper plants turning black, you will notice your plant wilting and suddenly turning yellow. This is due to the fact that no nutrients or water can pass up through the ring that is girdling the stem.

To avoid this disease along with many other pepper plant problems, don’t plant peppers in soil where eggplant, gourds or tomatoes have been planted in the past three years. Avoid overwatering plants and watering from overhead.

Black Joints on Pepper Plant

Got black joints on pepper plant? Black joints on your plant may actually be black cankers caused by fusarium, which is a fungal disease. This disease causes fruit to turn black and mushy.

It is imperative to prune diseased plant parts to keep the fungal infection from spreading to other parts of the plant. Keep pruning tools sterilized and avoid watering plants from overhead. Overcrowding sometimes causes this problem as well.

So next time you notice your pepper plants turning black and want to know why pepper plants have black streaks on stem parts, be sure to give them a closer look. While bell peppers naturally have discolored pepper stems, black rings accompanied by wilting or yellowing and cankers or soft spots on the stem are indications of something more serious.

This article was last updated on

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