Are the leaves yellowing, wilting and, dying?
Are there any tiny holes in leaves?
Are the leaves yellow and the plant looks weakened, tiny, white insects are present?
Are the leaves curled and distorted?
Are the leaves covered in coarse stippling and may appear silvery?
Yellow leaves that wilt and die usually indicate Root rot. Several pathogens cause root rots of seedlings as well as mature plants. Poorly drained, overly wet soil promotes rot so choose well-drained sites and add organic matter to improve drainage. Remove and destroy infected plants. Solarize the soil before replanting.
Tiny holes in Cupheas leaves are caused by Flea beetles. These tiny, black, brown, or bronze beetles hop when disturbed. Larvae are small and white, feed mostly on the undersides of leaves. Prevent problems by covering young plants with row cover. Control severe infestations by spraying or dusting plants with pyrethrin.
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.
Distorted and curled leaves are caused by aphids. These tiny insects cluster under leaves and on growing tips where they feed on plant sap. Leaves, stems, and buds get distorted and later leaves and flowers drop from the plant. You can control them by washing them off the plant with water spray. Insecticidal soap should be used with severe infestations.
These symptoms may indicate thrips. Thrips are tiny, yellow to black flying insects. Severely infected plant parts should be removed and destroyed. Control thrips by introducing lady beetles or lacewings, their natural predators. Insecticidal soap helps in severe infestations.
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.burpee.com/gardenadvicecenter/encyclopedia/annual-flowers/learn-about-cupheas/encyclopedia__Cuphea-article.html
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.
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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/