Why Does My Parsley Look Unhealthy?

Are there any brown-black necrotic lesions on leaves which may have chlorotic margins, lesions expand and coalesce causing the death of leaves and petioles?

Are there any small, necrotic flecks on leaves that develop a chlorotic halo and expand into tan brown necrotic spots?

Are there any small, water-soaked lesions on crowns or petioles in contact with soil?

Are the seedlings dying and the stems are girdled or rotted at soil line?

Are the leaves covered with white powder?

Do the leaves have reddish or pale yellow areas on their upper side and dusty orange blisters on the undersides?

Are there any small, angular, gray-brown spots with defined red-brown margins on leaves?

Are the leaves yellow and red, plant growth is stunted?

Are the leaves curled and yellow?

Are there singular, or closely grouped circular to irregularly shaped holes in the foliage?

Are the seedlings clipped off at the soil line?

Alternaria leaf blight is caused by a fungus that spreads primarily by planting an infected seed. Plant only pathogen-free seed from a reputable nursery. Apply copper-based foliar fungicide if the disease emerges. Rotate crops to non-umbelliferous varieties for 2-4 years.

Cercospora leaf blight is caused by a fungus that can be introduced through infected seed and spread by wind or water splash. Plant only pathogen-free seed from a reputable nursery. Apply copper-based foliar fungicide if the disease emerges. Rotate crops to non-umbelliferous varieties.

Crater spot is a fungal disease favored by warm, moist conditions. Destroy crop debris or plow them deeply into the soil. Avoid planting seeds too deep to prevent petioles from coming into contact with soil. Apply appropriate protective fungicides at plant bases.

If your seedlings are falling over and the stems are girdled or rotted at the soil line, the most likely cause is a damping-off disease. Remove and destroy all infected plants. To prevent damping-off let the soil surface dry between waterings, thin seedlings to avoid overcrowding and do not add nitrogen fertilizers until plants have developed leaves.

White, powdery patches on the leaves are caused by a fungal disease Powdery mildew. Powdery mildew usually appears in damp places. Encourage good air circulation around the affected plants by thining them and any surrounding plants. Water plants from bellow to keep foliage dry. Any affected leaves should be cut off and removed. Any commercial fungicidal spray will protect your plant from further infections.

Likely cause for these symptoms is a fungal disease - Rust. Provide good air circulation around plants by thining them. Avoid making leaves wet when watering. Remove and destroy all garden debris before spring. All infected leaves should be removed. Spray leaves with sulfur early in the season to prevent rust or to treat mild infections.

These symptoms indicate fungal disease - Septoria leaf spot. This disease overwinter on old leaf litter, so rake up the leaves or bury them under a thick mulch in autumn. Copper sprays will help in controlling the spread. If defoliation occurs late in the season, it does plant little harm.

Carrot motley dwarf is a disease caused by carrot red leaf virus together with carrot mottle virus. Both viruses must be present to cause carrot motley dwarf. Avoid planting parsley near overwintered carrot fields. Control aphids as they are likely to vector the virus.

Distorted, curled leaves are caused by aphids. These tiny insects cluster under leaves. You can control them by washing them off the plant with water spray. Insecticidal soap should be used with severe infestations.

Armyworm is a known pest of parsley. This insect can go through 3–5 generations a year. Organic methods of controlling armyworms include biological control by natural enemies that parasitize the larvae and the application of BTK spray (Bacillus thuringiensis).

If the seedlings of your plants are cut off at the soil level, most likely cause are cutworms. They feed at night by cutting off young plants and sometimes eating them whole. During the day, they are hidden below the soil surface. Control them by introducing parasitic nematodes to the ground. Using BTK spray on the ground will also control their numbers.

Yellow, stunted plants and roots that have swollen galls indicate root-knot nematodes. Other symptoms are plants wilting during bright, hot days. Prevent root-knot nematodes by applying chitin or introducing parasitic nematodes to the soil before planting. Solarizing the soil also helps in preventing root-knot nematodes.