Identifying Parsley Diseases

Parsley is a favorite herb that is a staple in culinary gardens. It is widely used in cooking and is ideal for garnishing a variety of dishes. The herb also has therapeutic and healing properties. Parsley is easy to grow and does not require much maintenance. Although seeds normally take a long time to germinate, once established the plant usually grows fairly well. It tolerates both cold and hot conditions and will do well in practically any location. Ideal conditions for successful growth include well-drained soils and adequate moisture. Following are some common diseases that may attack your parsley.

Leaf Spot

This is a fungal infection. Yellow specks develop on both sides of the leaves. The spots gradually turn dark brown in color and may enlarge although the spots retain a yellow border. The spots spread rapidly to surrounding foliage as the infection intensifies. You will notice tiny black pin-sized dots in the middle of the spots. Leaves are weakened and gradually end up wilting. Where the plants are extensively infected, most of the leaves will drop off. Use a fungicide to control the infection. If the parsley is severely infected, it is best to uproot and discard along with the surrounding soil.


High humidity conditions encourage development of this disease. Brown patches on the leaves are the earliest signs of blight. As the infection increases, the patches steadily spread and extend to most of the leaves. If unchecked, blight can cause the parsley to die. You can achieve some control by keeping humidity at low levels. Avoid watering the leaves and restrict water to soil level only. It is best to water the herbs in the morning to allow adequate time for foliage and flowers to dry. Exposure to sunlight is beneficial as it will enable drying out of water on the plant. Thin out the bushy herbs to encourage better air circulation which deters high humidity building up. You can also space your parsley containers to encourage better air circulation.

Crown and Root Rot

This affects both the crown and roots, resulting in decay of the plant. It is caused by bacteria and fungi found in the soil. Early signs of root decay include leaves turning yellow or brown. The entire plant gradually becomes yellow and eventually dies. You may observe a reddish discoloration at the roots with small feeder roots damaged. Red cankers may also develop on the taproots. Roots and stems may appear brown instead of white. Soggy or mushy roots indicate crown rot. You are likely to notice a water-soaked lesion at the bottom of the stem. Crown rot weakens the plant, leaving it sickly. It prevents emergence of new shoots whereas young shoots fail to become established. Roots turn black and decay. After a few days, the plant dies. Make sure your parsley is well exposed to sunlight as this will encourage the soil to dry well. Practice crop rotation as a control measure. If your parsley is planted in the garden, allow some time before you replant in the same site.