PhytophthoraandPythiumspecies Associated with Crown Rot in New York Apple Orchards

1982 ◽  
Vol 72 (5) ◽  
pp. 533 ◽  
Author(s):  
S. N. Jeffers
Keyword(s):  
New York ◽  
Crown Rot ◽  
Apple Orchards

scholarly journals Trap Response and Fruit Damage by Obliquebanded Leafroller (Lepidoptera: Tortricidae) in Pheromone-Treated Apple Orchards in New York

1996 ◽  
Vol 25 (2) ◽  
pp. 268-282 ◽  
Author(s):  
Arthur M. Agnello ◽  
W. Harvey Reissig ◽  
Steve M. Spangler ◽  
Ralph E. Charlton ◽  
David P. Kain
Keyword(s):  
New York ◽  
Apple Orchards ◽  
Obliquebanded Leafroller ◽  
Fruit Damage ◽  
Treated Apple

scholarly journals Rootstocks and Interstem/Rootstock Combinations for Lower Midwest Apple Orchards

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1128B-1128
Author(s):  
Bradley H. Taylor ◽  
Dagmar M. Geisler-Taylor
Keyword(s):  
Block Design ◽  
Fruit Size ◽  
Vertical Axis ◽  
Crown Rot ◽  
Apple Orchards ◽  
Southern Illinois ◽  
Biotic Stresses ◽  
Industry Standard ◽  
Negative Side Effects ◽  
Dwarfing Rootstocks

Use of precocious, high-yielding, dwarfing rootstocks for apple trees in southern Illinois has been limited by the prevalence of fire blight and crown rot diseases, as well as soil and climate stresses. Apple orchards in the region are generally situated on heavy clay soils and often receive excess rainfall in spring and fall, followed by drought in summer. New dwarfing rootstocks adapted to these biotic stresses were used as interstems on robust, vigorous rootstocks, to determine if earlier and greater cumulative yields could be obtained compared to the current industry standard MM. 111. The treatments consisted of 20 various interstem/rootstock combinations with `Ruby Jon Jonathan' as the scion that were propagated and grown as feathered maidens in the nursery. The trees were planted at 4.5 × 6.0 m in a randomized complete-block design with eight replications in May 1996 at the Southern Illinois University Horticultural Research Center at Carbondale, Ill. The trees were trained in a vertical axis system with minimal initial pruning and complete deblossoming in the first 2 years. Trees were allowed to crop during the third- through ninth-leaf. Cumulative yields of the best performing interstem/rootstock combinations were two to three times greater compared with MM. 111. The trees on the most vigorous rootstocks consistently produced the largest fruit size, but four dwarfing clones, G. 30, V. 1, Bud. 9, and M. 7, used as interstems, generally produced higher yields with similar fruit size. These advantages were obtained without the negative side effects (excess root suckers, lack of scion uniformity, and increased mortality) traditionally associated with interstem performance in the lower Midwest.

scholarly journals Multi-site Thinning Comparisons with `Empire' and `McIntosh' Apples

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 524C-524
Author(s):  
Alan N. Lakso ◽  
Terence L. Robinson ◽  
Eddie W. Stover ◽  
Warren C. Stiles ◽  
Stephen Hoying ◽  
...  
Keyword(s):  
New York ◽  
New York State ◽  
Fruit Size ◽  
Apple Orchards ◽  
Physiological Factors ◽  
Crop Load ◽  
York State ◽  
Climatic Regions ◽  
Trial Analysis ◽  
Fruit Stage

Many chemical, environmental, and physiological factors have been reported to be important to apple chemical thinning, so we have been developing a multi-site and multi-year database of chemical thinning results and potentially important factors. For 3 years, we have conducted replicated thinning trials in `Empire' and `McIntosh' apple orchards at six or seven sites around New York state in different climatic regions. Different concentrations of NAA and Accel (primarily benzyladenine), NAA/carbaryl and Accel/carbaryl combinations and unthinned controls were tested with treatments applied at the 10-mm king fruit stage by airblast sprayers. Flower cluster counts, set counts, yields, fruit sizes, and other factors thought important to thinning response (orchard condition/history, weather, application conditions, etc.) were measured or estimated in each trial. Analysis of factor importance is continuing, but some general results have come from the thinning trials so far. Thinning effectiveness varied among years from poor to adequate. There have not been consistent thinner concentration responses. Commercial NAA and Accel concentrations have not thinned adequately. NAA/carbaryl and Accel/carbaryl have thinned the most. For the same crop load, trees thinned with Accel or the carbaryl combination have had better fruit size than when thinned with NAA.

scholarly journals Prevalence of Streptomycin-Resistant Erwinia amylovora in New York Apple Orchards

Plant Disease ◽  
2016 ◽  
Vol 100 (4) ◽  
pp. 802-809 ◽  
Author(s):  
K. A. Tancos ◽  
S. Villani ◽  
S. Kuehne ◽  
E. Borejsza-Wysocka ◽  
D. Breth ◽  
...  
Keyword(s):  
United States ◽  
New York ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
The United States ◽  
Streptomycin Resistance ◽  
Apple Orchards ◽  
Wayne County ◽  
The Past ◽  
Shoot Blight

Resistance to streptomycin in Erwinia amylovora was first observed in the United States in the 1970s but was not found in New York until 2002, when streptomycin-resistant (SmR) E. amylovora was isolated from orchards in Wayne County. From 2011 to 2014, in total, 591 fire blight samples representing shoot blight, blossom blight, and rootstock blight were collected from 80 apple orchards in New York. From these samples, 1,280 isolates of E. amylovora were obtained and assessed for streptomycin resistance. In all, 34 SmR E. amylovora isolates were obtained from 19 individual commercial orchards. The majority of the resistant isolates were collected from orchards in Wayne County, and the remaining were from other counties in western New York. Of the 34 resistant isolates, 32 contained the streptomycin resistance gene pair strA/strB in the transposon Tn5393 on the nonconjugative plasmid pEA29. This determinant of streptomycin resistance has only been found in SmR E. amylovora isolates from Michigan and the SmR E. amylovora isolates discovered in Wayne County, NY in 2002. Currently, our data indicate that SmR E. amylovora is restricted to counties in western New York and is concentrated in the county with the original outbreak. Because the resistance is primarily present on the nonconjugative plasmid, it is possible that SmR has been present in Wayne County since the introduction in 2002, and has spread within and out of Wayne County to additional commercial growers over the past decade. However, research is still needed to provide in-depth understanding of the origin and spread of the newly discovered SmR E. amylovora to reduce the spread of streptomycin resistance into other apple-growing regions, and address the sustainability of streptomycin use for fire blight management in New York.

No Evidence of Resistance to Trifloxystrobin, Triflumizole, and Boscalid in Podosphaera leucotricha Isolates from U.S. Commercial Apple Orchards

Plant Disease ◽  
2021 ◽  
Author(s):  
Lederson Gañán-Betancur ◽  
Tobin Peever ◽  
Achour Amiri
Keyword(s):  
New York ◽  
Pacific Northwest ◽  
Apple Orchards ◽  
Protein Subunit ◽  
Podosphaera Leucotricha ◽  
Group I ◽  
Detached Leaves ◽  
In Vivo Testing ◽  
Positive Correlations

Apple powdery mildew, caused by Podosphaera leucotricha, continues to be a challenge in commercial apple orchards in the U.S. Pacific Northwest and worldwide. In this study, P. leucotricha isolates were collected in 2018 and 2019 from two organic (baseline) and eight conventional (exposed) apple orchards in Washington, New York, and Virginia, and assessed for their sensitivity to trifloxystrobin (TRI, n= 232), triflumizole (TFZ, n = 217), and boscalid (BOS, n = 240) using a detached leaf assay. Effective concentrations inhibiting 50% growth (EC50) were not significantly different between baseline and exposed isolates, and ranged from 0.001 to 0.105, 0.09 to 6.31, and 0.05 to 2.18 µg/ml, for TRI, TFZ, and BOS, respectively. Reduction in sensitivity by factors of 105, 63 and 22 to TRI, TFZ, and BOS, respectively, were observed in some isolates, but all isolates were controlled by the commercial label rates of the three fungicides on detached leaves. Sequencing of the cytochrome b (cytb), cytochrome P450 sterol 14α-demethylase (CYP51), and the iron-sulfur protein subunit (SdhB) genes in isolates with high EC50 revealed no mutation previously reported to confer resistance to these fungicides in other fungi, and presence of a group I intron after codon 143 in the cytb gene. Significant (P < 0.001) moderate positive correlations (r = 0.38) observed between sensitivity to TRI and TFZ warrant continuous rotations of fungicides with different modes of actions in conventional orchards. The established baseline sensitivities and the molecular markers will help in selecting discriminatory doses and by-passing the challenging in vivo testing for future sensitivity monitoring in P. leucotricha.

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