It can be absolutely heartbreaking to see your favorite plant or plants, start to fade away from one disease or another. There are a number of different plant diseases that can occur, which happens when an organism infects a plant and disrupts its normal growth habits. It can cause anything from slight yellowing to death.
Disease fungi take their energy from the plants on which they live. They are responsible for a significant amount of damage and can be characterized by problems like wilting, scabs, moldy coatings, rusts, blotches and rotted tissue. About 85% of all plant diseases are caused by fungi, according to the University of Florida, which means you’re more likely to encounter fungal diseases than any other type of disease.
This list of common plant diseases to look out for can help you quickly diagnose when there’s an issue, and keep your plants thriving and looking fresh. The next time you notice something strange going on with yours, you’ll know just what to do.
There are actually several types of blight to watch out for: fire blight, early blight and late blight, all of which are easily recognizable as it often causes the sudden death of all plant tissue, including the flowers, stems and leaves.
Fire blight. Fire blight is a bacterial disease that affects apples, pears, fruit trees, roses, and small fruits. When shoots are affected, they’ll look blackened. You may notice lesions on the branches and limbs that ooze an orangish-brown liquid on very warm days. Treat fire blight as soon as possible after you notice it, otherwise, it can spread quickly to the entire fruit tree and kill it.
To do so, first put on gloves to protect your hands, and then add four cups of water to a large bowl. Add one cup of bleach, pouring it in slowly so that it doesn’t splash out. Stir it up with a spoon. Before treating your plant, prune all the affected branches using shears. Dip the shears in the bleach solution after each cut so that you don’t spread the infection. Cut off all branches at least 12 inches below the last branch that is wilted and discolored, and then dispose of them in a place that’s at least 100 feet away from your tree.
Pour six cups of water into a one-gallon garden sprayer, and then add four cups of white vinegar. Close the lid tightly and then shake the sprayer to mix the contents. Put on safety glasses and then pump the handle on the sprayer to pressurize the solution. Point the nozzle at your tree and spray it from bottom to top, also making sure you get under the leaves. Step back, and spray it again, this time from top to bottom, until the leaves are saturated and dripping. Now thoroughly spray the tree trunk. Repeat the process in two weeks to ensure the fire blight is eradicated.
Early blight. Fungal blight can infect plants, vegetables, shade trees and fruit trees, but when it strikes tomatoes, peppers or potatoes, it’s referred to as early blight. Symptoms include brown to black colored spots on leaves which develop concentric rings. When they’re heavily blighted, the leaves dry up and die as the spots grow together. You’ll likely notice symptoms on lower leaves first. Potato tubers develop sunken, dark spots. In spite of its name, early blight can occur anytime throughout the growing season, with high temperatures and wet, humid conditions, causing it to spread rapidly. Like with most pests and diseases, plants which are stressed or just in plain poor health are more susceptible.
Prevention is key when it comes to early blight. It’s best to dispose of plants that are infected and use a three-year rotation when possible. Be sure that you purchase your starts and seeds from a trusted source, and make sure you allow enough space between your plants for air to circulate. During wet weather, check your plants frequently. If you see anything that remotely looks like a sign of blight, you can use an organic copper spray, which is considered safe, although you should spray early in the morning to avoid harming bees. Copper can also build up in the soil and cause toxicity, so if you plan to add more plants, you may want to choose another area.
Late blight. Late blight can infect flowers like azaleas, holly, lilacs and rhododendrons, causing dieback of shoots and stem cankers. It can also infect tomatoes, potatoes, and peppers. Initial symptoms include water-soaked spots on lower leaves, which gradually enlarge and are mirrored on the undersurface of the leaf with a white downy growth. On potatoes, dark-colored blotches penetrate the flesh. They may look like sunken lesions. During a wet season, the affected plant will rot and die. Again, prevention is key. Use trellis and plant supports to keep branches off the ground, and use plenty of mulch. Avoid watering your plants from above, and water in the early morning hours so that they’ll be dry by nightfall. If blight does show up, you’ll have to pull out all infected plants and place then into a trash bag – never compost them as it can cause this highly contagious disease to spread quickly, sometimes even affecting the neighbors’ plants.