Are there any small, round to irregular spots on older leaves?
Are the fruits and pods covered with white powder?
Are the leaves covered with small bumps?
Are the leaves yellow and the plant looks weakened?
Phyllosticta leaf spot causes small, round to irregular spots to form on older leaves. Spots have purple borders and yellow halos. Avoid overhead watering. Apply a fungicide to protect healthy plants.
White, powdery patches on the fruits and pods are caused by a fungal disease Powdery mildew (Oidium heveae and Oidium bixae). Powdery mildew usually appears in damp places. Encourage good air circulation around the affected plants by thining them and any surrounding plants. Water plants from below to keep foliage dry. The appropriate fungicidal spray will protect your plant from further infections.
Leaves covered by small bumps are caused by scales. These tiny, shelled insects often feed on the undersides of the leaves, causing an unhealthy appearance with yellowish blotches on the upper leaf surfaces. Scrape off minor infestations with your fingernail. Prune out badly infested growth, or use a soft brush and soapy water to gently scrub the scales off the stems. Control scales by spraying insecticidal oil during the growing season.
Yellow leaves and stunted look are caused by whiteflies. These tiny, mothlike flies and their larvae feed by sucking plant juices. Whiteflies secrete honeydew, a sugary substance that makes leaves sticky to the touch. Control whiteflies by eliminating garden weeds and by introducing green lacewings in the garden. Spray infested plants with insecticidal soap every 3 days for 2 weeks.
Feeding of the thrips causes stippling, discolored flecking, or silvering of plant surfaces, accompanied by black flecks of frass. Thrips are tiny, yellow to black flying insects. They hide under leaves and inside flowers. Severely infested plant parts should be pruned off and destroyed. Control thrips by introducing lady beetles or lacewings. Insecticidal soap helps in severe infestations.
https://www.cabi.org/isc/datasheet/9242#tonaturalEnemies
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/
