Mozambique: 40,000 Hectares of Farmland Lost Because of Pesticide Abuse

In the 2018-19 agricultural campaign, Mozambique lost over 40,000 hectares of cultivated land because of the abuse of pesticides in the attempt to control insect pests.

Aderito Lazaro of the Plant Health Department in the Ministry of Agriculture, said "the use of chemicals should be a last resort. However, at the first sign of a pest, the producers grab their pesticides, and one of the mistakes is that they use the same substance repeatedly. They should rotate".

Lazaro cited the case of Boane district, 30 kilometres west of Maputo, where farmers had doubled the amount of pesticides used per week - without getting rid of the pests damaging the maize crop. Insects are showing signs of resistance to pesticides throughout the country.

The Agriculture Ministry, in partnership with the United Nations Food and Agriculture Organisation (FAO), has publicised methods to handle pests through an integrated range of measures, including not only conventional insecticides, but also biological pesticides and improved seed.

Meanwhile, a new pest is threatening banana growers in Chokwe district, in the Limpopo valley. This is the banana bunchy top virus (BBTV). To prevent the spread of the virus the authorities are destroying infected banana trees in several plantations.

"This virus is lethal, and regardless of whether we cut the trees down or not, they will die", said Celso Rufasse, coordinator of the BBTV project, cited by the independent daily "O Pais".

"If we don't cut the trees down, there will be a greater dispersal of the disease", he continued. "The goal is to avoid the spread of the virus, so that we can eradicate the disease".

Destroying the infected plants began a month ago, and so far almost 30,000 banana trees have been cut down in Chokwe. There is ban in place on the movement of bananas from Chokwe to elsewhere in the country.

The elimination of infected plants is budgeted at 20 million meticais (about 323,000 US dollars), and this task is receiving assistance from South Africa and the United States.

The virus is transmitted plant to plant by banana aphids. The virus damages the cells of the host plant, and usually prevents it from producing fruit. Any fruit that is produced is likely to be deformed.

Since there are no varieties of banana that are resistant to the virus, the only ways to eliminate the disease are to control the aphids, or to remove and destroy infected plants before the virus spreads.

https://allafrica.com/stories/201907170819.html

Zimbawe: Seed Treatment Chemical To Fight Fall Armyworm Infestation

Agrochemical company Syngenta is set to introduce a maize seed variety treated chemically, which is said to protect the developing seed against the pest for several weeks after germination.

A spokseman for a company distributing Syngenta products in Zimbabwe said, "FD is a seed treatment chemical.It will have an effect of protecting the crop against fall armyworm during its early stages. It remains in the plant system for the first four weeks after germination, so you won’t need to spray against FAW during that period.”

He said the seed was undergoing necessary regulatory approvals before it was released on the market. The seed has been introduced in countries such as Argentina, Belize, Brazil, Canada, China, Guatemala, El Salvador, Honduras, Mexico, Paraguay and Turkey.

Full article...

Rain Failure Worsens Armyworm Attack On Kenyan Maize Farms

This is the third year in a row that the pest is attacking maize in the east African nation, with agriculture experts noting that the vagaries of climate change are getting worse.
The armyworm attack is expected to be worse this season due to insufficient rainfall, according to agricultural experts. This is because the current dry weather following failed rains offers perfect conditions for the fall armyworms to reproduce and spread faster to other areas.

Kenya Agricultural and Livestock Research Organization, a government agency, has warned that this year’s armyworm invasion would be worsened by the erratic rainfall.

Besides pesticides, the ministry of agriculture is advising farmers through an SMS service to use ash and even soapy water to eliminate the pests.

Full article...

Conference Proposes Anti-Fall Armyworm Protocol

At a recent conference in Nairobi organised by the International Centre of Insect Physiology and Ecology (ICIPE), scientists proposed seven best practices that could help maize farmers curb the pest.

1) Use of diversified maize cropping systems, including maize-legume intercropping, which research has shown reduces FAW incidence from 30 to 75 per cent as compared to monocrop.

2) Adoption of safe control methods, such as the use of biopesticides.

3) Strengthening of research...to understand the in-depth biology and ecology of the pest especially in the African context where the climatic conditions are different from North American countries where it originated.


4) Awareness creation...continuous education of farmers and extension officers.

5)  Pest develops resistance to chemicals. With the invasion of fall armyworm, a marked increase in the use of pesticides by maize growers and promotion of the same by governments through subsidies has been observed. However, the use of chemicals does not seem to work as would be expected. Although some chemicals show some degree of efficacy against the fall armyworm, the pest is developing resistance to some chemicals.

6) Danger of chemicals. Some chemical combinations showed some level of efficacy but poisonous residue remained on maize and in soils sprayed, making it poisonous for people and animals. Chemicals are known to kill non-target organisms like bees and natural enemies of FAW that could disrupt establishment of prey-predator balance that is essential in the natural control of FAW.

7) Natural methods more effective. Scientists advocated “push-pull technology”, maize-legume intercropping systems and use of botanical and microbial pesticides. Field surveys have also indicated the presence of effective parasitoids of FAW already in Africa.

Full article...

Rabbit Urine As a Pest Repellant

Farmers can reduce the money they spend on pesticide by using rabbit urine to wipe out whiteflies, sap-sucking insects that attack crops such as vegetables, coffee, macadamia, bananas and avocadoes, among others.

Alex Maina, who has been a rabbit farmer for more than four years has been  using the animals' urine to control the destructive insects on his banana and pawpaw crops, says he has been able to reduce his expenditure on insecticides to almost nil.

... insecticides only have a limited effect on whiteflies as most only work when they come in direct contact with the whiteflies and that harsh synthetic chemicals will generally kill all the natural enemies of the whiteflies before they kill the whiteflies themselves

... rabbit urine can be used in two ways; as a foliar fertiliser and as a pesticide or insecticide.

When used as an insecticide, a farmer would be required to mix two litres of concentrated rabbit urine with three litres of water and spray the mixture on affected crops after every two weeks three times to wipe the insects.

When used as a foliar fertiliser, one would be required to use a litre of concentrated rabbit urine and mixed it with four litres of water and apply it to crops three times every two weeks.

Full article...

South Africa's First Licensed Crop-Spraying Drone Takes Flight

After a lengthy process, a crop-spraying drone took its first legal flight in South Africa in May 2019.

The South African Civil Aviation Authority (CAA) granted a licence to Durban-based ROC holder DC Geomatics, who operates the drone. The company proved drones equipped with crop spraying operation specifications are safe to use, passing CAA regulations.

Drones can get much closer to crops than planes - to approximately 1.5 to 3 metres above the plants. This allows for more precise application, and is close enough to spray almost 100% of field areas of this challenging terrain.

The drones can be automated to fly a fixed route, at a fixed height above the crop. This is thanks to sensors and GPS mapping on the drones that are smart enough to adjust their height according to the terrain. This allows for farmers to remove human error and maximize the surface area of fields.

...drones also more fuel efficient, using up to 60% less fuel (used in generators to charge the batteries), than in manned aircraft.

Full article...

Biological Control Of Fall Armyworm Shows Promise

An egg parasitoid, Telenomus remus, could prove an important biological weapon in the fight against the devastating fall armyworm (Spodoptera frugiperda) that threatens the food security of more than 200 million people.

Dr Marc Kenis, Head of Risk Analysis and Invasion Ecology at the CABI Centre in Switzerland, led an international team of researchers from seven countries, who suggest Telenomus remus provides a 'great opportunity for the rapid deployment of a biological control agent' for fall armyworm in Africa.


Full Article...

Original Research Paper...

Research grant to fund vegetable pests’ research in three African countries

The German government has granted €1.2 million (about US$1.6 million) for research into pest management of tomato and pepper in Tanzania, Kenya, Madagascar and Thailand.

The project will also introduce interventions that will significantly lessen reliance on chemical pesticides in vegetable farms, consequently reducing hazards to farmers’ health and the environment.

The initiative will be led by the International Institute of Tropical Agriculture (IITA) and implemented in partnership with the World Vegetable Centre (AVRDC). Researchers from the University of Bonn in Germany, Kenyatta University in Kenya, and Kasetsart University in Thailand. National agricultural research services, NGOs, private sector, and vegetable farmers’ groups in the four countries will also take part.

CGIAR-IITA

Nitrogen fertilizer 'could prevent locust swarms'

byy Li Jiao
A surprising finding promises a cheap and environmentally friendly way of controlling locust swarms, a major plague that devastates crops around the world.

Land erosion caused by heavy livestock grazing promotes locust swarms by lowering the nitrogen content in plants that locusts feed on, according to a study published in Science today (27 January).

Conversely, the study also found that locusts do not thrive on nitrogen-rich food, as previously thought, but are in fact hampered by it.

"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 Arianne Cease, a researcher at Arizona State University, United States.

Most herbivores, including insects, are thought to be limited by the availability of nitrogen-rich protein in their diets.

But scientists were surprised to find that this is not the case for Oedaleus asiaticus, a dominant locust of the north Asian grasslands and a close relative of the common African pest O. senegalensis.

Field observations found that locusts were less likely to survive in fields that were fertilised with nitrogen, and their density was highest in the most heavily grazed fields - which were dominated by plants with low nitrogen content. Laboratory experiments showed that locusts preferred to eat plants with low nitrogen content.


more....SciDev.net

Ghanaian cocoa farmers introduced to environmentally friendly pesticide

Confidor OTEQ, an environmentally friendly pesticide has been launched in Ghana to boost the production of the cash crop and the drive of the country to overtake Cote d’Ivoire as the lead cocoa producing nation.
Confidor OTEQ...is a collaboration between Wienco, an agro-based company and Bayer, a global producer of agro-chemicals.

The product is accredited to possess excellent sticking effect, optimum canopy coverage, increased speed of action, high retention in plants and pods and reputed for its active ingredient. It is also safe and efficacious against Akate (MIRIDS) and other pests.

The new formulation technology has outstanding “rainforestness,” excellent biological performance, improved contact to plant surface and modified to avert imitation or counterfeiting.

Dr Isaac Opoku, Deputy Executive Director of CRIG emphasised at the product launch that Confidor OTEQ is safe to farmers and would facilitate the desire of Ghana to increase its current cocoa production from 900, 000 metric tonnes to one million metric tonnes.

He said pest control was very relevant to boost the crop production, explaining that cassid for instance was a disease that accounted for 25 per cent to 30 per cent cocoa loss.

Dr Opoku said it took CRIG between three-five years to recommend a new product and having certified Confidor OTEQ, the institute would organise a comprehensive training programme from July 18 on the pesticide. The programme would attract the 64,000 mass spraying gangs, local chief farmers and other stakeholders.

The product carries the warning that “it is harmful to bees and must therefore not be sprayed on flowers.”

Wienco (Ghana) Limited, established in 1979 is jointly owned by Dutch and Ghanaian s, and specializes in the importation and distribution of high quality agro-inputs that meet international standards.

Joy FM 

UN appeals for funds to battle locusts in Madagascar

A build-up of locust populations in south-western Madagascar could turn into a plague and seriously endanger the livelihoods of 13 million people unless a new campaign is launched to contain the crop-devouring insects, the United Nations Food and Agriculture Organization (FAO) has warned.

The agency called for a $7.3 million fund to treat 300,000 hectares of locust-infested territory from this November to May next year.

"We must break the locust population dynamics in order to prevent further developments that could affect the island for years and seriously impact on the livelihoods of two thirds of the population, or 13 million people," said FAO's Annie Monard, who is coordinating anti-locust operations in Madagascar. "Preventive control is the best and most cost-effective way of dealing with locusts in a sustainable manner."

Locusts do not always stay in swarms. In south-western Madagascar they typically live on their own as individuals. But if their population density passes the tipping point, their body chemistry changes and they undergo a behavioural, ecological and physiological transformation.

After these changes, individual locusts begin to concentrate and act as a synchronized group of hopper bands, or wingless locusts, or as adult swarms, moving out en masse to find new food sources. Changes in their bodies allow them to fly over greater distances, up to 100 kilometres a day, as well as making them able to digest a wider range of vegetation and crops.

An adult locust can consume its own weight - roughly two grams - in fresh food daily. A very small part of an average swarm eats the same amount of food in one day as about 2,500 people, FAO said.

UN

Organic pesticides: Not an oxymoron

by Maureen Langlois

It may seem counterintuitive, but foods that are grown to organic standards can contain commercially manufactured pesticides.

A U.S. Department of Agriculture survey of produce that found nearly 20 percent of organic lettuce tested positive for pesticide residues.

... Jeff Gillman, a professor of nursery management at the University of Minnesota, has written about organic practices for lay readers. He said:

When people are buying organic food, they often make the incorrect assumption that there are no pesticides. It's true that organic production often uses fewer dangerous chemicals, but certain pesticides are allowed.

...a key factor in chemicals being cleared for use on organic crops is whether they occur naturally.

The USDA maintains an official list of substances that can and can't be used for organic farming. Other potent natural extracts that have been approved for use as pesticides include pyrethrin, derived from chrysanthemums, and azadirachtin, from the Asian neem tree, which was also detected on some samples of organic lettuce.All three of these substances are considered slightly toxic by the EPA.

Synthetic compounds can also make it onto the list as pesticides, if they are relatively nontoxic combinations that include minerals or natural elements, such as copper or sulfur. But some naturally occuring substances, such as nicotine and arsenic are off limits.

Are naturally derived pesticides less toxic than synthetic ones?

The answer depends a lot on the dosage, says Gillman. "To control fire blight on the same acre of land," he explains, "I could use a tiny amount of a potent synthetic that has proved safe over the last 50 years, or a much larger amount of an organic pesticide." He demurs on saying which is better, saying, "I want people to know that there are definitely tradeoffs."

The seeming contradiction between organic labeling and potentially harmful pesticide practices may lie in the relative leniency of the USDA organic guidelines, Gillman says. Various organic certification agencies, such as the Oregon Tilth, have tighter rules. (Check out this roundup of acceptable and forbidden pesticides.)

Gillman says just because an organic farmer used some authorized chemicals is no reason to shun the food. But it's important for consumers to know what's going on. For him, the answer to the ambiguity around organic labeling is to go local. "I go to the farmers market and talk to the growers to see who is serious about reducing pesticide use," he says. "I'd rather buy food from someone who used Roundup once than someone who uses organic pesticides all the time."

...full article...NPR

Pest analysis laboratory to be set up in Kenya

Kenya will host sub-Saharan Africa’s first globally recognised pest risk analysis laboratory, ending a 15-year wait.

Established by the Kenya Plant Health Inspectorate Service (Kephis) in Muguga, with support from the United States Agency for International Development at a cost of $463,727, the lab has acquired the status of Africa’s Centre of Phytosanitary Excellence.

The laboratory will serve East African countries as well as some Southern African nations, being the only one of its kind, that can carry out pest analysis on plants exported in and out of the region, without subjecting materials to further tests at the points of entry.

The only other country in Africa with such a facility is South Africa.

Permanent Secretary in the Ministry of Agriculture Romano Kiome said the facility has elevated Kephis to high profile inspection bodies such as the US Animal and Plant Health Inspection Service, on which it is modelled, and will now make it easier for the country to export to the US, whose stringent importation requirements had remained a challenge.

James Onsando, Kephis managing director, said the laboratory will also serve as a training centre for the region, as individual countries set up their own facilities.

“We are receiving requests for human resource development across the region, while some countries like Rwanda and Ethiopia have requested us to second our staff to train their people.”

Exporters of agricultural produce will be the winners, as they will be spared the extra cost of obtaining certificates at both exit and entry points, Mr Kiome said.

Kephis has inspection offices in Nairobi, Mombasa, Busia and Eldoret, as the government parastatal strives to cover all entry and exit points to prevent introduction of new pests and diseases through importation of plant materials, a requirement of the World Trade Organisation.

Since Kenya is a big exporter of agricultural produce especially horticulture, tea and coffee, it was necessary to establish support mechanisms to smoothen movement of produce.

To test the efficacy of the facility before its launch, pest risk analysis was conducted on six crops including imported rice; wheat, beans, peas, broccoli and alliums for export.

Kephis’ mandate is to protect Kenya’s agriculture from pests and diseases that could have negative environmental and human health impact through the establishment of laboratories to monitor the quality and levels of toxic residues in plants, soils and other produce.

The institute also undertakes inspection, testing, certification, quarantine control and description of seeds and planting materials.

The East African

Ensuring the sustainability of organic cotton production in Mali

Mali is one of the largest cotton producers in Africa and about 40 per cent of rural households depend on cotton for their livelihoods. But with world cotton prices having plummeted since the 1970s, and organic Fairtrade cotton selling for up to 50 per cent more than conventional cotton, the Mouvement Biologique Malien (MoBiom), an organic farming cooperative, has been supporting its 8,000 members to produce cotton organically since 2002.

By growing organic cotton, farmers no longer use agrochemicals, which are often expensive and can harm the environment and health of the farmers. But as organic production has increased, so has the exploitation of local plant species used to control pests. Realising that their increasing exploitation of useful pest control species from the wild was becoming unsustainable, farmers from Yanfolila (a MoBiom community) approached the Millennium Seed Bank (MSB) to help them domesticate a number of the natural pesticide species they use.

Through training and the improvement of local facilities for seed storage and wild plant cultivation, the MSB has been working in Mali since 2003 to conserve useful plants and build the capacity of communities to successfully store and propagate species that are locally important. "Seed banks are depositories of precious genetic diversity of value to agriculture, forestry, horticulture and medicine," explains Moctar Sacandé, MSBP international coordinator. "They play an increasingly important role in helping communities find new ways of conserving and using natural resources sustainably."

In 2008, the MSB helped the 55 Yanfolila farmers establish a useful plants garden. One thousand plants of ten useful pesticide species, including Carapa procera, Lannea microcarpa, and Securidaca longepeduncalata were planted. These wild native species, which produce by-products that repel or kill pests, are spread on plants several times during cultivation to protect them from pests. "We know that these plants are at least as good, if not better, than chemical pesticides because organic production is efficient and does not suffer from pest infestations," Sacandé adds.

The community provided the land and invested their time and effort in planting and raising the seedlings. A number of community members stated that this activity was important so that their children would also be able to collect and utilise the useful species in the future.

By growing plants with pesticide properties, this community is able to produce organic crops which can be sold at a premium, enhancing livelihoods. "Families no longer have to get into debt to buy expensive fertilisers and pesticides," Sacandé says. "Farmers now have enough to live on and no longer expose their skin and lungs to chemical products." The extra funds also allow the villagers to send their children to school, improve their standard of living and re-invest in organic fertiliser and compost storehouses.

News of the model garden has spread quickly and over 70 MoBiom communities (3,500- 4,000 people) from the Sikasso region of Mali have now asked for help to set up their own gardens. To support these additional communities, MSB has requested extra funding from bilateral donors and also the government. MSB is also planning to do further research to determine the optimum dosages and mixture proportions to maximise the potential of these pest repelling plants.

With support from the Swiss NGO Helvetas, MoBiom is continuing to offer farmers training, organic certification and a minimum price guarantee to help them increase their incomes. Through Fairtrade labelling, markets for organic cotton are growing, particularly in Europe, and farmers are receiving higher prices for their products. This has resulted in a decrease in rural poverty and increased employment, particularly for women who usually process the cotton ready for sale. The environment has also benefitted from organic production with improved soil management and increased conservation of biodiversity.

Beginning with 174 farmers, MoBiom has grown to include 73 cooperatives with 6,500 members, of which 30 per cent are women. Due to their success with cotton, MoBiom is now moving into other cash crops that are selling well in international export markets, including organic sesame, mangoes, groundnuts, and shea butter.

Due to the fluctuations in the cotton trade and risks associated with climate change, MoBiom is also actively promoting diversification into other markets. MoBiom is also exploring Fairtrade certification for shea butter and fonio and has plans to install sesame oil processing plants and construct a spinning mill, which would add significant value to the farmers' raw products and provide more jobs, particularly for women.

With contributions from Moctar Sacandé, MSBP international coordinator

Date published: February 201

New Agriculturalist

Maize gene-modified to resist insects being monitored for risk in South Africa

by Hopewell Radebe

The job of opponents of genetically modified products has just become more difficult.

Scientists have developed a new generation of insect-resistant maize and have promised that the achievement comes with a "framework for environmental monitoring" to ensure there is no unintended effect on the land and other plant species, according to the South African National Biodiversity Institute.

Previously, pesticides were used to control pests on maize, but widespread usage had an adverse effect on the environment and human health.

The joint research project — involving the Department of Environmental Affairs and Norway’s Directorate of Nature Management , and co-ordinated by the institute — has led to the development of genetically modified maize with a transgene from Bacillus thuringiensis (Bt), which produces a toxin to manage a specific maize pest.

The report on the outcomes of the five-year SA-Norway environmental biosafety co-operation project was released last week .

Lukeshni Chetty, deputy director of the genetically modified organism unit at the institute, says that while the framework for genetically modified maize is relevant to the monitoring of insect- resistant maize, it also represents a blueprint for research and monitoring of other genetically modified crops in SA.

"This will go a long way towards strengthening and supporting the regulatory framework governing genetically modified organisms in the country, and will contribute to the responsible and sustainable use of this technology in meeting national imperatives," she says.

The report argues that globally all genetically modified products undergo stringent risk assessments prior to commercialisation, "however, there exists the possibility of unintended risks occurring." These can only be identified and investigated after commercial release. The project sought to identify these post-release risks.

The investigated risks included the effect on target and non-target organisms — the effect on the pests and other organisms in the maize cultivation ecosystem — and the effect on soil organism biodiversity, as well as the gene flow and its subsequent contribution to the development of insect resistance.

Ms Chetty says some key scientific research outcomes from this project include toxin levels which varied between plant tissues and plant-to-plant toxin transfer and influences. This variability in toxin production could contribute to resistance development, as insects may be exposed to sublethal dosages and thus become immune to the product.

The researchers also monitored the gene flow from Bt maize (maize with the toxin) to non-Bt maize (maize without the toxin) through cross-pollination, which often resulted in the production of low levels of Bt toxins, another potential contributor to development of resistance .

Resistance to the toxin has previously been detected in the Northern Cape, and another Bt-resistant population was recently recorded in North West . This suggests that such resistance has the potential to spread to other provinces .

SA is the largest producer of genetically modified food in Africa and the eighth-largest in the world after the US, Brazil, Argentina, India, Canada, China and Paraguay. Burkina Faso and Egypt occupy second and third place in Africa . At least 25 countries already plant genetically modified organisms .

In 2009, almost half (46%) of the global area planted with genetically modified organisms was in developing countries. It is expected that by 2015, this will increase as more developing countries take their cue from industrialised nations and adopt genetically modified crops.

The project partners include the Centre for Biosafety in Norway, North-West University, the University of Fort Hare and the University of the Free State.

The project’s results will allow researchers to provide proper estimates of yield, production costs and pest management, all of which affect the maize market and the cost of maize and maize products.

Businessday

Ancient Chinese ant remedy could help pest-control in Africa

by Devapriyo Das

Low-income farmers in Africa will be among the first to benefit from a pilot project that borrows from a centuries-old Chinese farming "technology."

Researchers from Aarhus University, Denmark, plan to use weaver ants to protect mango and cashew-nut tree plantations from pests.

Every year, African farmers lose large parts of their mango and cashew-nut harvests to attacks from harmful insects such as fruit flies. They often also spend heavily on costly pesticides to control these pests.

"It's very difficult to use conventional methods to kill these fruit flies," said Mogens Gissel Nielsen, Associate Professor in Biological Sciences at Aarhus University, who is managing the weaver ant project.

"But it looks like they can be scared away by the ants," the expert said in a telephone interview.

The idea is an old one. For centuries, Chinese farmers have combated pests by placing colonies of weaver ants in their fruit trees. The ants -- which are very aggressive -- will attack and eat any insect which lands on the tree's leaves or fruits.

Now, Aarhus University has received a 1.3-million-euro (1.73 million U.S. dollar) grant from the Danish International Development Agency (DANIDA), to refine this idea and make it commercially viable for African farmers.

Commencing in January 2011, the project will facilitate research into biological pest control methods in Benin and Tanzania, as well as develop model farms and train farmers in both countries to use ants in organic farming.

Mango and cashew-nut are valuable cash crops. By using weaver ants, and thus avoiding costly and sometimes harmful pesticides, farmers have a better chance of selling their fruit to the lucrative organic foods market in Europe and the United States.

As using wild weaver ants could upset natural eco-systems, Aarhus University researchers earlier this year found a way of breeding weaver ant colonies by capturing fertilized queen ants from the wild.

"To avoid too much impact on the natural fauna, we chose to 'rear' colonies of ants that can be released directly in the plantations, rather than collecting colonies that were already established in the surrounding countryside," Nielsen explained.

Rearing ant colonies could eventually become a commercial venture run by local farmers.

As weaver ants are rich in protein, researchers believe commercially farmed ants could also be harvested as a food source for poor farm households.

"It's a high protein source, that you can harvest in an area where there is low protein available," Nielsen said.

Xinhua

Striga weed needs more spirited efforts against it

by C. Bukenya

In 2008, a looming crisis was reported in Western Kenya and parts of eastern Uganda. This crisis was about the prevalence of striga weed, which was increasingly threatening the production of cereals, particularly maize. Since then, striga has continued to spread to new areas with devastating effects on crop yields and serious consequences for household food and income security.

Reports show that striga is infesting between 20 million to 40 million hectares of farm land in sub-Saharan Africa. It leads to drastic decline in the yield of crops like maize, millet, sorghum and rice. Believed to be a parasitic plant, striga competes for water and nutrients from the roots of the crop thereby reducing its growth. For example, the weed reduces the yield of maize by more than a half and leads to complete crop failure in severe cases.

In Uganda, striga infestation has been reported in the eastern districts of Busia, Budaka, Tororo, Namutamba and Iganga.

Because it has very small seeds and attractive flowers, striga can easily be spread by farm tools and equipment, wind, water plus animals and human beings.

There is ongoing research aimed at addressing the striga problem, both in Uganda and elsewhere. The research has focused on augmenting the conventional agronomic field management practices, such as crop rotation with the application of nitrogen fertilisers and herbicides in addition to the use of crop varieties that are resistant to the weed.

Unfortunately, these efforts have not yet yielded effective and practical solutions for controlling striga. As a recent visit to Bulamagi sub-county in Iganga district revealed, both traditional methods of weed management and individual farmer innovation do not seem to offer much success.

The striga weed problem has also not received much attention from government agencies like NAADS and the district production departments. I believe that the striga weed problem calls for urgent strategic intervention and concerted efforts involving sensitisation and mobilisation of communities in the same way the water hyacinth problem was addressed.

The writer is a lecturer at Makerere University

New Vision

Pest control on GM crops benefits nearby non-GM crops

by Joseph Milton

Genetically modified (GM) crops can save farmers using conventional seeds even more money than those using the transgenic varieties, according to an analysis published in Science this week1. And ensuring that some fields are kept free of the GM crops seems to be key to the overall success of the transgenic variety.

Researchers, led by entomologist William Hutchison of the University of Minnesota in St Paul, assessed the effects of planting maize (corn) genetically modified to produce Bt toxin, which kills the European corn borer (Ostrinia nubilalis). They found that since the crop was introduced in 1996, US farmers in the key maize-growing states of Iowa, Minnesota, Illinois, Wisconsin and Nebraska (see map below) had saved nearly $6.9 billion. Of that, conventional farmers saved just over $4.3 billion, some 62% of the total.

"We were surprised to find that a higher proportion of the total benefit is actually going to the non-Bt farmers," says Hutchison.

The reason for the conventional farmers' windfall is tied up in the effectiveness of the transgenic crop. Not only does Bt maize suppress the corn-borer population in fields planted with the GM crop, it exerts a 'halo effect', lowering the pest population in conventional maize fields too. As a result, farmers planting non-GM crops benefit from fewer pests, but don't have to pay the higher prices for the GM seeds.

Overall, Hutchison's team found that corn-borer populations have declined by between 27% and 73% across the five states in the 14 years since the transgenic crop was introduced.

"This work provides strong evidence for the reduced pest burden for non- Bt corn caused by the Bt corn, based on a reduction in overall pest-population size," says David Hopkins, director of science at the Scottish Crop Research Institute near Dundee, UK.

Conventional growers also help to stop corn borers becoming resistant to the Bt toxin by hosting pest populations that are susceptible to it, according to the team's research. Hutchison says that another species, the corn earworm (Helicoverpa zea), has evolved resistance to Bt toxin in situations where GM-crop coverage is 100%. But maintaining a mosaic of GM and non-GM fields means pests that develop a tolerance can breed with susceptible populations from conventional fields, slowing the evolution of full-blown resistance.

"Some farmers were very sceptical of entomologists telling them they needed to maintain non-Bt corn so they could grow corn borers," says Hutchison, "but over 14 years it's been very successful."
Conflict concerns

The results are positive news for GM seed producers. But 5 of the 18 authors listed on the Science paper work for big food or agri-business companies, including Syngenta Seeds in Slater, Iowa and General Mills in Le Sueur, Minnesota. Hutchison says that the authors who work for industry provided data about corn borers and were not involved in the financial calculations.

"By clearly providing all the affiliations of the authors in the paper, we provide transparency with regard to relationships that could have a bearing on the paper, and allow the reader to consider the affiliations when evaluating the research," says Natasha Pinol, a spokeswoman for Science. Margaret Mellon, director of the food and environment programme at the Union of Concerned Scientists based in Cambridge, Massachusetts, says that it is preferable if authors of scientific articles that could affect policy decisions don't have either financial or other interests in the outcome of the research. "But," she adds, "I wouldn't go as far as to say it undercuts the findings in this case."

Nature

Biological control of cassava pests tried in Thailand

by Ker Than

A huge swarm of parasitic wasps has been unleashed in Thailand as a last-ditch effort to control a devastating pest outbreak, scientists say.

More than a quarter million wasps filled the skies of the northeastern province of Khon Kaen recently. The hope is that the wasps will attack mealybugs, which have been infesting the country's valuable cassava crop.

The pill-shaped mealybugs suck sap from the crops—a main ingredient of tapioca—causing them to shrivel and die.


A Phenacoccus manihoti mealybug crawls on the end of a cassava stem on a Thai plantation last year. Photograph courtesy Neil Palmer, CIAT

But that's nothing compared with the killing technique of female Anagyrus lopezi wasps, which inject their eggs directly into the mealybugs' bodies. When the eggs hatch, the larvae eat their way out of their hosts, killing them.





An Anagyrus lopezi wasp. Photograph courtesy Georg Goergen, IITA.



Like the wasp and cassava, the Phenacoccus manihoti mealybug is native to the South American country of Paraguay. But the mealybugs "got into Thailand without their natural enemies, and the population has increased very rapidly over the past couple of years," said Tony Bellotti, an entomologist at the International Center for Tropical Agriculture (CIAT), a Colombia-based nonprofit research institute that is helping organize the effort. The Thai Department of Agriculture and the Thai Tapioca Development Institute are also involved in the project.

Mealybugs were probably accidentally imported to Thailand from stem cuttings from Africa sometime during the past few years, Bellotti said.


In 2009 mealybugs had spread to more than 700 square miles (200,000 hectares) of eastern and northeastern Thailand, where the pests are known to kill up to half of the plants in a given field, experts say.

Past experience shows the Thai wasp army should work, Bellotti said: The parasites were used to great effect throughout Africa in the 1980s to help control mealybug infestations of cassava.

Scientists consider the parasitic wasps a classic example of "biological control," in which the natural enemies of a pest are imported from its native country to curb the pest's spread.

In Africa "yield losses were estimated at the time to be as high as 80 percent ... I doubt it's even 10 percent now," Bellotti said.

Anthony Shelton, an entomologist at Cornell University in New York State, said the Thai wasp attack is "very logical."

Not all biological-control experiments work out as scientists intend, but those that do—such as the 1980s African intervention—tend to be "spectacular successes," said Shelton, who was not involved in the project. If the wasps work well in Thailand, they should not negatively impact other species, he said.

Unlike most predators—which often feed on many types of prey—some parasites, such as the Anagyrus lopezi wasp, attack only one or a few species, Shelton added. "As the pests spread around, it's also important to spread around their natural enemies"—the wasps, he said.

In time, the wasp and the mealybug should reach an equilibrium in Thailand, CIAT's Bellotti said. "The parasite can't eliminate the pest [completely] because it would eliminate itself," he said. "But you hope that the equilibrium will be at a low enough level that it's no longer damaging to the crops."


CIAT's Bellotti said it shouldn't take long for scientists to know whether unleashing the wasp swarm was a good idea.

"The big test will come during December, January, and February, which is Thailand's dry season," Bellotti said. "The mealybug is a dry-season pest."

If the Thai experiment works, CIAT may deploy the wasps in Cambodia, Laos, and other Southeast Asian countries where the cassava mealybug has been reported."We don't see this as just a Thai problem," Bellotti said. "We see it as a regional problem in Southeast Asia."

National Geographic

FAO says farmers can repel crop-eating elephants with pepper spray

Fight elephants with pepper spray, not murder, says the United Nations. The UN's Food and Agriculture Organization (FAO) suggests that angry farmers should use pepper spray in a fight with elephants, rather than killing them or other crop-destroying animals.

It seems as though farmers, particularly in Africa, are killing wild animals like elephants instead of taking other measures to keep them away from their crops. The United Nations' Food and Agriculture Organization (FAO) unveiled in a statement on their website a "toolkit" it suggests should be taught or handed out to farmers to stop them killing wildlife.

Competition between wild animals and humans has been a major problem in Africa, where growing populations require more land for crops and livestock.

Elephants and baboons having little space have been known to devastate the crops of farmers. "With the world's population growing at some 75 million a year, humans and wildlife are having to squeeze ever more tightly together, increasing the risk of conflict," the Web site stated. "Whatever the specific measures taken, it is important that they are introduced soon," FAO Forestry and Wildlife Officer Rene Czudek said in a statement. "The alternative could be the... loss of wildlife as we know it across much of Africa."

Pepper spray is recommended by the FAO to protect crops. Using a plastic gun to fire ping-pong balls full of chili would burst on an elephant's skin and send it running for cover. Another not so harsh method suggests setting fire to a chili-based mixture so the smoke deters the elephant. "Baboons which enter buildings to steal food may be scared off by placing a snake, preferably alive, inside a hollowed-out loaf of bread," the FAO statement suggested.