Insects in Kenyan capital no cause for alarm

June 24, 2010 12:00 am

, NAIROBI, Kenya, Jun 24 – In December of 2007, swarms of locusts invaded the North Eastern region destroying food crops barely a month after heavy rains had boosted crops and pasture in the region.

The locusts were said to have migrated from Somalia. Now, three years later, an upsurge of grasshoppers in Nairobi has raised concerns that a similar phenomenon could be in the making.

However, a scientist at the International Centre of Insect Physiology and Ecology (ICIPE) has told Capital News that this should not cause alarm.

“They are not locusts but grasshoppers but because they come in large numbers and are seasonal there is the assumption that they are locusts,” Dr Baldwyn Torto, Principle Scientist, Head Behavioural and Chemical Ecology department said.

Dr Torto explained that the difference between grasshoppers and locusts was that a grasshopper is typically harmless while a locust has the ability to transform into a harmful insect.

“When you have a long period of drought and then the rains come in, all the individual harmless locusts have to fly to places where they can find food and if the rains are centered within a certain area, all of them fly there and concentrate,” Dr Torto says.

“When they are together, they rub on each other and this causes a mechanical stimulation which stimulates a change in their color and their behaviour. That’s the way it starts,” he explained. 

He said the large emergence of the grasshoppers is due to the change in climate where Kenya experienced rains after a long dry spell but there is no likelihood of the grasshoppers causing any destruction because the climatic condition is not going to favour their survival.

“Insects are such that they just react to conditions. You might get rainfall in some parts of the country which is enough to trigger grasshoppers to begin to mate and lay but when that rain stops suddenly, the eggs continue to remain in the soil for even six months, to hibernate and wait for rain,” he states.

Dr Torto also said that most grasshoppers develop in warm climates so when they are found within Nairobi it should not cause worry because the conditions would not favour their growth.

He added that desertification is a major trigger of locusts and Kenya is likely to suffer periodic infestations of locusts following the 2007 attack because the eggs remain in the fields.

“The problem with Somalia is that it is a dry area and that’s what locusts like and (there is no) real government that can take care of interventions. The intervention is usually better when you deal with the eggs or the young ones because they just hop, they don’t fly,” he said.

“When they become adults, they are able to fly long distances and that’s what happened to Kenya.”

Dr Torto says that grasshoppers and locusts feed on cereals which can impact negatively on food security. He said ICIPE had identified a chemical that is naturally produced by locusts and which can be used to control the early stages.

“It does not kill the locust but it breaks the grouping and the insects become hyperactive and eventually eat each other which is really nice. The chemical is natural and easily available,” he says.

The scientist said there is need for the public to be vigilant so that they inform appropriate authorities of any grasshopper outbreak for necessary interventions to be taken.

“We have technologies like biological control agents (it’s a fungus and specific for grasshoppers) that can be used and they are not harsh to the environment but it’s up to the public to be vigilant and inform the authorities,” he said.


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