Archive for the ‘Snails’ Category

SEPTEMBER 21, 2022

Plant resources threatened by pests and diseases

by SciDev.Net

Credit: Pixabay/CC0 Public Domain

Imagine a world where farms bear no crops, forests have no trees and nature exists without plants.

Not only will our world look incredibly different, but humanity would likely cease to exist altogether. Plants provide 98% of the air we breathe and 80% of the food we eat. That’s how much our lives depend on plants, yet we often overlook how vital they are.

Our global plant resources are under threat from pests and diseases. Once plant pests are established in an area, it becomes nearly impossible and extremely costly to eradicate them. This sets back global efforts to achieve the Sustainable Development Goals by curtailing our ability to provide food security for all, protect our environment and biodiversity for future generations, and to ensure that crops and plant products are traded safely to help boost economic growth.

Every year, we lose as much as 40% of global crop yields or around US$220 billion due to plant pests. In Africa alone, nearly US$10 billion worth of annual maize yield is lost due to fall armyworm, a dangerous transboundary pest that has now spread in more than 70 countries. Reducing this menace will help alleviate hunger of the type faced by some 828 million people around the world in 2021, according to the latest report of the UN’s Food and Agriculture Organization (FAO).

Climate change has increased pest incursions, particularly in new places where they had not been detected previously but have now thrived. Changing temperatures, humidity, light and wind are the second most important factors for pests to disperse, next to international travel and trade.

Invasive pests remain the main drivers of biodiversity loss. As the world becomes more globalized and interconnected, the increase in the movement of people and goods has been associated with the rise of the introduction and spread of plant pests across borders.

That is why global frameworks are crucial such as the International Plant Protection Convention (IPPC), an international treaty ratified by 184 countries which makes provisions for the protection and safeguarding of plants and facilitation of safe trade.

International Standards for Phytosanitary Measures—the gold standard in plant health—are in place for countries to adopt in their national legislation and import requirements. These standards range from pest surveillance, pest risk analysis, guidance for countries in developing pest eradication programs, national reporting of important pests, and more.

Global network of plant experts

Building a global community of plant health experts and advocates is essential. The IPPC Secretariat works with partners and donors to develop standards, facilitate countries’ adoption of the Convention and implementation of standards, and build the capacity of national plant protection organizations.

Guides, training materials and e-learning courses help these plant stewards effectively carry out their duties in safeguarding plants. Innovative tools such as the ePhyto allow countries to trade safely using digital phytosanitary certificates that make the trade in plants safer, faster and cheaper.

Raising global awareness and action among the wider public is also important. In 2020, we celebrated the International Year of Plant Health through 680 events held in 86 countries.

On May 12, 2022, the first International Day of Plant Health was declared following its adoption at the General Assembly of the United Nations in March. We thank the governments of Zambia and Finland as tireless champions in tabling the resolution at the Assembly, supported by FAO and the IPPC Secretariat.

The IPPC Secretariat and the Department for Environment, Food and Rural Affairs of the UK this week partnered to gather the world’s best plant health experts and advocates. The first and largest International Plant Health Conference being held in London aims to address new and emerging challenges such as climate change impact, the increase in international trade, the rapid loss of biodiversity and new pest pathways such as e-commerce. We will explore more efficient policies, structures and mechanisms at the national, regional and global levels.

Much work remains in protecting our plants. We need to be cautious when bringing plants and plant products when traveling as these could carry plant pests and diseases. Likewise, we should be aware that buying plants and plant products online should come with phytosanitary certificates that attest they meet phytosanitary import requirements.

E-commerce is an emerging pathway for the introduction and spread of plant pests. Online purchases cross international borders through mail or express freight systems via air freight or sea containers. These purchases often include but are not limited to, ornamental plants, soil from imported plants, untreated wood packaging materials such as pallets and crates and even novelty items such as seed-infused “plantable bookmarks.”

We call on governments, legislators, policymakers and donors to invest in research, outreach and in building the capacity of national plant protection organizations, and to strengthen pest monitoring and early warning systems.

We need all industry actors and government partners to adhere to international plant health standards to mutually protect our plants, food supplies and our economies.

When we protect plants, we protect our health, our environment, our livelihoods and our lives.

Explore further

Researchers use science of light to reduce pesticides used to protect crops from pests and diseases

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NZ government funds targeted weeding initiative.

By Stuart Corner on Oct 16 2017 2:53PM

Killer drones coming – for weeds

It’s a vision straight out of a sci-fi movie: a fleet of drones criss-crossing a farm, scanning the ground below for weeds and when they are found zapping them with a laser-beam.

However, the New Zealand government is spending $NZ1 million in the hope of making that vision a reality. The Ministry of Business Innovation and Employment is giving the money to a partnership between government research organisation, AgResearch, the Universities of Auckland and NZ-based technology firm Redfern Solutions to examine the development of such technology.

Program leader Dr Kioumars Ghamkhar said the aim was to use cameras and software to identify the weeds based on their unique chemical signatures and how they reflect light, and then locate them precisely using GPS.

“From there, we think smart spraying (rather than systemic and non-targeted use of chemicals), or the right kind of laser mounted on the drone could hone in and damage the weed,” Ghamkhar said.

“We know there are lasers now available that could be suitable, and that they are extremely accurate, so if lasers are used, it would also avoid damaging the useful plants around the weed.

“The effectiveness of lasers against plants has been tested overseas before but that was in the lab, and we’ll be taking it out in the field to test and see if it works as we have planned.”

There are other initiatives underway suggesting that the weed identification, if not killing, is perfectly feasible.

IoT Hub reported last month that Netherlands-based crop spraying equipment maker Agrifac was a planning to incorporate weed recognition technology developed by French startup Bilberry, in conjunction with Nokia, CETA, Institut Mines-Télécom and Tampere University of Technology into crop sprayers sold in Australia.

Also, Hitachi Australia has developed technology that takes imagery from drone mounted cameras able to respond to a very wide range of wavelengths, analyses this data in the cloud and provides weed identity data to the farmer.

The company is looking to commercialise the service including providing the drone and training in its use to the farmer.

Earlier this year, the Electron Science Research Institute (ESRI) and Edith Cowan University in WA was reported to be close to commercialising a laser system for identifying (but not killing) weeds that used lasers of three different frequencies.

Copyright © IoT Hub, nextmedia Pty Ltd


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Invasive Apple Snails- Book Cover

Joshi R.C., Cowie R.H., & Sebastian L.S. (eds). 2017. Biology and management of invasive apple snails. Philippine Rice Research Institute (PhilRice), Maligaya, Science City of Muñoz, Nueva Ecija 3119. 406 pp.​”


Open link in new window to view:

 Invasive Apple Snails Book 2017 – final.pdf

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Written by Imelda Felix, Finbarr Horgan, and Alex Stuart.


Apple snails (Pomacea spp.) have been a problem for Asian rice farmers for decades. First introduced in the late 1980s to Taiwan and the Philippines, these snails have now spread to most countries in Southeast Asia, as well as East Asia, such as Japan and Korea, where they are among the most damaging pests of rice and other aquatic crops. Recently, established populations of apple snails were found close to major rice-growing regions in Pakistan. India, and Bangladesh. While a few other Asian countries are still free of apple snails, what can these countries expect should the snails someday arrive?

Events in Ecuador might give some clues. In 2005, rice damaged by apple snails was first noticed in Ecuador. Since then, and particularly after severe flooding in 2008, the snail has spread to most of Ecuador’s major rice-growing regions. Losses to the rice sector from apple snails in 2013 alone were estimated at over US$56 million. However, Ecuadorean rice farmers have one big advantage in dealing with apple snails over their Asian counterparts—the snail kite (Rostrhamus sociabilis), a predatory bird that specializes in eating snails.

Flying pest control

The snail kite’s natural range extends from Florida in the United States to subtropical region in Argentina, a region that is also the native habitat of several apple snail species, including the most invasive species: the golden apple snail. West of the Andes, snail kites are largely restricted to mangrove swamps and river estuaries in southern Ecuador, where they likely feed on less invasive snails such as the spike-topped snail.

Prior to the recent apple snail invasion of Ecuador, snail kites were a threatened species. Their population had declined dramatically because of habitat loss and the overuse of agrochemicals. Moreover, farmers often hunted and killed the birds, believing that they damaged livestock. In recent years, as the apple snails have continued to spread, snail kites have become a common feature of the Ecuadorean rice landscape and a welcome sight for farmers. Groups of these birds can be regularly seen perched over rice fields watching for snails, communicating with one another through haunting, rolling caws, or swooping down to catch the snails before gracefully flying off with their prey.

But are snail kites enough to control the snails? We found out that the snail kites first respond to high snail densities by building up their own populations. This means that the snail kites require ample food and suitable habitat for hunting and nesting. Thus, for some time, as the apple snails spread, they escaped the predatory snail kites.

During this time, snail densities peaked, and had terrible effects. A visit to any newly snail-invaded region is a lesson in an ecosystem out of balance: hundreds of bright pink egg masses, containing millions of eggs, can be seen on wooden posts or the trunks of trees near infested ponds and paddy fields. Large patches of rice fields, where the water is deepest, become denuded of rice and other aquatic weeds. Snails, the size of small apples, chew through any remaining green vegetation and decomposing matter at the water’s edges.

Desperate chemical measures

Agrocalidad, Ecuador’s agricultural extension service, has been working with farmers to control snail damage to rice. Experience in Asia had shown that delayed transplanting of rice plants, careful control of water depth, and other cultural control methods could help reduce snail damage. Agrocalidad has shared these methods with tens of thousands of farmers through workshops, talks, theater, videos, posters, and handbooks. However, although Agrocalidad discourages the use of highly toxic insecticides, farmers overwhelmingly used these chemicals, particularly endosulfan, to kill the snails. This reduced snail densities but at high environmental and health costs. Worst of all, farmers noted that the chemicals were also killing their greatest allies—the predatory snail kites. In 2011, the government of Ecuador banned the use of endosulfan, and promoted the use of a more selective molluscicide, methaldehyde—for which the effects on snail kites are still unknown.

Overall, 2013 seems to have seen a decline in snail numbers in some affected areas, particularly in fields at higher elevations. However, a large part of Ecuador’s rice is produced during the dry summer months (June-December) in vegas. Vegas are natural wetlands that are completely flooded for 6 months of the year. In June-July, the water recedes, and farmers track the water levels and plant their rice in a sequential manner in areas of shallow water. This results in an attractive rice landscape with rice of different stages in natural patterns (a system called arroz escalonado or stepped rice). Apple snails in vega systems have remained at very high densities and continue to damage rice significantly. Furthermore, these habitats are highly vulnerable to agrochemicals because they are the natural habitat for a diversity of amphibians, fish, birds, and other fauna and flora.

For scientists, the events in Ecuador are an opportunity to better understand how snails invade rice and how predators and prey interact with each other. Continued monitoring of the situation will highly benefit both scientists and farmers, and could help predict future effects and help design management options as apple snails continue to invade new areas.

Above all, the tremendous negative impact of the invasive apple snail on the Ecuadorean rice sector, despite the presence of a key predator, should encourage snail-free rice-producing countries to be vigilant against possible infestation by tightening quarantine regulations and banning the trade and import of exotic snails. The best way by far to avoid apple snail damage is to ensure that these voracious snails are not introduced to any new regions, where, without natural predators such as snail kites, losses to the rice sector could be even more severe than those experienced in Ecuador.

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Photo by Ian Foley – The eastern heath snail have been populating in an area near Belt in recent years. Efforts to control the invasive snail may begin in May.

April 04, 2014 11:00 am • By TOM KUGLIN

Independent Record

The Montana Department of Agriculture became aware of a population of eastern heath snails in parts of Cascade and Choteau Counties in 2012. The department has since drafted an environmental assessment, now in the public comment phase, with proposals to cull the snails.

The agency does not know how the snails got to Montana, but residents have reported seeing the snails for at least 25 years, said Ian Foley, pest management program manager for the Department of Agriculture.

“It’s fairly different and odd for Montana to have an invasive dry land snail,” he said.

Because the snail lives on dry land it falls under the jurisdiction of the Montana Department of Agriculture. If it was an aquatic invasive species, such as the better known zebra mussel, jurisdiction goes to the Department of Fish, Wildlife and Parks, he said.

The snails become pests in grains and other commodities causing quarantines, Foley said.

The only other populations in North America are in Detroit and Ontario at shipping yards. The invasion is rare enough in Montana that the USDA’s malacologist, or specialist in snails and slugs, came to advise the state department, Foley said.

The infested area encompasses nearly 100,000 acres, but snails are concentrated along highways, the town of Belt, Armington Junction and Sluice Boxes State Park. Given the widespread range of the snail, total eradication would be unlikely, the environmental assessment said.

The preferred alternative under the environmental assessment calls for continued monitoring of snails as well as education and outreach to impacted landowners. The agency would then conduct voluntary suppression efforts using pesticides called molluscicides.

The two molluscicides identified in the assessment are iron phosphate, which is non-toxic and common in law fertilizers and metaldehyde, a slightly to moderately toxic substance that quickly dissolves when wet.

Although the snails are fairly concentrated in the Belt area, officials worry that they could make it to the Missouri River. At that point, they could easily catch a ride downstream to other parts of Montana and even other states.

After public comment, the department will make a decision on their choice of action. If they decide to proceed with using molluscicides, application could begin in the first couple weeks of May, Foley said.

The public has until April 15 to comment on the environmental assessment. Written data, views, or arguments may be submitted to: Cort Jensen, Department of Agriculture, P.O. Box 2000201, Helena, Montana, 59620; telephone (406) 444-3144; fax (406) 444-5409; or email cojensen@mt.gov, and must be received no later than 5 p.m.


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Island apple snail is destroying crops and threatens to spread into other southern European wetlands

Snail invasion in Spain

Shells of the invasive island apple snail in the Ebro Delta, Spain. Photograph: Dani Forcadell

The EU has “washed its hands” of an invasion of snails in a Spanish river delta that are destroying crops and threaten to spread into other southern European wetlands, farmers say.

Rice-growers in the Ebro Delta on southern Catalonia’s Mediterranean coast have reported losing up to half of their crops since the island apple snail (Pomacea insularum) was first seen in 2009. The worst-affected fields have 12 snails per square metre, with each snail capable of eating the roots of up to 15 rice plants each day.

Authorities are attempting to destroy the snails by drying out their fields over winter and flooding some with salt water. The EU has supported the experiment by sharing the cost with the Spanish and Catalonian governments. But it will recoup €378,000 of this money from the delta’s struggling farmers. The EU pays farmers a subsidy to keep their fields flooded during the winter months and preserve wetland habitat for birds and fish. The EU gave growers permission to drain 7,000 hectares of fields this winter, but this meant losing their subsidies.

“The EU has washed its hands of the problem,” said Albert Pons, a rice farmer from the delta village of Camarles. “I have spent hours and hours setting up systems to catch and eliminate the snail, cleaning out filters and irrigation channels and physically searching for and killing the snails one at a time.”

The Ebro River’s delta of rice fields and wetlands provide habitat and breeding sites for a large range of bird species. More than 7,000 hectares is protected under the Ramsar convention on wetlands. The wetlands currently remain free of the snail.

The European Food Safety Authority (Efsa) says the snails could destroy wetland ecosystems if they spread across southern Europe. The vice-chair of Efsa’s panel on plant health, Joop van Lenteren, said juvenile snails, only millimetres across, could attach to the feathers of migrating birds and spread to wetlands hundreds of kilometres away. The hulls of local fishing boats could be covered with eggs, raising concerns the snail could hitch a ride to other waterways.

Efsa research indicates that the snail could thrive in large parts of Spain, southern France, Italy and Greece and the Danube. If this happens, the snail could push already fragile ecosystems into irreversible decline as it has done in Thailand and other countries in south-east Asia.

“When the snail establishes in rivers and wetlands the consequences can be serious. Because it is so voracious, there is a high risk to biodiversity,” he said.

According to tthe Global Invasive Species Database, the snails have an ability to reproduce at extraordinary rates. Between April and November, females will lay 400 bright pink eggs every five to 15 days.

Pons said when the snail first appeared on his farmland, he did not realise what an insidious threat it posed. “I first saw the snail in an irrigation channel in 2010. The following year we found them in my rice fields. This last year has been catastrophic and our struggle to remove or control them [is] extremely expensive.

“The plague has spread like wildfire. Now farmers and the public bodies cannot keep up with it. Seeing the extent of the damage, I feel anxiety for the future of my livelihood and family,” said Pons.

The South American species is a popular aquarium pet because of its size and can grow as big as an apple. Its release into the Ebro has been linked with Promotora Bama, an exotic animal importer, which bred the snails at a facility in the village of L’Aldea on the north side of the delta. The snails were first detected in a drainage channel in the town. Shortly afterwards, the company relocated its facility to the town of Tarragona, 80km to the north.

Promotora Bama, who were unavailable for comment, were taken to court by the Catalonian government in 2012 but a judge dismissed the action because it had passed the three-year statute of limitations. Efsa said the snails in the delta had genetic traits consistent with cultivation in the pet industry.

Snail invasion in Spain
 Eggs left by the snails. Photograph: Dani Forcadell

In November 2012, the EU banned the import of all snails in the genus pomacea.

An European commission spokesperson said: “The commission is very concerned about the economic and environmental damage caused by the apple snail and for that reason, under the EU plant health legislation, the snails of the genus pomacea are subject to emergency measures to prevent its introduction into and the spread within the Union.”

The EU has made €2.64m available to the Spanish authorities from 2010 until 2013 for control actions against the harmful organism. But the EU says the subsidy contracts farmers received for flooding their fields, which were suspended during 2013, expired at the end of last year and would not be reinstated because the fields no longer represent good habitat for birds.

“The commission does not consider appropriate to extend these commitments until 2014, given the economic and environmental damage caused by the apple snail.”

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Deccan Chronicle

The snails, which were once thought to be eradicated from South Florida, have returned to the Coral Gables area of Miami-Dade County - AFP

The snails, which were once thought to be eradicated from South Florida, have returned to the Coral Gables area of Miami-Dade County – AFP

No one knows how they got there. But an invasion of African giant snails has southern Florida in a panic over potential crop damage, disease and general yuckiness surrounding the slimy gastropods.

The US and Florida departments of agriculture have mobilized 34 agents to battle the infestation and the US Fish & Wildlife Service is heading up an investigation into how the mollusks — which can be up to 20 centimeters (eight inches) long — arrived.

“This is a big snail, a very big snail,” says Suzi Distelberg, a district inspector for the Florida Department of Agriculture, as she probes one of the shells with a gloved hand.

“No it’s not empty, see… eeew. It’s very heavy, you can tell the snail is still in there.

“We’ve been told that they like to eat the stucco off the sides of the houses because it contains calcium, and the calcium helps to build their shells.”

The lissachatina fulica, or giant African land snail, can live up to nine years, and are prolific, laying up to 1,200 eggs a year, making it extremely invasive. A single snail can create a mass that invades an entire neighborhood.

Local resident Yolando Garcia Burgos one morning discovered snail excrement on her exterior wall, and ended up collecting 583 of the mollusks in a week, finding them in her bushes, on her grill and in her ivy. State authorities say they have captured 35,000 since the invasion began in September.

But the concern is not simply a question of aesthetics: The snail’s mucus can contain a parasite which transmits a form of meningitis, which is not lethal but can provoke extreme abdominal pain.

The pest is also a threat to agriculture, feasting on some 500 plant varieties including peanuts and melons.

“If they were to become established, it could devastate Florida’s agriculture,” said Mark Fagan of the state agriculture department, who noted that agriculture is second only to tourism for the state’s economy.

It’s not clear how the world’s largest snail species arrived in Florida. Originally from east Africa, they have also been found in Caribbean islands including Guadeloupe and Martinique.

This is not the first invasion for Florida. In 1966, a boy imported three giant snails as pets, and his grandmother released them into the wild, which led to a colony of 18,000. The eradication effort took nine years and cost over $1 million.

Importation of these animals is illegal in the United States without a federal permit. But officials point out they are used in certain Afro-Caribbean religious practices.

Fagan says it’s not clear if the snails were brought over for religious ceremonies or as pets and got ‘out of control.’

The eradication effort is in full force even though the snails are in a sort of hibernation during which they dig themselves into the ground, making them less visible.

Authorities are hoping to bring down the population before the spring, when rains could cause a population surge.

Officials say the areas being cleaned up will remain under scrutiny for several months. Gardens are treated with iron phosphate, which is not harmful to other animals but disrupts the snails’ feeding habits.

The captured gastropods are taken to a lab where specialists like Mary Yong examine them and, ultimately, kill them off. The snails are effectively drowned in an alcohol solution or put in a freezer to ensure they are dead.

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