25 年以来全球最大的蝗灾席卷非洲

风清扬斈 2个月前 (02-15) 网络资料 448 0

联合国粮农组织公布的不同形态蝗虫分布图和沙漠蝗虫迁徙图

2月11日,联合国粮食及农业组织(FAO)向全球进行了预警,称希望全球高度戒备现在正在肆虐的蝗灾,防止被入侵国家出现粮食危机。据悉,本次蝗灾始于非洲,然后飞过红海进入欧洲和亚洲,目前已经到达了巴基斯坦和印度,距中国可以说仅一步之遥。

非洲飞蝗(图片源自网络)

蝗虫所到之处只能用“惨烈”二字形容。从FAO统计数据看,此次蝗灾对农作物的破坏力是东非地区25年之最,是肯尼亚70年之最;而索马里和埃塞俄比亚直接宣布农业生产完全停滞,数百万人生命受到前所未有的威胁。FAO副总干事Maria Semedo发出了最严厉的警告:“各国必须立即联合采取行动,蝗虫不会等待,它将铺天盖地而来并制造毁灭性灾难”。

巴基斯坦自然历史博物馆Abbas博士

就邻国巴基斯坦和印度而言,两国也正在承受着前所未有的压力。

巴基斯坦遭遇了非洲蝗虫与伊朗蝗虫双重入侵的打击,创下该国27年未见的蝗灾;巴基斯坦官方表示:蝗虫目前每天破坏约为3.5万人的口粮,如任其发展,国家将会无粮可收;为此,巴基斯坦已经宣布进入了紧急状态,动用了数百架飞机进行喷洒农药和驱赶,而其中1架飞机在作业时不幸在拉希姆亚尔汗坠毁;尽管面对如此大的蝗灾,“巴铁”在本次武汉新型冠状病毒疫情中,仍在第一时间无偿向中国捐赠了30万只口罩、6500套防护服和8000副医用手套,可谓是患难见真情。

印度和巴基斯坦一样遭受着前所未有的打击,根据印度拉贾斯坦邦财政部长的说法,有4000亿只蝗虫袭击了该邦,导致大量农作物被毁并有向其它邦蔓延之势;而该邦驻扎的70万印军因粮食被吃光不得不撤军,这也直接缓解了巴基斯坦的压力;印度有学者预测蝗灾将造成印度30%-50%的粮食减产,这极大引发了印度政府的担忧,印度总理莫迪更是主动向巴基斯坦伸出橄榄枝请求停战。

巴基斯坦和印度作为中国邻邦,其境内的蝗灾对中国是否存在威胁,又如何防御和治理是现在需要关注的一个问题。为此,中国科讯采访了中国科学院动物研究所、河北大学生命科学学院、广东省科学院生物资源与应用研究所的相关专家,就有关问题做了回答。

Q:目前巴基斯坦和印度的蝗灾会不会对中国造成威胁?

A:飞蝗全世界有7个亚种,中国常见的有3个:东亚飞蝗、亚洲飞蝗和西藏飞蝗,目前在非洲发生的蝗虫应该属于非洲沙漠蝗,在我国历史上还没有记载非洲蝗虫对中国造成重大危害的记录。

最近网上的消息说印度和巴基斯坦的蝗灾来源两个方面,一是非洲、二是伊朗;伊朗有可能也是两个来源,一是非洲沙漠蝗、二是否是地中海飞蝗,我们尚不清楚。从文献和历史上看,对我国的压力不大。但是,气候和环境的变化,以及非洲沙漠蝗生物学习性是否已有改变,需要进行进一步研究。

Q:您认为在什么条件下印度的蝗虫会入侵中国?哪个地区最有可能被入侵?

A:目前非洲蝗虫从印度直接进入中国的可能性不大,因为蝗虫的生存条件在中国并不完全具备,同时中国也拥有地理上的天然屏障。

但是,我认为也不能掉以轻心,我国云南曾有非洲沙漠蝗危害的记录,因此要密切关注印度蝗虫的迁飞路径,以及是否有新的本地虫源的参与。如果它们继续朝东到达了缅甸,这样极有可能对我国及泰、老、越地区造成直接的威胁。

Q:中国有没有可能也发生大面积蝗灾?

A:中国历史上蝗灾频繁,危害极大。新中国成立以后,党中央国务院高度关注蝗灾的问题,我国科学家协同攻关基本解决了蝗灾的危害,几十年来没有发生过大的危害。全国各级植物保护部门也建立起了比较完整的监测与防治系统,这是一个基本的保障。

但是,飞蝗造成灾害的基本条件是要有适宜的生存和繁殖环境,这是虫口基数的基本保障,往往在气候与雨水条件适宜时容易爆发。所以,限制蝗虫滋生地的存在是避免蝗灾爆发的关键,这也是我国蝗灾治理的经验总结。

值得关注的是,随着农村城镇化的快速发展,一些土地撂荒、环境治理滞后导致杂草丛生,这些成为蝗虫理想的生存之地,这是我国蝗灾发生的风险所在。

Q:各国面对突如其来的蝗灾为何会束手无策?

A:这个问题比较复杂。虫灾的发生与害虫本身的生物学习性关系非常密切,也与当地气候与生态环境关系非常密切。迁飞性害虫繁殖力极强,一旦发生,虫口密度异常之大,几亿甚至几十亿成群迁飞危害,它们的飞行能力极强、食性杂,很难有有效的防治办法。

同时,沙漠蝗的成虫寿命很长,最多可以生存100多天,以上这些特性给防治带来极大困难。最有效率的办法就是对滋生地的严格管理与封锁,减少虫口密度、避免造成灾害。

(原题为《蝗虫来袭!预警:4000亿只蝗虫已到达中国边境!【中国科讯】》)

近日,联合国粮食及农业组织(FAO)向全球进行了预警,称希望全球高度戒备现在正在肆虐的蝗灾,防止被入侵国家出现粮食危机。据悉,本次蝗灾始于非洲,然后飞过红海进入欧洲和亚洲,目前已经到达了巴基斯坦和印度,距中国可以说仅一步之遥。

肯尼亚奇杜伊县的一个村庄,蝗虫遮天蔽日。

据中新社12月14日报道,位于东非的埃塞俄比亚南部、肯尼亚部分地区正遭受蝗灾入侵,蝗虫数量庞大数十年仅见,眼见数十亿蝗虫大军逼进当地粮仓,却只有零星8架飞机可喷药,让专家急得像热锅上的蚂蚁。美国《新闻周刊》指出,迄今为止,最大的沙漠蝗虫群出现在肯尼亚的东北部,长达59公里,宽达40公里。

《华盛顿邮报》驻东非的记者这样形容这次蝗灾:“从远处看,它就像滚滚浓烟。但你走接近的时候,你会发现数以亿计的蝗虫,像暴风雪一样厚,像雨滴一样数不清。它们在空中扑打着翅膀,形成了一个庞大的阵型,遮天蔽日。”

2020年真的是不太平,除了中国正在经历疫情外,澳大利亚经历完火灾后又经历了洪灾,而最可怕的是,东非的很多国家正在经历蝗灾,蝗灾导致农作物受到了严重的损害,而且,东非在3月份还会迎来雨季,这不仅不会减少蝗虫,而且还会给蝗虫带来极有利的繁殖条件,到时候,蝗虫要比现在多得多。

一名埃塞俄比亚女孩在农场里驱赶蝗虫。

蝗虫所到之处只能用“惨烈”二字形容。从FAO统计数据看,此次蝗灾对农作物的破坏力是东非地区25年之最,是肯尼亚70年之最;而索马里和埃塞俄比亚直接宣布农业生产完全停滞,数百万人生命受到前所未有的威胁。

就邻国巴基斯坦和印度而言,两国也正在承受着前所未有的压力。

肯尼亚奇杜伊县,一名男子在乡间驱逐蝗虫。

巴基斯坦遭遇了非洲蝗虫与伊朗蝗虫双重入侵的打击,创下该国27年未见的蝗灾,蝗虫目前每天破坏约为3.5万人的口粮。巴基斯坦已经宣布进入了紧急状态,动用了数百架飞机进行喷洒农药和驱赶,而其中1架飞机在作业时不幸在拉希姆亚尔汗坠毁。

印度和巴基斯坦一样遭受着前所未有的打击。印度有4000亿只蝗虫袭击,导致大量农作物被毁。驻扎的70万印军因粮食被吃光不得不撤军。印度有学者预测:蝗灾将造成印度30%-50%的粮食减产。

埃塞俄比亚乡间的蝗虫蔓延数英里,车窗上布满蝗虫内脏。

中国科学院动物研究所专家表示,我国云南曾有非洲沙漠蝗危害的记录,因此要密切关注印度蝗虫的迁飞路径,以及是否有新的本地虫源的参与。如果它们继续朝东到达了缅甸,这样极有可能对我国及泰、老、越地区造成直接的威胁。由于迁飞性害虫繁殖力极强,一旦发生,虫口密度异常之大,几亿甚至几十亿成群迁飞危害,它们的飞行能力极强、食性杂,很难有有效的防治办法。同时,蝗虫成虫寿命很长,最多可以生存100多天,以上这些特性给防治带来极大困难。

2020可谓蝗害之年。今年天气变化多端,充足的雨水将持续至6月,蝗虫将在这段时间里繁殖、生长、蛰伏,等待下一个秋天。罕见的强降雨使得植被迅速生长,充足的食物使得蝗虫数量在6个月内翻了400倍。

Ethiopia and Somalia – and the worst Kenya has seen for 70 years. The impacts of the outbreak in these countries are particularly acute as pastures and crops are being wiped out in communities that were already facing food shortages.

As we write, the swarms have just crossed into Uganda and Tanzania, and moved within 50km (31 miles) of South Sudan. Djibouti and Eritrea are also affected. And Oman, Saudi Arabia, Sudan, Yemen, and Pakistan are fighting their own serious infestations.

The desert locust is considered the world’s most destructive migratory pest. A single locust can travel 150km and eat its own weight in food – about two grams – each day. A swarm the size of New York City can consume the same amount of food in one day as the total population of New York, New Jersey and Pennsylvania.

What we are seeing in East Africa today is unlike anything we’ve seen in a very long time. Its destructive potential is enormous, and it’s taking place in a region where farmers need every gram of food to feed themselves and their families. Most of the countries hardest hit are those where millions of people are already vulnerable or in serious humanitarian need, as they endure the impact of violence, drought, and floods.


We have acted quickly to respond to this upsurge. Local and national governments in East Africa are leading the response, and our respective offices are working closely together to keep this outbreak under control. The UN’s Office for the Coordination of Humanitarian Affairs has released $10 million from its Central Emergency Relief Fund to fund a huge scale-up in aerial operations to manage the outbreak.

The FAO is urgently seeking $76 million from donors and other organisations to help the affected countries fight the outbreak. The amount required is likely to increase as the locusts spread.

But the window to contain this crisis is closing fast. We only have until the beginning of March to bring this infestation under control as that is when the rain and planting season begins. The swarms are highly mobile; the terrain often difficult; the logistical challenges immense. But left unchecked – and with expected additional rains – locust numbers in East Africa could increase 500 times by June.


We must act now to avoid a full-blown catastrophe. And we will. At the same time, we need to pay attention to a bigger picture. This is not the first time the Greater Horn of Africa has seen locust upsurges approach this scale, but the current situation is the largest in decades. This is linked to climate change. Warmer seas mean more cyclones, generating the perfect breeding conditions for locusts.

Together, we express deep solidarity with the people and communities affected. And we call on the international community to respond with speed and generosity to control the infestation while we still have the chance.

 Qu Dongyu is director-general of the UN Food and Agriculture Organization; Mark Lowcock is the UN under-secretary-general for Humanitarian Affairs and Emergency Relief Coordinator.

In Somalia, an unprecedented effort to kill massive locust swarms with biocontrol

Somalia, one of several African nations being hit hard by enormous swarms of locusts, is planning to control them with a fungus in what would be the largest use of biopesticides against these insects.

“Large-scale use to control an invasion of desert locusts would be a first,” says Michel Lecoq, a retired entomologist who worked on locust control at the French Agricultural Research Center for International Development. “If successful, it will be a big step forward.”

The moment is crucial, because the next generation of locusts is now maturing and could devastate crops planted at the end of March. “We have a short window of opportunity to act,” Dominique Burgeon, director of emergencies at the Food and Agriculture Organization of the United Nations (FAO), said at a briefing Monday in New York City.

In recent months, the Horn of Africa has been invaded by desert locusts that have consumed food crops and pasture. For Kenya, it is the worst infestation in 70 years. One swarm there was estimated at 100 billion to 200 billion locusts, marauding through 2400 square kilometers. FAO warned again this week that the insects pose a severe humanitarian risk, as nearly 10 million people in the affected area already face food shortages because of recent floods and droughts. “We simply cannot afford another major shock,” Mark Lowcock, United Nations under-secretary-general for humanitarian affairs and emergency relief coordinator, said at the briefing. “Time is running out.”

Several factors caused the massive outbreak. In May 2018, a cyclone hit the desert “empty quarter” of Oman, Yemen, and Saudi Arabia. After the unusual rainfall, vegetation flourished, and the well-fed locusts increased their population 400-fold over 6 months. Normally, the populations would shrink when plants die after the desert dries out again, and timely control efforts can prevent populations from booming.

In this case, however, a second cyclone hit in October 2018 and the population continued to increase—an estimated 8000-fold by March 2019. The locusts headed to southern Iran, crossing territory that hadn’t seen the insects in 50 years, and moved east into India and Pakistan. Last summer, many flew south with prevailing winds into Yemen, where civil war prevented any spraying of pesticides. The swarms moved to Ethiopia and Somalia in October 2019.

Compounding the problem, yet another cyclone unexpectedly hit the Horn of Africa in December 2019 and more breeding ensued. By the end of that month, growing swarms had entered Kenya. They reached Uganda and Tanzania in the past few days.

Tackling large locust swarms is challenging and requires fast-acting chemical pesticides sprayed from aircraft. Ethiopia and Kenya are now spraying those chemicals. Although the pesticides break down within 1 day, villages must be warned to temporarily move their livestock.

In Somalia, which has large grazing areas, FAO is instead helping the country use biopesticides. They consist of spores of the fungus Metarhizium acridum, which produces a toxin that kills only locusts and related grasshoppers. Since the last major locust outbreak in Africa, in 2003–05, researchers have been able to make the biopesticide cheaper, more effective, longer lasting in the desert, and easier to store. “We’re really lucky now that we have a very effective product,” Keith Cressman, FAO’s locust forecasting officer, told ScienceInsider. Compared with chemicals, however, the biopesticide takes longer to kill the locusts, so it is more useful before the hopper bands of young locusts have begun to fly.

Such biopesticides have previously been used in several countries to stamp out locust outbreaks. In the past 3 years, China has applied biopesticides on more than 48,000 hectares annually, says Long Zhang of China Agricultural University. The main challenges are finding the bands of young locusts and hitting them with enough biopesticide, he says. “If the dose is too low, it will take a long time to kill locusts,” he says. Researchers in China have been selecting strains for greater virulence, but they still require that locusts to be exposed for several days longer than with chemical pesticides.

Last week, Cressman and others from FAO spent several days in Somalia discussing plans with the government. To help locate and spray the locusts, FAO is recruiting technical advisers from West African countries experienced in controlling outbreaks. They will also bring in backpacker sprayers and larger equipment that can be mounted on vehicles and aircraft. FAO has ordered 4 tons of the Metarhizium biopesticide, enough to treat about 80,000 hectares. Funding has mainly come from FAO’s emergency reserves, and more cash is urgently needed. So far, donors have committed about 28% of the $76 million needed.



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