BackLocust attack: 'They damage anything that comes in their way'
A nano biotechnology and plant genetics expert explains how preventive control is an effective way of handling such pest outbreaks
PremiumAs things stand, a vicious swarm of desert locusts have reached as far as the Indian states of Maharashtra, Rajasthan and Madhya Pradesh. Alarm bells were sounded in the Delhi-NCR region as of Wednesday, with a high probability of the swarms heading there, since the area has dense, green foliage.
Desert locusts (Schistocerca gregaria) are just one the many species of short-horned grasshoppers that can cause severe devastation when they form swarms. National Geographic describes them as a ‘notorious species’ of locusts that can cause massive agricultural damage. These migratory pests can travel long distances and a single swarm can consist of around 80-150 million locusts.
The latest locust bulletin update from the Food and Agriculture Organisation (FAO) of the United Nations noted that the current situation remains extremely alarming in East Africa, where Kenya, Ethiopia and Somalia continue to face an “unprecedented threat to food security and livelihoods".
KC Bansal, former director of the National Bureau of Plant Genetic Resources, a nodal organisation part of the Indian Council of Agricultural Research, says this is not an India-specific issue and requires global cooperation. “You need funds to tackle this globally," he says.
“It is an international problem. It's not specific to a particular country. There needs to be an international agreement to tackle this problem, like we control a lot of other such issues," adds Bansal, who is also a member of the board of directors at The Global Plant Council, a non-profit coalition of plant, crop, agricultural and environmental science societies.
In an interview with Mint, Bansal explains how climate change is just one of the parameters that is allowing new species of pests to emerge and what can be done to control such outbreaks. Edited excerpts:
How damaging can these locust swarms be?
They can be extremely damaging because they come in large numbers, to the extent that they can cover thousands of square kilometres. The swarm itself consists of millions of locusts per square kilometre and they can migrate over long distances per day. Since they are millions in numbers and spread over such a large area, they damage anything that comes in their way—any green vegetation or crops. A swarm covering just a square kilometre could damage up to a 100 tonne of crops daily. These are estimates based on analysis and studies, researchers and organisations like the FAO have carried out over time.
What role has climate change played here?
There was a declining trend (in recent years) when we talked about the number of countries affected by these swarms. But because of weather conditions and global climatic changes, these are coming up again. These insects find a conducive weather environment where they can reproduce faster. Normally, they are solitary individuals, but when they get favourable weather conditions, they can multiply in large numbers and aggregate. They reach a stage where they are called 'gregarious' in nature—they devastate any green crops after this. This happened recently in some East African countries.
What about crops in India?
They don't stop only at grains. It could be rice, wheat, cotton, vegetables, and so on. In India, states like Rajasthan, Madhya Pradesh, Maharashtra and parts of Punjab with rabi crops (are in danger from the swarms that entered from Pakistan). When the green parts of a crop are damaged, naturally, the whole crop is wasted.
Do you think these swarms have hit India at a complicated time, in terms of crop growing season and patterns?
It's difficult to predict this. Researchers are, in fact, trying to develop predictive models, based on weather conditions, to monitor these swarms. These modelling studies could be useful in understanding if these outbreaks occur during a specific part of the year or prevailing weather parameters. This could help with early detection and then preventive control can take place.
What's the best way to tackle this situation?
Preventive control is actually a better strategy than controlling it when it has already taken the shape of an outbreak. Internationally, several countries over the years have resorted to chemical spray control and pesticides. Decisions also need to be taken on the type of pesticides used, since these are really big insects, and the spraying technique: whether it needs to be sprayed on the ground or aerially.
In India, drones have been allowed to spray these chemicals. But this has its own disadvantages, because it poses a health hazard to humans. As we move ahead towards a more sustainable future, people have also tried bio-pesticides. These include the use of certain fungal species to kill the insects in the early stages of their growth cycle. But this needs weeks to work. The results are not instantaneous.
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