Complete Stem Parasite – Dodder
1. These are non-chlorophyll bearing leafless, twining parasitic seed plants. They are yellow, pink or orange in colour, they attach to the host.
2. The first appearance of parasite in field is noticed as small masses of branched, thread like, leafless stem, which are devoid of green pigment and twice around the stem or leaves of the hosts.
3. The leaves are represented by minutes functionless scales, which are evident on close examination, when the stem of parasites comes in contact with the hosts, the minute root like organs, haustoria penetrates into the host cortex and serves as an organ of food absorption.
4. When the relationship with the host is firmly established, the dodder plant losses the contact from soil.
5. The flowers are found in clusters, they are tiny, white, pink or yellowing in colour. The seeds are formed in capsule. A single plant may produce as many as 3000 seeds.
6. Dodder may also serves as a bridge for transmission of viruses from virus infected to virus free plant. There are 3 species of dodder:
i) Larger seed: – Cuscuta indicora
ii) Small seed: – Cuscuta planiflora
iii) Field dodder:- Cuscuta campestris
7. The common dodder Cuscuta granovil attacks clovers, berseem flag and many other oilseed crops. It also attacks ornamental and hedge plants. It is fast developing parasites and within 2-3 seasons may destroy a complete plant.
8. The dodder perepetuates through seeds which remain dormant in the soil unitl favourable seasons returns, stem portion of parasite is also meant of perpetuation.
Control Measures of Dodder:
1. Selection of dodder free seeds for sowing.
2. Preventing the movement of grazing animals from infected field to clean field.
3. Restriction of flow of irrigation water through infected field.
4. Destruction of flow of irrigation water through infected field.
5. Crop rotation with non host plants.
6. Dodder can be controlled by the use of soil herbicides, such as chloroproopham, DCPA, Dichobhil, Donoseb, glyphosate, these chemicals kills the dodder plant upon its germiantion from seed.