In May 2018, a red fire ant colony on the water surface in Zengcheng, Guangzhou. Photo courtesy of Lu Yongyue
Beijing News (reporter Huang Zhecheng Li Yukun) listed as one of the world's 100 most destructive invasive species of red fire ants, recently caused social concern. According to the monitoring of the Ministry of Agriculture and Rural Affairs, as of March this year, the red fire ant has spread to 12 provinces and 435 counties and municipalities in the mainland region, especially in the past five years, 191 new affected county-level administrative districts have been added, doubling compared with 2016.
Red fire ants are harmful to humans, agroforestry, public safety and regional biodiversity. The red fire ant was first found in Taiwan in 2003, and was first detected in Wuchuan, Guangdong in mainland China in 2004, and quickly spread to Guangdong, Guangxi, Hunan, Jiangxi and other regions.
Since 2004, domestic agriculture, forestry and grassland departments at all levels have strengthened the monitoring and prevention of red fire ants, and 40 pesticide preparations have been registered for the prevention and control of red fire ants. Recently, the Ministry of Agriculture and Rural Affairs, the Ministry of Housing and Urban-Rural Development, the Ministry of Communications and other nine departments have established a red fire ant collaborative joint prevention work mechanism, organizing and coordinating the prevention and control of red fire ants.
What kind of species is the red fire ant? What are the hazards? What should the public do when they encounter red fire ants? Why do red fire ants spread so fast? What are the other challenges facing domestic prevention and control? The Beijing News reporter contacted Lu Yongyue, director of the Red Fire Ant Research Center of South China Agricultural University, and Ran Hao, a researcher at the Key Laboratory of Ecology and Environmental Protection of Rare and Endangered Animals and Plants in Guangxi, to answer 10 questions about red fire ants.
Highly effective bait for red fire ants. Photo courtesy of Lu Yongyue
Question 1: What does a red fire ant look like?
The body length of the red fire ant is generally 3 to 6 mm, the head and thorax range from orange to dark reddish brown, and the hind abdomen ranges from brown to black brown. The head is nearly square to slightly heart-shaped, the middle of the head is slightly concave, there is no longitudinal groove with transverse stripes, and the middle teeth at the base of the lip are well developed. There are large, medium and small 3 types of worker ants, which have a brighter red appearance and are easier to distinguish from other ants. The nest of the red fire ant is also different from most domestic ants, and the mature red fire ant nest will bulge a large dirt bag on the grass, which is a more obvious identification feature.
However, the color of the red fire ant is relatively consistent between individuals in the same nest, but the color within the species changes greatly, and it is difficult for the public to identify the red fire ant. "There are at least a thousand species of ants in our country right now. In addition, there are no discoveries and no names, and it is estimated that there are almost two thousand kinds. This raises a big question, because the public, the media and some institutions don't actually know different ants. Some media reports have even used images of yellow ants, which are actually native ants or a model of biological control that we used to control citrus pests. Ran Hao said.
Question 2: What are the hazards of red fire ants?
Listed as one of the 100 most destructive invasive species in the world, the red fire ant is harmful to the human body, agroforestry, public safety and regional biodiversity.
Lu Yongyue introduced that after people are stung by red fire ants, they will become ill within five to twenty minutes, and the mild ones will have pustules, redness, swelling, itching, and pain, and the slightly heavier local allergies, and serious allergic reactions extend to the trunk of the main body, and a small number of people will have symptoms such as dizziness, fever, confusion, throat edema, and even shock and death. "The proportion of severe illness may be around one in a thousand to three thousandths." Lu Yongyue said that last year, the information data of a hospital in Fujian Province showed that more than a thousand patients were stung by red fire ants were treated in a year, and if it is estimated according to the existing area and population density, number and proportion of injuries in the country, it is estimated that more than 500,000 people are stung by red fire ants every year, and 40,000 to 50,000 people show serious symptoms.
Red fire ants also seriously affect agroforestry production. Red fire ants can directly harm dozens of crops such as soybeans, corn, sweet potatoes, potatoes, a variety of vegetables, fruit trees and so on. In the farmland infested with red fire ants, the germination rate of vegetable seeds is only 30%-40% of normal, the fruit trees and fruits are eaten badly, the bark of seedlings is nibbled, and the decay rate of potatoes, sweet potatoes and other underground parts is significantly increased due to the holes bitten out by red fire ants. During the investigation in Hunan, Lu Yongyue and his team found that red fire ants invaded a village, causing farmers to simply give up cultivating dozens of acres of arable land, and more than 30 acres of corn fields were harvested.
Red fire ants can also cause damage to public facilities such as electricity, communications, and traffic signaling systems. Lu Yongyue introduced that red fire ants have the habit of tending to electromagnetic waves and emitting heat, especially in the low temperature of winter, red fire ants like to nest inside street lights, traffic light boxes, program-controlled switch boxes, etc., eating wire rubber, resulting in facility destruction and functional failure.
In addition, the invasion of red fire ants can destroy the ecological diversity of the region. Red fire ants are omnivorous ants that are aggressive and have a great impact on livestock, poultry and other animals. According to survey statistics, if urban green areas are invaded by red fire ants, the local ant species in the area can be reduced by about 80%. A study in the United States showed that in some areas where red fire ants invade and flood, a variety of birds are harmed and threatened.
Red fire ants that have been drugged and killed on the side of the road in Guangdong. Photo by Ran Hao
Question 3: What should I do when I encounter a red fire ant?
If an individual encounters red fire ants, Ran Hao's advice is to "hide" and not to disturb them. Red fire ants are very aggressive and can emerge from the nest within a minute, covering the entire nest with dirt bags. If you touch it directly with your hand or stick, it is easy to climb on the body, and it is not recommended for individuals to deal with it directly. Ran Hao said that even boiling water does not make much sense, because the nest structure of the red fire ant is very complex, and the inside of the nest is honeycomb-shaped, which is difficult to kill all.
Lu Yongyue suggested that when encountering red fire ants outdoors, they should report to the territorial management department in time. If you are accidentally stung by a red fire ant, the human body will react within five to twenty minutes, and you should seek medical treatment at the first time and explain to the doctor that it is a red fire ant sting.
Question 4: Where is the "hometown" of the red fire ant?
Native to Latin America, the red fire ant is listed as one of the 100 most destructive invasive species in the world, as well as an agricultural, forestry and quarantine pest for imported plants in China. The red fire ant has a fierce temperament, rapid reproduction, and complex feeding habits, and can erupt into disasters in a short period of time after invasion.
The red fire ant was first found in Taiwan in 2003, and was first detected in Wuchuan, Guangdong in mainland China in 2004, and quickly spread to Guangdong, Guangxi, Hunan, Jiangxi and other regions.
In August 2014, in Jiahe, Hunan Province, the dense nest of red fire ant nests was planted with small colorful flags for warning. Photo courtesy of Lu Yongyue
Question 5: Why is the diffusion speed so fast?
The reporter learned from the Ministry of Agriculture and Rural Affairs that due to the increase in the number of commodities and the suitable climatic conditions, the spread of red fire ants in some provinces and regions has accelerated in recent years and the degree of occurrence has increased. According to the monitoring of the Ministry of Agriculture and Rural Affairs, as of March this year, the red fire ant has spread to 12 provinces and 435 counties and municipalities, especially in the past five years, 191 new county-level administrative districts have been added, doubling the number of 2016.
Lu Yongyue and his team have calculated that in recent years, the number of counties and urban areas where red fire ants have appeared in mainland China has increased by an average of 20-40 per year, mainly distributed in Southern Fujian, Guangdong, Guangxi, Hainan, Yunnan and other southern regions, and the northernmost one is currently in the Guangyuan area of Sichuan.
Ran Hao said that urban construction, soil flipping, and transplanting turf will destroy the previous soil ecology, and red fire ants, as invasive ants, occupy this blank ecological niche very quickly, thus blocking the recovery of native ants.
In addition, ants spread outward, and an important way is marriage and flight. Other ants are married and fly in a fixed season, but the red fire ant in China is married and flying all year round, and the spread speed is very fast.
Usually, red fire ants will choose to fly in marriage within 2 days after rain, and the wedding flight is carried out throughout the year, and the number of breeding ants participating in the wedding flight is also very large. Ran Hao believes that this frequency of marriage flight is rare among ants, which greatly increases the difficulty of eliminating red fire ants. After the marriage flight, the strong will usually establish a single queen ant colony, and the weak will usually choose to build a new multi-queen ant colony together.
Red fire ants can even form floating "ant rafts". Red fire ants are afraid of water, if they encounter a flood, they will crawl out of the nest, hug the ball, drift with the water, although the outer worker ants will drown a lot, but when the flood dissipates or docks, the remaining ant colony can reproduce again.
Lu Yongyue believes that the expansion of red fire ants and the rapid expansion of the scope of harm are also implicitly related to economic development and urban construction. Red fire ants are mainly transported and spread with items such as turf, building materials, and soil seedlings. Because urban and rural greening, traffic engineering, school construction and other urban construction projects often need to transport flowers, seedlings and turf and other commodities, this has become the main way for red fire ants to spread and spread, accounting for more than 80% of all transmission routes.
Red fire ants are large worker ants, small worker ants and unbred female breeding ants. Photo by Liu Yanming
Question 6: Why does the red fire ant have no opponent in China?
Ran Hao introduced that the red fire ant has natural enemies in the place of origin, and the food chain in the local ecosystem has a check and balance on it, so the harm is not very serious. But as an invasive species, there are not many natural enemies in china's entire ecosystem that can effectively control it.
"New ant invasions, the immediate competitors are ants, because they are located in the same ecological niche. Native ants are very uncomfortable with red fire ants, and they will suffer losses when they meet in many cases. The nest of mature red fire ants is very large, there are hundreds of thousands of ants, the breeding rate is fast, and the first clash of native ants may not be killed, but over time, they will be eaten by red fire ants little by little. Red fire ant poisonous liquid, but also more able to fight, more troops, may not react quickly at first, but it can continue to output. ”
Question 7: Should a large number of ants be exterminated in the prevention and control of red fire ants?
"From the perspective of the ecosystem, ants are very important, when we eliminate the red fire ant, we face a big problem, if the red fire ant eliminated is not right, eliminate other ants, but the ecological niche of the place is vacated, it is easier to let the red fire ant invade." Ran Hao explained that native ants survive in the local area and will have a certain defense against invading red fire ants. The survey found that it is difficult for red fire ants to invade woodlands because the forest ecosystem is "ruled" by native ants and is relatively stable.
Therefore, it is not possible to change from the prevention and control of red fire ants to an "ant-killing campaign", which will help red fire ants spread their sphere of influence.
Question 8: What measures are in place to prevent and control red fire ants?
Since 2004, agricultural and rural departments at all levels and forestry and grassland departments have strengthened the monitoring and prevention of red fire ants. At present, the country mainly uses chemical control, relevant institutions and enterprises for the development and production of a variety of high-efficiency, low-toxicity special pesticides for the red fire ant, has been purchased by the government, issued and guided the use of the way to demonstrate and apply, the country has also formulated a complete drug specifications.
At present, there are 8 kinds of pesticide active ingredients registered for the prevention and control of red fire ants, and 40 kinds of pesticide preparations have been registered, and complete drug specifications have been formulated in China. New equipment such as unmanned aerial vehicles and bait dispersers are also gradually being used in prevention and control work.
Recently, the Ministry of Agriculture and Rural Affairs, the Ministry of Housing and Urban-Rural Development, the Ministry of Communications and other nine departments jointly established an inter-ministerial red fire ant collaborative joint prevention work mechanism, and clarified the specific prevention and control responsibilities of each department. Lu Yongyue believes that the establishment of a cooperative joint defense mechanism is of great significance to the prevention and control of red fire ants. "Joint prevention and control has been proposed for many years, and now the initial joint prevention and control mechanism has finally been formally established, which is worth rejoicing." The invasion of red fire ants endangers not only the agricultural field, but also the joint management of nine departments, which is conducive to rapid collaboration in various fields, the implementation of comprehensive prevention and control, and the improvement of governance level and efficiency. ”
The relevant person in charge of the Department of Crop Industry Management of the Ministry of Agriculture and Rural Affairs said that efforts should be made to effectively curb the spread of red fire ants through 3-5 years of treatment, reduce the population density of the occurrence area, and avoid injury incidents.
In October 2020, Huili, Sichuan, a typical red fire ant nest. Photo courtesy of Lu Yongyue
Question 9: What are the problems faced by the prevention and control of red fire ants?
Lu Yongyue believes that the current red fire ant control in many parts of China is still facing problems such as uneven quality of pharmaceuticals, unscientific use of drugs, difficulty in comprehensive coverage of prevention and control, and insufficient inspection and supervision.
Lu Yongyue and his team found that many residents did not standardize their medication and still habitually used control methods for common pests to deal with red fire ants. "For example, there are people who use spray aerosols, or use red fire ant bait regardless of whether the temperature is suitable, whether the ground is wet and the amount of medicine. We once saw an ant nest full of bait, estimated to be more than 1 pound, asked the farmer why he used so much, he said he was afraid of killing. Lu Yongyue said that if the highly effective agent is used properly, the removal efficiency of a single use can reach more than 80%, and the use of two times can reach more than 95%. If it is not used scientifically, the effect will be greatly reduced, and it will be good to reach 20%-30%.
At present, new equipment such as manual and electric dispersers and unmanned aerial vehicles have been gradually applied to the prevention and control of red fire ants, but many farmers and even local technicians have not mastered the scientific use of pharmaceutical methods and technologies, and still use traditional or even outdated and unscientific medication methods, resulting in poor actual control effects.
In addition, the quality of pesticide preparations currently produced in China to control red fire ants is uneven. Lu Yongyue introduced that at present, there are more than 40 related pesticide preparations in China, but only 10% of the drugs produced by various manufacturers are estimated to achieve excellent quality.
There are also many areas due to insufficient funds, manpower, etc., it is difficult to understand the details of the occurrence of the red fire ant disaster, prevention and control deployment is also difficult to cover all the affected areas, in some places, several plant quarantine management and technical personnel to undertake hundreds of to thousands of relevant enterprises, organizations or individual units in the jurisdiction of the quarantine interception and pest control guidance and other work, the prevention and control effect can be imagined.
The interception of the transmission route of red fire ants also needs to be improved urgently. Although there are complete quarantine, prevention and control norms in China, due to the lack of effective supervision and inspection and punishment mechanisms, a large number of units and individuals planting, transporting and using do not strictly inspect the red fire ants in turf, flowers, seedlings and other goods, and some local construction departments and units also lack corresponding inspection links when using flowers, seedlings and turf. "The rate of inspection and quarantine for high-risk carriers of red fire ants may be only 1%."
Question 10: How to make up for the shortcomings of red fire ant prevention and control?
Lu Yongyue suggested that all localities should adopt various methods, especially through television, online media, etc., to strengthen the relevant publicity and training on the prevention and control of red fire ants, and go deep into the grass-roots level on a large scale, so that more people can master scientific drug use methods and know how to prevent them. At the same time, relevant departments should increase support for the research and development of efficient and safe prevention and control technologies for red fire ants, strengthen the management of pharmaceutical production, and improve the quality and use of pharmaceuticals.
In terms of prevention and control management, areas that cannot be comprehensively prevented and controlled due to their own conditions should focus on the treatment of areas with serious red fire ant disasters and dense crowds. Areas with conditions should comprehensively prevent and control all affected areas and eradicate the red fire ant infestation as much as possible.
In order to improve the interception effect of the transmission route of red fire ants, it is necessary to do a good job of source control, Lu Yongyue believes that a strong punishment mechanism should be established, and if it is found that there are red fire ants in the goods such as seedlings, flowers, and turf transported, it will be strictly investigated and punished, forming a deterrent effect.
Beijing News reporter Huang Zhecheng Li Yukun
Edited by Chen Si Proofreader Li Shihui
Source: Beijing News