What are the hazards of dodder seeds? Is it true that dodder seeds can nourish the growth of surrounding plants? Below is a detailed explanation.Dodder seeds, also known as yellow eel vine, include common varieties like Japanese dodder and Chinese dodder, with the former being more prevalent. They are distributed across Guangxi, Guangdong, Hainan, Fujian, Yunnan, Guizhou, Sichuan, Inner Mongolia, Hunan, and Taiwan. Besides parasitizing longan, they can also infest lychee, citrus, sand pear,butterfly fruit, tea, camellia, tung tree, Taiwan acacia, neem, rosewood, willow, and various other fruit trees and forest species.Dodder parasitizes fruit trees by absorbing water and nutrients from the host. Its vines grow rapidly, often twining around branches and even covering the entire canopy. This not only impairs photosynthesis in leaves, causing yellowing and defoliation, but also weakens the tree's vigor. In severe cases, affected trees fail to grow, flower, or bear fruit, and may experience branch dieback or complete plant death.【Growth Damage】
Host Plants: Hibiscus, azaleas, roses, snowball bush, osmanthus, peonies, coral trees, Japanese maples, holly, privet, potatoes, peanuts, flax, ramie, and leguminous forage crops.
Damage Symptoms: During seed germination, the young shoot appears colorless and filamentous, attaching to soil particles. The opposite end forms a thread-like dodder stem that twists in the air. Upon contact with a host plant, it wraps around it, forming a root-like structure at the point of contact. Once inside the host tissue, some cells differentiate into xylem and phloem vessels, connecting with the host's vascular system to absorb nutrients and water.At this stage, the primary dodder dies off, while the upper stem continues elongating and forming new rootlets. The stem branches repeatedly, extending rootlets that spread outward in all directions. In severe cases, the entire host plant becomes entangled with dodder, causing stunted growth. Some hosts may die entirely due to malnutrition compounded by dodder entanglement.
Dodder's Impact on Other Plants | Dodder's Hazards
【Primary Symptoms】
Morphology: Japanese dodder lacks roots and leaves or has reduced leaves. Its stems are relatively thick, slightly reddish, and grow by twining. It spreads rapidly, and severed stems can continue growing after forming sucker roots. Flowers are pale pink, and fruits are spherical. Each dodder plant produces 5,000–6,000 seeds. The seeds are small, smooth, and can survive in soil for several years.
Life Cycle: In Shanghai, dodder flowers in September and seeds mature in October. Seeds fall into soil, overwinter dormant, or germinate successively from February/March to June the following year. Upon finding a host, they entwine and cause damage. Without a host, they can survive independently for up to one and a half months under suitable conditions.Host range is broad, primarily woody plants but also herbaceous plants. It spreads rapidly, damaging seedlings, young trees, and shrubs, though it cannot harm aged bark. Tall trees are colonized via root-sprouted shoots or by using other hosts as bridges for upward spread.
【Control Methods】
⑴ Horticultural Control: In severely infested areas, perform deep tillage annually. Burying seeds below 3 cm depth prevents emergence. Conduct inspections in late spring to early summer. Upon detection, remove and destroy dodder along with weeds and infected plant parts. Eliminate sprouting shoots and wild plants serving as bridges.
⑵ Chemical Control: During peak seed germination, apply a ground spray of 1.5% sodium pentachlorophenol and 2% propyzam solution. Repeat spraying every 25 days for a total of 3–4 applications to kill dodder seedlings.
This concludes our overview of dodder's hazards and its impact on plant growth. We trust you now have a clearer understanding. Wishing you good health and happiness.