A disease is an interruption or disorder of a body or system. Diseases can be numeral and complex. Just as with humans, the best way to avoid diseases is to stay healthy. Diseases occur most often in weakened plants. Yet everybody gets sick sometime. Most diseases will pass automatically with time, but some are structural and can become be fatal. It is essential for a landscaper to be able to see the difference and act accordingly.
When diseases become structural, replace the plants with another species. Plants with diseases should not be moved. Investated plants and leaves should be removed and destroyed. Don’t add sickly plant litter to your compost either. Ventilation, sunhours and humidity are important factors for diseases, so make sure your plants are suitable for the local climate and their location.
plant viruses are intracellular parasites that use plants cells to replicate. There are many types of plant virus. Plant viruses are generally transmitted from plant to plant, through air or by insects. The viruses cause various types of plant diseases, but the diseases do not typically result in plant death. They do however, produce symptoms such as ringspots, mosaic pattern development, leaf yellowing and distortion, as well as deformed growth. . Some plant viruses are not limited to one particular plant host, but may infect different varieties of plants. Currently, there is no cure for plant viral disease. This means that any infected plants must be destroyed .The best methods being employed to combat plant viral diseases are aimed at prevention. These methods include ensuring the seeds are virus-free, creating optimal growing conditions and removing and destroying infected plants and plant parts.
Bacteria and Protozoa
Most bacteria that are associated with plants do no harm to the plant itself. However, a small number, around 100 known species, are able to cause disease.There are a few examples of plant diseases caused by protozoa They are transmitted as zoospores that may be able to survive in a resting state in the soil for many years. generally these zoospores attach and interact with the plant roots and cause few problems. Bacteria can also be used as organic pesticides; Milky spore is responsible for a disease of the white grubs and can be used in lawn care.
Nematodes are small, multicellular wormlike animals. Many live freely in the soil, but there are some species that parasitize plant roots. Just like bacteria, nematodes can be beneficial or damaging. Nematodes are able to cause radical changes in root cells in order to facilitate their lifestyle. Nematodes are common on the roots of legume plants and help transforming the nitrogen in the air into a form of nitrogen that can be used in the soil for fertilization. Nematodes are also used as a natural pesticide for lawn grubs.
The fungi reproduce via the production of spores . Spores may be spread long distances by air or water, or they may be soilborne.The fungus may appear on the foliage, near the base of the plant, in the soil or on the fruit and flowers of the plant. Though some fungal outbreaks can be a simple cosmetic hassle, other fungal outbreaks can cause permanent injury and even death of the plant. The fungal species that cause these outbreaks vary by the millions.Plants that are infected with fungal diseases may also develop cankers, lesions and rot. Phytophthora rot, crown rot and botrytis are common rot diseases caused by fungi. While some rot diseases are curable with fungicidal treatments, others are irreversible.
Blight is not a disease but a symptom. It is a rapid and complete decoloration, browning, then death of plant tissues such as leaves, branches, twigs, or floral organs Many diseases caused by viruses, bacteria or fungi exhibit this symptom and are called blights.