Red imported fire ants are among the most dangerous invasive species and have spread to more than 10 provinces in China.

　　Schematic diagram of body structure and stinging and biting of red imported fire ants.

　　The quarantine personnel carried out the quarantine of red imported fire ants on flower seedlings.

　　An ant hill formed by the nest of red imported fire ants.

　　Popular science poster about the knowledge of red imported fire ants.

　　Provided by WeChat public account "Foshan Agriculture"

　　Recently, nine departments, including the Ministry of Agriculture and Rural Affairs, the Ministry of Housing and Urban-Rural Development and the Ministry of Transport, jointly issued the Notice on Strengthening the Prevention and Control of Red imported fire ants (hereinafter referred to as the Notice), and held the launching ceremony of the National Joint Prevention and Control Action of Red imported fire ants in Zengcheng District, Guangzhou. The red imported fire ant and its prevention and control have aroused widespread concern and become one of the hot topics discussed by people.

　　What kind of insect is red imported fire ant? From where? Compared with the familiar ants, what are their characteristics and harmfulness? At present, what is the spread and harm of red imported fire ants in China? What are the effective scientific prevention and control measures for red imported fire ants?

　　Fierce in nature, with great ecological harm.

　　Many Chinese people are undoubtedly strangers to red imported fire ants. Indeed, this insect, which originated in the border areas of Brazil, Paraguay and Argentina in South America, is an authentic alien invasive creature, and its popularity in society was not high before. As its name suggests, the red fire ant is red scorpion-colored, and its shape is similar to that of common ants, about 3 mm to 6 mm long. It looks unattractive and seems to have nothing special.

　　Nine departments in the State Council jointly issued a notice of interception and prevention, and launched nationwide joint prevention and control. The high-standard "treatment" of red imported fire ants in China shows that this insect is not only very harmful, but also difficult to prevent and control. Indeed, the Latin scientific name of red imported fire ant means "invincible ant", which reflects its great harm from one side. According to Professor Lu Yongyue, director of the Red Fire Ant Research Center of South China Agricultural University, the invasion of red fire ants will lead to serious ecological problems, destroy the normal production and living order, and it is very difficult to kill and prevent.

　　Specifically, the harm of red imported fire ants can be summarized as the following four aspects: First, it destroys the local ecological structure. Solenopsis invicta has strong adaptability. After invading a place, it often develops rapidly into a dominant population, which not only "exterminates" other types of ants in the place, but also exterminates beneficial insects such as spiders, causing great damage to the original ecological structure and serious ecological imbalance. The second is to reduce crop production. Solenopsis invicta directly feeds on seeds, fruits, buds, tender stems, rhizomes, etc. of crops, and transports and grazes honeydew-secreting pests such as aphids and scales to spread plant diseases and insect pests. These directly caused great losses to local agricultural production. Third, it threatens people’s health and even life safety. After being disturbed, the red imported fire ants will not only escape in scattered directions, but also have strong group aggression. By injecting venom into the victim’s skin through stinging, people who are allergic will have symptoms such as blushing, urticaria, and even difficulty breathing. Those with severe allergic reactions will have symptoms such as vomiting, dizziness and shock. If they are not treated in time, they may be life-threatening. The fourth is threatening public safety. Because red imported fire ants often invade outdoor and home nearby electrical equipment, such as electric meters, telephone switchboard, traffic signal cabinet, etc., it may cause short circuit of wires or facility failure, which may lead to public safety accidents.

　　It is precisely because of the serious harm of red imported fire ants that the media have quoted experts’ symbolic evaluation that red imported fire ants are "one of the 100 most dangerous invasive species recognized worldwide".

　　Three-dimensional communication is difficult to prevent and control.

　　Solenopsis invicta is not only harmful, but also difficult to control, which is largely determined by its species characteristics and the process of economic globalization.

　　The breeding speed of Solenopsis invicta is amazing, which increases the difficulty of killing. In the colony of Solenopsis invicta, the queen is the key role responsible for laying eggs and reproducing offspring. In some nests, there will be several or even dozens of queens, and each queen can lay 1,500 to 5,000 eggs a day. The number of Solenopsis invicta can increase greatly in a short time, resulting in an extremely large scale of ant colonies. Some nests may have as many as hundreds of thousands or even hundreds of thousands of Solenopsis invicta.

　　In a certain area, Solenopsis invicta can spread and reproduce in a three-dimensional natural way. Solenopsis invicta can spread to the neighboring areas through nest migration and nest division. Although the distance of each crossing is not large, after a certain period of accumulation, this slow and steady strategy can show the long-term effect of "attacking the city slightly". In addition, red imported fire ants can spread in the air for a long time in a short time. Male and female reproductive ants can mate at a height of hundreds of meters and land several kilometers away to start nesting, thus rapidly expanding new space. It is worth noting that the water flow not only can not achieve the effect of killing red imported fire ants, but also helps them to migrate across distances. Some red imported fire ants build their nests on riverbanks or low-lying places. With the flood coming, although their nests will be submerged, the ant colonies will form an "ant cutting" and drift with the water. When they meet a suitable nesting place, they try to go ashore to build their nests and live in a new place.

　　With the development of domestic unified market and the deepening of economic globalization and regional economic integration, there are more and more cases of red imported fire ants spreading through logistics and human factors such as objects and vehicles, and it is more and more difficult to prevent and control them. It is through international trade, especially international horticultural plants and agricultural products and the subsequent soil movement that red imported fire ants escape customs inspection and realize transcontinental and transnational transmission, and then continue to spread in a country in a similar way in areas suitable for survival.

　　The difficulty of prevention and control of red imported fire ants lies in its concealment in the early stage of invasion. The mature nest of Solenopsis invicta will form an obviously raised mound of sand, which is easy to be identified, but it is relatively hidden and difficult to be detected when it is first built. By the time it was discovered, its invasion had developed to a certain extent, which delayed the opportunity of governance and increased the difficulty of prevention and control.

　　Invasion of more than 16 years, urgent need to contain.

　　In late September, 2004, a serious ant was found in Wuchuan City, Guangdong Province. Lu Yongyue, as one of the experts, identified this ant as red imported fire ant through morphological identification and field investigation in Wuchuan, and confirmed that red imported fire ant invaded Chinese mainland for the first time. Related experiments show that the newly discovered Solenopsis invicta in Wuchuan has 100% homology with Solenopsis invicta from Florida, USA. The results of field investigation show that the occurrence density of Solenopsis invicta in some places, such as barren slopes, grasslands and ridges full of weeds, is high, which has adversely affected local agricultural production, people’s health and daily life. These findings provide an important scientific basis for early warning, prevention and rapid eradication of the invasion of red imported fire ants.

　　In January, 2005, the Ministry of Agriculture issued an announcement, officially announcing the discovery of fire ants in Wuchuan and other places, and including fire ants in the list of quarantine pests of imported plants and the list of quarantine pests of agricultural plants in China. At the same time, the Ministry of Agriculture issued the Emergency Plan for the Prevention and Control of the Red Fire Ant Epidemic (hereinafter referred to as the Emergency Plan), announced the four levels of the red fire ant epidemic and the corresponding response mechanisms, and determined the organization and leadership system suitable for the first-level response, such as establishing the inter-ministerial joint meeting system and establishing the red fire ant epidemic prevention and control headquarters. In addition, the Emergency Plan also stipulates that after the corresponding level of emergency response, relevant parties should immediately start to do a good job in epidemic situation confirmation, epidemic situation report, epidemic situation announcement, blockade control, prevention and control, epidemic situation investigation and monitoring, and entry-exit quarantine. In April and November of that year, the Ministry of Agriculture announced the epidemic situation of red imported fire ants in Hunan, Guangxi and Fujian.

　　Although some achievements have been made in the prevention and control work, due to the huge number of transmission vectors, especially in recent years, due to the increase in the number of goods transported and the suitable climatic conditions, the spread of Solenopsis invicta in some provinces and regions has accelerated and the epidemic situation has aggravated. At present, Solenopsis invicta has spread to 435 counties (cities, districts) in 12 provinces (autonomous regions and municipalities), with the northernmost part reaching the Yangtze River valley, Zhejiang and Jiangxi in the east and Guizhou, Chongqing and Sichuan in the west.

　　The "Notice" jointly issued by nine departments recently is the latest deployment on the prevention and control of the interception of red imported fire ants under the background that the Biosafety Law of People’s Republic of China (PRC) was passed and will be implemented on April 15th, and the practical measures to strengthen the management of alien invasive species according to law have been introduced, which can be said to be unprecedented.

　　Joint prevention and control, comprehensive management

　　Solenopsis invicta invaded Chinese mainland through imported goods. More than 300 batches of 17 kinds of articles intercepted at the entry port confirmed that waste articles (waste paper, waste electronic products, etc.) and logs were the main ways to carry Solenopsis invicta into China. The spread of Solenopsis invicta in China is mainly carried by turf and flower seedlings, and 27 of the 95 flower seedlings surveyed carry Solenopsis invicta. The incidence of red imported fire ants in turf plantation was 48.8%; Among the 122 introduced areas, the invasion rate of turf/seedlings was 85.2%.

　　The "Notice" grasps the two keys of external defense input and internal non-proliferation, and requires strengthening departmental coordination. Specifically, the Ministry of Agriculture and Rural Affairs, together with the Ministry of Housing and Urban-Rural Development, the Ministry of Transport, the Ministry of Water Resources, the Health and Wellness Commission, the General Administration of Customs, National Forestry and Grassland Administration, the State Railway Administration and the State Post Bureau, established an inter-ministerial cooperation and joint defense mechanism for red imported fire ants to organize and coordinate the prevention and control of interception. Among them, the customs directly under the customs are required to be responsible for organizing the monitoring of the port of entry, imported goods and articles and container storage areas, and notifying the port management department to carry out prevention and control; All customs should strengthen the inspection and quarantine of imported goods (seedlings, wood, forage, etc.), articles and containers from countries and regions where red imported fire ants occur to prevent the spread of the epidemic. The "Notice" requires strict quarantine supervision and law enforcement inspection, focusing on strengthening the quarantine of seedlings of crops with soil, seedlings with soil greening, lawn grass, etc. transported from counties (cities, districts) where the epidemic occurs. If the epidemic is found, it should be stopped. If it is really necessary, it can only be transferred after passing the quarantine treatment; The transportation, railway and postal departments are required to urge road freight transport enterprises, railway transport enterprises and express delivery enterprises to do a good job in the inspection of phytosanitary certificates for carrying or receiving related goods, mail and express mail in counties (districts) where the epidemic occurred, so as to ensure that they do not carry or receive without a license.

　　Emergency killing is an important aspect of preventing and controlling red imported fire ants. Lu Yongyue said that the red imported fire ant research center of South China Agricultural University, where he is located, has built a technical system for monitoring, quarantine and prevention and control of red imported fire ants suitable for southern China. In the aspect of monitoring, three kinds of bait and placement methods with good effects were screened out, and the monitoring accuracy was higher than 98%. In the aspect of killing, the contact toxicity of 18 insecticides to 4th instar larvae and the contact activity of 17 insecticides to worker ants were confirmed. Developed low-toxicity bait and waterproof bait containing more than 10 pesticides such as spinosad and avermectin, and formed supporting application technology; A highly effective pesticide for killing red imported fire ants was created and a matching application technology was formed, which solved the bottleneck problem that it is difficult to prevent and control in rainy season and low temperature season.

　　Spring and autumn are the active periods of Solenopsis invicta, and the best period to carry out centralized prevention and control actions. Experts believe that as long as all parties concerned work together to strengthen prevention and control in accordance with the requirements of the Notice, they will certainly be able to curb the spread of red imported fire ants, provide an important guarantee for the continuous and stable development of grain production and planting industry, and further build a national ecological security and biosafety barrier.

　　Image source: Baidu