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The more than 100,000 Kenyan farmers grappling with locusts that have been blamed for destroying thousands of tonnes of farm crops have now been pointed to a simple and cheap solution by a survey that has shown that the locusts cannot thrive on plants fertilised with nitrogen.
"Nitrogen fertiliser, which plants use to make protein, may be an inexpensive, more environmentally friendly pest control solution for this species," said the lead author of the study, Arianne Cease, a researcher at Arizona State University in the US.
It is believed that most herbivores, including insects, are limited by the availability of nitrogen-rich protein in their diets. The scientists found in field observations that locusts were less likely to survive in fields that were fertilised with nitrogen, and that their density was highest in the most heavily grazed fields, which were dominated by plants with low nitrogen content.
A group of Farmers in Eastern Kenya, pushed by the ever increasing price of pesticides, have developed home-made pest control solutions with impressive results., a practice they are teaching fellow farmers from Iringa area of Tanzania, a move that has assisted them to recover 60 per cent of the crop they were losing to pests,
A group of farmers assisted by scientists are now courting certain parasites and insects on their farms to act as natural enemies to other plant threatening parasites, in a model described as ‘sending a thief to catch a thief’.
Insects that include Ladybird beetles, spiders, bats and red fire ants, all long vilified as farmers’ greatest enemies, are now becoming farmers’ friends as multiple applications of synthetic pesticides by farmers fail to resolve the problems responsible for four fifths of the country’s harvests losses. Kenya currently spends close to Sh5bn a year on pesticides, much of it to battle insects.
However, the new farmers’ friend insects either secrete unique fluids that chase away pests, or feed directly and swiftly on the pests. According to many farmers, it takes just a week to rid a farm of pests with natural enemies, as against months when using synthetic pesticides.
Ladybird beetles have been in the frontline of the new techniques. The beetles, both in the adult and larvae stage of growth, prey on aphids, leafhoppers, mealybugs, mites, scales and whiteflies, which are known to devour cereals. A single ladybird consumes approximately 200 - 300 aphids over its lifetime of 1-3 months. Farmers have even begun growing wild sunflowers, with a higher pollen count than domesticated varieties, to attract the Ladybirds.
Rove beetles, another of the new friends, eat all stages of a wide range of insects in the soil or in the foliage, including bean flies, cutworms, scale insects and spider mites. Young larvae search the soil for cocoons of flies and after eating the pupa emerge sometime later as adults.
Last year, a unique parasitic wasp was even introduced into the country by the International Centre for Plant and Physiology and Ecology (ICIPE), Agricultural Ministry and Kenya Agricultural Research Institute (KARI) and has recorded impressive results in parts of Rift Valley where it was dispatched to tackle the notorious African fruit fly that feeds on mangoes and avocados.
Orchards that have introduced the wasp, such as Lakita Orchard in Naivasha, have delivered yields of around 10 tonnes a hectare compared with 4 tonnes a hectare when they were using synthetic pesticides.
Beating the fruit fly has been vital to export revenues. The proliferation of the fly on avocados led to an export ban to South Africa that was only recently lifted, and which cost Kenya Sh200m a year for 4 years, particularly hurting smallholders, which account for 85 per cent of Kenyan avocado exports.
Farmers in Busia county of Western Province have even moved from the bugs and parasites to courting bats as predators to fight moths and other insects. “Besides eating tons of insects they have also been feeding on cucumber beetles and even Stink bugs which damage our tomatoes,” said Wekesa, a large scale farmer in Busia who claims bats are the most effective natural enemy of all because they form large colonies and have a huge appetite. One bat can feed on 2kgs of insects nightly, and they forage over large distances.
Scientists have also developed other natural enemies in the laboratories like the Diamond Black moth, which is very swift in feeding on the large grain borer that is catastrophic to both maize and woods. Scientists have been releasing them onto farms when there is an acute invasion of parasites in farms.
The moth provides swift pest control but does not harm the crops and allows for naturally grown food. “I strongly feel when we afford to control all pests without touching any chemicals will be when we say we have passed on a healthy chemical free future to our generation, and one way is embracing an agricultural system that imitates a natural system,” said Dr Ladslas Ritwo, a scientist from the University of Nairobi College of Agriculture and a consistent crusader of organic pest control methods.
Written by Bob Koigi for African Laughter
Laboratory experiments further proved that locusts preferred to eat plants with low nitrogen content.
The study further found that soil erosion and overgrazing could enhance locust swarms since they lead to loss of topsoil and nitrogen.
“What this, therefore, means is that farmers don’t have to spend fortunes in synthetic fertilisers like they have always done. In fact, locally available nitrogen fertilizers, including organic ones and even cow dung, which are cheap, saves them from the locust menace,” said Doctor Ayub Ochieng from the International Centre of Insect Physiology and Ecology.
Desert Locusts can destroy crops quickly because they eat so much. An adult consumes roughly its own weight in food every day, while even a small section of an average swarm can eat as much food as 2,500 people every day.
Swarms average 40 million locusts and can eat up to 80 million tonnes of biomass a day.
Research has shown that if not detected and prevented early, the cost of controlling locusts and other pests from invading and destroying crops goes up by up to 15 times.
Certainly, n Kenyan farmer would want to relieve the nightmare of the locust invasion of 2007, when desert locusts from Ethiopia crossed to Kenya and descended on farms. Mandera town of North Eastern province, which had been struggling to be food secure, bore the brunt of the 2007 invasion. More than 200 farming families lost their vegetable and cereal crops, with many more losing their livestock, due to locusts invading their pasture.
The families were placed under relief aid for a whole year having lost everything on their farms.
However, scientists saw it as a wake up call and have been pushing for preparedness, as Kenya still remains vulnerable to more attacks due to its shared border with locust invested Ethiopia.
The United Nations’ Food and Agriculture Organization, for example, has been consistent in warning of the risks of a possible invasion by recently hatched locusts from Ethiopia, after locusts exhaust farms in Ethiopia.
A meeting convened last month bringing together agriculture ministers under the umbrella body International Red Locust Control Organisation for Central and Eastern Africa (IRLCO-CSA0) noted that the threat of locust invasion was still imminent and real, sounding an alarm about the catastrophic effects this would have on millions of livelihoods across the region.
‘Locusts and other migratory pests have shown time and again that they do not respect man-made political boundaries as they migrate from one country to another causing havoc to crops and livelihoods,’ said Gideon Ndambuki, Assitant Minister for Agriculture during the meeting.
Written by Bob Koigi for African Laughter
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