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Celery pests and diseases

Published: 09.04.2023
pest/disease type symptoms on celery control/prevention
Aphids Pests Curling leaves, sticky residue Insecticidal soap, neem oil, ladybugs, lacewings
Armyworms Pests Ragged holes in leaves, uneven growth Bacillus thuringiensis, handpicking, row covers
Cutworms Pests Cut stems at soil level, wilting plants Row covers, cardboard collars around plants, handpicking
Leaf spot Disease Brown spots on leaves, yellowing leaves Fungicides, crop rotation, good air circulation
Root rot Disease Yellowing leaves, stunted growth, mushy roots Good drainage, avoiding overwatering, fungicides
Powdery mildew Disease White powder on leaves, distorted growth Fungicides, neem oil, good air circulation
Slugs and snails Pests Holes in leaves, slime trails Beer traps, diatomaceous earth, handpicking
Thrips Pests Stunted growth, distorted leaves Insecticidal soap, neem oil, good air circulation
Whiteflies Pests Sticky residue on leaves, yellowing leaves Insecticidal soap, neem oil, good air circulation


Aphids are tiny soft-bodied insects that can be a common pest in home gardens. They are usually found on the undersides of leaves or near new growth, and they feed by sucking the sap from plants.

Symptoms: The most common symptom of aphids is a sticky residue called honeydew, which is excreted by the insects as they feed. Honeydew can attract other pests like ants and cause mold to grow on plants. Other symptoms include yellowing or curling leaves, stunted growth, and distorted or deformed foliage.

Control or Prevention: Preventing aphids is key to avoiding an infestation. Keep your garden clean and free of debris, which can attract pests. Use companion planting to repel aphids, such as planting garlic or chives near your celery. You can also use insecticidal soap or neem oil to control an infestation. A strong blast of water from a hose can also dislodge aphids from plants.

In conclusion, aphids can be a common pest in home gardens but can be prevented with good gardening practices and controlled with natural methods.


Armyworms are a common pest that can cause severe damage to celery plants. These pests get their name from their tendency to move in large groups, like an army, and they can quickly strip a plant of its leaves and stems.

Symptoms of armyworm infestation include ragged holes in leaves, stripped stems, and piles of green or brown droppings around the plant. If left untreated, armyworms can cause significant damage to celery crops.

To control armyworms, you can use an insecticide containing Bacillus thuringiensis (Bt). This natural pesticide specifically targets caterpillars, including armyworms, and is safe to use in organic gardening. You can also try handpicking the worms off the plants and dropping them into a bucket of soapy water.

Preventing armyworms from infesting your celery plants is the best approach. You can do this by keeping your garden area clean and free of debris, as armyworms like to hide in piles of plant matter. You can also plant celery in a location that receives plenty of sunlight and airflow, as armyworms prefer damp and shady areas.

By following these tips, you can protect your celery plants from armyworm infestations and enjoy a healthy harvest.


Cutworms are a common pest that can damage and kill young celery plants. These pests are actually the larvae of several species of nocturnal moths that feed on the stems of plants near the soil line, causing wilting and death.

Symptoms of cutworm infestation include wilting or collapsed seedlings, chewed stems, and cut-off plants. They usually feed at night, so you may not notice them until damage has already been done.

To control cutworms, you can try physical barriers like collars made from cardboard or plastic cups with the bottoms cut out placed around seedlings. You can also use beneficial nematodes or natural predators like birds to help control their population. Another option is to use insecticides that contain Bacillus thuringiensis, which is safe for humans and pets but deadly to cutworms.

Preventing cutworm infestations is key, so keep your garden clean and free of debris that could attract pests. Also, avoid planting celery in the same area year after year, as this can lead to a buildup of cutworm populations in the soil.

Leaf Spot

Leaf spot is a common disease that affects many plants including celery. It is caused by various fungi and bacteria that attack the foliage of the plant, leading to brown or black spots on the leaves.

Symptoms: The first signs of leaf spot are small, water-soaked spots on the leaves. These spots gradually enlarge and turn dark brown or black, often with a yellow halo around them. As the disease progresses, the leaves may become distorted, wilted or yellowed. In severe cases, the infected leaves may fall off prematurely, leading to stunted growth and reduced yields.

Control or Prevention: The best way to control leaf spot is to practice good garden hygiene. Keep your garden clean and free of debris, especially fallen leaves and plant debris that can harbor fungal spores. Avoid overhead watering and instead water at the base of the plant. Use a fungicide spray labeled for leaf spot control when necessary, making sure to follow label directions carefully.

In addition to good gardening practices, you can also prevent leaf spot by planting resistant varieties of celery and rotating crops to prevent buildup of pathogens in the soil. With these preventative measures in place, you can keep your celery plants healthy and productive all season long.

Root Rot

Root rot is a fungal disease that affects the roots of plants, including celery. This disease thrives in wet soil conditions and can be devastating to plants if not detected and treated early.

Symptoms: The first signs of root rot are yellowing and wilting of leaves, followed by stunted growth and eventual death of the plant. When you pull the plant out of the soil, you will notice that the roots are brown, slimy, and may have a foul smell.

Control or Prevention: The best way to prevent root rot is to ensure good drainage in your garden beds. Avoid over-watering your plants and make sure the soil is not too compacted. If you suspect your plants have root rot, remove them from the garden immediately and dispose of them in a sealed plastic bag to prevent the spread of the disease. Do not compost infected plants.

To treat root rot, improve soil drainage by adding organic matter such as compost or peat moss to the soil. You can also apply a fungicide that is labeled for use on root rot. Be sure to follow the instructions on the label carefully.

By taking steps to prevent and control root rot, you can keep your celery plants healthy and productive.

Powdery Mildew

Powdery mildew is a fungal disease that commonly affects celery plants. It is easily recognizable due to the white powdery substance that appears on the leaves and stems of the plant. This disease can weaken the plant, reduce its yield, and even kill it if left untreated.

Symptoms: The initial symptom of powdery mildew is the appearance of white, powdery spots on the leaves and stems of celery plants. As the disease progresses, the spots can merge and cover larger areas of the plant. Infected leaves can turn yellow and eventually die. In severe cases, the entire plant can be affected.

Control or Prevention: Prevention is key when it comes to powdery mildew. It is important to keep plants healthy by providing adequate nutrition, water, and sunlight. Good air circulation is also important as powdery mildew thrives in humid conditions. In case of infection, infected leaves should be removed immediately to prevent further spread. Fungicides can be used as a last resort if other methods fail.

In conclusion, powdery mildew is a common disease that affects celery plants. However, with proper prevention and control methods, it can be managed effectively.

Slugs and Snails

Slugs and snails are common pests that can cause significant damage to your garden, including your celery plants. These slimy creatures love to feed on the leaves, stems, and roots of plants, and they can quickly decimate a garden if left unchecked.


The most obvious symptom of a slug or snail infestation is the presence of slimy trails on your plants or soil. You may also notice irregular holes in the leaves of your celery plants, as well as damage to the stems and roots. Slugs and snails are most active at night, so it's important to inspect your garden after dark to catch them in the act.

Control or Prevention

There are several methods you can use to control or prevent slug and snail infestations in your garden. One effective approach is to handpick them off your plants and dispose of them in a bucket of soapy water. You can also create physical barriers around your plants using copper tape or mesh, which slugs and snails are reluctant to cross.

Another option is to use natural predators, such as ground beetles or nematodes, to help control the population of slugs and snails in your garden. Additionally, you can reduce the likelihood of an infestation by keeping your garden clean and tidy, removing debris and fallen leaves where slugs and snails like to hide.

Overall, while slugs and snails can be a nuisance in your garden, with the right prevention and control measures in place, you can keep them at bay and protect your celery plants from damage.


Thrips are tiny insects that are commonly found in celery crops. These pests are known to cause significant damage to the leaves and stems of plants, resulting in reduced plant growth and yield.


One of the most common symptoms of thrips infestation is the appearance of silvery streaks or spots on the leaves of celery plants. In severe cases, the leaves may become distorted, curled or discolored. Additionally, thrips may cause the plants to wilt or become stunted.

Control or Prevention

The best way to prevent thrips from damaging your celery crop is to maintain good garden hygiene. Remove any dead plant material and weeds from your garden bed to prevent thrips from overwintering. Additionally, you can use sticky traps or insecticidal soap to control thrips infestations.

If you choose to use insecticides, make sure to follow the manufacturer's instructions carefully and wear protective clothing while applying the product. It is also important to rotate between different types of insecticides to prevent thrips from developing resistance to a particular chemical.

In conclusion, by taking proactive measures to prevent and control thrips infestations, you can help ensure a healthy and productive celery crop in your home garden.


Whiteflies are a common pest that can be found in gardens and greenhouses. These tiny insects feed on the sap of plants, causing wilting, yellowing, and stunted growth. They also secrete a sticky substance called honeydew that attracts ants and can lead to the growth of black mold.

Symptoms of whitefly infestation include white or yellow spots on the leaves of plants, as well as a sticky residue on the leaves and stems. Whiteflies are most commonly found on celery plants, but they can also attack other vegetables such as tomatoes and cucumbers.

To control whiteflies, it is important to regularly inspect plants for signs of infestation. Sticky traps can be used to catch adult whiteflies, and insecticidal soap or neem oil can be applied to the leaves to kill both adults and larvae. In severe cases, it may be necessary to use chemical insecticides.

Prevention is key when it comes to whiteflies. Keep your garden clean and free of debris, and avoid overcrowding plants. Introduce natural predators such as ladybugs or lacewings to help keep whitefly populations under control.

Author: Michael Chen
Bio: I'm gardening specialist with a mission to empower people to grow their own fruits and vegetables. With my background in Plant Science from the University of California and experience working with farmers and community gardens, I'm dedicated to promoting sustainable agriculture practices and helping individuals achieve bountiful harvests. Let's get growing!