Postharvest chitosan sprays reduce bitter rot and blue mold on apple fruit.

Chitosan is a natural product that has potential use in agriculture for managing diseases. Chitosan has been shown to effectively suppress storage rots when applied postharvest. Application of chitosan pre- and postharvest has potential to manage both latent and postharvest rots but these effects are not well studied.

Fungicide ingestion reduces net energy gain and microbiome diversity of the solitary mason bee.

Fungicides are frequently used during tree fruit bloom and can threaten insect pollinators. However, little is known about how non-honey bee pollinators such as the solitary bee, Osmia cornifrons, respond to contact and systemic fungicides commonly used in apple production during bloom. This knowledge gap limits regulatory decisions that determine safe concentrations and timing for fungicide spraying.

Systemic pesticides in a solitary bee pollen food store affect larval development and increase pupal mortality.

Solitary bees are often exposed to various pesticides applied for pest control on farmland while providing pollination services to food crops. Increasing evidence suggests that sublethal toxicity of agricultural pesticides affects solitary bees differently than the social bees used to determine regulatory thresholds, such as honey bees and bumblebees. Studies on solitary bees are challenging because of the difficulties in obtaining large numbers of eggs or young larvae for bioassays.

The Rapid Apple Decline Phenomenon: Current Status and Expected Associated Factors in Korea.

Rapid apple decline (RAD) is a complex phenomenon affecting cultivated apple trees and particularly dwarf rootstocks on grafted young apple trees. Since its first appearance in the United States, RAD has been reported worldwide, for example in Canada, South America, Africa, and Asia. The phenomenon has also been observed in apple orchards in Korea, and it presented similar symptoms regardless of apple cultivar and cultivation period.

Spore Dispersal Patterns of in Orchards and the Timing of Apple Bitter Rot Infection Periods.

Bitter rot is a major disease of apple fruit in warm and humid regions. It is caused by various species in the and species complexes, of which of the species complex is most common in the Mid-Atlantic region of the United States. While bitter rot management begins with good cultural practices, fungicides are generally used for consistent control.

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.

Putative transcription antiterminator RfaH contributes to Erwinia amylovora virulence.

The gram-negative bacterium Erwinia amylovora causes fire blight disease of apple and pear trees. The exopolysaccharide amylovoran and lipopolysaccharides are essential E. amylovora virulence factors.

Characterizations of an Emerging Disease: Apple Blotch Caused by (syn. ) in the Mid-Atlantic United States.

Apple orchards with minimal or reduced fungicide inputs in the Mid-Atlantic region of the United States have experienced outbreaks of severe premature defoliation with symptoms that matched those of apple blotch disease (ABD) caused by Fungal isolates obtained from symptomatic apple leaves and fruit produced uniform slow-growing, dark-gray colonies on peptone potato dextrose agar and had conidia. Internal transcribed spacer DNA sequences matched with and Koch's postulates were fulfilled when typical ABD symptoms occurred when reinoculated onto apple leaves and fruit. Spore dispersal in nonfungicide-treated orchards detected with quantitative PCR was low in early spring and dropped to undetectable levels in late May and early June before rising exponentially to highs in July and August, which coincided with symptom development.

Genetic Diversity of Isolated From Three Commercial Tree Fruit Packinghouses and Evidence of Persistent and Transient Contamination.

Whole genome analysis was performed on 501 isolates obtained from a previous survey which recovered 139 positive environmental sponge samples (i.e., up to 4 isolates per sample) from a total of 719 samples collected at 40 standardized sites in 3 commercial apple packinghouse facilities (i.

Fungicide Sensitivity of Species Causing Bitter Rot of Apple in the Mid-Atlantic U.S.A.

Apple growers in the Mid-Atlantic region of the U.S.A.

Prevalence and Distribution of in Three Commercial Tree Fruit Packinghouses.

A 2-year longitudinal study of three tree fruit packinghouses was conducted to determine the prevalence and distribution of . Samples were collected from 40 standardized non-food-contact surface locations six different times over two 11-month production seasons. Of the 1,437 samples collected, the overall prevalence of over the course of the study was 17.

Bitter Rot of Apple in the Mid-Atlantic United States: Causal Species and Evaluation of the Impacts of Regional Weather Patterns and Cultivar Susceptibility.

Apple growers in the Mid-Atlantic region of the United States have been reporting an increase in losses to bitter rot of apple and are requesting up-to-date management recommendations. Management is complicated by variations in apple cultivar susceptibility, temperature, rainfall, and biology of the spp. that cause bitter rot.

Author Correction: Identification and characterization of Colletotrichum species causing apple bitter rot in New York and description of C. noveboracense sp. nov.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Virulence Genetics of an Erwinia amylovora Putative Polysaccharide Transporter Family Member.

The Gram-negative enterobacterium causes fire blight disease in apple and pear trees. Lipopolysaccharides and the exopolysaccharide amylovoran are essential virulence factors. We found that mutations in disrupted amylovoran production and virulence in apple fruits and tree shoots and that the deletion of suppressed the mutant phenotype.

Quantification of in Orchards and Deciduous Forests Indicates It Is Primarily a Leaf Endophyte.

of the species complex is an important hemibiotrophic pathogen of vegetables and fruits in temperate regions worldwide. In apple, it is one of the primary species responsible for bitter rot disease. Understanding the disease cycle is complicated because many broadleaf plants can be hosts of By detecting and quantifying rain-splashed species complex conidia in more than 500 samples from heavily bitter-rot-infected apple orchards and nearby forested woodlots over two summers, we show that conidial quantities were higher in the woodlots than in the orchards.

Identification and characterization of Colletotrichum species causing apple bitter rot in New York and description of C. noveboracense sp. nov.

Apple bitter rot caused by Colletotrichum species is a growing problem worldwide. Colletotrichum spp. are economically important but taxonomically un-resolved.

Blistering1 Modulates Virulence Via Vesicle-mediated Protein Secretion.

The blue mold fungus, is a postharvest apple pathogen that contributes to food waste by rotting fruit and by producing harmful mycotoxins ( patulin). To identify genes controlling pathogen virulence, a random T-DNA insertional library was created from wild-type strain R19. One transformant, T625, had reduced virulence in apples, blistered mycelial hyphae, and a T-DNA insertion that abolished transcription of the single copy locus in which it was inserted.

Erwinia amylovora Auxotrophic Mutant Exometabolomics and Virulence on Apples.

The Gram-negative bacterium causes fire blight disease of apples and pears. While the virulence systems of have been studied extensively, relatively little is known about its parasitic behavior. The aim of this study was to identify primary metabolites that must be synthesized by this pathogen for full virulence.

Extragenic Suppression of Elongation Factor P Gene Mutant Phenotypes in Erwinia amylovora.

Elongation factor P (EF-P) facilitates the translation of certain peptide motifs, including those with multiple proline residues. EF-P must be posttranslationally modified for full functionality; in enterobacteria, this is accomplished by two enzymes, namely, EpmA and EpmB, which catalyze the β-lysylation of EF-P at a conserved lysine position. Mutations to or its modifying enzymes produce pleiotropic phenotypes, including decreases in virulence, swimming motility, and extracellular polysaccharide production, as well as proteomic perturbations.

Whole-genome comparisons of spp. reveals secondary metabolic gene clusters and candidate genes associated with fungal aggressiveness during apple fruit decay.

Blue mold is a postharvest rot of pomaceous fruits caused by and a number of other species The genome of the highly aggressive strain R19 was re-sequenced and analyzed together with the genome of the less aggressive strain RS1. Whole genome scale similarities and differences were examined. A phylogenetic analysis of and several closely related species revealed that the two pathogens isolated from decayed apple with blue mold symptoms are not each other's closest relatives.

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.

Characterization of a new apple luteovirus identified by high-throughput sequencing.

Background: 'Rapid Apple Decline' (RAD) is a newly emerging problem of young, dwarf apple trees in the Northeastern USA. The affected trees show trunk necrosis, cracking and canker before collapse in summer. In this study, we discovered and characterized a new luteovirus from apple trees in RAD-affected orchards using high-throughput sequencing (HTS) technology and subsequent Sanger sequencing.

An Erwinia amylovora yjeK mutant exhibits reduced virulence, increased chemical sensitivity and numerous environmentally dependent proteomic alterations.

The Gram-negative bacterium Erwinia amylovora causes fire blight, an economically important disease of apples and pears. Elongation factor P (EF-P) is a highly conserved protein that stimulates the formation of the first peptide bond of certain proteins and facilitates the translation of certain proteins, including those with polyproline motifs. YjeK and YjeA are two enzymes involved in the essential post-translational β-lysylation of EF-P at a conserved lysine residue, K34.

Characterization of Postharvest Fungicide-Resistant Botrytis cinerea Isolates From Commercially Stored Apple Fruit.

Botrytis cinerea causes gray mold and is an economically important postharvest pathogen of fruit, vegetables, and ornamentals. Fludioxonil-sensitive B. cinerea isolates were collected in 2011 and 2013 from commercial storage in Pennsylvania.