Remove infected leaves during the growing season and remove all infected plant parts at the end of the season. Apply a synthetic fungicide or an organic fungicide (fixed copper) according to label directions, early in the season, when symptoms appear to slow the spread of the disease.
While there is no cure for blight on plants or in the soil, 2 there are some simple ways to control this disease.
There are many different fungicides that can be used to control early blight. These products contain chemicals like azoxystrobin, pyraclostrobin, difenoconazole, boscalid, chlorothalonil, fenamidone, maneb, mancozeb, trifloxystrobin, and ziram. It is a good idea to rotate between different chemical compounds.
Field tests have shown that chlorothalonil, maneb, and mancozeb fungicides -- all available at gardening supply stores under a variety of trade names -- provide effective early blight control when used according to label directions and applications are started early in the season.
Mulch is your friend. From weed suppression to soil protection and eventual breakdown into the soil's organic matter, mulch is hard to beat. In the case of early blight, mulching reduces soil splash from rain or irrigation. It provides a barrier to fungus movement from the soil to the lower leaves.
Once you have blight there is very little you can do to stop it and there are no fungicides available to the home gardener to stop it. The more humid the summer, the more likely it is that the disease will spread. As soon as you spot any symptoms, remove the leaves, and harvest any unaffected crops.
Spraying fungicides should begin 7 to 12 days before late blight appears in the plot. Beyond that it is essential for the economic efficiency of the treatment that the choice of the product is adjusted to the infection pressure.
The fungus spends the winter in infected plant debris in or on the soil where it can survive at least one and perhaps several years.
Early blight is caused by the fungus Alternaria solani, which survives on infected plants or in plant debris. Early blight symptoms typically begin as plant canopies start to close. Denser foliage leads to high humidity and longer periods of leaf wetness that favor the disease.
GardenTech® brand's Daconil® fungicides stop, control, and prevent early tomato blight and more than 65 other fungal diseases. Treat tomato plants early in the season, as soon as soon weather conditions favor early blight. Then maintain control with treatments every seven to 10 days.
Start applications prior to or when symptoms first develop, and are at a low severity. Fungicides have little to no curative activity, and curative use can promote development of fungicide resistance. Select fungicides that are labeled for the targeted disease and demonstrated to be effective.
Early blight is favored by warm temperatures and high humidity. Symptoms. Spots begin as small, dark, dry, papery flecks, which grow to become brown-black, circular-to-oval areas. The spots are often bordered by veins that make them angular.
Excessive water in the form of rainfall or overhead irrigation can lead to Phytophthora blight problems in the home garden.
Many tree blight diseases cannot be cured, but it is possible to treat trees affected by blight if you react early enough. Tree blight diseases tend to attack branches first before they reach the trunk and root system which means there is time to save the tree.
Remove infected leaves during the growing season and remove all infected plant parts at the end of the season. Apply a synthetic fungicide or an organic fungicide (fixed copper) according to label directions, early in the season, when symptoms appear to slow the spread of the disease.
Pruning 12 to 18 inches below the visibly diseased (cankered) tissue into two-year-old wood generally reduces new symptoms and canker reformation caused by systemic movement of fire blight bacteria through the plant. Aggressive removal 2.5 feet below cankers was generally not better than removal at 12 to 18 inches.
Can tomato plants recover from blight? You may still get edible fruit from a plant that has blight, just make sure any fruit you eat has no signs of the disease. However, an infected plant will not fully recover.
Earth's Ally Disease Control is a new generation of disease control formulated from food-grade citric acid. The formula effectively controls powdery mildew, downy mildew, blight, canker, black spot and leaf spot while leaving no harmful residue on plants.
Carefully manage irrigation to avoid increasing disease risk through prolonged periods of wetness. Identify and destroy hot spots of infection in a field to reduce production and spread of spores. Bag and destroy individual plants, or use chemical and fungicide treatments for larger areas.
If you have had blighted tomatoes in the past, rotate crops on a three-year cycle to help keep soil disease-free. This means rotating where you plant your tomatoes and allowing three years to pass before planting them in the same spot. The absence of live plants should rid the soil of the disease in this time.
Bravo (chlorothalonil) and Dithane (mancozeb) are contact fungicides and you must start applying them early. Contact fungicides will be the backbone of any late blight spray program because they are cost effective.
This is mainly of use to farmers to time their sprays to catch the infections before they get established. Commercial non-organic crops of potatoes are sprayed every 7-14 days with powerful fungicides, which are a huge expense, a risk to the environment and also commonly lead to fungicide resistance.