What is the main harm of alternanthera philoxeroides? What are the prevention and control methods?

On the surface of the pond in summer, we can often see a piece of green covered with white balls in the middle. These are the heads of alternanthera philoxeroides. Alternanthera philoxeroides has been distributed in most parts of China, causing serious invasion in the southeast. What is the main harm of alternanthera philoxeroides? What are the prevention and control methods?

First, what are the main hazards of alternanthera philoxeroides?

1. Cover the water surface, block the waterway, and affect human aquatic economic activities.

2. Invade urban green space such as parks and lawns, destroy the landscape and increase the cost of maintenance.

3. Harm farmland and reduce crop yield

4. breeding mosquitoes and flies, and often attached to harmful parasites, endangering the health of human beings and animals

5. Strong fecundity, crowding out other plants, reducing the stability of plant community and destroying ecological environment.

Alternanthera philoxeroides is highly communicative. Its stem is hollow, brittle and easy to break, often a section of plant fragments or stem nodes may be a new source of infection, and its stored roots can produce a large number of adventitious roots and buds when disturbed or stimulated, so it is easy to spread with human activities. Genetic studies have shown that alternanthera philoxeroides, which is widely distributed in China, was widely spread in a short period of time after the invasion, and its population genetic diversity is very low, which may be cloned offspring of the same clone.

Second, what are the control methods of alternanthera philoxeroides?

Alternanthera philoxeroides can eat both land and water, which is inseparable from its fickle physiological characteristics. In the water body, alternanthera philoxeroides shows semi-erect and creeping growth, the root can be attached to the bank mud, while the stem has a larger cavity, which produces a greater buoyancy to float on the water surface, from which the word "hollow" comes from. While living in dry land, alternanthera philoxeroides shows a creeping growth state, relying on adventitious roots growing at nodes to continue to spread, while specializing in nearly 1 cm thick, more than one meter long storage root, root hair, plant height generally 30cm, stem solid. Its stem nodes, coarse roots and underground roots can all grow and spread through fragments. If we see a large area of plants with long oval opposite leaves and small white globose inflorescences on the lawn, mudflat or water surface, nine times out of ten, it is alternanthera philoxeroides. However, the control effect of alternanthera philoxeroides leaf beetle on terrestrial alternanthera philoxeroides is not good, so it is mainly controlled by artificial mechanical eradication and chemical herbicide spraying.

1. Biological control

When the minimum temperature in early spring rises to more than 10 ℃, the adult of lotus grass straight-breast jumper beetle is released, and 1000-3000 adults per hectare are released, which can control its damage and spread. However, it is effective to control aquatic type plants with lotus grass straight breast leaping beetle, a specialized natural enemy originally from South America, but not for land type.

2. Agricultural measures

At ordinary times, it is necessary to strengthen field management, not rough farming, intensive cultivation, repeated and meticulous pulling out and cleaning of alternanthera philoxeroides seedlings, digging up the residual stems and nodes in the soil, and concentrated drying and burning. In areas where alternanthera philoxeroides have not been found, precautions should be strengthened to prevent asexual reproduction from invading pastoral, grassland or water areas. In areas where it has occurred, measures should be taken to control its spread.

3. Physical prevention and control

When uprooting and salvaging alternanthera philoxeroides manually and mechanically, the alternanthera philoxeroides should be dug or salvaged as deep as possible. The alternanthera philoxeroides can be centrally burned or fully ripe and retted into green manure. In addition, in the case of unsatisfactory chemical control effect, we can first salvage and remove part of alternanthera philoxeroides, depress the population density of alternanthera philoxeroides, and then spray pesticides.