Do your plants suffer from fungus, powdery mildew, or a virus? Are you unsure as to what your plants have? A correct diagnosis is the difference between a small hiccup in your crop and complete devastation. Today we are going to cover a variety of fungal diseases that are often the most common. Plant diseases are seriously difficult to diagnose, but an experienced eye can tell instantly what a plant is stricken with. Diseases are spread from microscopic spores of fungus, and spores can be spread from air flow, fungus gnats and other vectors. The first thing to address is the air flow into your room, make sure it’s filtered and clean! Here is a variety of fungal diseases, what they are called, what they look like and how to treat them. Remember, an ounce of prevention is worth a pound of cure!
Powdery Mildew
Powdery Mildew: powdery mildew can infect a wide range of plants – from houseplants to trees to roses- powdery mildew can affect different plants at different times of the growing season. Some plants can tolerate this fungus and continue to thrive while others can be severely injured by a minimal infection. Powdery mildew appears as a gray powdery substance that covers the leaf surface and other plant parts. It will slowly accumulate to a light dusting. Usually circular powdery white patterns will appear. As these spots continue to grow they will eventually cover the entire plant if not treated. The fungus is most visible during hot humid conditions or in plants that are close together. Powdery mildew injury can cause the plants to present yellow leaves or leaf drop. This also can include the deterioration of buds, blooms, leaves and sometimes complete death of the plant. Select the proper fungicide to get the best control. Not all fungicides are labeled to control all fungus problems. On outdoor plants always make sure all fallen, infected leaf and plant material around the plants are gathered and destroyed during the growing season. The 1st time the fungus is noticed begin a fungicide applications immediately. Continue to use as needed during the humid weather as per label.
Solution – This is probably the most common problems indoor gardeners face. The key here is more AIR FLOW and less shade. Increase air flow through the stagnant areas and don’t leave any parts of your plant shaded. Powdery mildew HATES to be in full light and also does not like to be sprayed with water. Spray off any visible powder the instant you see it, early in the day when its cool and never let water sit on the leaf surface. If your not too far into flowering, you can apply a copper or Sulfur Fungicide. A Sulfur Vaporizer will also help tremendously. Be vigilant, this is something not to take lightly, it can DESTROY your crop!
Sooty Mildew
Sooty Mildew: The fungus’ darkened mycelium gives plants the appearance of being covered with soot, this fungus does not infect the plant but in fact grows on the outer surface where another problem may occur such as honeydew (a thick sticky layer of liquid left by sucking insects after feeding on sap from plants). Sooty Mildew does not infect the plant but it can inhibit the plants absorption of light. Without sunlight the plants ability to produce food for itself is reduced, possibly killing or slowing down the plants growth. For fruits, vegetables and other edible plants simply hose down the infected areas with soap and warm water. If, in fact, you do have sooty mold then the presence of sucking insects in your landscape is a good chance. Controlling sooty mold starts with the control of any insect population, for example, aphids are most likely the producers of honeydew so keeping the aphid population under control is step one in controlling sooty mold. Sometimes just a good strong spray from the garden hose will help to remove the insects from the plants. Another way to control the insect population is with beneficial insects such as ladybugs. Ladybugs can help reduce the aphid population therefore reducing the conditions for sooty mold. Once the insects are diminished the signs of sooty mold will be greatly reduced. If these methods do not control or greatly reduce the insect population apply neem oil to help control the insects. Always follow the directions on any product that you may decide to use.
Solution – Cool clean water applied early in the day and good logically applied insecticide will keep sooty mold from overcoming your garden. I really light green light neem.
Bacterial Leaf Spot
Bacterial Leaf Spot:Xanthomonas Compestris pv. Hederae- many plants are susceptible to bacterial diseases, especially when the weather gets hot and humid or during gloomy winter months. Plants can begin to show sign, such as wilting or leaf spot. Bacteria are almost always present on plant surfaces and only cause problems when the conditions are just right, including high humidity, crowded plants, poor drainage or air circulation or proper irrigation is key to helping control any bacteria on plants. This condition is most active under hot humid conditions. Common symptoms are leaf yellowing beginning at the leaf tip-leaf margins. They may turn reddish brown instead of yellow during hot conditions, early signs of infection are small spots that turn yellow. The center will then turn brown as it worsens, the leaves will turn yellow and fall. In some cases, on different plants, leaf spots turn green, with reddish margin, mature spots turn brown or black, leaf stems begin to turn black and shrivel.
Solution – All plant diseases are preventable, however this one is one of the worst you can get. Prevention is crucial to reduce this scourge from your garden. Neglected, hot, humid gardens are often the ones hit the hardest with leaf spot. Increase air flow, reduce temperatures and try an application of sulfur in either vapor or powder form.
Rust
Rust: Rust are fungi from the Uredinales order. The majority of these species are plant parasites. Most of the rust have two or more host and possibly up to five spore stages. These type of fungi reproduce asexually. They travel by air causing foliar problems for several types of plant material. Rust can attack many varieties of plants but only one kind of rust can infect a plant at a time. Rust appears as orange-red spots becoming dark with time. Some diseases/fungus will become more active with the presence of excess fertilization as well as unpredictable weather conditions.
Solution – This disease is often mistaken for over fertilization, although the two go hand in hand. This fungus actually likes it when you over feed your plants. Copper and sulfur application will help with a reduced feeding regiment. Keep your garden environment consistent!
Black Spot
Black Spot of Rose: Diplocarpon Rosae- Black spot is the most common pest with roses. Black spot causes the entire plant to become weak and to slowly begin to produce less blooms. Infected plants will begin to show black spots on the top of the leaf surface, the spots will eventually spread to 1/2″ and typically have a fringed border, yellowing will begin to surround the spots on the leaves, causing the leaves to ultimately fall off. Black spot will sometimes infect cones where lesions appear purple colored and later turn black. To help control black spot, rake and remove all foliage that has fallen from the plant, this is the main source of fungal spores in the early spring, also be sure to remove any infected cones that may be present with a light pruning. Always plant roses in full sun to encourage the foliage to dry quickly after rain or irrigation. There are several fungicides available to control black spot. Contact you nearest plant shed for questions or concerns.
Solution – Copper seems to work best for this disease but the key here is removal of any infected foliage ASAP. This is not too common of a disease in other plants other then Roses, but I have seen it. Sulfur will also help.
In conclusion, Sulfur tends to be one of the best weapons against a broad spectrum of fungal and pest borne diseases. Copper, Neem and air flow come next. Above all, the conditions of your garden will dictate the health of your plants. Keep your grow environment cool, clean and healthy, and fungal disease will be a non-issue. Happy ALOHA Friday gang… Have a tremendous weekend and try something new!
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