Grassland night moth, also known as autumn marching insect, autumn armyworm and grassland night moth, is listed by the Food and Agriculture Organization of the United Nations (FAO) as a major agricultural pest of cross-regional migration in global early warning, and after the first invasion of China, it quickly spread to 16 Asian countries such as Taiwan, South Korea and Japan, which has posed a serious threat to the food security of Asian countries. This year, a total of 25 provinces in China have found the grassland night moth, with an area of more than 15 million mu of insects and an actual harm area of 2.46 million mu.
Nocturnal moth: Is a moth in the genus Nocturnidae in the family Nocturnidae. The adults are nocturnal and lay about 100 eggs at the top of the plant leaves, and the egg stage is at a temperature of 25 ° C for 3 days. The newly hatched larvae feed on the egg shell itself and then let stand for 2-10 hours. Larvae, or caterpillars, prefer to feed on new leaves, and due to their eating habits, they usually find a new leaf each. The larvae change the skin seven times and at the last time leave the ink sac, penetrating the soil 0.5 cm deep, where they become pupae. The pupal stage lasts about 10-12 days during the hottest period of the year. The lifespan of an adult worm is about 12 days, and the full cycle of this pest is only 30 days.
Grassland nocturnal moth control
The life history of the meadow moth can be completed in 30 days in summer, 60 days in spring and autumn, and 80-90 days in winter. The number of generations that the species can reproduce in a year is affected by the climate, and the female can lay about 1500 eggs in her lifetime.
【Prevention and control technology】
1. The corrective prevention effect of 80-100 ml (340 times liquid) of 0.3% neem emulsion (Chengdu green gold) on the hatching larvae of the grassland nightcrawler was 93.33% mu. ---- excerpted from Lu Yanhui et al., "Indoor Virulence of 26 Insecticides on Grassland Nightcrawler Larvae of Different Ages", Zhejiang Journal of Agricultural Sciences, 2019, 31(12).
2. It is very difficult for chemical insecticides to control the grassland moth, the insect will quickly develop resistance, which will lead to high doses or a mixture of pesticides to reduce its number, but also affect natural enemies, pollute soil and water, causing environmental and human health risks; although the control of pests can be achieved through Bt insecticides, genetic modification will cause plant resistance, so it is necessary to find new prevention and control methods. Biological control is an effective way to control the grassland moth. In addition to the above methods, the use of predatory predators (such as spiders, centipedes, hunting bugs, wasps and salamanders, etc.), plant extracts (such as flavonoids and limonin, etc.) will play a certain role in prevention and control. At present, the study of biological control of grassland nightcrawler has been carried out in China, and the use of parasitic natural enemies (such as night moth black egg bees and cocoon bees) is undoubtedly the most important one in the biological control of grassland nightcrawler. ---- from Lu Hui et al., "Biological Control and Potential Invasion Risk of Grassland Nightcrawler", Journal of Tropical Crops 2019,40(6):1237~1244.
3. Extracts of some plants can also be used to control the grassland moth, such as neem, pepper, garlic vanilla, tobacco, white thorn and garlic six kinds of plant extracts and mixtures of the control effect on the grassland moth can reach more than 80%.
Distribution of the grassland moth
4. Neem, cypermethrin and cypermethrin at test concentrations can affect the embryo formation and development of the grassland moth, and the emergence of eggs that cannot survive independently. Neem promotes morphological changes that ultimately affect the effect of nutrient absorption, in addition to neem causing the disintegration of the chorionic membrane, allowing and facilitating the entry of substances into the cell, which interferes with the maturation of eggs and the ability to produce new individuals, and analytical data also show that no embryos are formed. Neem is a limonin compound found in neem leaves, fruits and seeds that is comparable to the best synthetic insecticides on the market. Neem has some special effects on insects (such as food refusal, inhibition of molt hormone synthesis, inhibition of chitin synthesis, deformity of pupae and adult worms, reduces the reproductive rate and lifespan of adult worms, changes the attractiveness of pheromones, infertility, egg laying inhibition, reduces the spread of the virus, avoidance and lethality), and at the histological level, neem, urea and cypermethrin can interfere with the embryonic development of the grassland nightcrawler, and can have the above effects even when treated at low concentrations. In both light microscopy and scanning electron microscopy analysis, the insecticides tested can be observed to cause changes in the embryonic development of the grassland moth immediately and independently of concentration. ---- excerpted from Wang Hao et al., "Microscopic Analysis of Embryonic Development before and after the Treatment of Grassland Nocturnal Moth with Neem, Cypermethrin and Cypermethrin", World Pesticides, June 2014, Vol. 36, No. 3.
5. Adult yellow-footed mantises show a certain search effect on the 2nd instar larvae of the grassland nightcrawler, but their search effect gradually decreases with the increase of prey density in a certain space. Therefore, it is shown that adult yellow-footed fat aphids have good control potential for young larvae of grassland night moth. ---- Zhao Yingjie et al., "The Predatory Function Response of Adult Yellow-footed Fat Aphids to the 2-instar Larvae of the Grassland Nightcrawler", Plant Protection, 2019, 45(6): 35~38.
6. The indoor virulence and field control effect of neem on grassland moth S were determined by leaf leaching method and spray method. The results showed that under indoor conditions, the LC50 values of the 2nd and 3rd instar larvae were 0.59 and 0.46 mg/L for 2 and 3 instar larvae after 0.3% neem emulsion (Chengdu Green Gold) was treated with grassland moth for 7 days, respectively, and the LC50 values of 2 and 3 instar larvae were 0.93 and 0.79 mg/L, respectively, after 40% neem dry powder was treated with grassland moth. After 0.3% neem emulsion treatment of grassland moth for 3d, the AFC50 values of 2-instar and 3-instar larvae were 0.30 and 0.12 mg/L, respectively, and after 40% neem dry powder treatment of grassland moth for 3d, the AFC50 values of 2-instar and 3-year-old larvae were 0.53 and 0.30 mg/L, respectively. After the 0.3% neem emulsion was diluted 500 times, the control effect on the grassland moth reached 24.83%, 50.34% and 75.50% respectively after the 500-fold spray treatment. Therefore, neem has good toxicity and food refusal activity on the grassland night moth, and the control effect is better after 7 days; neem has broad application prospects for the control of the grassland night moth. ---- excerpted from Lin Sukun et al., "Determination of Virulence and Field Prevention Effect of Neem on Grassland Nightmotmothus", Journal of South China Agricultural University, (Network first paper, network launch date: 2019-08-26).
7. The test shows that the control effect of 1% neem water dispersible granules (Chengdu green gold) on kale twill moth is obvious, the efficacy is better, the quick-activity is poor, and the safety of kale can be widely promoted and applied within the dosage range. It is recommended to use 40 to 50 grams per mu, and the control period is mastered at the peak of the egg incubation period of the twill moth in the field to the initiation period of the young larvae (before the 3-year-old larvae are dispersed), and the application time should be selected on a cloudy or sunny evening. Conventional method The foliar surface is sprayed evenly, focusing on the back of the leaf, and the amount of liquid sprayed per mu is 45 liters. Depending on the occurrence of insect conditions, spray once every 7 to 10 days, and spray 2 to 3 times. ---- excerpted from Deng Jinsong et al., "Experiment on the Control of Vegetable Twill Moth by Biopestic Neem", Plant Doctor, Vol. 28, No. 2, 2015 (bimonthly).
How to control the grassland night moth
8. The green control technology of the grassland night moth mainly includes: A. Agricultural control is mainly to take comprehensive measures to adjust and improve the growth environment of crops, so as to enhance the resistance of crops to diseases, insects and grass pests, and to create conditions that are not conducive to the growth, development or spread of pathogens, pests and weeds, so as to achieve the purpose of controlling, avoiding or mitigating the harm of diseases, insects and grasses; Biological control, including natural enemies of insects, pathogenic microorganisms (fungi, bacteria, viruses, nematodes); Physical control, including sexual and other trapping techniques; Pharmaceutical control, including chemical and biological agents; Application technology, including auxiliaries, application instruments, etc. ---- excerpted from Wang Dengjie et al., "Research Progress on Green Prevention and Control Technology of Grassland Nightcrawler", Plant Protection (First Paper on the Network, First Publication Date2019-11-06).
"Grassland night moth can be prevented and treated" For the prevention and control of technical measures, starting from the three stages of take-off, cruise and landing, one is not to let it take off, the second is aerial sniping, and the third is to land and move into the place for prevention and control.
The National Symposium on the Prevention and Control of Grassland Moth held in Guangzhou on November 24, 2019 pointed out that Neem oil was included in the lPM prevention and control technology scheme of grassland moth. The use of neem oil for the control of grassland moth can effectively inhibit the reproduction of neem moth, and neem as a repellent insecticide can affect the spawning positioning of grassland moth, which can significantly reduce the spawning rate of migratory grassland moth.