Diseases And Problems With Growing Basil

Basil Plant Leaves
organic basil 1
(Image credit: fotogal)

Basil is one of the most popular herbs to grow, but that doesn't mean there are no basil plant problems. There are a few basil diseases that can cause basil leaves to turn brown or yellow, have spots, or even wilt and fall off. Keep reading to learn more about the diseases that can cause problems with growing basil.

Common Basil Diseases

Fusarium Wilt

Fusarium wilt is among the most common basil diseases. This basil wilt disease most commonly affects sweet basil varieties, but other basil varieties are still somewhat vulnerable. Symptoms of fusarium wilt include:

  • stunted growth
  • wilted and yellowing leaves
  • brown spots or streaks on the stem
  • severely twisted stems
  • leaf drop

Fusarium wilt is caused by a fungus that can be carried by either the soil that affected basil plants have been growing in or by seeds from infected basil plants. There is no remedy for fusarium wilt. Destroy infected plants and don't plant basil or other mint plants in that area for two to three years. Even if a basil or mint plant cannot be hurt by fusarium wilt, they can carry the disease and infect other plants.

Bacterial Leaf Spot or Basil Shoot Blight

This basil disease is caused by a bacteria called Pseudomonas cichorii. Symptoms of bacterial leaf spot are black or brown spots that appear on the leaves and streaking on the stems of the plant. Bacterial leaf spot occurs when infected soil is splashed onto the leaves of the basil plant. While there is no fix for bacterial leaf spot, you can minimize the damage by making sure that your basil plants have plenty of air circulation and that they are watered in a way so that the bacteria is not splashed onto the leaves.

Downy Mildew

Downy mildew is a relatively new basil disease that has only started to affect basil in the past few years. The symptoms of downy mildew include yellow leaves that have fuzzy, grey growth on the undersides of the leaves. Downy mildew is aggravated by overly wet conditions, so if it appears on your basil plants, make sure you reduce overhead watering and that the basil plants have good drainage and good air circulation.

Other Basil Plant Problems

The basil diseases listed above are specific to basil plants, but there are a few other problems with growing basil that can happen. They include:

Heather Rhoades
Founder of Gardening Know How

Heather Rhoades founded Gardening Know How in 2007. She holds degrees from Cleveland State University and Northern Kentucky University. She is an avid gardener with a passion for community, and is a recipient of the Master Gardeners of Ohio Lifetime Achievement Award.