Parsley Leaf Spot: What Causes Leaf Spot On Parsley Plants
Unlike hardy sage, rosemary or thyme, cultivated parsley does seem to have its share of disease issues. Arguably, the most common of these are parsley leaf problems, usually involving spots on parsley. What causes leaf spots on parsley? Well, there are actually a number of reasons for parsley with leaf spots, but of these, there are two major parsley leaf spot diseases.
Parsley Leaf Spot Problems
One reason for parsley with leaf spots may be powdery mildew, a fungal disease fostered by low soil moisture along with high humidity. This disease starts on young leaves as blister-like lesions followed by curling leaves. The infected leaves then become covered with white to gray powdery mildew. Severely infected plants may suffer leaf drop, especially with young leaves. Low soil moisture combined with high humidity levels at the plant surface favor this disease.
Spots on parsley leaves may also be caused by bacterial leaf spot, which manifests itself in different ways. In the case of parsley leaf spot resulting from bacterial leaf spot, angular tan to brown spots lacking mycelia growth or fungal structure appear either on the top, bottom, or edge of the leaf. Infected leaves may become
papery and easily crushed. Older leaves are more likely than new ones to become infected.
While both of these diseases are of some concern, they can be treated with copper fungicide at the first sign of infection. Also, plant resistant strains when possible and practice good garden sanitation.
Other Diseases that Cause Parsley with Leaf Spots
Septoria – An even more common leaf spot disease is septoria leaf spot, which is introduced via infected seed and may survive on infected dead or dried leaf detritus for several years. Early symptoms are small, depressed, angular tan to brown lesions often surrounded with red/brown margins. As the infection progresses, the interior of the lesion darkens and becomes dotted with black pycnidia.
Neighboring, overwintered or volunteer plants are also possible sources of infection. The disease is spread either during rainy periods of under overhead irrigation, through people or equipment moving through the wet plants. Spore growth and increase of infection is fostered by mild temps and high humidity.
Stemphylium – More recently, another fungal leaf spot disease caused by Stemphylium vesicarium has been identified as afflicting parsley. More commonly, S. vesicarium is seen in garlic, leek, onion, asparagus and alfalfa crops. This disease presents as small leaf spots, circular to oval in shape and yellow. The spots begin to enlarge and turn tan to dark brown with a yellow corona. In severe cases, the leaf spots merge together and the foliage yellows, dries and then dies. Usually, the disease attacks older foliage, but not exclusively.
Like septoria leaf spot, it is introduced on infected seed and spread with splashing water from overhead irrigation or rainfall combined with activity around the plants.
To control either of these diseases, use disease resistant seed when possible or seed that has been treated to reduce seed-borne diseases. Use drip irrigation rather than overhead. Rotate to non-host crops for at least 4 years in areas the disease has been present. Allow room between susceptible plants to allow for air circulation. Practice good garden sanitation and remove or deeply dig in any crop detritus. Also, allow the plants to dry from rain, watering or dew before moving amongst them.
Apply a fungicide according to the manufacturer’s instructions at the earliest sign of symptoms. Combine cultural controls and potassium bicarbonate to organically certified crops.
White Spots On Parsley Leaves
by Corne Froneman
(Almaty, Kazakshtan, Central Asia )
I have grown the Parsley from seeds. I bought the soil, but as I live in Central Asia, there is never a guarantee about the quality of the product that you get here…and everything is in Russian, so I don’t even know what type of soil it is. The plant is indoors and receives lots of sunlight.
It has tiny white specks on the upper side of the leave, but nothing underneath. So could someone please help me identify this and what would be the treatment?
So glad someone from so far away from where I live in the United States views our website.
Let’s start off by eliminating a couple of things.
First, I don’t think your problem has anything to do with the soil you are using. In my opinion, if it did, your Parsley wouldn’t be growing so well. Your photo (thanks for submitting, by the way), shows a well-growing herb.
Also, the amount of sunlight it receives shouldn’t be causing white spots on the leaves.
The two things that could cause white spots, are insects or a fungus. If it’s a fungus, you’ll need to treat the plant with a fungicide made for edibles. If that’s what it is, it should disappear in a few days to a week if you follow the instructions on the label.
Secondly, it might be insects. Aphids or spider mites can make white spots on leaves. Look for whitish webbing as a sign of spider mites. But, also caterpillars can do this as well. Do the white spots turn into holes? If they do, than it’s definitely insects (most likely the caterpillar). Literally, turn over leaves and look for caterpillars. An insecticidal soap would be your best bet for this problem. Use the soap, and the insects should be a thing of the past.
Just don’t ignore the situation. They are a common thing for Parsley, but if it is a fungus or an insect, either way, you have to get rid of them or the plant will become unusable.
If you have limited access to supplies that are in a language that you can read, try clicking here to read some of my ideas on ridding insects in a cheap and natural way. More info here as well.
Hope this helps and please let us know how it turns out!!
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Parsley and cilantro problem – Knowledgebase Question
Parsley is a biennial. Older leaves may turn pale and fade, and a stressed or second year plant may taste bitter. Parsley plants can stress if the soil is allowed to dry out, when temperatures turn hot, or if the soil is not rich enough, or a combination of those factors. Second year plants will turn pale as part of their maturation process by which they then bolt or flower, set seed and die. At this point I would simply pull or cut off the affected leaves. The more you cut the parsley, the more new stems and foliage it will develop. Cutting off the affected leaves will ensure your plants remain healthy and they they continually develop new leaves.
Cilantro is a little different. It has a very short growing season – about 6-8 weeks. It doesn’t matter how well you treat the plants, they simply run their full lifecycle and then die. To always have fresh cilantro for your kitchen, plant seeds at 2 week intervals. This way the older plants can naturally die off and at the same time the younger plants will provide you with lots of foliage. This way you’ll always have fresh new plants with fresh new leaves to harvest.
Problems of Parsley
Parsleyworm In Action
How To Use This Problems Section
The chart is organized to give you a quick and dirty summary of the possible symptoms that you may encounter. Those problem causes for which we have full files will be linked to those files. Those causes with no link will have a paragraph below the chart helping you deal with that particular problem.
|Problems of Parsley|
|Holes Eaten in Leaves||Cabbage Loopers|
|Crowns Tunneled, Leaves Damaged||Carrot Weevils|
|Leaves Eaten to Stems||Parsleyworms|
|Plants Rotted or Stunted||Carrot Rust Fly|
|Plants Stunted, Leaves Yellowed||Nematodes|
|Leaves Stippled, Yellowed||Spider Mites|
|Large Ragged Holes in Leaves||Snails and Slugs|
|Seedlings Chewed or Eaten Entirely||Rabbits|
|Crowns and Roots Mushy||Crown Rot|
|Small Yellow Specks on Leaves||Septoria Leaf Spot|
Small Yellow Specks on Leaves are Caused by Septoria Leaf Spot
he leaf spots of septoria begin as small yellow specks, which later enlarge, becoming tan to brown with a yellow border. They can be either circular or irregular in shape, and often have a black dot in the center. Spray healthy foliage with general garden fungicide to protect it from infection. If that doesn’t halt the spread of the problem, pull up the infected plants. Try planting a disease resistant parsley variety, such as ‘Paramount.’
Crowns and Roots Mushy Due to Crown Rot
Crown and root rot, caused by soil-dwelling bacteria and fungi, occasionally attack parsley. The disease initially attacks a few spots on the crown where the roots join the stems at the soil line. Then it spreads to the entire crown, turning it into a malodorous mush. New shoots may fail to emerge in the spring. If the plant is already in leaf, the lower leaves discolor and the young shoots begin to wilt. The roots are blackened, rotten and covered with white fungal threads. The whole plant dies in a few days.
Remove and discard any infected plants and the soil of the rootball in the trash. Avoid replanting parsley in the same place for awhile. Thoroughly loosen the soil around the plants to encourage it to dry out, which retards fungus growth. If you catch the disease early, spray uninfected foliage with general garden fungicide containing sulfur. Wash it well before using it in the kitchen.
Since this disease is most likely to occur in a late winter thaw when dead leaves decompose on the ground and harbor bacteria and fungi which spread to healthy plants, treat your parsley plants as annuals and pull them up in the fall of their first season.
Click here for more information about Dealing with Fungal Disease
Flat Italian parsley planted in the same spot where I grew it well three years ago.Parsley planted in a partly shady spot.
By Renee Adam
I grew perfect parsley—the Flat Italian variety—three years ago. It stood out in my herb garden so much that my mother complimented how beautiful it was and that hers never looked that good. I should have taken a picture of that parsley because I’ve never grown one like it since! In fact, I planted two parsley plants in April and can’t seem to get them to thrive. This is a shame, because fresh parsley is one herb that I use constantly as either a garnish or as an ingredient in many of the recipes I like to cook. Eating it raw is a great organic way to freshen your breath, too!
My dear friend Charlotte from Hendersonville, North Carolina, likes to cook with parsley, too. She prepared a wonderful meal for my family and me over Memorial Day weekend called Laurel Pork Tenderloin (recipe below). She used a handful of fresh parsley from her garden and garnished the dish with some as well. Yum! Then, for my birthday a few weeks ago, Charlotte and her family came for a visit and she gave me a darling mug with a parsley plant enclosed, as well as the recipe for her yummy pork tenderloin.
I left her parsley gift in the mug for a couple of days and it started to wilt, so I transplanted it to a favorite pot on my back stoop. But it didn’t make it! I think I’ve figured out how I managed to kill it. Parsley (Flat Italian or Curled) needs 3-6 hours of sunlight a day and good soil that allows drainage. I had watered the pot just enough but because the water wasn’t draining, the roots stayed drenched. It rotted.
So, I’m doing an experiment. I’ve planted two new parsley plants. One in the spot where it grew beautifully three years ago and one in part sun. I’ve adjusted the watering hose on the two I planted back in April to see if maybe they weren’t getting enough water, and I’m also going to feed my Bonnie Herb & Vegetable Plant Food to them. One plant has some white spots on the leaves, and I’m not sure what they are. I’m sending a photo through Ask an Expert on bonnieplants.com to see what this might be. I hope all my parsley plants survive and thrive. I’ll report back on the experiment soon!
By the way…the recipe is wonderful so I’ve included it. Thanks Charlotte!!
Charlotte’s Laurel Pork Tenderloin
1 1/2 cups canola oil
3/4 cup reduced sodium soy sauce
2 tablespoons dry mustard
1 tablespoon pepper
1/3 cup lemon juice
1/2 cup balsamic vinegar (or white wine vinegar)
1 1/2 teaspoons minced fresh Flat Italian parsley
1 clove garlic (chopped)
1 or 2 pork tenderloins (1 1/2-2 lbs)
Combine all ingredients, except tenderloin, and mix well. Pour over tenderloin and marinate, covered in fridge for 24 hours (will work with minimum of four hours). Pierce tenderloin with a fork and grill over low heat for one hour or cook uncovered in oven at 350 degrees for about an hour, checking for doneness with a meat thermometer.
Cut tenderloin in slices. Bring remaining marinade to a boil in saucepan on the stove. Pour sauce over tenderloin slices. Garnish dish with more fresh parsley and enjoy!
Yields 4 to 8 servings.