Why the North Grassland Trapped Grasshopper Crisis
"As a shepherd, I am most afraid of locusts, because they often bring disaster to the sheep!" In the Inner Mongolia Autonomous Region Wulat grassland grazing pastor Siqin Bi Like said with concern.
In northern China's grassland areas, locust disasters are always an important problem in production. July and August this year, Inner Mongolia, Xinjiang and other grasslands due to pre-high temperature, less precipitation, making the locust disaster risk level is higher, many places there are locusts.
Locusts, commonly known as "grasshopper", a wide range, a large number of vitality tenacious. They can live in a variety of places, in the mountains, forests, grasslands, low-lying areas and semi-arid areas of the most distributed. According to the Inner Mongolia Autonomous Region Chifeng City Agriculture and Animal Husbandry Bureau Wang Jian introduced grassland locusts have hundreds, which can really produce only about ten kinds of harm, so most of the locusts will not produce large-scale agriculture and animal husbandry disasters.
"Locusts and grass is a symbiotic relationship, as long as there is grass where there will be locusts, but whether there is a certain standard of disaster." National Meteorological Center Agricultural Meteorological Center is a senior engineer Guo Anhong introduced.
Limited to natural conditions, the general situation the number of locusts remain stable. However, if meteorological conditions change, then the number of locusts will suddenly increase. The air temperature is high, air drying, soil drought is conducive to the growth of locusts the most important factor.
"Winter temperatures in 2014 are higher than in the same period of the year, which is detrimental to killing the wintering eggs of locusts, thus making the base of the locusts larger in the following year, laying the foundation for the outbreak of locusts." Guo said.
In addition, during this year's growth and development of locust larvae, temperature and humidity conditions are favorable for locusts. National Meteorological Center data show that as a result of April to May this year, most of the grassland area average surface temperature above 10 ℃, most of Xinjiang, Inner Mongolia and other places generally 12 ℃ to 24 ℃, the higher the temperature. "Coupled with the winter snow melt effectively complement the soil moisture, these conditions are very conducive to grassland locust embryo development and incubation." Guo Anhong said.
And in June the grassland locust larvae of the main growth stage, the northern grassland and no strong precipitation process. Therefore, in July, Inner Mongolia, Xinjiang and more locust disaster. Meteorological departments also as early as June, according to the grassland locust development weather forecast model calculation results to remind the relevant departments to pay attention to pest control.
For locusts, control locust experts have a saying: do not take off, no disaster. In other words, as long as the locusts do not fly, it will not form a disaster. However, once the locusts take off, the flight will be useless.
In 2004, the Inner Mongolia Wulatezhongqi Bayeha Tai Su wood locust plague. "The half-inch locusts were looking for targets everywhere, and the locusts had passed, and the original green meadows were barely bare and yellowed." Siqin Bi Geke recalls.
In fact, the grassland will be more or less a year of locusts, in the grassland natural ecosystem, the locust population due to its own biological characteristics and environmental factors, the population often fluctuate. Once the population density reaches a certain number, there can be locusts.
"The occurrence of locusts, development is a gradual process, itself has a cycle." Guo Anhong said, "but also by the environment, ecology and other external factors."
As the saying goes, long drought must have locusts. This is because locusts take water by feeding plants. If you encounter more dry weather, locusts need to feed more plants to meet their moisture requirements. In addition, the ability of mature locusts is very strong. When locust grassland has been unable to meet the needs of locust feeding, locusts will spread and migrate large areas, which will cause serious influence.
However, the occurrence of locusts is both a product of the natural process and the result of human activities.
"In addition to drought, desertification also increased the locust spawning place, easily lead to grassland locusts." Guo Anhong said, "due to excessive grazing, making grassland degradation, desertification, conducive to large-scale growth and reproduction of locusts at the same time, biodiversity , And the number of natural enemies of grasshoppers decreased drastically.
It is understood that locusts and drought, floods and known as the impact of China's agricultural three major natural disasters. As China continues to improve water conservancy facilities, the impact of drought is getting smaller and smaller, and after a long period of time after the founding of new China, the locusts have narrowed and the incidence of locusts has dropped a lot. However, since the seventies and eighties since the last century, with the degradation of some local ecological environment, coupled with the impact of climate warming and other factors, many places a new locust disaster area.
"Locust is actually every year, but the occurrence of area and the density of insects are different, the degree of disaster is also different." Wang said, "locusts are part of the grassland biological chain, we can not completely remove, can not be completely removed, as long as Moderate control of the population density does not allow locusts to appear on a large area.
Prevention and control of locusts have agricultural control, biological control, pharmacy control three ways. Agricultural control and improper construction of water conservancy, so that drought and disaster, and reclamation planting, to change the habitat of locusts; biological control that is in the locust disaster areas, the release of some locusts, such as animal husbandry, or large area of the application of locust microsporidia; Prevention is a large area of the use of chemicals.
For a long time, the meteorological department has been very helpful to the agricultural sector and the grassland ecological management department, especially in the analysis of the correlation between the palaeoclimate and locusts and the forecast of meteorological conditions for locusts. Meteorological technology for agricultural production and grassland ecological protection provides a strong technical support.
"We produce and publish the" agricultural and forestry pests and diseases weather forecast "products, submitted to the relevant units.For grassland locusts, we will come to the critical period before the control, according to grassland locust development weather forecast model to calculate the results, and through Comprehensive analysis, the grassland locusts were measured and the regional distribution of high, high and low meteorological grade was developed, and the classification suggestions for grasshopper prevention and management were put forward. "Guo Anhong introduced.
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