According to reports, the National Agricultural Technology Extension Service Center recently organized expert consultation and analysis, this year's grassland moth invaded China's region widely, the wintering range at home and abroad is wide, the insect source base is large, the planting layout and climatic conditions of corn and other crops are favorable, and it is expected that the recurrence of the grassland moth in 2020 is obvious, and the situation is extremely severe. The occurrence area involves the southwest, south China, Jiangnan, the middle and lower reaches of the Yangtze River, Jianghuai, Huanghuai, North China, and northwest corn planting areas, and there is a possibility of moving into the main spring corn production area in northeast China, and the occurrence area accounts for more than 80% of the area of corn planting area, and the insect area exceeds 100 million mu; all regions have the possibility of concentrated harm, and the southern provinces have many generations and heavy harm.
The occurrence of invasive organisms generally goes through three processes of "invasion-colonization-outbreak", and the grassland nightcrawler has invaded China this year and colonized in the southwest, south China and southern Jiangnan. As Wu Kongming, vice president of the Chinese Academy of Agricultural Sciences and academician of the Chinese Academy of Engineering, said: "This year's grassland night moth is just some tentative attack, and next year may be a year of full-scale outbreak." "So, farmers and friends in these areas, how to further prevent and control the harm of the grassland night moth next year?" Are you ready? Below, every day to learn farmers to help everyone strengthen the knowledge reserve, scientific insect awareness and insect control!
<h1 class = "pgc-h-arrow-right" >, what is the origin of the grass moth? </h1>
The grassland moth is a migratory pest that originates in tropical and subtropical regions of the Americas and is widely distributed on the American continent. In July 2018, India, which is adjacent to China, was first reported to have a grassland moth hazard, which led to a global warning issued by the Food and Agriculture Organization of the United Nations in August 2018. In the following six months, a total of nine Asian countries in Sri Lanka, Bangladesh, Myanmar, Thailand, China, Laos and Vietnam discovered the harm of the grassland nightcrawler, which spread rapidly in Africa and Asia for more than three years. Recently, many corn-producing areas in China have found traces of grassland nocturnal moths.
The ovule of the grass moth is 0.3 to 0.4 mm in size, pale green or white at first, brown before hatching, mostly on the front of the leaf of the crop, usually stacked in clumps, covered by white scales
The pupae of the grassland moth is reddish brown, oval, 14 to 18 mm long and about 4.5 mm wide. Mature larvae fall to the ground to borrow soil with a depth of 2 to 8 cm to make a pupal chamber, in which the cocoon wrapped in sand particles pupates, and can also pupate on harmful host plants, such as corn ears.
The larvae of the grassland moth are divided into six ages, and the elderly larvae are 30 to 36 mm long and have white or yellow "inverted Y-shaped" spots on the head. The surface of the larvae has many longitudinal stripes, the dorsal midline is yellow, and there is a yellow longitudinal stripe on each side of the dorsal midline, and the outer stripes are black yellow longitudinal stripes. The most obvious feature of the larvae of the grassland moth is that it has four black spots arranged in a square arrangement at the end of the abdomen, and the 1st to 3rd instar larvae have no shape stripes on their heads.
Adult wings of the grass moth are 32 to 40 mm long, the male's forewings are gray to dark brown, with dark spots and light dark stripes, the wing moles have a distinct gray tail-like protrusion, the hindwings are grayish white, the wings are brown and transparent, and the females are gray to grayish brown.
In addition to the above appearance characteristics, the larvae of the grassland night moth have a very significant habit characteristic, one is the suspended animation habit, if we touch it, we can see the old larva rolled into a clump, in the shape of a "C".
"Especially able to fly, especially able to grow, especially able to eat" is an important reason why the grassland night moth makes people feel frightened. Studies have reported that its adults can migrate more than 100 kilometers in one night with the air flow, and even as far as 1500 kilometers away; a female grassland moth can produce 10 to 20 egg blocks in her lifetime, and each egg block has 1000 to 2000 eggs; the grassland night moth is also a bulivorous pest, and the young larvae gather and harm, and the amount of food increases greatly after 3 years. The damaged leaves are incomplete, photosynthesis decreases, and the crop seedling stage can lead to a yield reduction of 10% to 25%, and even be cannibalized into a light rod, and the particles are not harvested. For this reason, it is also known as the "food killer".
<h1 class= "pgc-h-arrow-right" > two, how to defeat the grass moth? </h1>
According to the occurrence characteristics of the grassland night moth, we need to comprehensively prevent and control it to avoid the occurrence of large-scale disasters or the spread of epidemics. At present, the main control techniques of the grassland night moth are as follows:
Biocontrol
The implementation of intercropping between grass crops and non-grass crops (also known as three-dimensional planting) is a very important control technology. The principle of this method is to use biodiversity technology to nest some non-host plants to reduce the spread of grassland nocturnal moths, while also enriching the types of farmland plants and increasing the population of natural enemies. The specific method is to intercropping some plants that the grassland nightcrawler does not like, such as beans, turnips, bitter vegetables, beans, pumpkins and other plants that have a tendency to avoid pests and natural enemies to attract plants, increase biodiversity, and reduce the amount of grass moths, which is a proven effective method. At the same time, it is necessary to achieve scientific fertilization, increase the application of organic fertilizer, phosphorus and potassium fertilizer, in order to enhance the natural resistance of crops to insects; control the amount of nitrogen fertilizer, and control the growth of plants caused by partial application of nitrogen fertilizer, resulting in increased feeding and egg production of grassland moths.
As an insect, the grassland night moth has many natural enemies, so we can prevent and control it by protecting and using natural enemies in the natural ecological environment. Such as the parasitic natural enemies of the grassland night moth - nocturnal black egg bee, grassland borer Aggie bee, spotted mole hanging cocoon bee, etc.; predatory predators - hunting bugs, small flower bugs, grass bugs, spiders, ants and so on. Give full play to the natural control role of biodiversity, cultivate ecological protective belts in farmland, and continuously control the population of grassland moths.
After the invasion of the grassland night moth into China, a lot of research work has been done in China, and the field survey of the Plant Protection Institute of the Chinese Academy of Agricultural Sciences in Yunnan has found that both white zombie fungus and green zombie fungus can parasitize in its body. Taking this factor into account, we can screen some biopesticides that have a good effect on the control of grassland moths for prevention and control. For example, in the early stage of egg hatching of the night moth, select Coccidioides albicans, Scarab beetles, Bulbophyllum breve, Thuringiensis, karyotype polykeratovirus, polycycline, matrine, neem, etc., and spray the whole garden to achieve the treatment of insects with bacteria.
In addition, we can use Bacillus thuringiensis to formulate medicinal soil to spread on crops, which is a technology that is particularly suitable for use in areas where water is scarce. First of all, we first take a certain amount of sand in the ground, and then mix the sand soil with the biopesticide Thuringiensis agent according to the ratio of 5 parts of sand and 1 part of Thuringiensis, pay attention to the fact that the biopesticide and the sand soil are mixed evenly, and finally the configured medicinal soil is spread on the crop, such as the horn mouth of corn, which can effectively kill the larvae of the grassland night moth.
Physical control
During the occurrence period of adult grassland moth, the phototropism and chemotaxis of insects can be used to concentrate contiguous farmland in a large area, and set up a frequency vibration insecticidal lamp or black light every 30 to 50 acres to trap adult insects; the use of sexual pheromone cores with strong transferability to grassland nocturnal moths, such as "trapping more" and other active ingredients for (Z)-7-dodecacarbonene-1-yl acetate special core, in corn, rice, cotton, vegetables, sorghum and other crop fields, 1 to 1.2 meters from the ground or 20 cm above the position of crops, The pole is equipped with a sexual core and a supporting barrel or boat trap to attract male adults and trap them by releasing synthetic sex pheromone-type compounds, thereby reducing the mating probability of male and female moths, reducing the effective spawning amount and the incubation base of larvae. It should be noted that the sexual lure needs to be replaced every 2 months or so to avoid weakening the booby trap effect.
Like other pests, the grassland moth is also flavor-oriented. We can configure sweet and sour liquid as a food attractant, sugar, vinegar, wine, water ratio of 1: 4: 1: 16, can be combined with the attractant per acre hanging 6 sweet and sour liquid tanks, suspension height of about 1.5 meters, every day regularly remove the enticing adult worms, every 1 week or so to add a sweet and sour solution.
According to the pseudo-death characteristics of the grassland nocturnal moth larvae, it is also possible to shake the crop straw at the crop leaf injury, artificially capture the larvae that curl up into a "C" shape after being alarmed, collect them and then kill them in a concentrated manner.
chemical control
The high-efficiency, low-toxicity and low-residue agents that can effectively control the grassland nightcrawler are: 1% methylaminoavermectin benzoate emulsion, 5% methylaminoavermectin benzoate microemulsion, 5% acetamidine emulsion, 75% acetylmethamine soluble powder, 6% ethyl polyfungin suspension, 14% chlorine worm and perchlorofluoride microcapsulant suspension 1500 to 2000 times liquid, 10% high efficiency cypermethrin water emulsion 3000 to 4000 times liquid, 5% chloropromatomyle carboxamide suspension 1000 ~ 1300 times liquid, 24% methoxycarbazid suspension 2000 times liquid and 20% cypermethrin emulsion, etc. You can choose one of the above agents for spray prevention and control, and pay attention to the rotation of medication.
It is best to apply the drug in the early morning or evening of the young larval stage (1 to 3 years) of the grassland moth, and can also be controlled when the population density reaches 10 heads/100 plants. Take care to spray on the leaf centers, male and female ears of the crop.
summary
Grassland nocturnal moth has a wide range of hazards, food habits, more than 300 kinds of host plants, only more than 80 kinds of common plants, covering almost all crops, especially corn, rice, wheat, sorghum, millet, sugarcane and other grass crops are the preferred objects of its harm, it also endangers cruciferous, cucurbitaceae, mallow family, legumes, solanaceae, Asteraceae and other plants. All farmers and friends must wait in a strict line, conscientiously implement the plant protection policy of "prevention first, comprehensive prevention and control", on the basis of identifying the morphological characteristics and physiological habits of the grassland moth, according to their own actual situation, flexibly use several prevention and control technologies introduced in this article, which can effectively reduce the degree of harm of the grassland moth to crops and reduce economic losses.
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