The peach-necked celestial bull is endangering the street tree. Profile picture
Attentive Nanjing citizens found that the cherry blossom trees on Jimingsi Road were "stared" by the Tianniu, and some of the cherry blossom trees in the garden near Jiefangmen were eaten badly. The reporter learned that this year, these bad guys have become more "cunning" and have begun to drill into the soil, giving a big problem to prevention and control. Yangzi Evening News/Yang Eye reporter Xu Sheng
Tengu and termites are cherry blossom "killers"
Don't look at the "cherry blossom avenue" of Jimingsi Road is only more than 400 meters long, but it is definitely a "net red" road in the minds of Nanjing people and foreign tourists. Every year in March during the cherry blossom season, Jimingsi Road is always crowded, stretching for hundreds of meters from the archway to the Jiefang Gate, and countless people come to enjoy the cherry blossoms. However, in the summer, the cherry blossom trees are not very good.
"Cherry blossoms have many pests and diseases, Nanjing summer is humid and hot, cherry blossom trees are prone to disease: perforated brown spot disease, leaf blight, root cancer disease." Garden experts told reporters that in addition, termites and celestial cows will endanger cherry blossoms. Termites will fly into the xylem of the cherry blossoms, mothting the core of the tree. The Celestial Bull is a borer pest that bites the bark out of the slot before laying eggs, and then lays eggs in the slot. The hatched larvae feed on xylem upwards or downwards and open their bark as vents, pushing out excrement and wood chips outward. When the celestial cow matures, it pupates in the tree, and when the adults feather, they drill a hole outward and leave. These pest gods unknowingly gnaw on the inside of the trunk.
According to garden experts, in the north, the normal life expectancy of an ordinary cherry blossom is 50 or 60 years old, while the average life expectancy of cherry blossom trees living in Nanjing is 30 or 40 years old. In order to ensure the flower viewing effect of the cherry blossom avenue on Jimingsi Road, the conservation department replants several cherry blossom trees every year to replace the weakened ones.
The peach-necked celestial bull burrowed into the soil
The Celestial Bull is almost a natural enemy of all kinds of street trees. In Nanjing, the more common ones are Xingtianniu, Sangtianniu, Bare shoulder Xingtianniu, Peach-necked Tianniu, Cloud-spotted Tianniu, Thin-winged Saw tianniu, Songmo Tianniu and so on. Among them, the bare-shouldered star tianniu and the star tianniu love to eat fatong.
"The antler who eats the cherry blossom tree is the peach-necked celestial cow. Failure to take timely measures will affect the growth of cherry blossoms in the coming year. Hu Xiaolong, a technician at Xuanwu Landscaping Engineering Co., Ltd., told the Yangtze Evening News reporter that the cherry blossom trees on Jiming temple road are mostly grafted with peach trees, which especially attracts peach-necked tianniu. The larvae of this celestial cow like to eat the trunk of the tree, and over time, the interior of the cherry blossom tree will appear empty rot, which is easily broken by wind and rain.
The reporter's visit found that several cherry blossom trees near jiefangmen had some moth holes, as well as wood chips, and yellow-brown liquid flowed from the trees. "This summer, the pest is the same as before, but the trouble is that the celestial bull has become more cunning." Hu Xiaolong said worriedly that according to the feces and wood chips discharged by the Tianniu in the defecation holes of the tree, the larvae of the peach-necked Tianniu were not only active in the tree trunk, but also quietly moved to the roots of the tree and drilled into the soil, which increased the difficulty of treating the insects, "because injecting drugs can afford to dig the tree pond, which is very inconvenient." ”
"The breeding rate of Tianniu is high, with three or four generations a year. If a female adult is missed, it may lay more than 200 eggs. Hu Xiaolong said that this is also one of the reasons why insect pests are difficult to cure.
"Multi-pronged" approach to insect pests
The reporter learned from the Nanjing Academy of Landscape architecture and forestry sciences that the main methods used to deal with Tianniu are to release natural enemies, use biological pesticides, and physical trapping. Some time ago, many citizens saw many small brown paper packages hanging on the plane trees of the main road, which are parasitic natural enemies of insects used to "cure diseases" for trees. The body length of the mite is only about 125 microns (one micron is one hundred thousandth of a meter), which is thinner than a human hair, but it can parasitize more than a dozen pests. Pu mites can pierce into it and parasitize, eventually allowing pests to die. This year, the Municipal Bureau of Greenery and Landscape Architecture released a total of 15,000 packs of pu mites.
Flower velvet parasites, swollen-legged bees, and cattail mites are mainly aimed at the larval stage of the celestial cow. During the feathering of adult insects, the flower wool and mites cannot use their skills, and must adopt manual hunting and spraying to reduce the density of the insect population. Because the adult tianniu is suspended to death, it can shake the branches in the morning or after rain to kill the adults on the ground; during the egg laying period, the eggs in the incubation tank are killed with a small sharp knife; the larval stage often checks the branches and finds fresh insect feces and kills them with a wire hook.
Recently, many citizens also noticed the Tianniu trap in the Garden Plaza. The principle is to reduce the dry moth damage of the offspring larvae to the host plant by artificially synthesizing female insects to release some chemical components called sexual pheromones after sexual maturity, attracting males seeking to mate with the same species, trapping them in traps, and reducing the dry moth damage of the offspring larvae to the host plant.
Garden experts remind that if the public sees traps and natural enemies released by the garden department in the roads, squares, and parklands, please do not "disturb" them, they are the heroes of the "insect war".