Plant Diseases and How to Avoid Them
We all try to keep our gardens and plants in the best health we can, which means trying to avoid plant diseases. There are many different types, and not all plants are susceptible to the same kinds. Some key factors in avoiding disease is keeping soil in good health, regular watering and care, and choosing native plants which are not as prone to plant disease as plants not from our area. There is a wide range of plant diseases that can affect your yard and garden that range between bacterial and fungal. Below are a few of the most common kinds.
Different Types of Disease
Rust is a fungal parasite that grows on a wide range of plants, a common one being pear trees. It can be identified as yellow, brown, or red spore masses on the outside of the plant and appear as raised dots on the leaves and stems of the plant. Rust starts from the ground up and is most common on the underside of the leaves, but also can appear on the top and may cause leaves to fall prematurely from the plant. Rust can occur during wetter times of the year, especially if the leaves are wet for longer than 6 hours in 20-30°C weather.
Canker is caused by numerous species of fungi and bacteria and typically affects woody species. It can be defined as a dead area on the bark found on the trunk or branches and is usually found on wounded or stressed trees. Once a limb has canker, foliage does not grow past the infected spot and can also weaken branches, causing them to break off. This is a common disease for apple trees.
Scab is a fungal disease causing crustaceous lesions on fruit, tubers, leaves, or stems, potatoes and apples being some of the many affected. Leaves on affected plants or trees can wither or drop early and looks like pale yellow or olive green spots on the upper surface of leaves and dark, velvety spots on the lower surface of leaves. Symptoms on the fruit can appear as sunken and tan and may have velvety spores in the middle of the spots.
Powdery mildew is a fungal disease that looks like a white powdery substance, most common on the upper surface of leaves, but can also affect the stem, flower buds, and fruit of a plant. The fungus thrives when the soil is low in moisture and there are high humidity levels on the upper parts of the plant surface and affects plants in shady areas more than in direct sun. Some of the plants commonly affected by powdery mildew is squash plants, tomatoes, Roses, beans, and peas.
Black spot is a fungal disease that forms round black spots on the leaves and can cause leaves to turn yellow and fall off the plant. Roses are one of the main plants affected by black spot. It typically starts at the bottom of the plant and continues up the plant, causing it to lose all of its leaves. Newer Roses are bred to be more resistant to diseases nowadays.
Downy mildew is related to algae and produces fuzzy grey spots on the lower surface of leaves and pale green or yellow spots on the upper surface of leaves. Downy mildew occurs most in cool, moist weather such as in spring and fall. Affected leaves will wilt and die early. Powdery mildew and downy mildew often get confused and the easiest way to tell the difference is powdery mildew does not get spots, only the white powdery substance.
What to do if Your Plants Have a Disease and How to Avoid Them
If you have any of these diseases in your yard, most are treated the same way for removal. Prune or remove all affected plants and place them in bags to be taken to your landfill, do not put infected plants in your compost as they will continue to thrive and infect gardens your compost will get added to. When watering, try to water the bottom of the plants so leaves do not end up with water on them for hours, and space plants far enough apart to increase airflow. When using your pruners, make sure to disinfect them after using so as not to spread any disease to healthy plants. Many people only prune apple trees in the fall, but doing a prune in the summer can benefit the trees by removing any disease and thinning fruit to allow the fruit left will get the most of the trees growing energy and produce bigger, healthier fruit, as well as improve the harvest for the following year. If you would like help with your apple trees, we can do the pruning for you. Contact us to book for next year!