Applications of Germicidal Ultraviolet Light as a Tool for Fire Blight Management () in Apple Plantings.

Nighttime applications of germicidal UV light (UV-C) have been used to suppress several fungal diseases of plants, but less is known of UV-C's potential to suppress bacterial plant pathogens. Fire blight of apple and pear, caused by the bacterium , is difficult to suppress using cultural practices, antibiotics, and host resistance. We therefore investigated the potential of UV-C as an additional means to manage the disease.

Multisite Field Evaluation of Bacteriophages for Fire Blight Management: Incorporation of Ultraviolet Radiation Protectants and Impact on the Apple Flower Microbiome.

Fire blight, a disease of pome fruits caused by the bacterium , has become increasingly difficult to manage after the emergence of streptomycin-resistant strains. Alternative antibiotics and copper are available; however, these chemicals have use restrictions in some countries and also can carry risks of phytotoxicity. Therefore, there is growing interest in biological-based management options, with bacteriophage (phages) showing promise, as these naturally occurring pathogens of bacteria are easy to isolate and grow.

Type III Secretion System Inhibitors Reduce Fire Blight Infection Under Field Conditions.

Fire blight, caused by , is an economically important disease in apples and pears worldwide. This pathogen relies on the type III secretion system (T3SS) to cause disease. Compounds that inhibit the function of the T3SS (T3SS inhibitors) have emerged as alternative strategies for bacterial plant disease management, as they block bacterial virulence without affecting growth, unlike traditional antibiotics.

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.

Assessment of Fungicide Resistance via Molecular Assay in Populations of , Causal Agent of Apple Powdery Mildew, in New York.

, causal agent of apple powdery mildew, is a pathogen endemic worldwide where apples are produced. In the absence of durable host resistance, the disease is most effectively managed in conventional orchards with single-site fungicides. In New York State, increasingly erratic precipitation patterns and warmer temperatures due to climate change may create a regional environment more conducive to apple powdery mildew development and spread.

Refining Management of Apple Powdery Mildew in New York State with Weather-Based Fungicide Application Timing Programs.

In the absence of durable host resistance among commercial cultivars, chemical management continues to be an essential component of disease control in apple production. Apple powdery mildew, caused by the ascomycete , is largely managed with regular fungicide applications from the host phenological stages of tight cluster to terminal bud growth set, with applications typically being made in a prophylactic manner irrespective of existing disease pressure. Here we evaluated two management programs that aligned fungicide applications to specific weather thresholds conducive to powdery mildew development using a rotation of single-site fungicides and sulfur.

Would You Like Wood or Plastic? Bin Material, Sanitation Treatments, and Bin Inoculum Levels Impact Blue Mold Decay of Stored Apple Fruit.

Blue mold, caused primarily by , is a significant postharvest disease of apples. It not only causes economic losses but also produces mycotoxins that contaminate processed fruit products, which contributes to food waste and loss. Previous research has shown that packing and storage bins harbor spores and that steam and hot water efficiently reduce spore inoculum levels.

Optimizing Use of DMI Fungicides for Management of Apple Powdery Mildew Caused by in New York State.

Powdery mildew, caused by the ascomycete , is an endemic disease found wherever apples are grown that reduces both tree vigor and fresh market yield. In the absence of durable host resistance, chemical management is the primary means of disease control. Demethylation inhibitor (DMI) fungicides are widely used to manage apple powdery mildew, but members within this fungicide class have been observed to differ in efficacy with respect to disease control.

Investigating the Distribution of Strains of and Streptomycin Resistance in Apple Orchards in New York Using Clustered Regularly Interspaced Short Palindromic Repeat Profiles: A 6-Year Follow-Up.

Fire blight, caused by the bacterium , is one of the most important diseases of apple. The antibiotic streptomycin is routinely used in the commercial apple industries of New York (NY) and New England to manage the disease. In 2002 and again, from 2011 to 2014, outbreaks of streptomycin resistance (SmR) were reported and investigated in NY.

Global transcriptomic responses orchestrate difenoconazole resistance in Penicillium spp. causing blue mold of stored apple fruit.

Background: Blue mold is a globally important and economically impactful postharvest disease of apples caused by multiple Penicillium spp. There are currently four postharvest fungicides registered for blue mold control, and some isolates have developed resistance manifesting in decay on fungicide-treated fruit during storage. To date, mechanisms of fungicide resistance have not been explored in this fungus using a transcriptomic approach.

Assessing and Minimizing the Development and Spread of Fire Blight Following Mechanical Thinning and Pruning in Apple Orchards.

The adoption of mechanical thinning and pruning in commercial apple orchards has been limited largely by the risk of development and spread of fire blight. This devastating disease, caused by the bacterial pathogen , may be transmitted by mechanical injury such as pruning, especially under warm, moist conditions conducive to bacterial growth, infection, and disease development. However, risk may be mitigated by avoiding highest-risk times and applying a bactericide, such as streptomycin, after mechanical thinning or pruning.

The Effects of Succinate Dehydrogenase Inhibitor Fungicide Dose and Mixture on Development of Resistance in .

Understanding how fungicide application practices affect selection for fungicide resistance is imperative for continued sustainable agriculture. Here, we examined the effect of field applications of the succinate dehydrogenase inhibitor (SDHI) fluxapyroxad at different doses and mixtures on the SDHI sensitivity of , the apple scab pathogen. Fungicide applications were part of selection programs involving different doses (high or low) and mixtures (with a second single-site fungicide or a multisite fungicide).

Management of Fire Blight Using Pre-bloom Application of Prohexadione-Calcium.

Fire blight, a bacterial disease of rosaceous plants caused by , is one of the most important diseases affecting commercial apple production worldwide. Antibiotics, applied at bloom to protect against blossom infection, are the most effective means of management but raise concern due to the potential for antibiotic resistance in both the pathogen population and nontarget organisms. In addition, most fire blight outbreaks in New York State often emerge in late June to July as shoot blight, calling into question the role of blossom infections and the antibiotic applications made to manage them.

A Genome Resource for Several North American Isolates with Multiple Fungicide Resistance Phenotypes.

The apple scab pathogen, , is among the most economically important fungal pathogens that affects apples. Fungicide applications are an essential part of disease management. Implementation of cultural practices and genetic sources of resistance in the host are vital components of scab management.

Behavioral evidence for contextual olfactory-mediated avoidance of the ubiquitous phytopathogen Botrytis cinerea by Drosophila suzukii.

Herbivorous insects may benefit from avoiding the smell produced by phytopathogens infecting plant host tissue if the infected tissue reduces insect fitness. However, in many cases the same species of phytopathogen can also infect host plant tissues that do not directly affect herbivore fitness. Thus, insects may benefit from differentiating between pathogen odors emanating from food and nonfood tissues.

Characterization of the and Genes in , and Sensitivity to Fluxapyroxad, Pydiflumetofen, Inpyrfluxam, and Benzovindiflupyr.

Succinate dehydrogenase inhibitors (SDHI) are an important class of fungicides for management of apple scab, especially as resistance to other classes of fungicides has become prevalent in the northeastern United States. Considering their single-site mode of action, there is high risk of resistance development to SDHI fungicides. Such risk mandates the need for proper monitoring of shifts in population sensitivity.

Baseline Sensitivity of Penicillium spp. to Difenoconazole.

Penicillium spp. cause blue mold of stored pome fruit. These fungi reduce fruit quality and produce mycotoxins that are regulated for processed fruit products.

Paecilomyces niveus: Pathogenicity in the Orchard and Sensitivity to Three Fungicides.

Paecilomyces rot of apples is a postharvest disease caused by the thermotolerant fungus Paecilomyces niveus (Byssochlamys nivea). The etiology of disease and the activity of fungicides against P. niveus are not yet well understood.

Xylosandrus germanus (Coleoptera: Curculionidae: Scolytinae) Occurrence, Fungal Associations, and Management Trials in New York Apple Orchards.

Xylosandrus germanus (Blandford) has caused increasing damage in high-density New York apple orchards since 2013, resulting in tree decline and death. We documented their occurrence and timing in > 50 orchards using ethanol-baited traps from 2014 to 2016. First captures ranged from 48 to 83 degree days (base 10 °C) from 1 January.

Fire Blight Symptomatic Shoots and the Presence of Erwinia amylovora in Asymptomatic Apple Budwood.

Erwinia amylovora, the causal agent of fire blight, causes considerable economic losses in young apple plantings in New York on a yearly basis. Nurseries make efforts to only use clean budwood for propagation, which is essential, but E. amylovora may be present in trees that appear to have no apparent fire blight symptoms at the time of collection.

Resistance to Increasing Chemical Classes of Fungicides by Virtue of "Selection by Association" in Botrytis cinerea.

Previous research has shown that Botrytis cinerea isolates with resistance to multiple chemical classes of fungicides exist in eastern strawberry fields. In this study, the fungicide resistance profiles of 2,130 isolates from flowers of commercial strawberry fields located in multiple states was determined over four consecutive strawberry production seasons. Producers were asked to alternate single-site fungicides that were considered low risk in their specific location based on resistance monitoring results in their fields.

Molecular Characterization of the sdhB Gene and Baseline Sensitivity to Penthiopyrad, Fluopyram, and Benzovindiflupyr in Venturia inaequalis.

The succinate dehydrogenase inhibiting (SDHI) fungicides are a class of single-site fungicides that are increasingly important in the management of Venturia inaequalis. In this study, the baseline sensitivity of V. inaequalis to penthiopyrad, fluopyram, and benzovindiflupyr was investigated.

Overexpression of the CYP51A1 Gene and Repeated Elements are Associated with Differential Sensitivity to DMI Fungicides in Venturia inaequalis.

The involvement of overexpression of the CYP51A1 gene in Venturia inaequalis was investigated for isolates exhibiting differential sensitivity to the triazole demethylation inhibitor (DMI) fungicides myclobutanil and difenoconazole. Relative expression (RE) of the CYP51A1 gene was significantly greater (P < 0.0001) for isolates with resistance to both fungicides (MRDR phenotype) or with resistance to difenoconazole only (MSDR phenotype) compared with isolates that were resistant only to myclobutanil (MRDS phenotype) or sensitive to both fungicides (MSDS phenotype).

Prevalence of Myclobutanil Resistance and Difenoconazole Insensitivity in Populations of Venturia inaequalis.

Demethylation inhibitors (DMIs) are a class of single-site fungicides with high levels of protective and curative efficacy against Venturia inaequalis, the causal agent of apple scab. To determine the prevalence of resistance to the DMI fungicide myclobutanil, 3,987 single-lesion conidial V. inaequalis isolates from 141 commercial, research, and baseline orchard populations were examined throughout New England, the mid-Atlantic, and the Midwest from 2004 to 2013.