Recently, a large number of caterpillars have appeared in many areas of Beijing, and the local points are densely distributed, in addition to causing diseases to trees, caterpillars after landing have also brought certain impacts on residents' lives. What exactly are these caterpillars? Why is there a sudden increase this year?
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On-site visits
The caterpillar descended from the sky into the neck collar, and the leaves were nibbled away
According to the situation reflected by the citizens, the reporter visited Dongcheng District, Xicheng District, Haidian District, and Chaoyang District in recent days.
Located in the small wool alley on the west side of the ancient observatory in Dongcheng District, there are a large number of dead caterpillars under the trees and bushes on the roadside, and a small number of them are still squirming. They are black-brown in color, about 3 cm long, and have white hairs and many feet around them.
Nearby residents said the number of bugs had gradually increased since the beginning of September. "Sometimes when I walk, I drop a few on my body, and it is too much to fall into the neck collar." Last week, someone had been drugged in this area, so there were more dead insects under the trees.
In the Happy Home Community in Dongcheng District, dozens of trees crawl on both sides of a road. The community security guard said that on the morning of the 22nd, the property organization staff took medicine, but the branches in the high place could not hit the medicine, and there were often live insects falling from the height.
Residents of Yimin Lane in Xicheng District reported that caterpillars had burrowed into private cars and corridors. The reporter saw at the scene that on both sides of the alley, as long as there are trees, this caterpillar can be easily found, and the number is very large. One resident reported that the electric car was parked on the side of the road for one night, the car seat could be crawled with caterpillars, and he put a plastic bag to clean it every time.
In the Dongli Community of Baijiazhuang in Chaoyang District, some residents have American white moth larvae gathered under the windows of their homes. Beijing News reporter Wang Fangjie photographed
The bushes in the Dongli community of Baijiazhuang in Chaoyang District have been chewed out of many holes by caterpillars, and when you look around, they are densely packed with bugs, and some have climbed to the door of the unit and under the window sill of the residents. "A few days ago, there were many bugs in the next neighborhood, everywhere on the car and on the road." Our community has only existed in these two days, not serious there, and no one has come to treat insects at present. ”
Near the unit door of the Baijiazhuang Dongli Community in Chaoyang District, there are many American white moth larvae crawling. Beijing News reporter Wang Fangjie photographed
In the garden behind the Yingdu Building in Haidian District, two plane trees have become the "habitat" of caterpillars, and almost every leaf has traces of their "nibbling", some leaves have been mutilated, and some are only dry stems and veins. According to the property staff of the building, in order to control insect pests, the street has recently sprayed pesticides on the surrounding trees.
On the west side of The North Bio-City road at the east gate of Yuhe Jiayuan in Haidian District, about 20 landscape trees on the side of the road have been attacked by caterpillars, of which about 10 trees have completely eroded their leaves, leaving only bare trunks and dry stems. On some trees that have not been completely eaten, there are traces of nibbling on almost every leaf. The sidewalk under the trees is littered with caterpillar excrement.
The green trees along the west road of Beida Bio City in Haidian District have become the "habitat" of caterpillars, and almost every leaf has traces of nibbling. Photo by Wang Miaomiao, an intern at the Beijing News
The reporter noted that recently on the website of the Beijing Municipal Landscaping Bureau, it was reflected that the problem of found caterpillars increased. Netizens said that it was found in Jingda International Apartment on Chaoyang Park West Road, Langxinzhuang Village in Heizhuanghu Township, Chaoyang Hongmiao Beili Community, and Xinjiekou Street in Xicheng District.
Residents of Yimin Lane in Xicheng District reported that the walls of the community were crawling with bugs. Video screenshots
Probe for causes
This year there was a lot of rain, and the American white moth had three peaks of harm in Beijing
Yang Zhongqi, counselor of the State Council and chief expert of the Chinese Academy of Forestry, told reporters that many of the caterpillars that the public has recently reported are actually the larvae of the American white moth.
The American white moth is distributed in Tianjin, Hebei, Liaoning, Shandong, Shaanxi and Henan provinces, and has now crossed the Yangtze River and is distributed in Hubei, Anhui and Jiangsu provinces. According to the survey, the American white moth in the Beijing area can harm more than 80 species of forest trees, fruit trees, flowers and crops. The U.S. white moth has been included by the State Environmental Protection Administration in China's first list of 16 invasive alien species.
Yang Zhongqi said that the American white moth usually appears after rising temperatures in late April and early May, and can breed two to three generations in Beijing during the year. Because the current temperature is still relatively high, the climatic conditions are suitable for their survival, so the American white moth has seen three spikes in harm in Beijing this year.
This judgment has also been confirmed by the front-line landscaping staff, and the relevant staff of the Chaoyang District Landscaping Bureau also said that this year's high temperature and humidity, rain and rain, such weather led to an increase in the number of white moths in the United States. The staff of the Dongcheng Greening Team said that the American white moth has spread from the community to the outside, and this year's breeding production is very fast.
This white moth has a characteristic, that is, it reproduces quickly and is harmful. Adult insects are pure white, often laying eggs on the back of the leaves of mulberry trees, ash trees and other trees that it likes to eat, they lay a large amount of eggs, they can lay more than 2,000 eggs at a time, and lay a layer of piles. Therefore, after the eggs grow into caterpillars, they also live in clusters at first. "These caterpillars have black and white longitudinal stripes that are easy to identify."
He said that hundreds of larvae gathered together to spit out a silk knot net, connecting the leaves together to feed on it, and they "reported the ball for warmth", and the net was so thick and dense that it was very resistant, and birds and other predators were not easy to drill into. Caterpillars will grow slowly after peeling, peeling once to increase the age, the American white moth to the end of the fourth instar, the height is already very large, will break the net out of the "single fight", climb to the treetops to eat leaves. At the end of the fourth to the sixth age, it is a period of binge eating, and it takes a few days to eat the leaves of a tree. So the American white moth is very harmful. "All the leaves of broad-leaved trees, they basically eat, they also eat flowers and crops, and when they meet what they like to eat, they eat more and grow faster." But they don't eat conifers because they can't digest the pine resin in the conifers. ”
After eating the leaves, the caterpillar will crawl around in search of other plant leaves that can be eaten, and even enter the homes of residents and climb to the floor, beds and ceilings. Sometimes they also climb onto cars or vans and are taken elsewhere by vehicles, so they spread quickly.
In Dongfuzang Hutong, Xicheng District, the walls are crawling with bugs. Video screenshots
prevention and cure
The Municipal Landscaping Bureau has set up a special class for the prevention and control of the American white moth
In view of the situation that the American white moth in Beijing is more heavy this year, the Municipal Landscaping Bureau has laid out 2479 monitoring and reporting points for the American white moth in key areas and key road sections of the city, set up 120 inspection lines, found that the problem was first fed back to the districts for disposal, and recently issued the "Notice on Further Strengthening the Prevention and Control of Forest pests such as The American White Moth Pine Wood Nematode Disease" and the "Beijing Municipal Autumn and Winter Major Forest pest Control Technology Program".
From September 20 to 21, the Municipal Landscaping Bureau arranged for professionals to go to 16 districts of the city in three groups to carry out the supervision and inspection of the American white moth. At present, the Municipal Landscaping Bureau has set up a special class for the prevention and control of white moths in the United States, launched the daily reporting system of the epidemic situation of white moths in the United States, and supervised the implementation of prevention and control tasks in various districts. At the same time, it is pointed out that all units should strictly adhere to the responsibility system of "who operates, who prevents" and "who manages and protects, who prevents and treats", so as to discover and eliminate the treatment at the first time, and further strengthen the responsibility of territorial management.
It is reported that the Municipal Landscaping Bureau will strengthen overall coordination, actively carry out inspection and supervision, improve emergency drug reserves, and make every effort to do a good job in the prevention and control of the current American white moth in the urban area to reduce the damage caused by insect pests to garden plants and the inconvenience caused to residents' lives.
The American white moth also has natural enemies. "There are hundreds of American white moth larvae on the walnut tree outside my window, and in the end there are very few, and the leaves are not eaten, because birds, beetles, parasitic bees, etc. are its natural enemies, and these natural enemies work together to make it basically controlled." Yang Said he had investigated that there were 32 species of natural enemies in northern China that could control the American white moth.
He said that in recent years, Beijing has made great efforts to control the American white moth, and everyone can often see a large tulip cocoon hanging from the tree, and 5,000 to 12,800 white moth Zhou's small bees can be cultivated in a cocoon. It is very small, with a body length of only 2 mm, and can parasitize more than 200 white moths in an American white moth pupa. When the American white moth pupates, the female bee can pierce the pupae, lay eggs into the pupae of the American white moth, become larva after hatching, eat the nutrition and internal organs in the American white moth pupa, and finally eat the pupae, cultivate into a new generation of small bees, and continue to look for the American white moth to lay eggs and parasitize.
In response to the public's reflection on the possible increase of the American white moth, he said that the prevention and control efforts should be increased this year, and some communities can use a small amount of high-efficiency and low-toxic pesticides or the American white moth karyo-polyhet virus to kill the American white moth larvae. At the same time, it can continue to cultivate and release its natural enemy, the white moth Zhou's small wasp, to carry out biological control.
Residents of Yimin Lane in Xicheng District reported that the trees and walls of the community were crawling with bugs. Video screenshots
Know a little more
What should I do if the American white moth appears in the community?
What should I do if the American white moth appears in the community? The relevant staff of the Chaoyang District Landscaping Bureau said that residents can reflect the situation to the landscaping department or contact the property management unit directly, "The landscaping department can provide technical support for pest prevention and control." ”
The staff member reminded that when the property is medicated, residents try not to open windows. If the larvae crawl into the house, the larvae can be swept clean and placed in a garbage bag to prevent them from continuing to lay eggs.
Beijing News reporter Zhang Lu Wang Fangjie intern Wang Miaomiao
Edited by Fan Yijing Proofreader Wu Xingfa