Potato dodder damage

(host crop) potatoes, tomatoes, eggplant, chili, green onions, soybeans and other crops. (disease diagnosis) sporadic or nesting in the field. Dodder wrapped around the stem of the plant with rattan stem, twisted, sucked roots grew in contact with the potato plant and extended into the stem or petiole tissue to absorb the water and nutrients of the plant, resulting in the growth of the injured plant. The plant is short, the stem is curved and thin, the leaves are small and yellow, and the tubers are few and small. The stems and leaves of severe plants are covered with dodder, and the whole plant does not decay for long until it dies. The pathogenic dodder is Chinese dodder. The stem of dodder is slender, yellow and chlorophyll-free. After contact with the host stem, the stem comes into contact with the haustorium and attaches to the host surface to absorb nutrition and water. Flowers small, white, style two, capitate, sepals ridged, ridged longitudinally, sepals angled, sepals abaxially longitudinally ridged, stamens and Corolla split alternately, fruit a capsule, completely wrapped in Corolla when ripe, circumflex when broken, seeds round.

Dodder seeds fall into the soil after maturity, or mix among host seeds and overwinter with organic fertilizer. In the following spring, the dodder seeds overwintering in the soil germinated, and a bud (young stem) 6 to 10 centimeters long stood in the field, its top constantly turning or shaking, and winding it once it came across a parasitic plant. After the stem of dodder comes into contact with the stem of the entangled host plant and sucks out the root, and firmly wedges into the interior of the host plant to establish a parasitic relationship, dodder and its underground part immediately detach and begin parasitic life. The sucking root of dodder is formed by protruding vascular bundle sheath, which extends into the host tissue and differentiates into ducts and sieve tubes, which are connected with the ducts and sieve tubes of the host plant, respectively. as a result, it continuously absorbs a large amount of water and nutrients needed for its growth and development from the host. Dodder is twining one host plant after another in the field, constantly spreading in all directions. Dodder blossoms throughout the growth period. Although the flowers are small and numerous, they produce a large number of seeds. After the seeds are mature, most of them fall into the soil, the seed shell is hard and the stress resistance is strong, and the seeds can survive in the soil for 5 to 10 years. The terrain is low-lying, moist, the plant is closed, dodder damage is serious.

(control measures) (1) select seeds to prevent dodder seeds from mixing into the field. (2) the dodder plot should be turned over to a depth of more than 20 cm immediately after harvest, and the dodder seeds should be turned into the deep soil so that they can not germinate. (3) the manure mixed with dodder seeds must be fully fermented to make dodder seeds lose their germinating power or rett. (4) plastic film mulching cultivation can significantly reduce the incidence of disease. (5) ploughing and weeding should be carried out in time when dodder sprouts and is not yet wound. (6) when you see sporadic dodder winding for the first time, remove the dodder vine thoroughly before blooming and bearing seeds, take it out of the field and burn it or bury it deeply. When removing, remember not to leave the egg decapitated. (7) for chemical control, the most effective agent is spraying Lubao No.1. The concentration required is not less than 30 million live spores per milliliter of water, 22.5 liters per 667m2. Spray after rain or evening and on cloudy days. If the wound is caused by breaking the stem of dodder with a stick before spraying, the control effect is more obvious.