Sign up for our newsletter. Downy mildew thrives in infected crop residue. If you suspect downy mildew, the best bet is to remove and destroy the plant. Septoria leaf spot is a fungal disease that may cause white or grayish spots on leaves. white mold on door. Mold symptoms appear on blossoms, stems, leaves, and pods that have water-soaked spots. The fungus that creates angular leaf spot forms white spots … Fungal lettuce diseases, such as damping off or sclerotinia drop (white mold), are caused by soil borne fungi that thrive in cool, damp soil and are primarily lettuce seedling diseases. Downy mildew is my number one culprit simply because it seems to attack all types of vegetation. Yes? If that is the case, it is likely something in the air that has drifted down onto the leaves. The Causes of Bitter Lettuce Sap. Another possibility is called white rust or Albugo candida.Another fungal disease, white rust may commonly affect not only lettuce but mizuna, Chinese cabbage, radish and mustard leaves.Initial symptoms are white spots or pustules on the underside of the leaves. Bacterial canker also creates whitish spots on leaves, but they will be slightly raised off the surface of the leaf. This fact sheet details the causal pathogen, favorable environmental factors and recommendations for control for greenhouse producers. White molds can either remain white or change to green, black, grey, or practically any other colour over time. The leaves will be surrounded by a brown or black ring. Septoria leaf spot is a fungal disease that may cause white or grayish spots on leaves. White mold, also known as sclerotinia, is a fungal disease that affects over 360 different plants, including beans, peas, lettuce, and members of the cabbage family.White mold is sometimes called timber rot when it affects tomatoes. vitians was first described in the United States by Nellie Brown in 1918 from diseased lettuce in South Carolina and Virginia. Bacterial canker also creates whitish spots on leaves, but they will be slightly raised off the surface of the leaf. Hi Random, Thanks for posting. Lettuce and Endive > Leaves > Spots or blotches on leaves. Powdery mildew is caused by cool temps, dim light and high humidity. Symptoms appear in about 5-10 days from infection often following cool, humid weather with rain or heavy fog or dew. You are right to avoid wetting leaves if possible. White Rust Scientific Name: Albugo Candida Disease Type: Fungus Plants Affected: Lettuce, Mizuna, Chinese Cabbage, Radish, and Mustard Leaves Symptom: White spots or "pustules" on underside of leaves; Wilting and browning of leaves Next time around, plant varieties of lettuce that are resistant to this disease such as Arctic King, Big Boston, Salad Bowl and Imperial. Because the tender leaf of lettuce is eaten, I don’t recommend spraying lettuce with white spots that are suspected as coming from a fungus. Some diseases are more benign than others, but even so, fungi spread through spores that are pretty hard to tackle. Powdery mildew is different than other fungi, in that it does not need water on the leaves to infect the leaves or grow on them, so spraying water will not increase powdery mildew, but it could increase the chances of getting other collard diseases, such as downy mildew or Alternaria leaf spot. The spores are wind borne. With its refreshingly light taste, lettuce (Lactuca) can become bitter-tasting if it is exposed to certain growing conditions. Decrease humidity; Increase air circulation and ventilation It has since been reported from the major lettuce growing regions worldwide probably due to contamination of seed. Leaf miners are destructive pests that suck sap and feed on the leaves, causing white tunnels or trails on the crop. The botanical name for the substance is lactucarium, which comes from lactus, the Latin word for milk (the botanical name for lettuce is lactuca sativa, which also stems from this word).The white sap is a little bitter and, interestingly, has a sleep-inducing compound. Actually, do better than look – see if you can wipe the spots off. It is well known to cause great damage to beet, spinach, and chard. The disease was first reported in California in 1964. Pale yellow to very light green spots appear on the mature leaves of the lettuce. For best production, keep your lettuce in the coolest spot in your home – you’ll have trouble finding a spot so cool it isn’t happy! If the white spots on the lettuce cannot be removed, the cause is likely a fungal disease. Above that, it can tend to bolt because it thinks it is summer and time to go to seed. Sign up to get all the latest gardening tips! As with downy mildew, remove any infected plants. The Causes of Bitter Lettuce Sap. When they first develop, white molds are very hard to detect since the spores are so tiny that they can only be seen under a microscope. Lettuce with white spots might mean a few different things, usually a fungal disease but not always. In the future, plant resistant varieties and use drip irrigation or focus on watering at the base of the plant to keep the leaves of the plants dry since fungal infections generally coincide with moisture that lingers on the leaves of plants. > Vegetable > Lettuce and Endive > Spots or blotches on leaves. Initial symptoms are white spots or pustules on the underside of the leaves. Powdery mildew is a common fungal disease encountered in greenhouse production of lettuce. Keep reading to find out the causes of white spots on lettuce plants. Another possibility is called white rust or Albugo candida. Sure, AgSil16H is a good source of potassium silicate you can use (which I refer to in my post about silicate in general), however there are many other sources so I didn’t want to go straight to an AgSil16H reference. Many growers struggle with controlling the disease on lettuce crops grown in protected environments, especially during the fall and winter months. As the disease progresses, the leaves brown and wilt. First appears as small white spots on the tops of the leaves, but then progresses a fine, pale gray-white powder, all over. So suddenly you’re vibrantly green, healthy lettuce has white spots. Treating these lettuce diseases is achieved by spacing the plants apart to provide airflow and by reducing the amount of irrigation the seedlings receive. Another fungal disease, white rust may commonly affect not only lettuce but mizuna, Chinese cabbage, radish and mustard leaves. The leaves will be surrounded by a brown or black ring. It could be ash if there are forest fires nearby or dust from a nearby quarry. The fungus that creates angular leaf spot forms white spots … With its refreshingly light taste, lettuce (Lactuca) can become bitter-tasting if it is exposed to certain growing conditions. This post is filed under Defect Identification.. You can follow any responses to this entry through the RSS 2.0 feed.. You can leave a response, or trackback from your own site.. 2 Comments on “Romaine- Rib Discoloration” Jeff Provost Says: June 20th, 2012 at 10:25 am I was inspecting Romaine just yesterday, and came across yellow spots on the leaves (discoloration). 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Leaf tissue around the spots turns yellow; Fuzzy white growth can be seen on the underside of the leaves; How to treat this common plant disease? Plants Affected: Lettuce, Mizuna, Chinese Cabbage, Radish, and Mustard Leaves, "Mizuna: White rust" by Scot Nelson is licensed under CC BY 2.0, "White rust of Chinese cabbage caused by Albugo candida" by Scot Nelson is licensed under CC BY 2.0, If you require information in an alternative format, please contact us, Copyright 2020 by College of Tropical Agriculture and Human Resources, White Rust of Cruciferous Vegetables in Hawai‘i by Erik Patnude and Scot Nelson, White rust of Chinese cabbage caused by Albugo candida, White spots or "pustules" on underside of leaves, Reduce leaf wetness, such as by using drip irrigation.