Archive for the ‘Insects’ Category

PiercesDiseasePierce’s disease on grape


Newly identified enzyme may be the culprit in Pierce’s disease grapevine damage
January 12, 2016

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An enzyme appears to enable Xyllela fastidiosa bacteria to infect grapevines with Pierce’s disease, causing serious leaf damage. UC Davis plant scientists have identified an enzyme that appears to play a key role in the insect-transmitted bacterial infection of grapevines with Pierce’s disease, which annually costs California’s grape and wine industries more than $100 million.
The researchers hope that the discovery, which runs counter to existing theories, will lead to new diagnostics and potential treatments for Pierce’s disease. Their findings are reported in Scientific Reports, an online journal of the Nature Publishing Group.
“With a bacterial disease — much like cancer — if you understand how the virulent form spreads, you can better control or remove it, ” said Abhaya Dandekar, a professor of plant sciences and senior author on the study.
“We anticipate that this discovery could open new ways to think about dealing with Pierce’s disease and highlight other areas of immune response, in general, that haven’t yet been considered,” he said.
About Pierce’s disease
Pierce’s disease, first identified in the 1890s, is caused by the bacterium Xylella fastidiosa and is characterized by yellowed and browning leaves that eventually drop from the vine. The disease is transmitted from vine to vine by small, winged insects called sharpshooters.
Pierce’s disease is established in Northern California, where it is transmitted by the blue-green sharpshooter, which lives near rivers and streams. The disease became a serious threat to California agriculture in 1996 when the glassywinged sharpshooter — another Pierce’s disease carrier native to the Southwest — was discovered in the Temecula Valley of Southern California.
How infection progresses
It’s been known for a number of years that when Xyllela fastidiosa invades a grapevine, it produces a biofilm or gel in the xylem — the vascular tissue that transports water and some nutrients throughout the vine.
Scientists have theorized that this biofilm damages the vine by clogging up the xylem, preventing the flow of water to the leaves. That theory seemed to explain the yellowing of the leaf edges and eventual death of the leaf tissue.
But not all of the evidence stacked up to fit that theory, Dandekar said. For example a heavy accumulation of Xyllela fastidiosa in grapevine leaves was not always accompanied by severe disease symptoms in leaves. And, in some infected grapevines as well as other host plants, the leaves showed severe symptoms but the xylem had very little blockage.
So Dandekar and colleagues set out to investigate an alternative mechanism by which Xyllela fastidiosa might be wreaking havoc with the vine’s physiology.
Secrets of the “secretome”
The research team began by analyzing the bacteria’s secretome — the entire collection of enzymes and other proteins secreted by a disease-causing agent like Xyllela fastidiosa during the infection process. Such secreted proteins are known to play key roles in triggering many plant diseases.
The resulting data indicated that an enzyme, which the researchers named LesA, was quite abundant during Xyllela fastidiosa infections and shared characteristics with similar enzymes known to be capable of breaking down plant cell walls.
The researchers went on to confirm their suspicions by demonstrating that a mutant strain of Xyllela fastidiosa bacteria — with a specific gene knocked out, or inactivated — lacked the ability to cause infection in grapevines.
“The LesA enzyme has the ability to move through cell membranes, equipping the Xyllela fastidiosa bacteria to invade the grapevine and to live in its xylem tissues, where it feeds on fatlike compounds called lipids,” Dandekar says.
In this way, the LesA enzyme triggers the process that causes the typical Pierce’s disease leaf damage — a process completely unrelated to the xylem blockage and water stress that had previously been thought to cause the symptomatic leaf damage.
The research for the newly published study was conducted by Rafael Nascimento and Hossein Gouran, both graduate students in Dandekar’s laboratory. Dandekar said that his research team plans to move forward with Pierce’s disease research in hopes of developing ways to counteract the disease.

Funding for the newly published study was provided by the Pierce’s Disease Board of the California Department of Food and Agriculture.
Additional information:
• Related: Fused genes tackle deadly Pierce’s disease in grapevines
• Related: UC Davis cracks the walnut genome
• Related: Springtime for wheat starts with a gene that ‘sees’ light
Media contact(s):
• Abhaya Dandekar, Plant Sciences, (530) 752-7784, amdandekar@ucdavis.edu
• Pat Bailey, UC Davis News Service, (530) 752-9843, pjbailey@ucdavis.edu

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Grahame Jackson
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Phone: +612 9387 8030
Mobile: +61 412 994 206
Skype: gvhjackson


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Inter Press News

Africa Closer to a Cure for Banana Disease

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A farmer showing a banana affected by the Banana Xanthomonas Wilt (BXW) whose signs include premature ripening of the bunch and rotting of the fruit. Credit: Busani Bafana/IPSA farmer showing a banana affected by the Banana Xanthomonas Wilt (BXW) whose signs include premature ripening of the bunch and rotting of the fruit. Credit: Busani Bafana/IPS

BULAWAYO, Zimbabwe, Dec 14 2015 (IPS) – In one Ugandan dialect, ‘kiwotoka’, describes the steamed look of banana plants affected by the Banana Xanthomonas Wilt (BXW) – a virulent disease that is pushing African farmers out of business and into poverty.

A bacterial pathogen affecting all types of bananas including sweet banana (Cavendish type) and plantain bananas, a staple for more than 400 million people in developing countries, BXW is so destructive that there is a 100 per cent crop loss where it strikes.

Smallholder farmers and the other actors in the banana value chain lose more than half a billion dollars in harvests and potential trade income across East and Central Africa. Signs of the disease first identified in Ethiopia more that 40 years ago, include wilting and yellowing of leaves with plants producing yellowish bacterial ooze, premature ripening of the bunch and rotting of the fruit.

Currently, there is no cure for BXW. It is spread by insects or using infected tools and has been controlled through a combination of methods. Farmers have been taught to remove and destroy affected plants, taking out the male bud which is the first point of attack by BXW, using sterilized farm tools and destroying single infected stems. But the disease has forced many smallholder farmers in Africa to abandon growing bananas, which hold the potential to improve food nutrition and income security. This is in line with the new Sustainable Development Goals (SDGs) agreed to by more than 160 global leaders in September 2015.

For farmer Lubega Ben from the Kayunga district in Uganda, a cure is long overdue. Each banana plant claimed by BXW on his 15-acre plot is one too many. Growing bananas for the past 40 years has helped Ben provide food and income for his family.

“Bananas are and have been very important for providing food and income for my family,” says Ben, who has been growing bananas for 40 years. “Though my children have all grown up and left home, bananas are what has seen them through their schooling and also fed them.”

Ben is convinced the 200 banana bunches he harvests each year could be more with better methods if the banana bacterial wilt is controlled.

From control to a cure
In addition to the package of efforts to control the disease, in 2007 researchers turned to science for a cure.

Scientists at the International Institute of Tropical Agriculture (IITA) headquartered in Ibadan, Nigeria in partnership with the National Agriculture Research Organisation (NARO) in Uganda are close to a breakthrough after more than eight years researching solutions to BXW.

In 2007, IITA and NARO, together with the African Agricultural Technology Foundation (AATF) and Taiwan-based Academia Sinica successfully engineered resistance of the African banana to BXW using genes from green pepper in the laboratory. Green pepper contains what researchers call ‘novel plant proteins’ that give crops enhanced resistance against deadly pathogens.

The genetically modified (GM) banana varieties with resistance to the banana bacterial wilt disease were developed using genetic engineering. Genetic modification refers to techniques used to manipulate the genetic composition of an organism by adding specific useful genes. These useful genes could make crops high-yielding, flood, drought or disease resistant – key traits important for smallholder farmers in Africa who are experiencing weather variability linked to climate change.

IITA biotechnologist, Leena Tripathi, has been part of the research team leading the fight against the Banana Xanthomonas Wilt.

“We are still a long way. The project has a plan for commercialisation of the GM bananas resistant to BXW in 2020 for use by farmers,” Tripathi told IPS. ” We have tested ten independent lines we picked from bigger trial of 65 lines and have found them to be completely resistant to BXW compared to the non transgenic plants for several generations in two different trials confirming durability of the trait.”

The transgenic varieties have undergone confined field trials in Uganda, a major grower and consumer of banana in Africa. The results are so encouraging that smallholder farmers in sub-Saharan Africa could soon be growing the new varieties commercially soon, says Tripathi.

According to Tripathi, with the encouraging results so far, IITA and NARO are working on Matoke varieties which are preferred in Uganda and dessert varieties preferred in Kenya.

“With a few more trials starting next year, then meeting the biosafety, environmental safety and satisfying regulatory processes, we hope by 2020 to get approvals and deregulation for commercialization and dissemination to farmers,” Tripathi said.

Raising the Africa Banana Export Potential
Developing GM banana cultivars resistant to BXW is seen as economically viable because of the banana’s sterile character and long growth period which have been a challenge in developing a resistant banana through conventional breeding.

“Genetic engineering is one of the most important crop breeding tools in the 21st century,” Daniel Otunge, Regional Coordinator of the Open Forum on Agricultural Biotechnology (OFAB) told IPS, adding that biotechnology has given breeders a faster, cleaner and certain way of producing crop varieties resilient to climate change, resistant to pests and diseases and that are nitrogen and salt-use efficient.

“Africa should be celebrating these crops because they provide us with the best chance to be more food secure and nutritionally robust,” said Otunge.

Researchers estimate that farmers will adopt GM bananas by up to 100 per cent once it is released, with an expected initial adoption rate of 21 to 70 per cent. The financial benefits could range from 20 million to 953 million dollars across target countries where the disease incidence and production losses are high, says research study, Ex-Ante Economic Impact Assessment of Genetically Modified Banana Resistant to Xanthomonas Wilt in the Great Lakes Region of Africa published in the PLOS ONE Journal in September 2015.

Concerned about the march of BXW, nine Uganda farmers got together in 2011 and formed a non-profit community-based organization, the Kashekuro Banana Innovation Platform (KABIP), to specifically control the pathogen on their plantations. More than 300 farmers in the Sheema District lost their plantations and 200 others were forced to replant or open new fields when BXW hit. They hope a solution lies in GM bananas.

“Our farmers have not been exposed to GM bananas. Therefore, we need to try them and test whether they can be a solution,” says Anthlem Mugume, the coordinator of KABIP representing more than 2000 farmers, told IPS.

Arguably one of the world’s favourite fruit, banana are the forth most important staple crop after maize, rice, wheat, and cassava with an annual world production estimated at 130 million tonnes, according to the African Agricultural Technology Foundation. Nearly one-third of this production comes from sub-Saharan Africa (SSA), where the crop provides more than 25 per cent of the food energy requirements for over 100 million people.

East Africa produces and consumes the most bananas in Africa, with Uganda being the world’s second largest producer after India.

According to the WorldTop Export, a website tracking major exports, banana exports by country totaled 11 billion dollars, a 32.8 per cent overall increase in 2014. A cleaner, healthier banana, offers Africa a sweet opportunity to break into the global export markets, reduce poverty and boost business for smallholder farmers.


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Department of Primary Industries and Fisheries

Field Guide


Cover of the Field Guide to Pests, Beneficials, Diseases and Disorders of Vegetables in northern Australia

This field guide provides easy and quick access to text and images to assist with the identification of pests and disease symptoms in the field. Correct identification of pests, beneficials, diseases and disorders is important in helping to minimise crop damage and when considering management options. The guide provides descriptions, life cycles and biology, monitoring and pest management.
This field guide is an invaluable resource for primary producers, researchers, extension staff and students. It is available in both English and Vietnamese printed versions or can be downloaded below.
How to get a copy of the Field Guide

1. Download a PDF Version of the Field Guide
English Print version PDF – 14.8MB | Online version PDF – 90.1 MB
Vietnamese PDF 6.7MB
2. Request a printed version
tel: 08 8999 2258 or email haidee.brown@nt.gov.au
About the Field Guide

This publication is the first comprehensive field guide to pests, beneficials, diseases and disorders of commercially grown vegetables in the Northern Territory. The information has been derived from more than 20 years research and extension experience with commercial vegetable crops by staff of Entomology, Plant Pathology and Horticulture, within the Plant Industries Group, Northern Territory Department of Primary Industry and Fisheries. The vegetable field guide is a useful resource for primary producers, researchers, extension staff and students.
The format of the book has been designed to provide easy and quick access to assist in the recognition of pests, diseases or symptoms in the field. Each opening includes text on the left page and photographs on the right page. The tabs along the right edge are labelled and colour-coded, making it easier to navigate.
Due to regular updates and changes in the recommendations of pesticides, specific products have not been listed. However, growers are encouraged to contact Department staff if they require assistance with pest or disease management.
Information regarding pesticide registrations is available from the Australian Pesticides and Veterinary Medicines Authority (APVMA) website.
A comprehensive Agvet chemical database is available free online from Infopest which is owned and managed by Growcom.
Monitoring and Integrated Pest Management (IPM)

Growers are encouraged to use this guide as a resource to assist in the identification of pests and their natural enemies as well as diseases and disorders when monitoring vegetable crops. Correct identification of pests and diseases is important when considering management options. Integrated pest management (IPM) is the management of pest populations using all relevant control practices in a complementary manner, so that the pest will be maintained below the economic injury level and adverse effects to the environment will be minimal. When diseases are incorporated, IPM is referred to as integrated pest and disease management (IPDM).
The majority of vegetables are grown over the ‘dry season’ (May to September) and many pests and diseases are suited to the dry and warm conditions with mean temperatures in the range of 15-36°C (for the Darwin area). The ‘build-up’ to the wet season starts in September and higher temperatures and humidity is generally experienced. Most of the rainfall occurs in the ‘wet season’ between October to April.
This guide provides descriptions, life cycles and biology along with colour photographs to help recognise and distinguish pests from beneficials (which includes natural enemies that attack pests as well as pollinators). Since beneficials help regulate the levels of pests, it is important to monitor pest numbers to assess the level of natural control by predators or parasites before considering other pest management options. Regular monitoring of the crop will assist in the detection of pests and diseases, as well as providing an indication of the change in populations or spread of symptoms.
Departmental contact information

Entomology (pests and beneficials)
Telephone: 08 8999 2258
Email: insectinfo@nt.gov.au
Plant Pathology (plant diseases and disorders)
Telephone: 08 8999 2265
Email: plant.pathology@nt.gov.au
Horticulture (growing advice)
Telephone: 08 8999 2222
Email: horticulture@nt.gov.au


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daily star logo-black 12:00 AM, May 14, 2015 / LAST MODIFIED: 12:27 AM, May 16, 2015

Although the overall mango production is likely to be good in the northern region, the production in Rajshahi and Chapainawabganj districts may be hampered by unfavourable weather this year. The farmers in the two districts are concerned as a large number of green mangoes have been torn from the trees by the recent nor’westers and hailstorms. The unfavourable weather follows the earlier attack by leaf hoppers which had caused many green mangoes to fall before ripening properly. Farmers told the news agency that the dropping of green mangoes would reduce production, particularly in the two districts. Dr Alim Uddin, principal scientific officer of Fruit Research Station, agreed that the production of mangoes would be slightly less than expected, but not considerably because mango trees remain unaffected by bad weather in many other parts of the region. “Mango production will not be satisfactory in my area this year as almost 70 percent of the fruits fell from the trees before ripening,” said Nurul Islam, a farmer from Shibganj upazila in Chapainawabganj. He said mango trees in his area had initially blossomed well, but many of the mangoes had become victims of the attack by leaf hoppers caused by sultry weather from March 15 to 30. “We are cursed with Moha this year,” said Nurul. Horticulturists explained that Moha is a kind of disease that appears in the form of mould on leaves. It happens especially when the mist shrouds the nature during summer nights, another change in the weather pattern. They said adequate rainfall could save mango trees from this kind of diseases. The mango growers of Chapainawabganj and Rajshahi are worried as the number of trees bearing fruits is inadequate. The farmer said they generally used insecticides once a season but they were forced to apply it three times this year, but there was no impact. Shariful Islam, a mango trader of Lalbag village in Godagari upazila, said mango production was likely to suffer a setback this year due to unfavourable weather. The annual average mango production is about five lakh tonnes from over 45,000 hectares of land in eight districts under Rajshahi division including Chapainwabganj where mango grows on 22,000 hectares of land while it is about 8,500 hectares in Rajshahi. The unexpected sultry weather due to change in climate caused mangoes to drop prematurely, said agriculturist Dr Saifur Rahman. Most mango growers in the two mango producing districts have used pesticides and other chemicals at least 20 times for “protection and better yield”. Excessive use of toxic chemicals in the country’s mango producing zone is posing a serious threat to public health as well as to environment and wildlife.


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Released: 14-May-2015 8:05 AM EDT
Source Newsroom: University of Florida Institute of Food and Agricultural Sciences more news from this source

Newswise — GAINESVILLE, Fla. — A wasp the size of a pin head may control the nuisance Rugose spiraling whitefly, which leaves a sticky white mess that becomes covered in black mold on everything from plants to cars and pools, University of Florida scientists say.
“Although the Rugose spiraling whitefly damages plants, what really gets people worked up is that it’s a huge nuisance because it makes a mess,” said Catharine Mannion, an entomology professor at the UF/IFAS Tropical Research and Education Center in Homestead, Florida. “You get a sooty mold on everything. It’s hard to get pools cleaned. People start chopping their trees down.”
But a new breakthrough shows the tiny wasp encarsia noyesi reduces the population of the Rugose spiraling whitefly, according to a new UF/IFAS-led study funded by the Farm Bill, through the U.S. Department of Agriculture.
After scientists from UF/IFAS and the Florida Department of Agriculture and Consumer Services identified the wasp and its potential, former UF/IFAS Post-Doctoral Associate Anthony Boughton confirmed biological information about the wasp.
Boughton did his research under the guidance of Mannion and fellow UF/IFAS entomology professor Lance Osborne. The study is published online in the journal Biological Control.
Boughton’s experiment, conducted in the laboratory and greenhouses at the Tropical REC from 2012-2014, confirmed that encarsia noyesi attacks and kills most stages of the whitefly, thereby reducing its population.
In addition to controlling a nuisance, the new finding likely saves Floridians untold amounts of money on pesticides and tree-cutting to control the whitefly, said Osborne, a faculty member at the UF/IFAS Mid-Florida Research and Education Center in Apopka, Florida.
Once Rugose spiraling whiteflies get on palm and gumbo limbo trees, cars, golf courses and homes people use pesticides to kill them, Osborne said.
While UF/IFAS scientists were performing their experiments in Homestead, they conducted several investigations, he said. They tried to solve the problem in the field while performing the experiments in the lab in Homestead. The parasite worked so well in many locations around Florida that scientists have had trouble finding locations to conduct additional programs.
But as Mannion said: “These problems are never completely over. It’s never gone, but it’s greatly, greatly reduced.”
Rugose spiraling whitefly is most common in South Florida, but has been seen in 17 Florida counties, as far north as Orange, Osborne said.
Now that UF/IFAS scientists have found a biological control, homeowners who still experience what they deem an intolerable level of Rugose spiraling whiteflies, UF/IFAS researchers urge residents to use soap and water to get rid of the whitefly. If they use harsh pesticides, they’ll kill the natural enemies, in this case, encarsia noyesi.

By: Brad Buck, 352-294-3303, bradbuck@ufl.edu
Sources: Catharine Mannion, 305-246-7001 Ext. 220, cmannon@ufl.edu
Lance Osborne, 407-410-6963, lsosborn@ufl.edu

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sci dev logo

Weaver ants

Speed read

– African weaver ants offer a natural way to cut insect pests

– Feeding them sugar further increased cashew nut yields

– The ants eat other insects and their pheromones repel fruit flies

Patrols of ants on cashew nut trees can roughly double the yield of the crop, according to researchers in Benin. The researchers say that African weaver ants (Oecophylla longinoda) are an effective natural way to reduce considerable losses of cashew nuts from insect pests, such as fruit flies, and improve cashew quality, on farms in many African countries.

Cashew is a highly valued commodity in Benin, where the nuts have overtaken cotton to become the top export. It is also important elsewhere in Africa. But pests can destroy up to 80 per cent of the crop.

The researchers compared three methods of ant-based pest control on trees with existing ant populations. On the first set, the ants were left as they were. On the second, they were fed sugar solution. A third set were sprayed with an organic pesticide that kills fruit flies. Finally, as a control, some trees had sticky bands placed around their main stem so no ants could reach them.

The research, published on 16 February in Agricultural and Forest Entomology, found that all treatments involving ants increased the cashew nut yield. Compared with the ant-free control plants, the yield increased by 78 per cent on plants with the ants alone, by 122 per cent on plants with ants fed with sugar and by 151 per cent on plants with ants that were sprayed with pesticide.

Interestingly, the researchers saw that a higher proportion of nuts on the ant-treated plants were damaged by thrips. These insect pests “have a great effect on the quality of nuts, scarring the leaves, flowers and fruits, leading to deformity and nut abortion”, says Florence Anato, an author of the study and an agricultural scientist at Benin’s Université d’Abomey-Calavi. But the study says the net increase in nut yield outweighed this damage.

The paper was based on a two-year study involving partners including Aarhus University in Denmark and the International Institute of Tropical Agriculture (IITA), with funding from Danida, Denmark’s agency for development assistance. Biologist Jean-François Vayssières, who leads a project looking at controlling the West African fruit fly and is based at the IITA, says the study shows that ants could significantly improve cashew yield. “The presence of weaver ants patrolling the trees provides protection against pests,” he says. “They can have a direct impact by capturing insects as prey, through excretions that act as a repellent or simply by their physical presence.” Vayssières adds that his fruit fly project has “already shown that the ants’ pheromones also have a repellent effect on fruit flies. However, further extensive research is needed to get the maximum benefit from the presence of these ants in our plantations.”

A version of this story originally appeared in SciDev.Net’s Sub-Saharan Africa French edition.


Florence M. Anato Reducing losses inflicted by insect pests on cashew, using weaver ants as a biological control agent (Agricultural and Forest Entomology, 16 February 2015)


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The New York Times


Last year, Tanzania had exciting news: a bumper harvest of corn. But even as farmers were celebrating — corn is a staple eaten at almost every meal — much of the crop had already been spoiled, having grown moldy or been infested by insects and rodents. The problem was that farmers lacked the capacity to store food safely. Even the government’s national reserve system had run out of space to hold the overflow.

Such shortages of capacity persist, and not just in Tanzania. The Food and Agriculture Organization reports that largely because of a lack of infrastructure for refrigeration, transportation and sanitary, airtight storage, 15 to 20 percent of grain crops in sub-Saharan Africa and about half of fruits and vegetables show spoilage before they reach market.

The fight against hunger in Africa has experienced many successes in boosting agricultural production — from improving seeds to disseminating solar-powered irrigation. It’s only now that agricultural organizations and experts are recognizing that lack of storage represents a major impediment to keeping all those harvests edible. It’s a difficult problem because a vast majority of Africa’s crops are grown by smallholder farmers, who lack the resources to invest in refrigeration or effective storage facilities for staples like corn and beans.

Moreover, the expectation of large losses discourages farmers from taking steps to further increase their output, explained Zablon Ernest, an independent agricultural consultant and extension officer in Arusha, Tanzania. “A farmer will say, ‘Why should I produce more if I can’t store or sell it?’ ” he said.

Ernest graduated in February from an online class run by the United States-based Postharvest Education Foundation, which has taught basic crop management to students from 22 countries over the last four years. Tanzanian agriculture officials support such education, recognizing that teaching agricultural extension officers how to manage harvested crops has long been neglected in favor of focusing on production. “Farmers in the villages are desperate for this kind of information,” said Ernest.

In trying to salvage more of the nation’s harvest, Tanzania is of course pursuing the broader goal, common across Africa, of reducing hunger and boosting income. But while other developing countries are taking piecemeal steps to reduce crop losses, Tanzania’s response has been particularly robust. The government has a department devoted to reducing food waste, and its initiatives are informed by independent research.

Small-scale success stories are beginning to emerge. Julius Akanaay, for example, grows corn, beans and sunflower in the small village of Endagaw, south of Arusha. Before 2004, he and his family lived in a small mud hut, vulnerable to insects, rodents and rain. As a result, their stored crops often spoiled. “We sold early and easily lost what we kept,” said Akanaay. They now live in a cement house, which offers better protection — and more food security.

Partly out of fear of spoilage, but also out of a need for fast cash to pay debts, farmers often sell crops early in the season, when prices are low. If they wait for prices to rise, they risk their corn becoming infested. The tragedy is that, later in the season, they will have to buy corn at high prices to feed their own families. That is how some families get trapped in cycles of poverty.

Shamim Daudi and Janine Rüst of the Swiss nonprofit Helvetas want to change this situation. On a hot, dusty Sunday afternoon in February, I accompanied them while they took samples of corn from Akanaay’s storage room. With the Tanzanian government’s support, Helvetas is exploring methods of storing corn that will prove more effective than the polypropylene bags used by most rural farmers.

One promising tool is a triple-layer polyethylene-polypropylene bag (known as a PICS bag) that was developed by an entomology professor at Purdue University in Indiana; another is a simple metal silo small enough — a medium-size silo is about five feet tall — to be housed indoors. Both work by sealing out oxygen, thereby killing insects. The difference between a PICS and the common polypropylene bag is actually audible; with a bad infestation, you can hear insects squirming inside the polypropylene.

That’s why outreach workers like Daudi and farmers like Akanaay are optimistic: With these new tools, farmers who now sell low and buy high can see opportunities to hold on to more crops to feed themselves — or sell when it benefits them most.

Whether Akanaay and other farmers will be able to afford the metal silo (the one at his house now is part of the Helvetas experiment) remains a question. PICS bags are more affordable for farmers — although any added expense is still burdensome — but they are also more vulnerable to rodents. Which, if any, tool farmers will decide to purchase won’t be clear until the next harvest season.

Another challenge is preserving perishable goods in tropical regions that lack wide access to electricity. For years, Mariam Mustafa sold her tomatoes to the local open-air market near her farm in Lushoto, a major fruit- and vegetable-producing region in northeast Tanzania. “The customers didn’t care about quality,” she said. “They only cared about quantity.” She sold as much as she could — and threw away the rest.

Now, she belongs to a group of farmers who use a packinghouse in Lushoto that was built last year with support from the Tanzanian government and U.S.A.I.D. For almost half the year, farmers sort and pack snow peas for export. An Arusha-based export company sends a refrigerated truck — an extreme rarity in most of sub-Saharan Africa — to pick up the snow peas from cold storage units (also largely unheard-of) at the packinghouse. For the remainder of the year, farmers use the facility to improve the quality of their other produce and then sell it to higher-paying buyers like supermarkets. That, too, reduces the amount of waste.

The packinghouse operation is still a work in progress. Concepts like sorting good tomatoes from bad to reduce the spread of rot are new to many farmers; they have to be trained.

Mustafa still sells at the local market, but only after selling as much as possible through the packinghouse, where a harvest of tomatoes can bring in 400,000 Tanzanian shillings (about $215). That’s more than double the local market’s potential, because the improved quality and packaging allow the produce to fetch higher prices after being transported to more distant, higher-end buyers.

More From Fixes
Read previous contributions to this series.
The packinghouse is not suitable for every town, not least because the market for high-quality produce is minuscule compared with the scale of the rural markets, where an estimated 95 percent of horticultural trade in Africa still takes place. But where it’s feasible, it has the potential to simultaneously reduce waste and boost incomes, so other areas are now building or considering packinghouses.

As with most major changes, the biggest challenges are often behavioral and cultural. Farmers are accustomed to selling produce quickly, and consumers are used to eating farm-fresh food, not dried fruit or canned vegetables. It’s likely that the market potential for value-added produce will be greater among distant buyers like supermarkets and export companies than rural dwellers. Indeed, some farmers groups are looking to turn the region’s agricultural bounty of tropical fruits like mangoes and bananas and nutritious vegetables like amaranth and sweet potato leaves into products that wealthier customers will pay extra for.

This kind of endeavor requires an attitudinal shift. “Many women think, ‘When I grow crops, they are just for feeding my family,’” said Odette Ngulu, an agricultural consultant in Arusha. “They don’t have the idea of preserving.”

Ngulu has been training women’s groups to use solar dryers — simple boxed-in shelves of mesh designed for optimal heat absorption and air flow — to dry sliced or shredded produce in a day or two with adequate sunlight. The dryers protect the produce from contaminants like dirt and insects, and the UV-treated plastic cover allows light in but still protects the nutrient value. Production and sales are uneven, but the goal is to refine and perfect the process in order to appeal to people in those larger, wealthier markets.

There’s some reason for optimism. Packaged dried vegetables are already for sale in a few supermarkets in some African cities, including Nairobi, Kenya’s capital. In Rwanda, a women’s group dries pineapple in larger versions of the solar dryers Ngulu uses; they already sell to high-end clients around the country, and a client in Switzerland is interested in importing.

There are encouraging signs that food waste can be reduced in other parts of the developing world as well. Some involve other tools like the zero-energy cool chamber, a brick structure invented in India that uses evaporative cooling. In Rwanda, the government plans to improve farmers’ access to storage facilities nationwide; and in India, a network of agencies is offering subsidies for investments in post-harvest infrastructure and simple related technologies.

Bertha Mjawa was Tanzania’s first point person on post-harvest losses, as a senior agricultural officer with the Ministry of Agriculture, Food Security and Cooperatives. She now works with a separate, but government-affiliated, project on the same issue. And she is seeing great changes from these efforts, which started over a decade ago but kicked into high gear only around 2010.

“Just last week, I met some women selling tomatoes on the side of the road,” she said. “Some of them graded, some didn’t,” she added, referring to the process of separating good tomatoes from bad. The women who sorted their tomatoes told her that they didn’t see any impact at first, but eventually customers noticed and buying habits changed. First came a bit of customer loyalty toward sellers offering the highest quality; economic benefit for the producers followed. “They’re starting to charge more — and people are willing to pay,” said Mjawa.

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Rachel Cernansky is a freelance journalist in Denver. She writes about agriculture, health, and the environment.


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