Overview
Pertusaria trochisea is a type of crustose lichen that belongs to the family Pertusariaceae. This lichen is characterized by its circular, thin, pale gray thallus that is often adorned with small perforations called ostioles.
Appearance
This lichen has a circular, thin, pale gray thallus that measures about 0.5-2 cm in diameter. It has small perforations called ostioles that give it a sieve-like appearance. The ostioles are slightly raised and range in color from dark gray to black. The underside of the thallus is smooth and black.
Origin and Distribution
Pertusaria trochisea is found in many parts of the world and is commonly found in North America, Europe, Asia, and Africa. This lichen is known to grow on bark, mossy rocks, limestone, and other calcareous substrates.
Uses
Like most lichens, Pertusaria trochisea is not known to have significant medicinal or culinary uses. However, it is often used as an indicator species to determine the quality of air and water in a given area. It has been found that this lichen is sensitive to air pollution, particularly sulfur dioxide, and can be used to detect levels of air pollution in an area.
Light Requirements
Pertusaria trochisea Norman typically grows in a shady environment, such as in the forest floor or under a canopy. It can tolerate some exposure to sunlight but is generally found in areas with less intense light.
Temperature Requirements
The optimal temperature range for Pertusaria trochisea Norman growth is between 5°C to 20°C. It may tolerate lower temperatures but is not known to tolerate higher temperatures.
Soil Requirements
Pertusaria trochisea Norman can grow in nutrient-poor soil but thrives better in well-drained, humus-rich soil. It is often found in rocky or gravelly soil that provides good drainage.
Cultivation Methods
The plant Pertusaria trochisea Norman is a type of lichen and can be found growing in the wild on rocks and trees in areas with high humidity and rainfall. However, if you want to cultivate it at home, you need to recreate these conditions. You can start by obtaining a small fragment of the lichen and attaching it to a rock or other substrate with tree bark, moss, or soil. Ensure that the substrate is moist but not waterlogged, and keep it in a shaded or partially shaded spot with good air circulation.
Watering Needs
Pertusaria trochisea Norman does not require frequent watering as it absorbs moisture from the air and rain. However, if the substrate dries out completely, you can mist it with water to keep it moist. Avoid over-watering as this can lead to the growth of mold and other fungi, which can harm the plant.
Fertilization
Pertusaria trochisea Norman does not require fertilization as it obtains its nutrients from the air and the substrate it grows on. However, you can add a small amount of organic fertilizer to the substrate once a year to provide additional nutrients if necessary.
Pruning
Pertusaria trochisea Norman does not require pruning as it grows very slowly. However, if you notice any dead or damaged areas, you can gently remove them with a pair of scissors or a sharp knife. Avoid damaging the healthy parts of the lichen.
Propagation of Pertusaria trochisea Norman
Pertusaria trochisea Norman, commonly known as "Wheel Disc Lichen," is a slow-growing lichen that grows on rocks and tree barks. Propagation of this plant can be done through two methods; vegetative propagation and spore propagation.
Vegetative propagation
Vegetative propagation involves dividing the plant into smaller parts and planting them in suitable conditions, giving each segment the opportunity to generate a new colony. This method requires careful selection of the parent plant and the lateral lobes or fragments which would be used for propagation.
The propagation process should be done during the growing season or during periods of resumption from dormancy. It is important to ensure that the segments or lobes are not pulled off the parent plant to avoid damaging the main colony.
After the selection process, the lobes should be planted into suitable substrates that would provide adequate nutrition, moisture, and necessary growth conditions. Suitable substrates include tree barks, rocks, or other natural materials found in the lichen's natural habitat.
Spore propagation
Spore propagation involves isolating the spores from the lichen and propagating it in a suitable growth media. This method requires a significant amount of effort to ensure the spores' hygiene and successful germination.
The spores are collected from the fruiting bodies of the lichen, which generally mature between late autumn to early spring. These spores should be collected through pipette or brush and placed in nutrient media such as potato dextrose agar or oatmeal agar.
The petri dishes should be incubated in a cool, dark place with proper ventilation. The spores germinate between 4 to 6 weeks and develop into a thallus. The spores should be mature before detachment to avoid any damage to the immature thallus.
Finally, the mature thallus can be transplanted into a suitable substrate that provides a good environment for growth. It can take several years for the transplanted thallus to fully colonize the substrate.
Disease Management
Pertusaria trochisea Norman is susceptible to several diseases including:
- Lichenicolous fungi: These fungi infect the lichen thallus (body) and subsequently alter its morphology or kill the lichen. Lichenicolous fungi can be controlled by adopting strict hygiene practices such as removing infected plant debris and using sterilized pruning tools to prevent the spread of spores. Additionally, fungicidal sprays can be applied to the plant to control fungal infections.
- Phytophthora cactorum: This fungus causes stem cankers that may result in wilting, dieback and eventual death of the plant. There is no cure for Phytophthora cactorum, but preventative measures such as providing adequate drainage and irrigation can aid in reducing infection levels. In cases of severe infection, infected plants should be removed and destroyed to prevent the spread of disease.
- Lichodina pini: This parasitic alga causes yellow or orange patches on the lichen surface. Prompt removal of infected plant material can help reduce disease incidence. Fungicidal sprays can also be used to control Lichodina pini.
Pest Management
Several pests can attack Pertusaria trochisea Norman, including:
- Spider mites: These pests can cause yellowing of the plant leaves and stunted growth. Spider mites can be controlled using a suitable insecticide spray or by introducing biological control methods such as predatory mites.
- Scale insects: These pests feed on plant sap, causing stunted growth and yellow leaves. Scale insects can be managed by introducing predatory insects such as parasitic wasps or by using insecticidal sprays.
- Mealybugs: Mealybugs cause yellowing of plant leaves and the secretion of honeydew, which can attract ants and other pests. Biological control methods such as introducing parasitic wasps can be used to manage mealybugs. Insecticidal soaps or oils can also be applied to control mealybug populations.
