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ARS scientists at the Plum Island Animal Disease Center in Orient Point, NY, have made two important advancements against African swine fever virus, which causes a lethal disease in pigs.

Scientists with the U.S. Department of Agriculture's Agricultural Research Service (ARS) announced that a vaccine candidate for African Swine Fever (ASF) passed an important safety test required for regulatory approval, moving the vaccine one step closer to commercial availability.

Humans adores trees. But humans also migrate and trade, habits that led to the accidental introduction of insects and diseases that harm trees and alter the landscape. Examples are easy to find and may be outside your front door: American elms that once dotted streets across America succumbed to Dutch elm disease. Now all colors of ash species – black, green, white, pumpkin, and blue – are threatened by emerald ash borer. The already uncommon butternut tree, also known as white walnut, faces the possibility of extinction from a mysterious attacker. Many invasive insects and fungi come from regions where native trees have evolved to resist their attacks. When these species enter the United States, they find trees that lack this resistance. There's no immediate end to this dismal pipeline, but there is hope on the horizon.

Agriculture Secretary Tom Vilsack today applauded research and protection efforts underway at the U.S. Department of Agriculture’s (USDA) Agricultural Research Service (ARS) and Animal and Plant Health Inspection Service (APHIS) to prevent the spread of African Swine Fever virus, which has been causing devastating losses to the swine industry across the globe. "USDA agencies are working together to protect U.S. livestock from foreign and emerging animal diseases that could harm our economy and public health," said Secretary Vilsack. "I am proud of the extraordinary research underway at the Agricultural Research Service to develop vaccine candidates to prevent African Swine Fever virus. In addition, the Animal and Plant Health Inspection Service has done tremendous work to establish protection zones to safeguard the entire U.S. swine industry."

African Swine Fever (ASF) was originally detected in 2007 in the Republic of Georgia and is known to cause virulent, deadly disease outbreaks in wild and domesticated swine. Since the original outbreak, ASF has had a widespread and lethal impact on swine herds in various countries in Eastern and Central Europe and throughout Asia. Although the virus is causing profound economic losses to the swine industry, there have not been any U.S. outbreaks.

ITP and the APHIS PPQ S&T Beltsville Lab are pleased to announce the release of IDphy: Molecular and Morphological Identification of Phytopthora Based on the Types, ITP’s first pathogen tool. This website offers PPQ and its partners the most complete, valid, and up-to-date resource for identifying the culturable species of Phytophthora. IDphy includes detailed standard operating procedures for all steps involved in culturing, sequencing, and identifying suspect samples, covering both molecular and morphological methods. Some species of Phytophthora are devastating plant pathogens that have a significant impact on agriculture and natural ecosystems.

A genetic discovery by ARS and University of Florida scientists could speed the search for hybrid citrus trees that tolerate citrus greening disease (Huanglongbing) and produce orange-like fruit ideal for making juice.

Dogs specially trained by Agricultural Research Service (ARS) scientists have proven to be the most efficient way to detect huanglongbing—also known as citrus greening—according to a paper just published in the Proceedings of the National Academy of Sciences. Currently, the only solid hope of curtailing the spread of citrus greening is to eliminate trees with the disease as quickly as possible to prevent further spread. Early detection of the citrus greening pathogen is crucial because trees can be infected and act as a source to spread the disease months or years before showing symptoms that are detectable by the naked eye. ARS plant epidemiologist Timothy R. Gottwald with the U.S. Horticultural Research Laboratory in Fort Pierce, Florida, discovered that dogs can be trained to sniff out the presence of Candidatus Liberibacter asiaticus, the bacteria that causes citrus greening, with greater than 99 percent accuracy.

Meet the Honeysweet Plum: A virus-resistant plum that ARS hopes to bring to market soon. They are large and oblong with a very sweet, flavorful taste. ARS created the Honeysweet variety using RNAi, a biotechnology method that makes them immune to the plum pox virus. Plum pox infects stone fruit trees: plums, peaches, apricots and cherries. Once infected, the fruit discolors and falls from the tree prior to maturation. There is no natural, genetic resistance to the virus.

The yield losses attributed to Asian citrus greening disease once established can be devastating. If the disease continues to spread unabated in the citrus growing regions of East Africa, the annual value of lost production could potentially reach up to US $127 million over the next ten to 15 years, according to a recent paper published by CABI. The paper, The Asian Citrus Greening Disease (Huanglongbing): Evidence Note on Invasiveness and Potential Economic Impacts for East Africa (Jun 2021) [PDF, 2.9 MB], provides a review of the global literature on Asian citrus disease or huanglongbing (HLB) and estimates its potential economic impact on East Africa. The paper also makes recommendations for biosecurity preparedness, surveillance and management options to help decision-makers and citrus growers.

Understanding how wild birds facilitate the maintenance, reassortment, and dispersal of influenza A viruses (IAV) is key to forecasting global disease spread. The current highly pathogenic avian influenza outbreak in North America highlights the question of how viruses are transported between continents. Recent NWHC research sheds light on this question and the potential role Iceland may play.

Boxwood blight is a fungal disease that can cause the leaves of boxwood plants to fall off prematurely. ARS scientists in Fort Dietrick, MD, are studying how boxwood blight evolves and are working closely with the floriculture and nursey industry to develop methods for testing, controlling, and mitigating the disease.

A unique program run by the Agricultural Research Service in Fort Pierce, FL, uses specially trained dogs to detect citrus greening in orchards. The canine-detection method has an accuracy rate of 99 percent.

USDA Forest Service researchers are monitoring the effects of white-nose syndrome, a fungal disease from Eurasia that has decimated cave-hibernating bats across the U.S. since its arrival in 2006. "The fungus that causes white-nose syndrome grows on bats in the wintertime. It causes them to wake up during their hibernation and burn their fat reserves," says Phillip Jordan, wildlife biologist. Jordan is among the experts featured in a new video, Bats on the Brink. Forestry technician Virginia McDaniel created and produced the video.

The Maine Department of Agriculture, Conservation and Forestry has announced an addition to the state's invasive species list. Beech leaf disease, leading to the decline and mortality of beech trees from Ohio to southern New England, has arrived in Maine's forests. The disease was confirmed in leaf samples from a forest in Lincolnville (Waldo County) by Dr. Robert Marra of the Connecticut Agricultural Experiment Station. The Maine Forest Service is asking the public's help in identifying additional areas impacted by beech leaf disease. If you suspect you have found affected leaves submit photos using the MFS tree ailment form, email foresthealth@maine.gov, or call (207) 287-2431. Photos should include a clear shot of the underside of an affected leaf or leaves. However, please report concerns even if photos cannot be provided.

The Michigan departments of Natural Resources and Agriculture and Rural Development today announced the addition of beech leaf disease to the state's invasive species watch list. Invasive species on the watch list have been identified as posing an immediate or potential threat to Michigan's economy, environment or human health. These species either have never been confirmed in the wild in Michigan or have a limited known distribution. Beech leaf disease is associated with the microscopic worm Litylenchus crenatae, a nematode that enters and spends the winter in leaf buds, causing damage to leaf tissue on American beech and European and Asian beech species. Infestations result in darkened, thick tissue bands between leaf veins, creating a striped effect on the leaves, leaf distortion and bud mortality. Trees weakened by leaf damage become susceptible to other diseases and can die within six years. Beech leaf disease has not been found in Michigan. The disease was first discovered in Ohio in 2012. Since then, it has been identified in seven eastern states and Ontario.

Beech leaf disease has now been confirmed in Prince William County – the first detection in Virginia. The disease affects American beech (Fagus grandifolia) trees and is associated with a foliar nematode. Symptoms include dark stripes between leaf veins, thickening and curling of leaves, and canopy thinning. Contact VDOF's forest health program if you see these symptoms. For more information, view this Beech Leaf Disease Pest Alert (Jan 2021) [PDF, 312 KB] publication.

See also: More Information Relating to the First Report of Beech Leaf Disease in Virginia [Aug 2021) [PDF, 951 KB]

This portal shares information about how ARS research is combating the disease that is devastating the citrus industry and provides information for the general public, as well as points of contact for those seeking more specialized answers.

Huanglongbing, also known as citrus greening, poses the most serious threat that the Florida citrus industry has ever faced. ARS scientists across the country are actively engaged in research with university and industry partners on all aspects of this disease problem, including the host, pathogen, and insect vector. Our goal is to overcome citrus greening and ensure the U.S. citrus industry can provide consumers with tasty, high quality citrus fruits for years to come. 

Scientists from the Connecticut Agricultural Experiment Station (CAES) are reporting that Beech Leaf Disease (BLD) has increased dramatically in both severity and distribution in 2022 compared to 2021. First detected in lower Fairfield County in 2019, BLD is now widespread on American beech (Fagus grandifolia) throughout all eight Connecticut counties, with symptoms most severe in Fairfield, New Haven, Middlesex and New London Counties. Given that BLD is now widely established throughout Connecticut, reports of BLD to CAES and DEEP are no longer requested.

Researchers have been working on a solution to fight citrus greening disease and may have found one in the unique antibodies found in camels, llamas, and alpacas.

Environmental DNA (eDNA) has gone from new science on the block to a star of the show. With just a water, soil, or snow sample, ecologist Tommy Franklin and fellow scientists at the Rocky Mountain Research Station are detecting rare aquatic and terrestrial species by identifying the genetic material they leave behind.

Scientists at the Rocky Mountain Research station recently used eDNA to preserve headwater bull trout populations in a warming climate, track white nose syndrome — a killer bat fungus, and reveal the role of human transport in the spread of invasive northern pike in the Columbia River basin. A recent article highlights eDNA research at the station and features National Genomics Center Director Mike Schwartz.