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Archive for the ‘Emerging/invasive pests’ Category

fall-armyworm-frontal-MER-563x744FAW on corn leavesfall-armyworm-frontal-MER-563x744

Maize damaged by the fall armyworm, Spodoptera frujiperda

Photos courtesy of Marlin E. Rice

 

Fall Armyworm Workshop for East Africa

Harmony Hotel, Addis Ababa, Ethiopia, July 14-15, 2017

 Background

The Fall Armyworm (FAW), Spodoptera frugiperda, a native to the tropics and sub tropics of North and South America, is a polyphagous pest attacking more than 80 different plant species, including maize. Maize is a major food staple in sub-Saharan Africa upon which more than 300 million people depend. Depending on the degree of infestation, the FAW can cause huge losses in maize yields and in some cases, total crop loss.

This pest has recently invaded Africa and is ravaging crops in more than 20 countries. It was first reported in Nigeria, West Africa, in early 2016. It soon spread to southern Africa in late 2016 and by early 2017 was confirmed to be in East Africa. If it is not effectively controlled, it is expected to cause $3bn loss to maize in Africa along with serious food shortages expected in the next year.

Needed action

Rapid action, immense awareness creation, and technological innovation, along with national, regional and international collaboration are required to thwart the threat of the fall armyworm in order to avoid severe economic losses among smallholder farmers across Africa. Crucial concerted efforts from international research centers, national research and extension programs, international development organizations, policy makers, and donor communities in East Africa are required to develop and deploy an effective integrated pest management strategy, which can provide sustainable solutions to effectively tackle the adverse effects of the FAW. Millions of East African farmers are currently on the road to recovery from last year’s shocking drought that resulted in a humanitarian crisis. Now, they are facing this new threat to their livelihood.

Workshop objectives

To effectively fight this pest, the IPM Innovation Lab/ Virginia Tech and USAID, in partnership with icipe, is organizing a regional FAW awareness and management workshop. This workshop will bring stakeholders and experts from the United States, Ethiopia, Kenya, Niger, and Tanzania to share their experiences and challenges in dealing with the FAW. The workshop will also include discussions on needed action in terms of research and development in the region. The results and recommendations made from this workshop will be used as feedback to design an effective management strategy to manage the FAW in East Africa and beyond.

On behalf of the workshop organizers

Tadele Tefera

Country Head icipe Ethiopia, PI for IPM Innovation Lab Grains IPM for East Africa Project and IAPPS Coordinator, Region V East Africa

 

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seedquestlogo

July 13, 2017


The photo is from https://doi.org/10.1017/wsc.2017.14. It shows one of the plants that come from a population that apparently adapted to taller crops and is GR and another that comes from a population adapted to smaller crops and is GS. Additionally, below you can see a few examples of the great diversity in morphology that we found among Palmer amaranth populations. – Credit: Photo by Ramon Leon

Palmer amaranth is widely considered to be one of the most damaging and difficult to control agricultural weeds in North America. A lot of time and attention has been devoted to herbicide-resistant Palmer amaranth and the significant yield losses it can produce. Research featured in the journal Weed Science, though, shows other “life history” traits may be contributing to crop losses by making Palmer amaranth more aggressive and difficult to control.

Researchers from the University of Florida collected samples of Palmer amaranth from 10 fields in Florida and Georgia. The sites had widely divergent cropping histories – from short-statured vegetables and peanut crops to tall corn and cotton crops. The fields also varied in herbicide use. Some were devoted to organic production, while others had a history of intensive herbicide use.

Significant differences were observed in the traits of the Palmer amaranth from the various fields, such as fresh and dry weight, days to flowering, plant height, leaf shape and canopy. Researchers say these differences could not be explained by whether the Palmer amaranth population was glyphosate resistant or glyphosate susceptible. Instead, crop rotation and crop canopy better explained the many variations found. For example, the tallest populations of Palmer amaranth came from corn fields, while the shortest came from fields planted with the shortest crops.

“It appears Palmer amaranth can evolve life-history traits that increase its potential to grow and reproduce in various cropping systems,” says Ramon Leon, Ph.D., a member of the research team. “To avoid the development of more aggressive weed biotypes, it is important to consider these evolutionary consequences when designing crop rotation systems and weed management strategies.”

Full text of the article “Differentiation of Life-History Traits Among Palmer Amaranth Populations (Amaranthus palmeri) and its Relation to Cropping Systems and Glyphosate Sensitivity” is now available in Weed Science Vol. 65, Issue 3, July-September, 2017.

 

More news from: Cambridge University

 

Website: http://www.cam.ac.uk

Published: June 13, 2017

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Phys Org

Researchers identify protein target to halt citrus tree disease

June 7, 2017

University of Florida researchers may have come a step closer to finding a treatment for a disease called Huanglongbing, or citrus greening, that has been decimating citrus trees in the state. In work published this week in mSphere, an open access journal from the American Society for Microbiology, the investigators describe identifying a small protein from one bacterium living in Asian citrus psyllids—the flying insects that spread the disease as they feed on the trees—that can “cross-talk,” moving to another bacterium within the insects to silence so-called “prophage genes” containing viral material in the second bacterium, helping prevent an insect immune reaction that would likely be detrimental to both bacteria.

The , from the Wolbachia bacterium, could serve as a potential target to develop spray treatments to protect trees against the psyllids, and could potentially help the trees themselves fight off bacterial invasion, said senior study author Dean W. Gabriel, Ph.D., a professor of Plant Pathology at the University of Florida in Gainesville. Wolbachia is a natural bacterium present in up to 60 percent of all insect species. (image: citrus greening disease on mandarin oranges, wikimedia commons)

“In this case, one bacterium is doing a favor to the whole bacterial community living within the psyllid by shutting down a potential threat to survival of insect host,” Gabriel said.

Gabriel and colleagues had been looking for ways to interrupt , a disease process caused when psyllids carrying but not affected by a bacteria called Candidatus Liberibacter feed on healthy trees and inject this bacteria into the trees’ phloem, a tubular system normally used to transport sugars produced during photosynthesis from the leaves of a plant to the rest. The bacterium suppresses the plants’ defenses as it moves, Gabriel said: “It’s like a little cunning burglar sneaking in under the radar.” It impacts the tree from its roots to its shoots, he said, and has a long incubation period: “By the time disease is detected in one tree, the entire grove is thoroughly infested and much more difficult to treat.”

Citrus greening causes a severe decline in the —leaves turn a blotchy, mottled yellow color, the fruits produced are smaller and have an off-taste, and fruit yield is much reduced. The disease has devastated Florida over the last 10 or so years, Gabriel said. As a result, the state’s overall citrus production has declined by about 60 percent over the last six years. Scientists have been desperately seeking a cure.

In a series of laboratory experiments, Gabriel’s team discovered that expression of proteins that help drive the spread of the Candidatus bacteria were suppressed when they were treated with extracts from the psyllids. Further studying the process, they identified a fragment of the protein doing part of suppression as encoded by the Wolbachia strain and secreted into the insect. This protein could move within the insect into the Candidatus bacteria causing greening, bind itself to a genetic region that would normally promote prophage activity, and repress these genes.

Gabriel’s group has a grant from the U.S. Department of Agriculture to grow the Candidatus Liberibacter bacterium in culture, a process that has been difficult because, once removed from its host, the bacterium historically has destroyed itself. Now that a protein target has been identified, it can be commercially synthesized and added to culture media, where the may be more likely to grow, Gabriel said.

Explore further: Blue-bellied insects may play a role in the fight against citrus greening

Read more at: https://phys.org/news/2017-06-protein-halt-citrus-tree-disease.html#jCp

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By Sam Otieno. Reblogged from SciDevNet A facility has been launched in Kenya to aid commercial production of a protein bait to control fruit flies in Sub-Saharan Africa. The US$250,000 facility, which resulted from public-private partnership involving the International Centre of Insect Physiology and Ecology (icipe) and Kenya Biologics Ltd, will enable smallholders control fruit flies that devastate their fruits […]

via Kenya gets new production facility to control crop pest — The Plantwise Blog

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Entomology Today

pierces-disease-foliar-symptoms1.png

Pierce’s disease is one of many plant afflictions caused by the bacterium Xylella fastidiosa and spread by a variety of insects known as sharpshooters and spittlebugs. (Photo credit: Lisa Overall, Ph.D.)

In many areas across the southern United States and California, one bacteria species complex is responsible for a long list of plant diseases: Pierce’s disease of grape, citrus variegated chlorosis, phony peach disease, plum leaf scald, alfalfa dwarf, almond leaf scorch, oleander leaf scorch, and leaf scorch of blueberry, pecan, and many shade trees. The bacterium, Xylella fastidiosa, attacks plant xylem, and its primary means of spreading is a variety of insects that specialize in drinking from that plant tissue.

In a new profile published last week in the open-access Journal of Integrated Pest Management, researchers in Oklahoma offer an in-depth guide to the biology and vectors of X. fastidiosa and the diseases it causes—with an eye toward the southern United States, where research on vectors and management practices has been less extensive than in California.

“There are unique features associated with each insect species that is capable of serving as a potential vector of X. fastidiosa. However, the first step to improving control practices for these species is to identify those insects feeding on a susceptible crop that can acquire the pathogen and transmit it to healthy plants,” says Eric J. Rebek, Ph.D., associate professor of entomology and plant pathology at Oklahoma State University and co-author of the research. The JIPM article is an adapted version of the literature review from the doctoral thesis of lead author Lisa Overall, who completed her Ph.D. at OSU in 2013 and is now an instructor of biology at Rogers State University.

“Dr. Overall conducted a survey of potential insect vectors occurring across the state, identified species harboring X. fastidiosa, and verified their ability to transmit the pathogen to susceptible plants through feeding assays. Armed with this information, we can now tell our growers what vector species to monitor, how to identify them, and how best to control them,” says Rebek.

glassy-winged-sharpshooter1

The glassy-winged sharpshooter (Homalodisca vitripennis) and other insect vectors of Xylella fastidiosa spread the bacteria when they use their piercing-sucking mouthparts to feed on plant xylem, where X. fastidiosa colonizes and multiplies. (Photo credit: Lisa Overall, Ph.D.)

As in California, the glassy-winged sharpshooter (Homalodisca vitripennis) is the most important vector of diseases caused by X. fastidiosa in the southern United States, but Overall’s research identifies a dozen other species that have been shown to vector the pathogen across the South, as well as some that reach the East Coast or even north into Canada. They include several species of sharpshooters in the family Cicadellidae, as well as three species of spittlebugs in the family Cercopidae.

Growers can employ a range of integrated pest management methods for glassy-winged sharpshooter, such as applications of imidacloprid and dinotefuran, screen barriers, and parasitoid wasps of the genus Gonatocerus. Researchers have also found that introducing a modified version of the glassy-winged sharpshooter’s gut bacteria through feeding can reduce its ability to transmit X. fastidiosa.

The JIPM profile also compiles various agricultural methods for reducing the spread of X. fastidiosa—a tricky pathogen that Overall and Rebek note is the only known insect-transmitted pathogen that can both reproduce in the insect’s foregut and spread to other plant hosts without first passing through the insect’s digestive tract. Rebek says the research will prove useful to growers in the southern United States.

“The Journal of Integrated Pest Management offers an ideal venue for publishing this type of work that typically ends up sitting on a shelf, unseen by most extension practitioners and stakeholders who can use the valuable information contained within a thesis,” he says.

Read More

Insect Vectors and Current Management Strategies for Diseases Caused by Xylella fastidiosa in the Southern United States

Journal of Integrated Pest Management

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From Pestnet

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2017/065 First reports of a new bacterial leaf blight of rice caused by Pantoea anana and Pantoea stewartii in Benin and Togo

In Benin, surveys were carried out from 2011 to 2015 in rice fields to assess the importance of bacterial leaf blight caused by Xanthomonas oryzae pv. oryzae (EPPO A1 List). Symptomatic leaf samples were collected and tested. As all isolates gave negative results in a multiplex PCR test for X. oryzae, further studies were conducted and revealed the presence of bacteria belonging to the genus Pantoea. Molecular and pathogenicity tests (to fulfill Koch’s postulates) confirmed that the bacteria which had been isolated from rice leaves were P. ananatis and P. stewartii (EPPO A2 List). It is noted that symptoms were  observed in all surveyed localities (14 sites) with a disease incidence varying from 30 to 100%. In Togo, surveys were also carried out in 2013 and 2014 in the main rice-growing regions (Kovié and Kpalimé) to evaluate the prevalence of plant-pathogenic bacteria. Rice leaves showing characteristic symptoms of bacterial leaf blight were collected and tested. Similarly, the bacteria which were isolated from rice leaves and grains were shown to be P. ananatis and P. stewartii. According to the authors, this is the first time that P. ananatis and P. stewartii species are found causing a leaf blight disease on rice crops in Benin and Togo. According to the EPPO Secretariat this is also the first time that P. stewartii is reported from Africa.

Source: Kini K, Agnimonhan R, Afolabi O, Milan B, Soglonou B, Gbogbo V, Koebnik R, Silué D (2017) First report of a new bacterial leaf blight of rice caused by Pantoea ananatis and Pantoea stewartii in Benin. Plant Disease 101(1), p 242. Kini K, Agnimonhan R, Afolabi O, Soglonou B, Silué D, Koebnik R (2017) First report of a new bacterial leaf blight of rice caused by Pantoea ananatis and Pantoea stewartii in Togo. Plant Disease 101(1), 241-242.

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From Pestnet

USDA releases proposals to fight citrus greening & diamondback moths

In the past two weeks, USDA’s Animal and Plant Health Inspection Service (APHIS) has released documents on proposals to release two genetically modified (GM) organisms: diamondback moths and a virus designed to control the citrus greening disease attacking the citrus industry.

DB moth

Diamondback moths are a global pest of cruciferous crops such as broccoli, Brussel sprouts and cabbage. On April 18, the USDA released a draft environmental assessment of a proposed experiment by a Cornell entomologist with GM diamondback moths.

The scientist, Anthony Shelton, plans to release tens of thousands of GM moths into a 10-acre vegetable field to test their potential as an “insecticide-free” control option for diamondback moths. The GM moths have been engineered to repress female survival, known as a “female autocidal trait.”

You can read the full assessment which concludes it will have no harmful effects here.

Citrus Greening
A Florida nursery, Southern Gardens Citrus Nursery, is proposing the release of a GM virus, Citrus tristeza virus, which has been engineered to express bacteria-fighting proteins found in spinach. The GM virus, which has been undergoing controlled field tests since 2010, would be grafted — not sprayed — onto citrus trees in Florida. USDA has announced its intent to launch an environmental impact statement on Southern Garden’s proposal.

source: dtnpf.com

Publication date: 4/25/2017

Diamondback moths are a global pest of cruciferous crops such as broccoli, Brussel sprouts and cabbage. On April 18, the USDA released a draft environmental assessment of a proposed experiment by a Cornell entomologist with GM diamondback moths.

The scientist, Anthony Shelton, plans to release tens of thousands of GM moths into a 10-acre vegetable field to test their potential as an “insecticide-free” control option for diamondback moths. The GM moths have been engineered to repress female survival, known as a “female autocidal trait.”

You can read the full assessment which concludes it will have no harmful effects here.

Citrus Greening
A Florida nursery, Southern Gardens Citrus Nursery, is proposing the release of a GM virus, Citrus tristeza virus, which has been engineered to express bacteria-fighting proteins found in spinach. The GM virus, which has been undergoing controlled field tests since 2010, would be grafted — not sprayed — onto citrus trees in Florida. USDA has announced its intent to launch an environmental impact statement on Southern Garden’s proposal.

source: dtnpf.com

Publication date: 4/25/2017

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