Archive for the ‘Emerging/invasive pests’ Category

As Georgia’s corn crop enters the tassel stage, farmers are weighing whether to make a fungicide application. And Asian soybean rust is in the state now, the earliest the troubling disease has been detected in Georgia in more than a decade.

The Asian soybean rust was confirmed in Miller County, Ga, located in southwest Georgia May 17, and this means the disease will likely be problematic for Georgia soybean producers this year, said Bob Kemerait, University of Georgia Extension plant pathologist. Growers are advised to stay alert and scout soybean fields. Current conditions favor the spread of the disease within kudzu.

And as Georgia corn progresses, rapidly entering the tassel stage, Kemerait advises growers, at the least the more disease aggressive growers, to consider a protective fungicide application. “This is especially true if southern corn rust has been detected in the area, if northern corn leaf BLIGHT is problematic in a field (typically with a less-resistant hybrid), conditions have been favorable for disease (very wet), the corn was planted LATE or if the grower is aggressive in a disease management program and wants to make sure the crop is protected,” he said.

Kemerait’s further thoughts on corn disease management at this time for Georgia are:

  • As of May 17, we have not found SOUTHERN CORN RUST in Georgia and conditions have not been especially favorable for southern rust.
  • As of May 17, we have had one report of common corn rust from Mitchell County. Common rust typically forms pustules on both sides of the leaf and does NOT need a fungicide application.
  • As of May 17, the only report of northern corn leaf BLIGHT in Georgia is from Ty Torrance in Decatur County. Northern corn leaf blight can be an important problem that requires a fungicide treatment IF it is severe (e.g., a susceptible variety and favorable weather). The NCLB in Decatur County was confined to the bottom leaves and there were only a few lesions on about one plant out of 15. The grower is right to be aware of the problem but I do not think a fungicide is needed for NCLB in that particular field.
  • Northern corn leaf SPOT has been found in Mitchell County by Andy Shirley.  Typically we do not spray for this disease, except in severe cases. The northern corn leaf spot in this field was confined to the lower leaves and did not appear to be spreading.
  • We have not detected southern corn rust in Georgia yet. Conditions over the next few days are more favorable for disease spread, but (overall) conditions have been unfavorable. I would not argue with a grower who wants to apply a fungicide at this time (to corn) as it reaches the tasseling growth stage; HOWEVER I think the grower is better advised to DELAY a fungicide application at this point and wait at least a week or so.

Information in this article courtesy of Andrew Sawyer, UGA Extension agent in Thomas County, at Thomas County Ag.

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Tuta absoluta  tuta S american

Symposium: Global Spread and Management of the South American Tomato Leafminer, Tuta absoluta

Tuesday, September 27, 2016  09:15 AM – 12:00 PM

Organizers: IPM Innovation Lab and IAPPS

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Emerald ash borer

Minn. Dept. of Natural Resources/AP/File

The Emerald ash borer is one of the non-native insects wreaking havoc in forests throughout the country.

By David Abel Globe Staff  May 10, 2016

Most arrive as stowaways on the wooden pallets and crates that help transport some 25 million shipping containers into the United States each year.

The invasive forest pests are ravaging forests and urban canopy throughout the country and cost property owners and communities, especially in the Northeast, as much as $2 billion a year, according to a study released Tuesday by the journal Ecological Applications.

The steady march across the continent of the Emerald ash borer, Asian longhorned beetle, hemlock wooly adelgid, and other non-native insects have been wreaking havoc that requires urgent solutions, said the authors of the study, which they called the most comprehensive review of forest pests in the US to date.

The pests, which also enter the country on plants that are destined for nurseries, have taken an especially harsh toll on trees in Massachusetts. Massachusetts has 57 types of pests, more than every other state but New York and Pennsylvania.

“The introductions of invasive pests that we continue to have is unacceptable,” said Dave Orwig , a forest ecologist at Harvard Forest in Petersham and one of 16 authors of the paper. “We’re just not doing enough.”

There are more than 400 forest pests in the country, and every state has invasive insects and pathogens. Louisiana has the fewest, with 12, while New York has the most, with 62.

Imported insects

Despite federal efforts to prevent their entry, such as having ports spray pallets with pesticides, between two and three new forest pests, on average, arrive in the country every year, Orwig said.

In Massachusetts, the pests include winter moths, which have devastated forests in the eastern part of the state; oak crypt gall wasps, which have been killing black oaks to the south and the islands; and a range of others, including the emerald ash borer, which has killed billions of dollars worth of ash trees across the country and was first found in Massachusetts in the Berkshires town of Dalton in 2012.

The state’s trees have also suffered from a range of pathogens, including butternut canker, dogwood anthracnose, Dutch elm disease, and beech bark disease.

Elsewhere in the state, hemlock wooly adelgid, a small insect, are killing many of the state’s hemlock trees, while Asian longhorned beetles have devastated red maples, especially in Worcester, where authorities have removed more than 34,000 trees at a cost of about $150 million, Orwig said.

“It looked like a hurricane had struck the city,” he said of Worcester. “It will take decades or more for the community to recover the benefits of the trees.”

David Abel can be reached at dabel@globe.com. Follow him on Twitter @davabel.

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NATURE International weekly journal of science

Devastating wheat fungus appears in Asia for first time

Scientists race to determine origin of  Bangladesh outbreak, which they warn could spread farther afield.

27 April 2016 Updated:

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Ruth Fremson/NYT/eyevine

Wheat in northern India could be threatened by an outbreak of fungal disease in Bangladesh.

Update: On 26 April, a team led by microbial population geneticist Daniel Croll, who is at the Swiss Federal Institute of Technology in Zurich, reported on github.com that the Bangladeshi wheat-blast strain is closely related to those collected in Brazilian wheat fields and on nearby weeds. His team’s analysis, which uses the data on the website Open Wheat Blast, reveals that the sample is not closely related to known rice-blast-causing strains of M. oryzae. Croll’s team concludes that wheat blast was probably introduced to Bangladesh from Brazil, and warns that other Asian countries that import Brazilian wheat, including Thailand, the Philippines and Vietnam, should be on the lookout for the disease.

Fields are ablaze in Bangladesh, as farmers struggle to contain Asia’s first outbreak of a fungal disease that periodically devastates crops in South America. Plant pathologists warn that wheat blast could spread to other parts of south and southeast Asia, and are hurrying to trace its origins.

“It’s important to know what the strain is,” says Sophien Kamoun, a biologist at the Sainsbury Laboratory in Norwich, UK, who has created a website, Open Wheat Blast (go.nature.com/bkczwf), to encourage researchers to share data.

Efforts are also under way to find wheat genes that confer resistance to the disease.

First detected in February and confirmed with genome sequencing by Kamoun’s lab this month, the wheat-blast outbreak has already caused the loss of more than 15,000 hectares of crops in Bangladesh. “It’s really an explosive, devastating disease,” says plant pathologist Barbara Valent of Kansas State University in Manhattan, Kansas. “It’s really critical that it be controlled in Bangladesh.”

After rice, wheat is the second most cultivated grain in Bangladesh, which has a population of 156 million people. More broadly, inhabitants of south Asia grow 135 million tonnes of wheat each year.

Wheat blast is caused by the fungus Magnaporthe oryzae. Since 1985, when scientists discovered it in Brazil’s Paraná state, the disease has raced across South America.

The fungus is better known as a pathogen of rice. But unlike in rice, where M. oryzae attacks the leaves, the fungus strikes the heads of wheat, which are difficult for fungicides to reach. A 2009 outbreak in wheat cost Brazil one-third of that year’s crop. “There are regions in South America where they don’t grow wheat because of the disease,” Valent says. Wheat blast was spotted in Kentucky in 2011, but vigorous surveillance helped to stop it spreading in the United States.

In South America, the disease tends to take hold in hot and humid spells. Such conditions are present in Bangladesh, and the disease could migrate across south and southeast Asia, say plant pathologists. In particular, it could spread over the Indo-Gangetic Plain through Bangladesh, northern India and eastern Pakistan, warn scientists at the Bangladesh Agricultural Research Institute (BARI) in Nashipur.

Bangladeshi officials are burning government-owned wheat fields to contain the fungus, and telling farmers not to sow seeds from infected plots. The BARI hopes to identify wheat varieties that are more tolerant of the fungus and agricultural practices that can keep it at bay, such as crop rotation and seed treatment.

Guillermo Isidoro Barea Vargas

Wheat blast strikes the heads of wheat, which are difficult for fungicides to reach.

It is unknown how wheat blast got to Bangladesh. One possibility is that a wheat-infecting strain was brought in from South America, says Nick Talbot, a plant pathologist at the University of Exeter, UK. Another is that an M. oryzae strain that infects south Asian grasses somehow jumped to wheat, perhaps triggered by an environmental shift: that is what happened in Kentucky, when a rye-grass strain infected wheat.

To tackle the question, this month Kamoun’s lab sequenced a fungus sample from Bangladesh. The strain seems to be related to those that infect wheat in South America, says Kamoun, but data from other wheat-infecting strains and strains that plague other grasses are needed to pinpoint the outbreak’s origins conclusively.

The Open Wheat Blast website might help. Kamoun has uploaded the Bangladeshi data, and Talbot has deposited M. oryzae sequences from wheat in Brazil. Talbot hopes that widely accessible genome data could help to combat the outbreak. Researchers could use them to screen seeds for infection or identify wild grasses that can transmit the fungus to wheat fields.

Rapid data sharing is becoming more common in health emergencies, such as the outbreak of Zika virus in the Americas. Kamoun and Talbot say that their field should follow suit. “The plant-pathology community has a responsibility to allow data to be used to combat diseases that are happening now, and not worry too much about whether they may or may not get a Nature paper out of it,” says Talbot.

Last month, Valent’s team reported the first gene variant known to confer wheat-blast resistance (C. D. Cruz et al. Crop Sci. http://doi.org/bfk7; 2016), and field trials of crops that bear the resistance gene variant have begun in South America. But plant pathologists say that finding one variant is not enough: wheat strains must be bred with multiple genes for resistance, to stop M. oryzae quickly overcoming their defences.

The work could help in the Asian crisis, says Talbot. “What I would hope for out of this sorry situation,” he says, “is that there will be a bigger international effort to identify resistance genes.”

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Yemen braces for locust ‘plague’

Copyright: Panos/ Dieter Telemans

Speed read

  Many juvenile locusts have matured into flying adults

  • Presence of vital honeybees limits insecticide control efforts
  • Any outbreak could go on to hit Oman, Saudi Arabia, the UAE and Iran

Yemen is bracing itself for a “locust plague” that scientists are unable to stop due to fears that any intervention would also kill bees that are vital to its economy.

The country’s Desert Locust Control Centre issued a warning on 18 April that many desert locusts in the country had reached their flying adult phase, while the remaining juveniles could do likewise in a matter of weeks.

The centre says control efforts this month, especially in the southern coastal province of Shabwah, have largely failed. Yemen is already struggling under the weight of civil war, which has made many affected areas unsafe.

“The intervention process to control locusts through insecticide spraying was very difficult due to a number of obstacles, the most important of which were the security aspect and the presence of beehives,” says Ahmed Al-Eryani, a spokesman for the centre. This is because pesticide spraying is likely to kill the bee populations crucial to the region’s agriculture and honey production, he explains.

“The expected locust plague portends a true disaster which will negatively affect food security in all districts of Yemen and may extend beyond its borders.”

Salah Hajj, FAO

Yemen’s civil war has made it difficult for scientists to reach some areas to carry out regular monitoring and control efforts. As a result, teams have been unable to kill substantial amounts of juvenile locusts to prevent them becoming adults, the centre says.

The UN’s Food and Agriculture Organization (FAO) has warned that the locust outbreak threatens the country’s farming. It added that the locusts could reach neighbouring countries, including Oman and Saudi Arabia, and even the United Arab Emirates and Iran.

Adult desert locusts can withstand extreme heat and drought, and travel up to 150 kilometres a day.

Swarms inflict heavy losses on crops. According to the FAO, even a small swarm — which might cover one square kilometre and contain about 40 million locusts — can eat as much food in a day as 35,000 people.

– See more at: http://www.scidev.net/global/food-security/news/yemen-locust-plague-desert.html?utm_medium=email&utm_source=SciDevNewsletter&utm_campaign=international%20SciDev.Net%20update%3A%203%20May%202016#sthash.0q2r5hzS.dpuf

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Southwest Farm Press Daily

Survey will collect data resistant pigweed control systems

  • Survey to gauge extent of herbicide resistant problem

Texas AgriLife survey will gather information on herbicide resistant pigweed.

“Glyphosate resistant Palmer amaranth has caused costly impacts on cotton production in many areas of the Cotton Belt,” according to the PCG report. “The team at Texas A&M AgriLife Extension is conducting a survey to determine weed management systems commonly used by growers, as well as the current extent of glyphosate resistance. They sent a survey about this time last year, but need to collect one more year of data to complete the study.”

The Extension team solicits farmer support in collecting data to help gauge the extent of glyphosate resistant Palmer amaranth in West Texas. “Results from the survey will be used by the Texas A&M AgriLife Extension Weed Science Team to guide research efforts and provide better information to cotton producers.”

The PCG report notes that producers can complete the survey in three to give minutes. “Participation is voluntary; you may skip any question or quit the survey at any time. No personal information will be collected.”

The survey can be reached by link below; simply enter the password “pigweed” to access the survey questions. Survey link

Contact Rand Merchant at rand.merchant@ag.tamu.edu if you have any questions.

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