A rapid LAMP assay for the diagnosis of oak wilt with the naked eye.

Background: Oak wilt disease, caused by Bretziella fagacearum is a significant threat to oak (Quercus spp.) tree health in the United States and Eastern Canada. The disease may cause dramatic damage to natural and urban ecosystems without management.

Mechanistic links between physiology and spectral reflectance enable previsual detection of oak wilt and drought stress.

Tree mortality due to global change-including range expansion of invasive pests and pathogens-is a paramount threat to forest ecosystems. Oak forests are among the most prevalent and valuable ecosystems both ecologically and economically in the United States. There is increasing interest in monitoring oak decline and death due to both drought and the oak wilt pathogen ().

A Global Assessment of the State of Plant Health.

The Global Plant Health Assessment (GPHA) is a collective, volunteer-based effort to assemble expert opinions on plant health and disease impacts on ecosystem services based on published scientific evidence. The GPHA considers a range of forest, agricultural, and urban systems worldwide. These are referred to as (Ecoregion × Plant System), i.

Vacuum Steam Treatment of Logs for Eradication of and .

A new and devastating disease, rapid ohia death (ROD), in Hawaii led to a state quarantine that regulates interisland transport of ohia wood and plant material to prevent spread of the causal pathogens. Heat treatments of ohia logs in commercial trade were considered for phytosanitary treatment. Vacuum steam (VS) was evaluated for its ability to eradicate the pathogens, and , in main stem logs from ROD-affected forest trees.

Vacuum Steam Treatment Effectiveness for Eradication of the Thousand Cankers Disease Vector and Pathogen in Logs From Diseased Walnut Trees.

Logs of high-value eastern black walnut (Juglans nigra L.) are commonly exported from the United States for production of veneer and lumber. Veneer logs are not debarked to minimize degradation of wood quality and reduce moisture loss.

Spectral differentiation of oak wilt from foliar fungal disease and drought is correlated with physiological changes.

Hyperspectral reflectance tools have been used to detect multiple pathogens in agricultural settings and single sources of infection or broad declines in forest stands. However, differentiation of any one disease from other sources of tree stress is integral for stand and landscape-level applications in mixed species systems. We tested the ability of spectral models to differentiate oak wilt, a fatal disease in oaks caused by Bretziella fagacearum ``Bretz'', from among other mechanisms of decline.

Effect of Bark Application With Beauveria bassiana and Permethrin Insecticide on the Walnut Twig Beetle (Coleoptera: Curculionidae) in Black Walnut Bolts.

Formulations of entomopathogenic (insect-killing) fungi represent alternatives to synthetic insecticides in the management of forest and shade tree insects. We evaluated bark spray applications of the entomopathogen Beauveria bassiana (Balsamo) Vuillemin (Hypocreales: Cordycipitaceae) strain GHA (BotaniGardES), permethrin insecticide (Astro), and water (control) on colonization of black walnut (Juglans nigra L.) (Fagales: Juglandaceae) bolts by the walnut twig beetle (Pityophthorus juglandis Blackman) (Coleoptera: Curculionidae), vector of the fungus that causes thousand cankers disease.

Vacuum Steam Treatment Eradicates Viable Bretziella fagacearum from Logs Cut from Wilted Quercus rubra.

Methyl bromide (MB) fumigation is required for U.S. Quercus log exports due to concern over unintentional spread of Bretziella fagacearum.

Seasonal and Regional Distributions, Degree-Day Models, and Phoresy Rates of the Major Sap Beetle (Coleoptera: Nitidulidae) Vectors of the Oak Wilt Fungus, Bretziella fagacearum, in Wisconsin.

Oak wilt is a lethal disease caused by the invasive fungus Bretziella fagacearum, which is transmitted belowground via root grafts and aboveground by sap beetles (Nitidulidae). Attempts to limit spread and impact of B. fagacearum emphasize limiting harvesting and pruning to periods of vector inactivity.

Rapid and PCR-free DNA Detection by Nanoaggregation-Enhanced Chemiluminescence.

The aggregation of gold nanoparticles (AuNPs) is known to induce an enhancement of localized surface plasmon resonance due to the coupling of plasmonic fields of adjacent nanoparticles. Here we show that AuNPs aggregation also causes a significant enhancement of chemiluminescence in the presence of luminophores. The phenomenon is used to introduce a rapid and sensitive DNA detection method that does not require amplification.

Use of Nested and Real-Time PCR for the Detection of Ceratocystis fagacearum in the Sapwood of Diseased Oak Species in Minnesota.

Oak wilt caused by Ceratocystis fagacearum is a significant disease of Quercus spp. in the eastern United States. Early and accurate detection of the pathogen is particularly important when disease control is planned.

Colonization of Artificially Stressed Black Walnut Trees by Ambrosia Beetle, Bark Beetle, and Other Weevil Species (Coleoptera: Curculionidae) in Indiana and Missouri.

Thousand cankers disease (TCD) is a new disease of black walnut (Juglans nigra L.) in the eastern United States. The disease is caused by the interaction of the aggressive bark beetle Pityophthorus juglandis Blackman and the canker-forming fungus, Geosmithia morbida M.

Multiple Ceratocystis smalleyi infections associated with reduced stem water transport in bitternut hickory.

Hundreds of cankers caused by Ceratocystis smalleyi are associated with hickory bark beetle-attacked bitternut hickory exhibiting rapid crown decline in the north-central and northeastern United States. Discolored sapwood colonized by the fungus commonly underlies the cankers. Field studies were conducted to test the hypothesis that C.

Fusarium Canker of Bitternut Hickory Caused by Fusarium solani in the North-Central and Northeastern United States.

Multiple annual cankers were observed on the upper main stems of bitternut hickory (Carya cordiformis) exhibiting top dieback in Indiana, Iowa, Minnesota, New York, Ohio, and Wisconsin during a 2006 to 2008 survey of declining hickory. The top-killed trees had normal-sized, green leaves below and the cankers were oval, sunken, and bounded by heavy callus that seemed to arrest further canker expansion. Fusarium solani was consistently isolated from the margins of inner bark lesions or discolored sapwood of the cankers.

Decline as a disease category: is it helpful?

Many, but not all, forest pathologists use "decline" to describe forest tree diseases of complex etiology. We contend that this distinction from abiotic or biotic diseases is completely arbitrary, has caused undue confusion, and provides no practical insights for forest managers. All diseases are complex and can be characterized within the conceptual framework of the disease triangle.

Propiconazole distribution and effects on Ceratocystis fagacearum survival in roots of treated red oaks.

We investigated the interaction between the oak wilt pathogen (Ceratocystis fagacearum) and propiconazole in lower stems and roots of Quercus rubra to better understand published reports of fungicide failure after 2 years. Propiconazole was infused into mature oaks in July 2004 and roots were inoculated with pathogen endoconidia 1.0 m from injection sites at ±2 weeks of fungicide treatment.

Ceratocystis Canker of Bitternut Hickory Caused by Ceratocystis smalleyi in the North-Central and Northeastern United States.

Between 2006 and 2008, diffuse cankers without surrounding callus and callus-edged sunken cankers were observed on main stems of poletimber (13 to 28 cm in diameter at 1.4 m high) and sawtimber (>28 cm in diameter) bitternut hickory (Carya cordiformis) in Iowa, Indiana, Minnesota, New York, Ohio, and Wisconsin. Reddish, inner bark necrosis and reddish brown sapwood discoloration were associated with the cankers.

The origin of Ceratocystis fagacearum, the oak wilt fungus.

The oak wilt pathogen, Ceratocystis fagacearum, may be another example of a damaging, exotic species in forest ecosystems in the United States. Though C. fagacearum has received much research attention, the origin of the fungus is unknown.

Three Colopterus Beetle Species Carry the Oak Wilt Fungus to Fresh Wounds on Red Oak in Missouri.

Beetles in the family Nitidulidae can transmit the oak wilt fungus, Ceratocystis fagacearum, to fresh wounds on healthy oak trees, leading to infection and disease development. Historically, nitidulid beetles have not been considered important vectors of the pathogen in Missouri. Studies were conducted in the spring of 2005 and 2006 to determine frequencies of nitidulid beetle species contaminated with C.

Phytophthora spp. Associated with Forest Soils in Eastern and North-Central U.S. Oak Ecosystems.

A survey of soils associated with oak species was conducted in 2003 and 2004 in Indiana, Illinois, Maryland, Michigan, Minnesota, Pennsylvania, Ohio, West Virginia, and Wisconsin to investigate the occurrence of Phytophthora spp. Soils taken from around the base of healthy and declining oak trees were flooded with HO and Quercus robur leaflets were used as bait for Phytophthora spp. From 829 soil samples collected near trees, 21% were positive for Phytophthora spp.

Phytophthora Species in Soils Associated with Declining and Nondeclining Oaks in Missouri Forests.

Periodic episodes of oak decline have occurred in the Missouri Ozark forests since the early 1900s and the disease is currently severe (2). Several Phytophthora spp. contribute to oak decline in Europe (1), but the role of Phytophthora spp.

First Report of Phytophthora europaea in Oak Forests in the Eastern and North-Central United States.

In 2003 and 2004, soils in oak forest ecosystems in nine central and eastern states of the United States were surveyed for Phytophthora spp. Soil samples were collected around healthy and symptomatic trees. Symptoms included dieback of branches, gaps in lateral branch systems, yellowing of foliage, wilting and clustering of leaves, and the presence of epicormic shoots.

Fumigant distribution in forest nursery soils under water seal and plastic film after application of dazomet, metam-sodium and chloropicrin.

Adequate concentration, exposure time and distribution uniformity of activated fumigant gases are prerequisites for successful soil fumigation. Field experiments were conducted to evaluate gas phase distributions of methyl isothiocyanate (MITC) and chloropicrin (CP) in two forest-tree nurseries. Concentrations of MITC and CP in soil air were measured from replicated microplots that received dazomet, metam-sodium and CP.