CATDOLL : CATDOLL: The harm of locusts

Locusts have a wide range of food, and can feed on leaves, young stems, flower buds and young fruits of wheat, rice, millet, corn, beans, tobacco, reeds, vegetables, fruit trees, trees and weeds. They bite the leaves into notches or holes. When a large outbreak occurs, they can eat the crops down to bare stalks or eat them completely, causing serious economic losses.

Locusts are herbivorous, and their adult stage requires a lot of nutrition, accounting for more than 75% of their total food intake. They chew plant leaves and flower buds with their chewing mouthparts, leaving notches and holes. In serious cases, they eat up all the leaves and flower buds of large areas of plants, causing significant economic losses to agriculture, forestry and animal husbandry.

Locusts are an important part of the agricultural, forestry and animal husbandry ecosystems, and many harmful locust species can cause varying degrees of damage to agriculture, forestry and animal husbandry.

There are more than 1,000 known locust species in my country, of which about 60 species can cause damage to agriculture, forestry and animal husbandry. The species that harm crops such as beans, potatoes and sweet potatoes include the short-winged locust and the benzene locust. The cotton locust and the negative locust can harm cotton. The bamboo locust can seriously harm bamboo forests.

When a large number of locusts occur, they can seriously harm pasture and crops and directly affect the development of agriculture and animal husbandry. According to the records of Chinese history for thousands of years, the locusts that cause devastating disasters in agriculture are mainly migratory locusts. It is believed that the chance or correlation of drought and migratory locusts occurring in the same year is the highest, followed by drought in the previous year and floods followed by droughts, when locusts form in large numbers.

Additional information:

Habits

1. Food habits and ways of feeding and causing harm

Adults have the same diet as locust nymphs, both are herbivorous, and they need to supplement their nutrition strongly during the adult stage, accounting for more than 75% of their total food intake in their lifetime. They chew plant leaves and flower buds with their chewing mouthparts, leaving notches and holes. In severe cases, they will eat up the leaves and flower buds of large areas of plants, causing significant economic losses to agriculture, forestry and animal husbandry.

2. Activity habits

Both adults and locust nymphs hide at night and come out during the day, and have no obvious phototaxis.

When the density of locust nymphs is high, they form conditioned reflexes due to mutual sensation, intensify their activities, and are prone to form groups, lie dormant, and crowd together, and then jump and migrate in a certain direction.

References Sources:

Baidu Encyclopedia - Locust

1 Characteristics of locust damage

Locusts are an important part of the agricultural, forestry and animal husbandry ecosystems. Many harmful locust species can cause varying degrees of damage to agriculture, forestry and animal husbandry. There are more than 10,000 species of locusts in the world, of which about 300 species can cause damage to agriculture, forestry and animal husbandry. Locusts can occur in all regions of the world except Antarctica and the Eurasian continent north of 55° north latitude. The area where locusts occur all year round in the world is 46.8 million km2, and 1/8 of the world's population is often attacked by locust plagues. The most serious locust in the world is the desert locust Schistocerca gregaria (Forskal), of which the maximum spread area can reach 28 million km2, including all or part of 66 countries, accounting for about 20% of the world's land area, and the affected population accounts for more than 1/10 of the world's population. In 1971, my country collected scattered desert locusts in the Zhangmu area of ​​Nyalam County, Tibet Autonomous Region.

There are more than 900 known locust species in my country, of which about 60 species can cause harm to agriculture, forestry and animal husbandry. The locusts that can cause great harm to Gramineae plants mainly include East Asian migratoria manilensis (Meyen), Ox-ya spp., Hieroglyphus spp. and Epacromius spp., etc. The species that harm crops such as beans, potatoes and sweet potatoes include Calliptamus abbreviatus Ikonnikov, Haplotropis bruneriana Saussure, Aractomorpha spp., etc. Cotton locusts Chondracris rosea rosea (De Geer) and Negative locusts can harm cotton. Bamboo locusts Ceracris spp. can seriously harm bamboo forests. In the vast pastoral areas, there are many species that harm forage grass, mainly including Siberian locust Gomphocerus sibiricus (Linnaeus), Halberd-striped locust Dociostaurus spp., Oedaleus spp., Omocestus spp., Chorthippus spp., Bryodema spp. and Italian locust Calliptamus italicus (Linnaeus), etc., which can seriously harm forage grass and crops and directly affect the development of agriculture and animal husbandry when they occur in large numbers. According to the records of Chinese history books for thousands of years, the locusts that cause devastating disasters in agriculture are mainly migratory locusts, and it is believed that the probability or correlation of drought and migratory locusts occurring in the same year is the highest, followed by drought in the previous year and floods followed by droughts, and grasshoppers are in large numbers; locust disasters and water and drought disasters often occur one after another, and have always been the three major natural disasters that seriously threaten my country's agricultural production and affect people's lives.

Locusts Locusta migratora (Linnaeus) are the most widely distributed locusts in the world, with 10 known subspecies, distributed throughout Europe, Asia, Africa, and Australia. There are three subspecies in my country: the East Asian migratory locust is mainly distributed in the eastern monsoon region (in this region, 2 to 4 generations can occur from north to south each year), the Asian migratory locust L. mgratoria mgratoria (Linnaeus) is mainly distributed in the arid and semi-arid grasslands of the northwest (in this region, except for the Tushantuo area in Xinjiang, where 2 generations can occur, all other generations occur once a year), and the Tibetan migratory locust Locusta migratoria tibetnsis Chen is mainly distributed in many river valleys and lake shores in the Qinghai-Tibet Plateau (in Tibet and southern Qinghai, most of them occur once a year).

In the early days of the founding of the People's Republic of China, the area of ​​the East Asian migratory locust was about 5.21 million hectares. After implementing the locust control policy of "relying on the masses, controlling locusts with diligence and thrift, and eradicating locusts", the country has transformed a total of 3.678 million hectares of locust areas from 1951 to 1997, reducing the area of ​​locust areas by 70.6% compared with the early days of the founding of the People's Republic of China. The number of counties in locust areas has been reduced from 328 in the early days of the founding of the People's Republic of China to 151, achieving remarkable achievements in the history of locust control in the world.

Since the 1980s, affected by abnormal global climate change, disrepair or improper construction of some water conservancy projects, and sudden changes in agricultural ecology and environment, the East Asian migratory locust has frequently occurred in the Huanghuaihai region and the southwest of Hainan Island, with an annual occurrence area of ​​about 1 to 1.5 million hm2, covering more than 100 counties in 9 provinces (cities), and agricultural production has been seriously threatened. In the 12 years from 1985 to 1996, the East Asian migratory locust occurred year after year in locust areas such as the Yellow River Beach, Hainan Island, and Tianjin. In the autumn of 1985, a high-density gregarious swarm of East Asian migratory locusts in Beidagang, Tianjin, ate more than 100,000 mu of reed leaves and hundreds of mu of corn cob leaves, and took off and migrated south at noon on September 20. The locust swarm was about 30 kilometers wide from east to west, and landed in five counties of Cangxian, Huanghua, Haixing, Yanshan and Mengcun in Hebei Province and two farms in Zhongjie Dagang, affecting an area of ​​2.5 million mu. This is the first inter-provincial migration of gregarious East Asian migratory locusts since the founding of New China.

In 1998, the summer locusts of the East Asian migratory locust occurred in Shandong, Henan, Hebei, Tianjin and other eight provinces (municipalities) with an area of ​​more than 800,000 hm2. In 1999, the summer locusts of the East Asian migratory locust occurred in Shandong, Henan, Hebei, Tianjin and other nine provinces (municipalities) with an area of ​​more than 800,000 hm2. This year, locusts have ravaged Henan again, with an affected area of ​​2.375 million mu. In some areas, the locust density has reached more than 4,000 locusts/m2. The large area and high insect population density are unprecedented in Henan in the past 25 years. Although the damage has been controlled, it is necessary to strengthen the elimination and monitoring of the egg-laying areas of the remaining adults in summer, accurately understand and grasp the occurrence of autumn locusts and the development trends of water and drought and meteorological dynamics, and timely carry out the prevention and control of autumn locusts and the third generation of migratory locusts to reduce the area and number of migratory locusts.

The Asian migratory locust is mainly distributed in Xinjiang, Qinghai, Inner Mongolia, and some river valleys and lakeside areas in the north of Shaanxi, Gansu, Shanxi, and Hebei provinces. In Tacheng, Xinjiang, gregarious migratory locusts caused damage in 1983-1984 and 1986. In 1987, 46 gregarious migratory locusts occurred in Altay, with an average density of 1,000 to 2,000 locusts per square meter, covering an area of ​​about 51,500 hectares. In recent years, high-density migratory locust swarms have occurred in parts of Hami and Turpan (1996) and Toksun (1997-1999). This year, the affected area of ​​locusts in Xinjiang reached 30.05 million mu, with a density of more than 10,000 locusts per square meter in Tacheng and Altay.

Tibetan migratory locusts occurred in 45 places in Tibet between 1928 and 1952. From 1846 to 1857, there were 12 consecutive years of locust plagues, affecting 18 regions. In severe cases, crops failed to be harvested for consecutive years, and barley and wheat were completely wiped out, and no grass was harvested on the grassland. In 1970, 1974, 1979, 1988 and 1991, Tibetan migratory locusts broke out in Linzhi, Milin, Bailang, Lhasa, Linzhou and Dagze, seriously affecting agricultural and animal husbandry production. On June 19, 1988, more than 1,000 mu of Tibetan migratory locusts occurred in Qiangna District, Milin County, and flew over the Yarlung Zangbo River to harm barley. In 1999, high-density migratory locust swarms also occurred in parts of Lhasa, Shigatse and other places.

Since the 1980s, rice locusts have occurred in more than 4.6 million square meters in some rice-growing areas in more than 10 provinces (cities) in my country. Bamboo locusts have damaged more than 3 million square meters of bamboo forests in the south. As for the locusts in the grasslands of each season in the northern pastoral areas and the agricultural and pastoral transition areas of my country, their occurrence characteristics are many species, high density, and the maximum occurrence area can reach more than 20 million square meters in 1985. According to incomplete statistics, in 1985, the annual disaster-affected area is about 4.6 million square meters, and the actual prevention and control area is about 1 million square meters. In 1998, high-density locust swarms occurred in the Ili and Altai of Xinjiang Uygur Autonomous Region in my country's pastoral areas and agricultural and pastoral transition areas, and the grasslands of Inner Mongolia Autonomous Region, covering an area of ​​more than millions of hectares. In 1999, the locust outbreak area reported in Ili, Altai, Changji, Balikun and other regions of Xinjiang Uygur Autonomous Region was about 40 million mu, and the main locust species were Italian locust, Halberd locust, Siberian locust, black-striped locust, etc., with an outbreak density of 600 to 8,000 per square meter, and in some areas it could be as high as 10,000 per square meter. Various locust areas have adopted various methods such as ultra-low dose preparations, microsporidia, attracting red starlings and raising chickens to control locusts.

In addition, in 1984, the outbreak of the Australian locust Chortoicetes terminifera (Walker) in Australia alone caused direct economic losses of 1 to 2 million US dollars. Since the end of 1985, many locust species have been rampant in many African countries and regions, causing extremely serious losses. In 17 states in the western United States, grassland losses caused by steppe locusts are about 8 million US dollars each year. In 1999, more than 1 million square meters of farmland in more than 20 states in central Russia, eastern and western southern Siberia, near the Caspian Sea, and bordering Kazakhstan were attacked by locusts.

Locusts are one of the most important pests in my country's agricultural production, and there are many species of locusts. However, the migratory locusts have the greatest impact on agricultural production and cause the most serious damage.

The occurrence and damage of locusts are shocking, especially in the years of locust plagues, which are sudden and destructive. The host plants of migratory locusts are mainly plants of the Gramineae and Cyperaceae families. They like to feed on crops such as corn, wheat, millet, sorghum, and barley, as well as weeds such as reeds, sedge, foxtail grass, barnyard grass, and dog bud roots.

Symptoms

Both the adults and nymphs (hoppers) of migratory locusts feed on the leaves and stems of plants. When a large outbreak occurs, they can eat all the crops down to the bare stalks. This is especially harmful when they migrate in large groups, often eating every grain of crop.

Living habits

The East Asian migratory locust has no dormancy phenomenon. Generally, one generation occurs per year north of Beijing; two generations usually occur in the Bohai Bay, the lower reaches of the Yellow River, the Huaihe River, and the Yangtze River Basin; but three generations can occur in the Weishan Lake and Hongze Lake areas in drought years; and three generations can occur per year in South China. All parts of the country overwinter as eggs in the soil. Migratory locusts are divided into two types: gregarious and solitary. The solitary type generally does not have the habit of long-distance migration, while the adults of the gregarious type have the habit of migrating and flying in groups, and the migration has a certain directionality. During migration, they can stay in the air for 1 to 3 days, and the adult locusts have a large appetite.

The occurrence of migratory locusts is closely related to environmental conditions. The suitable temperature for summer locusts to emerge is between 25 and 30 degrees Celsius. In the range of 17 to 36 degrees Celsius, the higher the temperature, the more they feed. Adults are selective in terms of soil moisture and salt content when laying eggs, and also have requirements for the compactness of the soil surface. Generally, more eggs are laid in compacted soil. The most suitable soil moisture content for laying eggs is 10% to 20%, and most eggs are laid in areas with a salt content of less than 0.5%. Therefore, it is easy to occur in low-lying areas, prone to waterlogging and drought, lake beaches or beaches with unstable water levels, large areas of wasteland, or wasteland with extensive farming.

Prevention and treatment methods

1. Agricultural prevention and control

⑴ Develop water conservancy to ensure that there is no disaster from drought or flood.

⑵ Reclaim large areas of wasteland and plant crops to change the habitat of locusts and reduce the area of ​​the outbreak base.

⑶ Plant trees and afforestation to change the microclimate in locust areas and reduce the number of suitable places for locusts to lay eggs and reproduce.

⑷ Improve farming and cultivation techniques to control locust eggs, adapt to local conditions, change crop layout, and reduce locust damage.

⒉ Biological control

⑴ In locust-infested areas, use highly effective and low-toxic agricultural and biological pesticides to protect the predatory natural enemies in the locust areas.

⑵ Apply locust microsporidia on a large scale.

⒊ Chemical control

When using pesticides to control locust nymphs on a large scale, the locusts should be before the third stage.

Use 75% malathion EC for ultra-low volume or low volume spraying. For aircraft control, use 60-70 grams per mu; for ground spraying, use 75 grams per mu, or use 45% malathion EC for ultra-low volume spraying, use 75-100 grams per mu, or 20% dima mixture, use 100 grams per mu, or 1.5% lindane powder, use 1.5-2 kg of spray powder per mu.

Locusts are one of the most important pests in my country's agricultural production, and there are many species of locusts. However, the migratory locusts have the greatest impact on agricultural production and cause the most serious damage.

The occurrence and damage of locusts are shocking, especially in the years of locust plagues, which are sudden and destructive. The host plants of migratory locusts are mainly plants of the Gramineae and Cyperaceae families. They like to feed on crops such as corn, wheat, millet, sorghum, and barley, as well as weeds such as reeds, sedge, foxtail grass, barnyard grass, and dog bud roots.

Symptoms

Both the adults and nymphs (hoppers) of migratory locusts feed on the leaves and stems of plants. When a large outbreak occurs, they can eat all the crops down to the bare stalks. This is especially harmful when they migrate in large groups, often eating every grain of crop.

Living habits

The East Asian migratory locust has no dormancy phenomenon. Generally, one generation occurs per year north of Beijing; two generations usually occur in the Bohai Bay, the lower reaches of the Yellow River, the Huaihe River, and the Yangtze River Basin; but three generations can occur in the Weishan Lake and Hongze Lake areas in drought years; and three generations can occur per year in South China. All parts of the country overwinter as eggs in the soil. Migratory locusts are divided into two types: gregarious and solitary. The solitary type generally does not have the habit of long-distance migration, while the adults of the gregarious type have the habit of migrating and flying in groups, and the migration has a certain directionality. During migration, they can stay in the air for 1 to 3 days, and the adult locusts have a large appetite.

The occurrence of migratory locusts is closely related to environmental conditions. The suitable temperature for summer locusts to emerge is between 25 and 30 degrees Celsius. In the range of 17 to 36 degrees Celsius, the higher the temperature, the more they feed. Adults are selective in terms of soil moisture and salt content when laying eggs, and also have requirements for the compactness of the soil surface. Generally, more eggs are laid in compacted soil. The most suitable soil moisture content for laying eggs is 10% to 20%, and most eggs are laid in areas with a salt content of less than 0.5%. Therefore, it is easy to occur in low-lying areas, prone to waterlogging and drought, lake beaches or beaches with unstable water levels, large areas of wasteland, or wasteland with extensive farming.

Prevention and treatment methods

1. Agricultural prevention and control

⑴ Develop water conservancy to ensure that there is no disaster from drought or flood.

⑵ Reclaim large areas of wasteland and plant crops to change the habitat of locusts and reduce the area of ​​the outbreak base.

⑶ Plant trees and afforestation to change the microclimate in locust areas and reduce the number of suitable places for locusts to lay eggs and reproduce.

⑷ Improve farming and cultivation techniques to control locust eggs, adapt to local conditions, change crop layout, and reduce locust damage.

⒉ Biological control

⑴ In locust-infested areas, use highly effective and low-toxic agricultural and biological pesticides to protect the predatory natural enemies in the locust areas.

⑵ Apply locust microsporidia on a large scale.

⒊ Chemical control

When using pesticides to control locust nymphs on a large scale, the locusts should be before the third stage.

Use 75% malathion EC for ultra-low volume or low volume spraying. For aircraft control, use 60-70 grams per mu; for ground spraying, use 75 grams per mu, or use 45% malathion EC for ultra-low volume spraying, use 75-100 grams per mu, or 20% dima mixture, use 100 grams per mu, or 1.5% lindane powder, use 1.5-2 kg of spray powder per mu.