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.
Archive for the ‘Insects’ Category
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, email@example.com
Sources: Catharine Mannion, 305-246-7001 Ext. 220, firstname.lastname@example.org
Lance Osborne, 407-410-6963, email@example.com
– 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)
The New York Times
By RACHEL CERNANSKY MAY 1, 2015 7:00 AM
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.
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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.
The International Institute of Tropical Agriculture (IITA)
The International Institute of Tropical Agriculture (IITA) is expected to request about USD 200,000 from the UN Food and Agriculture Organisation (FAO) to contain a new destructive pest which is rapidly spreading through the coastal areas of Tanzania around Dar es Salaam and Zanzibar, attacking important food crops such as pawpaws and cassava as well as ornamental plants like hibiscus and frangipani.
The pest has been identified by scientists at the International Institute of Tropical Agriculture (IITA) as the pawpaw (commonly known as papaya) mealybug (Paracoccus marginatus), according to a press statement issued by the institute’s Tanzania office in Dar es Salaam recently.
In recent years, this highly invasive pest has also been spreading and causing damage in many Asian and West African countries.
With its origin in Mexico, it was first observed on the African continent in Ghana in 2010 from where it spread to Benin, Nigeria, Togo and Gabon.
The discovery of the mealybug in Tanzania means that the rest of East Africa will now likely be affected as well, the statement said.
Describing their nature, the statement said the pests are tiny, white and flat which sap the life out of the plants.
Their preferred hosts are pawpaws, but they also affect a wide range of crops including cassava, beans, coffee, pepper, melons, guavas, tomatoes, eggplants, cotton and jatropha.
If not controlled, it said, the pest may result in massive damage and loss of livelihoods for many farmers in the country.
The pawpaw mealybugs appear as white fluffy spots on the undersides of leaves, branches and fruit, and are often accompanied by an unsightly black, sticky substance coating these surfaces – a result of a sugary excretion by the pests which attracts mould.
The affected plants don’t grow properly, and farmers are unable to sell the often misshapen, discoloured and, in severe cases, completely shrivelled fruits.
According to IITA entomologist Dr James Legg, one of the scientists leading efforts to contain the pest after first noticing its damage at his home garden, the pawpaw mealybug is currently one of the most destructive and rapidly spreading invasive insect species.
“In Tanzania we have observed the pests along the coastal belt around Dar es Salaam and its environs, mostly on pawpaws, cassava and ornamental plants such as hibiscus and frangipani. But we need to carry out a survey throughout the country to determine the full extent of spread and the range of plants affected,” he said in recent remarks.
“Samples sent to IITA’s Biological Control Centre for Africa, located in Cotonou, Benin, have been positively identified as the pawpaw mealybug by the institute’s entomologist, Dr George Goergen,” Dr Legg said.
“Now that we know what we are dealing with, we need to act fast. The pest can easily spread throughout the East African region causing major damage and threatening the food security and incomes of tens of thousands of Tanzanian farmers,” he added.
The mealybugs are easily blown by the wind or transported by ants from one plant to another, and are transported longer distances by people who unknowingly carry infested plants or fruit from one part of the country to another, or from country to country.
Efforts are under way from IITA, the Agriculture, Food Security and Cooperatives ministry, and the UN Food and Agriculture Organisation (FAO) to mobilise funds to use biocontrol agents to contain the pest before it gets out of hand, the statement said.
This involves introducing natural enemies of the pest such as parasitoids – extremely tiny insects that lay their eggs inside the pawpaw mealybug. As the eggs hatch, tiny worm-like “larvae” emerge, which then eat the mealybug from the inside out.
According to Elibariki Nsami from the National Biological Control Programme of the Agriculture, Food Security and Cooperatives ministry, using biological control is the only effective way to manage the pest menace. Most pesticides are not effective since these mealybugs coat themselves with a protective wax, he said.
“The biocontrol mechanisms are safe as they are very specific and only attack the pawpaw mealybug. They are also cheap, cost-effective, and safe for the environment,” he added.
Experts say it will also be important to set up a surveillance system to track the spread of the pest in the country and the wider region and to create awareness among the farmers and larger public on how to control it.
IITA is one of the world’s leading research partners in finding solutions for hunger, malnutrition and poverty.
Its agricultural research for development (R4D) addresses the needs of the poor and vulnerable in the tropics.
It works with public and private sector partners to enhance crop quality and productivity, reduce risk to producers and consumers and generate wealth from agriculture.
The institute’s R4D covers biotechnology and genetic improvement, natural resource management, plant production and plant health, and social science and agribusiness.
For the last 45 years, IITA has focused on key tropical food crops such as bananas and plantains, maize, cassava, soybeans, cowpeas, tree crops and yams.
It is determined to use research in improving food security, increasing the profitability of foods and other agricultural products, reducing risks to producers and consumers, and helping national entities expand agricultural growth.
SOURCE: THE GUARDIAN
The 18th International Plant Protection Congress will be held in Berlin, Germany, August 24-27, 2015. In this congress, there will be a workshop on “Management of the South American Tomato Leafminer, Tuta absoluta” on August 25, 2015 starting at 7.30 pm and lasting three hours.
This workshop will review the biology, spread, damage, monitoring and the control tactics including regulatory, physical, cultural, chemical and biological methods. There will be a discussion on current Tuta absoluta projects worldwide and the possible initiation of national, regional and global projects for the management of T. absoluta and the current and potential role of donor agencies.
For information contact:
Prof. Rangaswamy Muniappan
Region XIII: North America
One of the leading pests of rice, brown planthoppers can grow up to have either short or long wings, depending on conditions such as day length and temperature in the rice fields where they suck sap. The hormone insulin controls the switch that tells young planthoppers whether to develop into short- or long-winged adults, finds a new study. Photo by Chuan-Xi Zhang of Zhejiang University in China
Insulin tells young planthoppers whether to develop short or long wings
DURHAM, NC – Each year, rice in Asia faces a big threat from a sesame seed-sized insect called the brown planthopper, Nilaparvata lugens. Now, a study reveals the molecular switch that enables some planthoppers to develop short wings and others long — a major factor in their ability to invade new rice fields.
Lodged in the stalks of rice plants, planthoppers use their sucking mouthparts to siphon sap. Eventually the plants turn yellow and dry up, a condition called “hopper burn.”
Each year, planthopper outbreaks destroy hundreds of thousands of acres of rice, the staple crop for roughly half the world’s population.
The insects have a developmental strategy that makes them particularly effective pests. When conditions in a rice field are good, young planthoppers develop into adults with stubby wings that barely reach their middles.
Short-winged adults can’t fly but they’re prolific breeders. A single short-winged female can lay more than 700 eggs in her lifetime.
“The short-winged ones have great big fat abdomens. They’re basically designed to stay put and reproduce,” said biologist Fred Nijhout of Duke University, who co-authored the study with colleagues at Zhejiang University in China.
But in the fall as days get shorter and temperatures begin to drop — signs that the rice plants they’re munching on will soon disappear — more planthopper nymphs develop into slender adults with long wings. Long-winged planthoppers lay fewer eggs but are built for travel, eventually flying away to invade new rice fields.
Until now, scientists did not know exactly how the shorter days and cooler temperatures triggered the shift between short and long wings, or which hormones were involved.
To find out, the researchers used a technique called RNA interference (RNAi) to silence the genes for two different insulin receptors — regions on the cell membrane that bind to the hormone insulin — and measured the effects on the animals’ wings.
“Previously it had been assumed that all insects only had a single insulin receptor gene. We discovered that brown planthoppers have two,” Nijhout said.
When the researchers silenced the first insulin receptor, short-winged adults emerged. Silencing the second receptor produced adults with long wings.
Further study revealed that long wings are the default design. But when planthoppers secrete a particular type of insulin in response to changing temperatures or day length, the second insulin receptor deactivates the first receptor in the developing wings, leading to short-winged adults.
“The second insulin receptor acts by interfering with the first one, therefore shutting down the signal,” Nijhout said.
It’s too early to say whether the findings could lead to techniques to treat planthopper populations so they are unable to invade new rice fields, Nijhout says.
But the researchers have found similar mechanisms in other planthopper species, and are now trying to find out if insulin plays a similar role in other insect pests with flying and flightless forms, such as aphids.
This research was supported by the National Basic Research Program of China (973 Program, no. 2010CB126205) and by the National Science Foundation of China (no. 31201509 and no. 31471765).
The appeared Mar. 18 in the journal Nature.