Looking at locusts from space: How much is the impact of Pakistan’s locust plague?

Pakistan is suffering its worst locust plague in 27 years. The raging desert locusts have been “destroyed” in India, but are still raging in Pakistan. The locust plague has reached Pakistan’s Punjab, Baluchistan and other places, within the border with China’s Xinjiang. How bad is the impact of the locust plague in Pakistan? Can locusts be detected directly by satellite? Recently, commercial remote sensing application enterprise Beijing Four Elephant Siai-Sis stech (hereinafter referred to as “Four Elephants Love Number”) used remote sensing satellites to collect images and data from the three regions of north, central and southern Pakistan, and to see locusts from space.

Reduced vegetation density in central Punjab and northern Sindh province

Desert locusts are the most destructive migratory pests of all locusts, with strong flight capacity and large intake, and can gather to form huge locust swarms. They are usually found only in semi-arid and arid desert areas of Africa, where annual rainfall is less than 200 mm. Desert locusts lay eggs in the moist sand, and rainfall is conducive to their survival and reproduction.

Desert locusts entered Pakistan last March. Pakistan once largely controlled the locust plague, but this year, due to the long rainfall time in the Indo-Pakistani desert region, for desert locusts to provide a good living environment, resulting in the deterioration of locust plague, to the agricultural cause of great losses. Punjab alone lost 100 billion rupees of wheat to locusts.

Zhou Zhenjiang, a researcher in the 100-person program at Zhejiang University and a doctoral tutor at the School of Biological Systems Engineering and Food Sciences, told The News that 70 percent of Pakistan’s crop cultivation is concentrated in the northern province of Punjab and 20 percent in the southern province of Sindh.

Looking at locusts from space: How much is the impact of Pakistan's locust plague?

Northern, Central and Southern Sampling Areas of Pakistan

The commercial remote sensing application company Beijing Four Elephants Technology Co., Ltd. has sampled vegetation in northern Pakistan (i.e. central Punjab), central region (i.e., northern Sindh province), southern region (i.e., southern sindh province) from October 2018 to February 2019. October 2019 to February 2020, collected every 16 days.

From the image map transmitted under the satellite, the darker the color, indicating that the denser the vegetation, the better the growth of crops, the closer to maturity. Therefore, comparing the green area and color depth in the contemporaneous image, the degree of vegetation density can be seen intuitively.

Looking at locusts from space: How much is the impact of Pakistan's locust plague?

Satellite images of central Punjab on 2 February 2019 and 2 February 2020

Looking at locusts from space: How much is the impact of Pakistan's locust plague?

Satellite images of northern Sindh province on 2 February 2019 and 2 February 2020

Satellite imagery from 2 February 2020 in central Punjab and northern Sindh province sat out that the green area and color depth decreased and the density of vegetation decreased compared to 2 February 2019. The opposite is true in the southern part of Sindh.

Looking at locusts from space: How much is the impact of Pakistan's locust plague?

Satellite images of southern Sindh province satmaron on 2 February 2019 and 2 February 2020

The impact of locust plague in southern Sindh province is small

How to quantitatively analyze vegetation affected data and confirm the results of visual observations? One method is to calculate the vegetation index by using the difference in light absorption between the two wavelengths of near-infrared and red light.

Yao Yonghang, chief technical officer of The Four Elephants, introduced to The News, using the spectral characteristics of the reactions of different periods of plant growth, combined with remote sensing multispectral sensors to obtain multispectral images of interest areas, and then through professional algorithm inversion, we can obtain the index of reactive vegetation growth. This data can often be used to assess plant growth and determine crop yields.

The range of values is usually between 0-1, and a higher value indicates that the plant grows more prosperous. Among them, the low density state of 0-0.3 represents grassland, sparse vegetation, 0.3-0.5 of medium and low density represents vegetation extraction period, 0.5-0.7 medium and high density represents the extraction period, when vegetation leaves increase rapidly, grow rapidly, and high density of 0.7 or more represents vegetation close to maturity and semi-maturity.

Looking at locusts from space: How much is the impact of Pakistan's locust plague?

Percentage of density vegetation in central Punjab from October 2018 to February 2019, October 2019 to February 2020

According to the four elephant sage, from the central Punjab data, the proportion of high-density vegetation in the early January to early February 2020 decreased year-on-year. The proportion of high-density vegetation in early January 2020 was 6.8%, down about a quarter from 9.2% in the same period in 2019. The proportion of high-density vegetation in late January 2020 was 24.03%, down about 12% from 27.39% in the same period in 2019. The share of high-density vegetation decreased by about 27% year-on-year in early February.

Looking at locusts from space: How much is the impact of Pakistan's locust plague?

Percentage of density vegetation in northern Sindh, October 2018- February 2019, October 2019-February 2020

According to data from northern Sindh, the proportion of high- and high-density vegetation decreased year-on-year from late January to early February 2020. The proportion of high-density vegetation in late January was 4.67 percent, down about 43 percent from 8.21 percent in the same period in 2019, and the proportion of medium- and high-density vegetation decreased by about 1/3 year-on-year. In early February, the proportion of high-density vegetation decreased by about 29% YoY, while the proportion of medium- and high-density vegetation decreased by nearly 10% YoY.

Looking at locusts from space: How much is the impact of Pakistan's locust plague?

Percentage of density vegetation in southern Sindh province, October 2018-February 2019, October 2019-February 2020

The locust plague has had a smaller impact in southern Pakistan, the four elephants said. From early January to early February this year, the proportion of medium- and high-density vegetation in southern Sindh province was higher than in the same period last year.

February marks Pakistan’s wheat pregnancy

Pakistan is suffering its worst locust plague in 27 years. On 31 January, the Government of Pakistan declared a state of emergency.

According to Zhou, wheat and rice are the two most important staple crops in Pakistan, growing in winter and summer, respectively. “In February, Pakistan’s main growing crop is wheat, which is in the middle of a fertility phase and will soon enter a spike flowering period, a critical period of yield formation. “

In Pakistan, where corn is also grown between January and mid-February, he says effectively curbing the spread and reproduction of locusts is crucial to ensuring food security in Pakistan.

On February 24, the Chinese Locust Control Working Group arrived in Pakistan. The working group, composed of the Department of International Cooperation of the Ministry of Agriculture and Rural Affairs, the Prairie Management Department of the State Forestry and Prairie Bureau, the National Agricultural Technology Extension Service Center, the China Agricultural University and the Shandong Plant Protection Station, will conduct field research on locust plagues in Sindh, Balochistan and Punjab provinces of Pakistan and provide technical support for locust control and control in Pakistan.

In view of the special situation and needs of Pakistan, they put forward the combination of short-term emergency prevention and control with long-term sustainable management, chemical control and green prevention and control, air aircraft administration and ground-based large-scale equipment sowing, control of local hatching pests and resistance to migration pests abroad, accurate monitoring, zoning management, Effective prevention and control and comprehensive management program supported by science and technology.

According to the satellite data of the four-like love number, commodity futures and the Global Macro Research Institute Chaos Tiancheng Research Institute issued a research report that the locust plague has a greater impact on Pakistan’s wheat and rapeseed production, the locust plague is estimated to cause 7%-9% of Pakistan’s wheat production reduction, the global wheat production caused about 0.36% of the loss.

Punjab and Sindh provinces are the main cotton-producing regions of Pakistan, but since Pakistani cotton began planting in April and was fully harvested at the end of December, the current locust plague has had little impact on cotton. “If the locust plague continues into April-May, cotton, sorghum, grain (rice, millet, corn) will all enter the planting period, with potential implications for future agriculture,” said the Institute of Chaos. “

Can locusts be detected directly by satellite?

Pakistan’s food production accounts for 18.5 per cent of GDP, and a severe locust plague threatens its food security.

“Thirty-eight percent of Pakistan’s land is suitable for locust breeding, and Pakistan is one of the few countries in the world with two locust breeding periods a year, and if locust plagues are not brought under control in a timely manner, they will invade more areas,” said Mohammad Tariq, technical director of the Plant Protection Division of pakistan’s Ministry of Food Security and Research. Mid-March is likely to reach another peak of locust plagues. “

Desert locusts flew over the Red Sea from Sudan and Eritrea in the Arabian Peninsula in January last year, reached Yemen, Saudi Arabia and Iran in February, southwestern Pakistan in March and north-central China in June.

Looking at locusts from space: How much is the impact of Pakistan's locust plague?

Desert locust flight route Source: CCTV News

Khusro Bakhtiar, Pakistan’s minister of national food security and research, said the first locusts were found in Pakistan in March last year, flying from the deserts of Punjab and Sindh provinces to Balochistan and spreading to Dera Ismail Khan in Khyber Pakhtunkhwa province. According tomedia reports, about 80,000 hectares of crops have been damaged and pastures and woodlands have been damaged in Pakistan’s Sindh and Balochistan provinces.

Desert locusts can fly 150 kilometers a day with the wind. A common-sized locust population can have as many as 40 million locusts, and a one-square-kilometer-sized swarm of locusts can eat the equivalent of 35,000 people a day.

So can the swarms of surging locusts be detected directly by satellites?

According to the United Nations Food and Agriculture Organization, meteorological satellites and other satellites used to monitor the environment cannot detect individual locusts or locust swarms, and the highly complex satellites used by the military can indeed detect locusts, but these images cannot be used for civilian use. Even if it can be used, national and international locust organizations are unlikely to explain the hundreds of images produced every day.

To find the migration trajectory of locusts, Yao Yonghang said that the data collected so far is still very difficult, because the locusts fly very fast, which requires high-frequency and high-resolution satellites to do real-time monitoring. “Later with the development of satellite technology, and gradually replenish the number of satellites and various payloads in the sky, it is possible to have such capabilities in the future. “