Are there any small, necrotic flecks on leaves that develop a chlorotic halo and expand into tan brown necrotic spots?
Are the leaves mottled with dark green?
Are there any yellow and wilting leaves, brown streaks appear on a lower surface of leaves, the growth is stunted?
Are the leaves curled and distorted?
Do the leaves have holes?
Cercospora leaf blight is caused by a fungus that can be introduced through infected seed and spread by wind or water splash. Plant only pathogen-free seed from a reputable nursery. Apply copper-based foliar fungicide if the disease emerges. Keep the area clean and be sure to dispose of plant debris. Prune all affected tissue, but before pruning the plant, dip the shears in a mix of 70 percent denatured alcohol and 30 percent water to retard the spread of the disease.
Mottled or streaked leaves are caused by Mosaic Virus. There is no cure for infected plants. Remove and destroy all plants that have the symptoms of the mosaic virus. Mosaic virus is spread by aphids, so the best way of preventing the disease is to control these insects.
Fusarium wilt is a fungal disease that causes these symptoms. High soil temperatures favor the disease emergence. Use only disease-free seed. Treat seeds with hot water to kill fungi before planting. Destroy affected plants at the first sign of fusarium. Rotate crops to non-susceptible species.
Distorted and curled leaves are caused by aphids. These tiny insects cluster under leaves and on growing tips where they feed on plant sap. You can control them by washing them off the plant with water spray. Insecticidal soap should be used with severe infestations.
Various caterpillars attack patchouli foliage, and make holes in the leaves. You can handpick and destroy them if the infestation is not severe. BTK spray will help in controlling caterpillars.
Yellow, stunted plants and roots that have swollen galls indicate root-knot nematodes. Other symptoms are plants wilting during bright, hot days. Prevent root-knot nematodes by applying chitin or introducing parasitic nematodes to the soil before planting. Solarizing the soil also helps in preventing root-knot nematodes.
https://www.gardeningknowhow.com/edible/herbs/patchouli/growing-patchouli-herb-plant.htm
http://nhb.gov.in/model-project-reports/Horticulture%20Crops/Patchouli/Patchouli1.htm
Ellis, B. W., Bradley, F. M., & Atthowe, H. (1996). The Organic gardener's handbook of natural insect and disease control: a complete problem-solving guide to keeping your garden & yard healthy without chemicals. Emmaus, Pa.: Rodale Press.
Sreten null
Hi! I’m Sreten Filipović. I graduated from the Faculty of Agriculture at the University of Belgrade, with a master's degree in Environmental Protection in Agricultural Systems. I’ve worked as a researcher at Finland's Natural Resources Institute (LUKE) on a project aimed at adapting south-western Finland to drought episodes. I founded a consulting agency in the field of environment and agriculture to help farmers who want to implement the principles of sustainability on their farms. I’m also a founding member of the nonprofit organization Ecogenesis from Belgrade whose main goal is non-formal education on the environment and ecology. In my spare time, I like to write blog posts about sustainability, the environment, animal farming, horticulture, and plant protection. I’ve also published several science-fiction short stories.
You can find me on LinkedIn at https://www.linkedin.com/in/sreten-filipovi%C4%87-515aa5158/
