Recently, a message spread on the Internet and WeChat circle of friends has aroused people's attention and concern, and the general content of the information is: "Do not dry the quilt, clothes, and do not eat outside food (barbecue and other outdoor food) on the 15th-25th of this month." Minimize activities in the countryside and outdoors. Airplanes spray medicine to cure white moths. ”
At present, the forestry departments in many places have publicly issued rumors: the American white moth referred to in the news is still in the pupal stage, and it will not come out of the cocoon until May, and there is no need for spray control; aircraft spraying is not as terrible as imagined.
Screenshot of the rumors that spread wildly in the circle of friends (network map)
Announcement of qiu city urban landscaping office on spraying rumors (Anqiu Municipal People's Government website)
So, what kind of "evil" is the American white moth, how harmful is it to the forest, and is it worth using an airplane? What are the moth control measures usually taken in various parts of China? Where are the loopholes in the aircraft spraying rumors?
What is the "demon" of the American white moth?
The American white moth (Hyphantria cunea), also known as the American lamp moth, autumn caterpillar, autumn moth, is native to North America, and later gradually spread to Eastern Europe, Japan, Korea and other countries. In 1979, it was first discovered in Liaoning Province, China, and then spread from the north to the central region. According to the Announcement of the White Moth Epidemic Area in the United States (No. 2 of 2017) issued by the State Forestry Administration in 2017, there are now outbreaks of white moths in the United States in Beijing, Tianjin, Hebei, Inner Mongolia, Liaoning, Jilin, Jiangsu, Anhui, Shandong, Henan, Hubei and other places.
The American white moth is an international quarantine pest that causes disasters that U.S. foresters call "smokeless fires." In China, it is also a bad record: in 1995, the leaves of 280,000 mu of forest in Tanggu District, Jixian County and Baodi County of Tianjin Were eaten away by this guy. Therefore, it is also the only harmful species in China that is listed as quarantine by the agricultural and forestry departments at the same time.
Researchers show American white moths devouring leaves (International Herald Herald)
Why does the American white moth harm one side?
The American Bai'e can run rampant around the world for several years, known as the "forest locust", in addition to no natural enemies, but also rely on 4 major capabilities:
1, can eat: the American white moth in northern China can breed two or three generations a year. Pupae under the bark or the ground where the dead branches and leaves are overwintering, the larvae will spit out a net after hatching, eat the leaves, and then move the position to form a new net, and they can eat a large tree in a week; they are not picky, the leaves and flowers of more than two hundred kinds of broad-leaved trees, hungry green onions, peppers, etc. can become their "feast".
Net curtain of larvae on sycamore branches (Peninsula mesh)
2, can survive: american white moth can survive in the high temperature of 40 °C and the low temperature of minus 16 °C; the older larvae can develop normally without eating for 15 days.
3. Fertile: The American white moth has super fecundity, and the female moth spawning process takes 2-3 days, with an average of 500 to 700 eggs per egg, up to 2000 grains; it can breed two or three generations a year in northern China. If the conditions are right, a female moth can breed 400,000 offspring.
Eggs of american white moths (Shijiazhuang Municipal Bureau of Gardens and Forestry website)
4, can run
The American white moth undergoes four insect states in its lifetime: egg, larva, pupae, and adult (moth). Among them, adults can quickly move positions by flying and larvae by crawling; adults and pupae can also achieve "long-distance travel" with the transport of wood. Especially in the pupal stage, the American white moth can tolerate low temperatures of minus 30 ° C, strong concealment, and is the most ideal form for long-distance transmission. This has brought great difficulties to humans to control and eliminate the American white moth in situ.
Four insect states of American white moth eggs, larvae, pupae, and adult (moth) (network map)
Since the arrival of the American white moth in 1979, Northeast China, Shandong, Shaanxi, Anhui, Hebei, Tianjin, Beijing and other places have been fighting "deworming operations" against this "forest locust" for more than thirty years. So, what are the effective prevention and control measures? Is spraying at height necessary?
High-altitude spraying is a necessary means and is basically harmless to people and animals
For more than thirty years of the human-insect war, China has also accumulated relatively rich experience in dealing with the American white moth, and there are three main types of methods adopted:
Artificial physical control measures: such as manual pupaeing, catching adult insects, light booby-trapping, manual cutting of the screen.
Drug control measures: such as spraying pesticides.
Biological control measures: release of biological predators Chow's wasps
Technician hangs insect traps in trees (Inner Mongolia Daily)
( Beijing Morning Post Yang Yufeng / Photo)
Zhou's wasp can parasitize eggs in the American white moth pupae, sucking up all the nutrients in the parasitic pupae, so as to achieve the purpose of eliminating the American white moth. The picture shows the staff preparing to release the bees.
Among them, spraying and killing after the American white moth emerges from the cocoon is an important means for China to deal with the American white moth, which is mainly divided into two forms: artificial ground spraying and air spraying. Among them, aircraft spraying has been widely used in many provinces and cities in China for many years due to its high efficiency, speed and economy.
The American white moth breeds three generations a year, and the first generation of American white moth comes out of the cocoon from mid-to-late April to late June, which is a critical period for the control of the American white moth. Because at this time, the American white moth has just feathered, the flight ability is weak, which is convenient for manual capture and spraying, plus spring is an important reproductive period for female moths, the so-called spring extinction "a moth", young "billion worms". Therefore, the aircraft spraying plans of the year deployed in various parts of our country are in this time period.
On May 23, 2013, Wen'an County, Hebei Province, rented a helicopter to spray biopesticides on the forest land under its jurisdiction to control the American white moth (Xinhuanet)
The agents used in aircraft spraying generally use bionic preparations of chlorbenzuron and mieyuniao, which have a certain impact on sericulture and bees, but are harmless to humans, animals and birds, and have no pollution to the environment. According to the reports on the "aircraft spraying to control the American white moth" (referred to as "flight defense") in various parts of China, there has never been news that people and animals have been endangered.
In summary, the American white moth, a "forest locust" that spreads from the Americas, is extremely harmful, and for many years China has been taking measures including aircraft spraying to prevent and control it. The aircraft spraying period only begins at the end of April every year, and the drugs are harmless to people and animals, so the rumors circulating in the recent circle of friends are indeed not enough to believe.