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Archive for the ‘Nematodes’ Category

Western Australia
August 13, 2014

Growers are reminded to investigate uneven crops to check if plant parasitic nematodes are present, after root lesion and burrowing nematodes were found in the Moora area.

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Roots of barley crop impacted by P. penetrans

Department of Agriculture and Food nematologist Sarah Collins recently visited the area where a number of wheat and barley crops have been damaged by burrowing (Radopholus) nematodes and by root lesion nematodes (Pratylenchus, RLN).

Samples were diagnosed by AGWEST Plant Laboratories as the RLN species Pratylenchus penetrans.

“This was unexpected as this species is more often associated with cropping in the cooler growing areas but we have had a number of P. penetrans diagnoses this season from locations across areas of the Wheatbelt including Moora, Northam and Wagin,” Dr Collins said. “It is one of the species that we know less about.

“The ‘burrowing nematode’ detected in a nearby barley crop is also interesting as crop damage has not been reported for this plant parasitic nematode for a number of years.”

Correct identification of nematodes is important because the choice of suitable break crops to mitigate future damage is dependent on knowing which plant parasitic nematode species are present.

“It is possible that consecutive seasons favourable to RLN and burrowing nematode and the increasing inclusion of canola to crop rotations may be contributing to the build-up of nematode numbers,” Dr Collins said.

The reports follow survey work by the Focus Paddocks project, supported by Grains Research and Development Corporation, which has detected increasing levels of RLN across 184 paddocks surveyed since 2010.

“We are seeing the highest prevalence of RLN populations in at least a decade,” Dr Collins said.

Above ground symptoms of plants infected with root lesion and burrowing nematodes include stunting, poor growth, early wilting, premature yellowing of lower leaves and dying back from the tips.

Below ground symptoms often include reduced root systems with fewer lateral roots and root hairs compared to nearby healthy plants. Brown/dark coloured lesions along the roots may also be seen.

Suspected root disease or nematode problems in-crop can be confirmed by a chargeable laboratory analysis of soil and/or roots by AGWEST Plant Labs, which are contactable on 9368 3721 or agwestplantlabs@agric.wa.gov.au.

Nematodes will be on the agenda at a plant disease ID course for agronomists and development officers run by the department in South Perth next week (19 and 20 Aug). The department can deliver courses on root disease identification for grower groups at their local centre. To enquire about these courses contact Dominie Wright at the department on 9368 3875.

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PUBLIC RELEASE DATE: 3-Jul-2014

Contact: Caroline Wood
cwood4@sheffield.ac.uk
44-7771-765335
Society for Experimental Biology

http://www.eurekalert.org/pub_releases/2014-07/sfeb-owh062714.php

 

Many modern crops have high productivity, but have lost their ability to produce certain defence chemicals, making them vulnerable to attack by insects and pathogens. Swiss scientists are exploring ways to help protect 21st century maize by re-arming it with its ancestral chemical weapons.

The researchers, led by Dr Ted Turlings (University of Neuchâtel, Switzerland), found that many varieties of modern maize have lost their ability to produce a chemical called E-β-caryophyllene. This chemical is normally produced by traditional ancestors of modern maize roots when the plant is under attack from invading corn rootworms. The chemical attracts ‘friendly’ nematode worms from the surrounding soil which, in turn, kill the corn rootworm larvae within a few days.

The scientists used genetic transformation to investigate if restoring E-β-caryophyllene emission would protect maize plants against corn rootworms. After introducing a gene from oregano, the transformed maize plants released E- β-caryophyllene constantly. As a result, these plants attracted more nematodes and suffered less damage from an infestation of Western Corn Rootworms.

“Plant defences can be direct, such as the production of toxins, or indirect, using volatile substances that attract the natural enemies of the herbivores” says lead scientist, Dr Ted Turlings (University of Neuchâtel, Switzerland). One of the types of toxins that maize plants produce against their enemies is a class of chemicals called benzoxazinoids. These protect maize against a range of insects, bacteria and fungi pests, yet some species have developed resistance against these toxins and may even exploit them to identify the most nutritious plant tissues.

These results show how knowledge of natural plant defences can be practically applied in agricultural systems. “We are studying the wild ancestor of maize (teosinte) to find out which other chemical defences may have been lost during domestication of maize” Dr Turlings added. “These lost defences might then be reintroduced into modern cultivars”.

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Logo for IPM CRSP

Annual Report 2013
Posted on May 27, 2014 by Kelly Izlar
The IPM Innovation Labs’s FY 2013 (October 1, 2012–September 30, 2013) annual report is now available. Click below to download the document.

http://www.oired.vt.edu/ipmcrsp/publications/annual-reports/annual-report-2013/

For users with lower bandwidth and/or with interest in only certain specific topic areas, we will split individual chapters and major sections out of the Annual Report for you to view individually. Check back in the coming weeks for a list of individual chapters and sections for download. For more information contact: rmuni@vt.edu

Table of Contents

Management Entity Message
Highlights and Achievements in 2012–2013

Regional Programs
Latin America and the Caribbean
East Africa
West Africa
South Asia
Southeast Asia
Central Asia

Global Programs
Parthenium
International Plant Diagnostic Network (IPDN)
International Plant Virus Disease Network (IPVDN)
Impact Assessment
Gender Equity, Knowledge, and Capacity Building

Associate & Buy-In Awards
Indonesia
Nepal
Bangladesh

Training and Publications
Short- and Long-Term Training
Publications

Appendices: Collaborating Institutions and Acronyms

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http://www.ekantipur.com/the-kathmandu-post/2014/05/02/onsaturday/back-to-basics/262360.html

Kathmandu Post

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By: PRAGATI SHAHI

KATHMANDU, MAY 02 -
Integrated Pest Management has been adopted by a growing number of organic farms in all districts of Nepal

Arjun Neupane, a farmer in Dhaibung, Rasuwa, owns a farm that’s all organic. His prize produce is tomatoes, and they grow in a plastic-roofed shed that’s surrounded on all sides by marigold plants. The rest of his farmland, used for growing cauliflower and spinach, is spotted with plastic drums that house a slurry of buffalo dung and urine mixed with titepati, neem and sisnu leaves. It’s the employing of slurries of this kind that’s at the heart of a farming method called Integrated Pest Management (IPM)—a method that’s been adopted by a growing number of organic farms in all districts of Nepal.

The IPM philosophy is a simple one: It’s a way of using, as much as possible, plants (mostly those that grow in the wild) and animal waste to keep pest numbers down and fertilise the soil at the same time. The buffalo urine in the slurry, which Neupane ferries by the bucketloads to his vegetable beds, acts as a fertiliser—by adding nutrients such as ammonia in its natural form to the soil—and the plants used in the slurry kill germs and keep away animals such as rodents, with their bitterness. Live plants, too–such as the marigold plants around Neupane’s greenhouse—can be marshalled as a defensive front: in Neupane’s case, they keep at bay the nematodes, a kind of worm, which would otherwise prey on his tomatoes.

IPM took off in the late 90s in Nepal, with the government’s encouraging farmers to make use of the method as an alternative to depending on chemical fertlisers, which are harsher on the soil and whose use over time can lead to the land’s turning effete. The government knew that it had to wean the farmers off chemical fertilisers if they wanted to preserve the farmlands’ soil. The advent of globalisation had by then seen a marked increase in Nepali farmers’ switching to various types of chemical fertilisers and pesticides, which had become readily available in all markets across the country. And the farming sector had transformed from one which primarily used organic fertilisers and biological agents to one that relied increasingly on fertilisers that degraded the soil quality of the farms and which furthermore had untold adverse effects on the environment and in turn on public health.

Most farmers who use only chemical fertilisers are locked in a vicious cycle. The chemical fertilisers produce better yields, and as most other farmers now opt for using chemicals (even as they further degrade their land), they have to keep up if they want to compete in the marketplace. Furthermore, many of them have also taken to using industrial-strength pesticides to keep away pests—such as insects, disease-bearing pathogens, weeds, rodents, and mites—which are the major constraints to increasing agricultural production and which can cause productivity losses of up to 40 percent. This increase in the use of chemical pesticides ends up not only upsetting the natural balance of chemicals of the soils in the fields, but also leads to an increase in the populations of secondary pests.

It was to help those farmers who wanted to get back to using biopesticides that the concept of the IPM approach was pushed by the government. The first phase of IPM farming in Nepal was launched just before the turn of the century by the Department of Plant Resources, under the Ministry of Agriculture and Cooperatives. The government was aided in its venture by various developmental partners and together they helped set up the practice for farmers in various districts, including Jhapa, Morang, Bara, Chitwan, Kapilvastu, Bardiya, Banke, Kailali, Ilam, Kavre, Syangja, Surkhet, Dadeldhura, Tanahu, Dhading, Mustang and Manang.

Ironically, the government had to sell the idea as a ‘modern’ method of farming, even though local versions of IPM were what the farmers used to work with before the farmers switched wholesale to chemical fertilisers. Wood ash, for example, has been widely used for pest control in west Nepal for generations. Today, the national IPM Programme seeks to teach the farmers how to find their way back, says Yubak Dhoj GC, a government official and former coordinator at the Plant Protection Directorate. To help farmers make the switch, the government and various non-governmental agencies have set up IPM farmer schools all across Nepal, in which farmers such as Neupane learn the science of using botanical pesticides, which can be made from more than 50 plant species readily available in Nepal: plants such as neem, marigold, titepati, sisnu, garlic and timur are used in IMP to ward off pests such as the cabbage butterfly larvae, hairy caterpillars, cutworms, red ants, termites and aphids.

Today, it is estimated that around 11,000 farmers in 17 districts have completely adopted IPM techniques and that the number is increasing at the rate of more than 10 percent each year. Thus there are quite a few farmers who are getting sold on the idea, but there still remains the challenge of helping the IPM farmers compete with those who still haven’t given up the use of chemical fertilisers. The IPM model requires more man-hours in the field; furthermore, as Neupane, says, it’s difficult for IPM farmers like him to compete with farmers who use chemical fertilisers, andwhose tomatoes look larger, redder and juicier than his.

According to GC, the IPM programme is at a crossroads now. He says the government has to play a larger role in helping farmers such as Neupane. At present, the agricultural produce grown using chemical fertilisers and the IPM methods are competing in the same markets. The government doesn’t have the mechanism in place to certify certain products as being organic. If that were to happen, Neupane thinks that he could sell his tomatoes to hotels in Dhunche, where the tourists who prefer organic produce could seek vegetables like the ones he grows.

In cities like Kathmandu, there are already many farmers who are able to sell their products in the niche markets that the organic farmers, who employ IPM, have carved for themselves. For the farmers outside the Valley, the main draw of IPM farming is that the soil will remain fertile in the long run. These farmer can only compete with those who use chemical fertilisers, says GC, if the government were to provide subsidies and help improve market access for them. “We have been successful in involving the farmers in the IPM approach but have failed to improve the accessibility to the market for their products. Thus it’s still difficult for most of them to benefit from the agriculture practice they are adopting,” says GC.

Posted on : 2014-05-03 08:15

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NTV/NEBRASKA.TV

Posted: Apr 07, 2014 10:52 AM CDT
Updated: Apr 07, 2014 10:52 AM CDT

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Investigators from the state Department of Agriculture are on the lookout for pest-ridden potato seeds in an effort to protect Nebraska’s potato industry.

Two of the state’s three potato inspectors recently quarantined nine boxes of potato seeds at a Lincoln True Value hardware store because the store’s owners didn’t have paperwork needed to prove the seeds were free of the Columbia root-knot nematode worm. The pest eats roots of plants like grasses, legumes and cereals.

Ag Department spokesperson Christin Kamm says they take seriously the need to protect Nebraska’s potato industry.

 

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Reported by pestnet@yahoogroups.com by Grahame Jackson <gjackson@zip.com.au>

March 5th, 2014 in Biology / Ecology

This is a root of a banana plant infected by the nematode Radopholus similis. The roundworms infect the roots and kill root tissue.

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Credit: Rony Swennen and Dirk De Waele

The banana variety Yangambi km5 produces toxic substances that kill the nematode Radopholus similis, a roundworm that infects the root tissue of banana plants – to the frustration of farmers worldwide. The finding bodes well for the Grande Naine, the export banana par excellence, which is very susceptible to the roundworms.
The parasitic nematode Radopholus similis is the invisible nemesis of the banana plant, says Professor Dirk De Waele (Laboratory for Tropical Crop Improvement, KU Leuven), a co-author of the study: “This roundworm infects banana crops worldwide. The nematodes are invisible to the naked eye, but they can penetrate the roots of banana plants by the thousands. Once infected, these plants absorb less water and nutrients, resulting in yield losses of up to 75 percent. Lesions in the roots also make the plant more susceptible to other diseases. Eventually, the roots begin to rot. In the final stage of the disease, the plant topples over, its fruit bunch inexorably lost.”
Combating nematodes isn’t easy, adds Professor Rony Swennen (Laboratory for Tropical Crop Improvement, KU Leuven), another co-author: “Synthetic pesticides are toxic and expensive. Moreover, pesticides usually do not actually kill the nematodes, they just temporarily paralyze them. Nematodes can also build up resistance to pesticides.”

This is a banana field in Uganda planted with Grande Naine, a banana variety commonly sold in the supermarket. The nematode Radopholus similis infects the roots of banana plants. In the final stage of disease, the plant topples over and its fruit bunch is lost.

Imagec

Credit: Rony Swennen and Dirk De Waele

While the Grande Naine is very susceptible to nematodes, other varieties are known to be resistant to them. Enter the Yangambi km5, a variety first grown in the 1950’s at a Belgian research station in Yangambi, DR Congo. The researchers compared the two banana varieties and studied their defense responses to Radopholus similis. “Researchers have always wondered how the Yangambi km5 manages to fight off roundworms,” says De Waele. “This study goes a long way in answering that.”
With colleagues at the Max Planck Institute for Chemical Ecology (Germany), the KU Leuven researchers identified which metabolites are responsible for fighting off the nematodes. “We found nine different nematode-killing metabolites in Yangambi km5. These metabolites are also produced in the Grande Naine, but much more slowly and in lesser quantities. In that banana variety, the nematodes win the fight.”
The new knowledge of metabolites will be helpful in developing edible and pest-resistant banana varieties, says Swennen. “The next step is to screen other banana varieties for metabolites. This method could also be applied to other crops and other species of nematode. Nematodes pose a growing threat to rice production in Asia, for example. Our findings also provide the industry with perspectives to develop a generation of new pesticides against nematodes.”
The researchers’ findings were published in a recent issue of the journal PNAS.
More information: PNAS DOI: 10.1073/pnas.1314168110
Provided by KU Leuven

 

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Logo: Spiral nematode encircling African continent

2014 International Congress of Nematology – Cape Town, South Africa

The 6th International Congress of Nematology will be presented by the Nematology Society of Southern Africain (NSSA) during May 2014 in Cape Town, South Africa.

The website is open and we have logo for the 6th ICN meeting. Go and check everything on www.6thicn.com

Nematology Short Course – 2013

A short course in Nematology will be presented at the North-West University from 2 to 13 September 2013. More information will be made available by 28 February 2013.

Contact persons: Proffs Alex Mc Donald (alex.mcdonald@nwu.ac.za; Tel: 018 293 3749) and Driekie Fourie (driekie.fourie@nwu.ac.za; Tel: 018 293 3683).

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