Fund Project: Biological characteristics and prevention and control strategies of Fushou snail
Fund Project: Jiangxi Special Aquatic Industry System (JXARS-10) FundIng.
_ Yang Zongying
Pomacea canalicu-lata Lam, also known as large bottle snail and apple snail, is an amphibian of the gastropod family Ampullariidae belonging to the mollusk phylum Ampullariidae, and was identified as one of the first 16 most harmful alien species to invade China in 2003. Fushou snail prefers to eat aquatic plants such as rice seedlings, mustard fruit, and russet white, which has caused serious damage to agricultural production and ecosystem integrity in the invaded areas. At the same time, Fushou snail is also an important intermediate host for the zoonotic parasite Angiostrongyliasis cantonen-sis, which can cause eosinophilic meningitis in humans. The survey showed that the infection rate of Guangzhou tube schindular schindrichosis in Fushou snails was as high as 7.6%.
Fushou snail has a strong tolerance to high temperature, the highest critical water temperature can reach 45 °C, but the tolerance to low temperature is low, generally requires the water temperature to be maintained above 0 °C, Fushou snail can overwinter normally, which is also a key factor that has been restricting the invasion of Fushou snail. However, in recent years, due to global warming, there has been a continuous warm winter phenomenon, and Fushou snail can not only overwinter safely in many areas of China, but also is spreading north at a rate of 8-10km per year. In general, Fushou snail has posed a threat to biodiversity and public health in China and even the world, this paper summarizes the biological characteristics of Fushou snail and the corresponding prevention and control strategies, in order to provide technical guidance for the healthy development of aquaculture production, especially the comprehensive breeding of rice and fishery.
First, the biological characteristics of Fushou snail
1. Large amount of food, wide range of food. Fushou snail contains a large number of digestive enzymes, especially cellulase, and its strong digestive ability makes Fushou snail eat a large amount and miscellaneous. According to incomplete statistics, Fushou snail can feed on rice, lotus root, rhombus horn, russet white and other plants in up to 24 families and 43 species.
2. Strong resistance to stress. Fushou snail has both gills and lungs in the body, and can breathe in water with the gills, and can also breathe with the help of the lung sac, which is amphibious. Studies have shown that as the snail is moved north from subtropics to temperate farming, the biological zero degree of its egg hatching has decreased significantly, showing strong adaptability to environmental changes. At the same time, Fushou snail also has the habit of hibernating and hibernating, even in anhydrous conditions, it can sleep in moist soil for 6-8 months.
3. Strong fertility. Fushou snail is an hermaphrodite, and can lay eggs multiple times at a time of fertilization, with an annual egg production volume of up to 5000-9000 eggs.
4. Have the ability to protect yourself. Fushou snail shell is thicker, can play a good barrier role for itself, effectively avoid predators; snails in the encounter with natural enemies, will immediately sink into the water or hide in the soil, to avoid prey on eating; Fushou snail in spawning, generally choose to lay eggs above the water surface of the plant stem, stone or slope and other objects to avoid being ingested by aquatic animals, and the eggs contain neurotoxins, can also play a role in vigilance and avoid being eaten; the blood circulation of Fushou snails can quickly repair infected cells, This function can resist the infestation of pathogens such as Guangzhou tube strongiae.
Second, the diffusion mode of Fushou snail
It spreads in three ways: natural migration, aquatic plant introduction, and artificial introduction. Due to the poor food taste and strong fishy taste of Fushou snail, it has been abandoned; coupled with the limited natural migration ability of Fushou snail, the awareness of ecological protection in various regions, the continuous expansion of ecological restoration area and landscape construction, the introduction of aquatic plants has been increasing, and the introduction of aquatic plants has become the main way of transmission of Fushou snails in recent years.
Third, Fushou snail prevention and control strategy
At present, chemical control is still an important measure for the prevention and control of Fushou snail. However, many snail killing drugs, such as spiroclamide and its ethanolamine salt, are amide mollusk drugs recommended by the World Health Organization, which are low in toxicity to humans but more toxic to fish. With the vigorous development of comprehensive rice and fishery breeding in China, the aquatic animal-friendly "snail control" method will be the first choice.
1. Clean the rice paddies. In addition to eradicating field weeds and ditch edges after rice harvest and destroying the wintering site of Fushou snails, it is also necessary to plough and dry the fields and dredge the ring ditches, and cooperate with the sprinkling of quicklime.
2. Set up an interception network. The setting up of interception nets is one of the most effective and economical measures to prevent Fushou snails from entering agricultural production areas, and the interception nets set up in the inlets and outlets of rice fields or breeding ponds can prevent Fushou snails from entering.
3. Remove the egg mass. Snails mainly live in water, once they enter the breeding waters, it is not easy to kill, in the breeding season, the artificial removal of egg blocks, blocking egg hatching, is an effective way to prevent and control the spread of Fushou snails.
4. Manual snail hunting. In places where Fushou snails are dense, manual snail capture can be carried out and burned centrally, which does not damage the environment and is simple and easy to operate, but the cost is higher.
5. Artificial egg collection. Using the habit of Fushou snail to lay eggs on waterside supports, inserting several bamboo pieces on the edge of rice fields or ditches, inducing Fushou snails to lay eggs on bamboo chips, collecting egg blocks in a timely manner, and burning them centrally, can effectively reduce the number of Breeding Snails.
6. Quarantine of aquatic plants. Since the introduction of aquatic plants has become the main way of spreading Fushou snails, the relevant departments to strengthen the introduction and quarantine of aquatic plants is also an effective technical measure to prevent the accompanying spread of Fushou snails.