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,
Simple home made solutions using African Marigold, papaya and neem with soap water are proving 60 per cent more effective in controlling the bean fly menace than conventional pest control, with farmers reporting having saved 30 per cent of their pest control budget through the novel solutions.
Bean flies, also called bean stem maggots, are serious pests in Africa where in 2006 they entirely swept out some large bean farms, costing the Nigerian and Ghanaian economies $100 million in lost crops.
The adult is a tiny fly, about 2mm long, of a shiny black-bluish colour. The female fly pierces the young leaves to lay eggs and sucks the exuding sap. This creates yellow blotches on the leaves, which are the first signs of bean fly attack and can serve as an early warning of the infestation. The young maggots then mine their way from the leaves down to the base of the stem.
The maggot feeding destroys the tissue causing the stem to swell and split, with the flies often visible in the stem splits. Attacked plants tend to produce extra roots in compensation. But young seedlings and plants under stress wilt and die when attacked by bean flies. The damage is more severe in plants growing under poor conditions, with infertile soils or during drought.
But with the help of ethnoveterinarians - veterinarians who rely on traditional knowledge in pest control – farmers are now using common plants like Sodom Apple, pawpaw and African Marigold to spray their bean cultivated land with home-made solutions that act as repellants to the bean fly.
Conventional pesticides like Uquash 22100 from Russia, which farmers have used for many years, were only partially effective in controlling the fly, but also had long term adverse effects on the soil, with farmers needing to spend more on fertilizer after spraying the land with the pesticides. “It took us some time to detect why there was a drop in yields. Though we had managed to bring down the number of pests in the farm by a considerable number, yields in subsequent harvests were pathetically low. It took officials from the Ministry of Agriculture to identify that the problem was with the pesticides we were using,” said Conrad Ndegwa from Nyahururu.
Now, the organic pest control methods that began in Nyahururu borders are now being taken up in neighbouring districts, not only warding off the flies but assisting in fertilizing the soil.
Farmers using Sodom Apple mix a kilo of its fruits and leaves with 3 litres of water, and crush the fruits together with the leaves before adding a little soap. They soak the solution for a day after which they spray the solution either early in the morning or late in the afternoon. “The secret with spraying during these times is because pests are concentrated in one area during early morning as they plan where to go feed on during the day or late afternoon when they converge in one place in the afternoon. So far the method is working wonders,” said Mrs Nduguta Njeru, an ethnoveterinarian working with the Nyahururu farmers.
With papaya, farmers add a kilo of finely shredded papaya leaves to 1 litre of water and shake vigorously. This is then added to around 4 litres of soapy water. “If you have quarter acre of land, you get about half a kilo of leaves mixing them with half a kilo of water,” said Mrs Njeru.
However, the new methods have been met with dismay by local agrovets as the Nyahururu farmers have stopped buying the pesticides. The word of mouth reporting on the stellar performance of the home made solutions has become so widespread that some 5 agrovet dealers have closed shop in the last six months.
Farmer Smile agrovet is one of the shops that closed down two months ago after being in operation for five years.
“Our joy is not to drive them out of business, but to work for the greater good of the farmers. If farmers can save their land from pests, increase yields and save money to use elsewhere, that's all that matters. We have made several enemies in this pursuit, but we are guided by the principle of empowering farmers,” said Gachoka Tande, another ethnoveterinarian.
Written by Bob Koigi for African Laughter
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
A graduate has invented a way of eliminating weevils by using maize cobs to kill a pest blamed for over 60 per cent of crop losses after harvesting. His solution is now being adopted rapidly across the Rift Valley, and billed as a near complete cure.
Weevils, which have drill-like mouth parts, make a hole in a kernel and store their eggs inside. After hatching, the larvae feed on the kernel and emerge as adults. The adult insects lay their eggs in another maize kernel, and the cycle repeats itself. By the time one weevil cycle is over the farmer is left with a sack of maize emptied of its nutritional value and maize seed that cannot be planted.
“Farmers realise when it’s too late that their maize is weevil infested, since at the earlier stage of infestation it is very hard to detect. However, one way to ascertain if the maize is infected is looking at the kernels, if they are full of holes, they break down when you press them between your thumb and index finger,” said Ngotho Kagia, the graduate from the College of Agriculture and Veterinary Sciences of the University of Nairobi who invented the new weevil blocker.
His method, now being used by farmers across the Rift Valley, halts the multiplication of the weevils.
After removing the maize cob and shelling the maize, farmers are now pounding the maize cobs in a mortar and mixing the powder with maize kernels, which are then stored in jute sacks. The mixture of the cob powder and the fine films from the cobs reduces the weevils' activity, with the maize cob additionally containing a pungent smelling substance that suffocates the weevils without harming the maize kernels.
When the mixture is well compressed in jute sacks, the adult weevil that comes out of a maize kernel cannot find another kernel immediately. The fine film and the powder from the cob hinder its movement. The weevil finally gets tired and dies therefore reducing to almost nil the chances of any further eggs being laid.
Scientists are encouraging farmers to additionally embrace harvesting methods to further cushion them from weevil attacks during storage. A late harvest increases the chances of pest attacks. According to the scientists, maize opens the husks- ears- when it reaches maturity. If it is raining, water enters the maize cob with the maize acquiring a yellow colour and it eventually starts rotting. Once the maize ears are open, weevils and other pests also gain easy access and start destroying the maize even before it is harvested. Maize that is left to stay on farms after it matures also becomes prone to fungal infestations. “Farmers should understand that the most serious problems always come from trying to store grains that are already infested,” said Jamleck Karanja one of the scientists said.
The success of the new indigenous method of pest control, which farmers say is achieving almost total eradication of the weevil, has even inspired applications in other crops like cowpeas, beans and sorghum, which are equally susceptible to weevil attacks. “We were grappling with the twin menace of afflatoxin and weevil attack, but we are comfortably managing the weevil and this new application has proven equally effective in our other crops like beans and cowpeas,” said Ruth Ndarwa a Rift Valley farmer.
Ngotho developed the method at a time when he was struggling to get a job after graduating. Of the many indigenious knowledge applications he is developing to save farmers from pests, the weevil blocker has been the most embraced, owing to the high cost of pesticides and the huge attachment farmers have to maize production.
Written By Bob Koigi 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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