[Edit this paragraph] Professional information
Scientific name: American white moth
English name: Fall Webworm, American white moth.
Chinese synonyms: autumn curtain caterpillar, autumn curtain moth
Taxonomic status: Arctiidae, Lepidoptera, Lepidoptera.
Identification features: the adult is white, with a body length of 12- 15 mm, and the male has a comb-shaped antenna with several brown spots on the antenna. The female has serrated antennae with white oval front wings. Larvae can be divided into two types according to head color: red head type and black head type. Pupa is spindle-shaped, dark reddish brown, cocoon brown or dark red, sparse.
Biological characteristics: Hyphantria cunea has a second generation in Liaoning and other places 1. Pupa overwinter under bark or ground litter. After hatching, the larvae spin silks and make webs, and feed on the leaves in the web. After the leaves are eaten up, the larvae move to another part of the branches and twigs to weave new webs.
Origin: North America.
Distribution Status of China: It is now distributed in Liaoning, Hebei, Shandong, Tianjin, Shaanxi and other places.
Causes and harm of spread: 1940 was introduced to Europe, and now it has been introduced to many countries in Europe 10, as well as Japan, Korean Peninsula and Turkey. 1979 was introduced to Dandong, Liaoning, China, and the wood brought by fishermen in Liaoning was introduced to Rongcheng County, Shandong Province on 198 1, and it was circulated in Shandong successively. Damage was found and formed in Wugong County 1985, Shaanxi Province. Mainly spread through wood, wooden packaging, etc. And it can be further spread by flight. Strong reproductive ability and rapid diffusion, which can spread 35-50 kilometers every year. It can harm more than 200 kinds of plants such as fruit trees, trees, crops and wild plants. In orchards, tourist areas and places with dense roads, you can eat up the whole leaf in serious cases. It seriously threatens sericulture, fruit industry and urban greening, causing amazing losses. In addition, the damaged trees are weak and vulnerable to other pests and diseases, reducing their cold resistance and stress resistance. Larvae like to eat mulberry leaves, which poses a threat to sericulture.
[Edit this paragraph] Distribution and hazard characteristics
Hyphantria cunea is distributed in the United States, Canada, Eastern European countries, Japan, North Korea and other countries. It was first discovered in Liaoning Province on 1979 and reported in Xi 'an City on 1985. Since 1999, the pest has been damaged in Tangshan and its surrounding areas and has been controlled as a major pest. Its larvae have a variety of feeding habits, and the main victims are Bai La, Ailanthus altissima, Fraxinus mandshurica, Mulberry, Apple, Begonia, Melilotus, Prunus mume, Peach Tree, Elm and Willow. The newly hatched larvae have the habit of netting and living in groups. There are hundreds of larvae that are harmful to every tree. They often eat all the leaves of trees, which seriously affects the growth of trees.
[Edit this paragraph] Morphological characteristics
Adult white medium-sized moth with a body length of 9- 12mm. The compound eye is dark brown with short and slender mouthparts; The chest and back are densely covered with white, most individuals have white abdomen without spots, and a few individuals have yellow abdomen with black spots. Male adults have black antennae and comb teeth; The wings spread 23-34 mm, and the front wings are scattered with dark brown spots. Female adults have brown serrated antennae; Wings spread 33-44 mm, the front wings are pure white, and the rear wings are usually pure white.
Oval, about 0.5 mm in diameter, pale yellow-green or pale green at the beginning of spawning, then grayish green, and grayish brown before hatching, with strong luster. The eggs are arranged in a single layer covered with white scales.
Mature larvae are 28-35mm long and their heads are black and shiny. The body is yellowish green to grayish black, and the back line, upper valve line and lower valve line are light yellow. Hairy tumors on the back are black, and hairy tumors on the side of the body are mostly orange with white long hair clumps. The outside of abdomen is black. The valve is white and oval with a black edge.
The pupa is 8- 15 mm long, dark reddish brown, and all abdominal segments except internodes are covered with pits. There are 8- 17 gluteal spines, and the end of each barb is trumpet-shaped.
[Edit this paragraph] Life history and habits
Hyphantria cunea has 2 generations in Tangshan and other northern areas 1. It uses pupae as cocoons and overwinters under the epidermis of ancient trees, ground litter and topsoil. The emergence began in May of the following year, and the occurrence period of the second generation adults was from mid-May to late June and from late July to mid-August respectively. The larval occurrence period is from late May to late July and early August to1early October respectively. In early September, pupation began to overwinter.
Adults like nocturnal activities and mating. After mating, they lay eggs on the back of leaves, and the eggs are arranged in a single layer. There are hundreds of eggs in an egg, up to thousands, and the egg period is about 15 days. After hatching for several hours, the larvae spun silk, formed a web and began to spin silk, forming 1-3 leaves. With the growth of larvae, their food intake increases, more new leaves are wrapped by net curtains, and the net curtains also increase. Finally, it was like a layer of white gauze wrapped around the entire crown. Larvae * * * is 7 years old. After 5 years old, it enters the gluttony period, and after eating all the leaves, it transfers the harm. Older larvae can tolerate hunger 15 days. This is beneficial to the spread and diffusion of larvae by means of transportation. Larvae eat leaves, leaving only veins, which makes the trees grow badly and even the whole plant dies.
[Edit this paragraph] Prevention and control methods
1, strengthen quarantine. It is strictly forbidden to transport seedlings in epidemic areas abroad without quarantine or treatment, and the epidemic areas actively carry out prevention and control to effectively control the spread of the epidemic.
2. artificial control. The larvae found the net curtain behind the net before the third instar, and cut it off manually. If the larvae have dispersed, before the larvae pupate, the trunk is tied with grass to trap the pupated larvae, and the pupated larvae are treated regularly by designated personnel.
3. Use the sex attractant of Hyphantria cunea or environmental protection insect sex attractant to trap and kill adults. In the adult stage, the bait core is put into the trap, and the trap is hung in the forest, so as to directly trap and kill male adults, block the copulation of pests, reduce the reproduction rate and achieve the purpose of eliminating pests.
Scholars in Europe, America and Japan began to study the biology, chemical structure identification, artificial synthesis and application of sex pheromone of this insect from the late 1960s. The research in China started late (1980s), but the synthetic pheromone and its application have reached the international advanced level.
4, the use of biological and chemical agents spraying prevention and control. Early detection and prevention should be done during the larval damage period. In the prevention and control, it is important to check whether mulberry, Platanus acerifolia, Ailanthus altissima, Ulmus pumila, Hypericum perforatum, Peach Tree, Bai La and other tree species have larval hazards. If there are larval hazards, it is necessary to check the jurisdiction and prevent them in time. 400-fold solution of Bt emulsion and 2500-fold solution of 2.5% deltamethrin EC were selected. Spraying 80% dichlorvos EC 1000 times solution and 5% Laifuling 4000 times solution can effectively control the insect.
5. Biological control. Peristichus is a newly discovered species, native to China, but has become the natural enemy of Hyphantria cunea.
Since the middle of last century, the harm of Hyphantria cunea in China has become increasingly serious, and the effect of traditional control methods has become worse and worse. From 65438 to 0998, China started the prevention and control project of American white moth, and biological control became a breakthrough.
Hosted by Yang Zhongqi, a researcher from Chinese Academy of Forestry, the parasitic natural enemies of Hyphantria cunea were systematically investigated from the perspective of biological control, and a variety of natural enemies were raised from their eggs, larvae and pupae. After screening, a pupa parasitic bee, Hyphantria cunea, was found, which has a high parasitism rate and a large number of bees and can effectively control Hyphantria cunea. This wasp can find the American white moth pupating, spawning and parasitizing in various hidden places. The research results protect the ecological environment and do not kill natural enemies, which is an advanced technology to control the American white moth.
In epidemic areas such as Dalian, Shaanxi, Shandong and Qinhuangdao. This pest control measure, combined with biological agents such as Hyphantria cunea nuclear polyhedrosis virus (NPV) and Bacillus thuringiensis (Bt), has achieved remarkable control effect. It is a pioneering work of biological control in China to control Hyphantria cunea by using the week of biting wasps, which makes China's technology of controlling Hyphantria cunea by using insect natural enemies jump to the forefront of the world and reach the international advanced level. At present, this efficient, economical and pollution-free biological control research technology has passed the appraisal and is widely used in epidemic areas.
6. During the invasion of Hyphantria cunea, I happened to find another natural enemy of Hyphantria cunea in the soybean field-smelly elder sister, also known as "smelly bug", because there is a smelly gland opening at the back of the body, which stinks when it meets the enemy, commonly known as "fart bug" and "smelly elder sister". The body is flat, with a length of 90- 1 10MM, the mouthparts are beaks, the front wings are leathery at the base, the ends are membranous, and the rear wings are membranous or degenerated. It mainly inserts a long mouthpiece into the larva of the white-haired American white moth and sucks the juice of the larva, resulting in its death. Therefore, the cost of releasing smelly sister is low.