scholarly journals Evaluation of Low-maintenance Landscape Roses in Central Florida

2013 ◽  
Vol 23 (2) ◽  
pp. 252-257 ◽  
Author(s):  
Jozer Mangandi ◽  
Sydney Park Brown ◽  
Natalia Peres
Keyword(s):  
Black Spot ◽  
Plant Quality ◽  
Cercospora Leaf Spot ◽  
Poor Growth ◽  
Local Conditions ◽  
Knock Out ◽  
Central Florida ◽  
Flower Production ◽  
Scirtothrips Dorsalis ◽  
Major Factors

Environmental conditions in Florida are favorable for the development and persistence of insects and diseases that affect rose (Rosa sp.) plants, necessitating periodic applications of pesticides to maintain plant appearance. In addition, nutrient-deficient and well-drained soils in Florida force gardeners to provide supplemental fertilizer and water. Landscape performance is rarely considered for the development of new rose cultivars; consequently, careful selection of cultivars adapted to local conditions is necessary to reduce maintenance. The objective of this study was to develop recommendations of own-root, low-maintenance roses among 11 old garden and modern cultivars for central Florida. Plants were provided with minimal amounts of water and fertilizer, no control for diseases and insects, and no grooming or deadheading. Weekly evaluations were performed on all plants for plant quality, flower coverage; and incidence of black spot (caused by Diplocarpon rosae), cercospora leaf spot (caused by Cercospora rosicola), and foliar damage [caused by chilli thrips (Scirtothrips dorsalis)]. Damage caused by the foliar diseases and chilli thrips were the major factors that affected plant quality, vigor, and subsequently, flower production. Differences in susceptibility to these three factors were found among cultivars, enabling the classification of the 11 cultivars as recommended, cautiously recommended, and not recommended for central Florida. After two years, ‘Mrs. B.R. Cant’ appeared to be the most suited for central Florida as plant quality and flower production were fairly constant. ‘Duchesse de Brabant’, ‘RADrazz’ (Knock Out®), and ‘Spice’ were the next best performers and are cautiously recommended for central Florida. These cultivars were minimally affected by both diseases, showing low severity of yellowing and defoliation nor a decline in flower production. “Bailey Red”, ‘Old Blush’, ‘Belinda’s Dream’, ‘Perle d’Or’, ‘BUCbi’ (Carefree Beauty™), ‘Mutabilis’, and ‘WEKcisbako’ (Home Run®) had severe defoliation, poor growth, and low vigor in this study and do not appear to be low-maintenance landscape roses for central Florida.

scholarly journals Resistance of Shrub and Groundcover Roses to Black Spot and Cercospora Leaf Spot, and Impact of Fungicide Inputs on the Severity of both Diseases

2005 ◽  
Vol 23 (2) ◽  
pp. 77-85 ◽  
Author(s):  
A.K. Hagan ◽  
M.E. Rivas-Davila ◽  
J.R. Akridge ◽  
J.W. Olive
Keyword(s):  
Powdery Mildew ◽  
Leaf Spot ◽  
Black Spot ◽  
Ground Cover ◽  
White Flower ◽  
Polar Ice ◽  
Cercospora Leaf Spot ◽  
Knock Out ◽  
Weather Patterns ◽  
The Impact

Abstract Reaction of selected shrub and ground cover roses to black spot, Cercospora leaf spot, and powdery mildew, as well as the impact of fungicide inputs on the control of the above diseases, was assessed from 1999 through 2003 in a simulated landscape planting in Brewton, AL. Chlorothalonil at 1.25 g ai/liter was applied at 2- and 4-week intervals from mid-March until October to randomly selected plants in each replicate. An unsprayed control was also included in each replicate. Although black spot was the predominate disease observed, a number of rose selections suffered from objectionable Cercospora leaf spot-induced leaf spotting and premature defoliation. Few mixed outbreaks of black spot and Cercospora leaf spot on a single selection were seen. In all years, significant differences in the reaction of rose selections to black spot and Cercospora leaf spot were noted. Of the roses damaged by black spot, the least leaf spot and defoliation were noted on the unsprayed Ice Meidiland®, Mystic Meidiland®, Red Cascade™, ‘Hansa’, ‘Pink Grootendorst’, ‘Pink Pet’, and to a lesser extent Carefree Wonder™ and Pearl Sevillana™. In a residential planting, monthly applications of chlorothalonil or other recommended fungicide would be needed to protect the above rose selections from a destructive black spot outbreak. ‘Betty Prior’, Bonica®, Cherry Meidiland®, First Light™, Kent™, Jeepers Creeper™, ‘Livin’ Easy™, Lilian Austin™, ‘Nearly Wild’, ‘Nozomi’, Butterfly rose, Ralph's Creeper™, Raven™, Royal Bonica™, ‘Sea Foam’, Sevillana™, and Sweet Chariot™ were susceptible to black spot. While black spot did not appreciably damage Carefree Delight™, Flower Carpet®, White Flower Carpet®, Fire Meidiland®, Fuchsia Meidiland®, Happy Trails™, ‘Petite Pink Scotch’, Polar Ice™, R. wichurana, The Fairy™, and ‘Therese Bugnet’, considerable Cercospora leaf spot development occurred on all of the above rose selections. Of these roses, Polar Ice™, Fuchsia Meidiland®, and Fire Meidiland® exhibited the highest resistance to Cercospora leaf spot and may not require any fungicide inputs to maintain plant health and vigor. Magic Carpet™ and Knock Out™ roses, which were susceptible and resistant to black spot, respectively, as well as Flower Carpet®, and White Flower Carpet® appeared to be poorly adapted to the hot and sometimes dry summer weather patterns of South Alabama. In nearly all years, chlorothalonil gave better control of both diseases when applied on a 2-week than on a 4-week schedule. Significant chlorothalonil-induced leaf burn was seen on First Light™, Flower Carpet®, ‘Hansa’, Happy Trails™, Magic Carpet™, Mystic Meidiland™, ‘Nozomi’, and Raven™. Consistent powdery mildew development was found only on ‘Therese Bugnet’ and to a lesser extent on Red Cascade™ and ‘Petite Pink Scotch’. Canopy spread of the roses that were heavily damaged by black spot and Cercospora leaf spot often was often reduced in size when compared with that of adjacent chlorothalonil-treated plants of the same selection. In contrast, little if any increase in growth was obtained with fungicide inputs for the more disease resistant rose selections.

scholarly journals Flowering, Drought and Disease Tolerance, and Landscape Performance of Landscape Roses Grown under Low-input Conditions in North Central Texas

2019 ◽  
Vol 29 (3) ◽  
pp. 234-240 ◽  
Author(s):  
Derald Harp ◽  
Gaye Hammond ◽  
David C. Zlesak ◽  
Greg Church ◽  
Mark Chamblee ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Drought Tolerance ◽  
Black Spot ◽  
The United States ◽  
North Central ◽  
Knock Out ◽  
Landscape Performance ◽  
North Central Texas ◽  
Central Texas ◽  
The Impact

Landscaping today involves the struggle to balance aesthetically pleasing plants while minimizing the impact on the environment, reducing water usage, decreasing fertilizer use, and eliminating or significantly reducing pesticide usage. Roses (Rosa sp.), although seen as challenging plants, remain the most popular flowering shrub in the United States. The identification of new cultivars that combine beauty, pest and disease resistance, and drought tolerance are important to Texas landscapes. Sixty roses were assessed over a 3-year period to determine flowering, drought tolerance, disease resistance, and overall landscape performance in minimal-input gardens in north central Texas. Atypical weather during the study had a significant impact on performance. A 2-year drought (2010–11) was accompanied by the hottest summer on record (2011), which included a record number of days of at least 100 °F or higher. As a result, supplemental irrigation was provided three times both summers. Roses generally fared well under these conditions and survived the drought. Flowering was most abundant during the spring and fall, and it was least abundant in the summer. Powdery mildew [PM (Sphaerotheca pannosa var. rosae)] was a minor problem. Nine of 60 cultivars developed no visible symptoms of PM during the study. Most PM occurred in Spring 2010, with very little found after June; none was found in 2011. Black spot [BS (Diplocarpon rosae)] was serious for some cultivars, but most were BS-free; RADrazz (Knock Out®) and Lady Banks White had no observed BS during the study. BS occurred mostly in May, June, and November. Overall landscape performance ratings were high, with 23 cultivars having a mean landscape performance rating equal to or better than the Belinda’s Dream standard. The best-performing cultivars were RADrazz (Knock Out), RADcon (Pink Knock Out®), RADyod (Blushing Knock Out®), WEKcisbaco (Home Run®), and Alister Stella Gray. This study was able to identify many other highly performing roses in north central Texas.

scholarly journals Performance of Garden Roses in North-central Texas under Minimal Input Conditions

2008 ◽  
Vol 18 (3) ◽  
pp. 417-422 ◽  
Author(s):  
W.A. Mackay ◽  
S.W. George ◽  
C. McKenney ◽  
J.J. Sloan ◽  
R.I. Cabrera ◽  
...  
Keyword(s):  
Black Spot ◽  
Nutrient Content ◽  
Plant Performance ◽  
Quality Data ◽  
North Central ◽  
Knock Out ◽  
North Central Texas ◽  
Foliar Nutrient ◽  
Central Texas ◽  
Overall Performance

One hundred sixteen rose (Rosa spp.) cultivars were evaluated under minimal input conditions in north-central Texas for 3 years. Plant quality data included overall plant performance, number of flowers, percentage of bloom coverage, final vigor, and survival. Disease ratings for black spot (Diplocarpon rosae), petal blight (Alternaria alternata), powdery mildew (Sphaerotheca pannosa), and aphid (Myzus spp.) infestations were previously reported. Of the original 116 cultivars, 25 had 50% or higher mortality during the trial. Own-root cultivars performed significantly better than the grafted cultivars and had significantly better survival (P = 0.001). As a class, the Polyantha cultivars exhibited the best overall performance, mean bloom percentage, final vigor and survival, while cultivars in the Hybrid Tea class had the worst performance in all measures. Foliar nutrient content, bloom number, and mean percentage of bloom were not good predictors of overall performance. Of the diseases monitored, black spot was the most severe and was closely correlated to overall performance and final vigor, but was not the only factor determining overall performance. The top five cultivars in mean overall performance were RADrazz (Knock Out™), Caldwell Pink, Sea Foam, Perle d'Or, and The Fairy, in descending order.

scholarly journals Evaluation of Roses from the Earth-Kind® Trials: Black Spot (Diplocarpon rosae Wolf) Resistance and Ploidy

HortScience ◽  
2010 ◽  
Vol 45 (12) ◽  
pp. 1779-1787 ◽  
Author(s):  
David C. Zlesak ◽  
Vance M. Whitaker ◽  
Steve George ◽  
Stan C. Hokanson
Keyword(s):  
Specific Resistance ◽  
Black Spot ◽  
Field Trials ◽  
Root Tip ◽  
Lesion Length ◽  
Resistance Level ◽  
Knock Out ◽  
Diplocarpon Rosae ◽  
South Central ◽  
The Earth

Regional, replicated cultivar trials of landscape roses are an ongoing component of the Earth-Kind® program, which was started at Texas A&M University in the 1990s to support environmental landscape stewardship. The rose trials within the Earth-Kind program identify and promote the most regionally adapted rose cultivars and are conducted without fertilizers or pesticides and greatly reduced irrigation. Black spot (caused by Diplocarpon rosae Wolf) is the most serious disease of outdoor-grown roses worldwide as a result of the potential for rapid leaf yellowing and defoliation. Earth-Kind designated cultivars for the south–central United States and roses under trial in other regions or considered for future Earth-Kind trials (n = 73 roses) and two susceptible control cultivars were challenged with North American Races 3, 8, and 9 of D. rosae, which were previously characterized at the University of Minnesota. Young expanded leaves were inoculated using detached leaf assays. Lesion length (LL) was measured for susceptible reactions and cultivar ploidy was determined using root tip squashes. Diploid, triploid, and tetraploid cultivars (n = 20, 30, and 23, respectively) were identified, and race-specific resistances and partial resistances were also identified. Race-specific resistance was generally more prevalent in newer rose cultivars and rose cultivars more recently included in Earth-Kind trials. Nine cultivars were resistant to all three races (Brite Eyes™, ‘Grouse’, Home Run®, Knock Out®, Paprika™, Peachy Cream™, Pink Knock Out®, Rainbow Knock Out®, and Yellow Submarine™). Blushing Knock Out®, a sport of Knock Out®, was susceptible to Race 8. Partial resistance rank for LL was generally consistent across races for roses susceptible to multiple races. The application of these data includes: characterizing the minimum resistance level needed for roses to warrant inclusion in Earth-Kind field trials, the identification of additional race-specific resistance genes, identifying resistance-breaking isolates of D. rosae, understanding race composition in field trials based on infection patterns of key cultivars, selection of parents for resistance breeding efforts, and continued comparisons between LL and growing bodies of Earth-Kind field resistance data.

scholarly journals An Updated Host Differential Due to Two Novel Races of Diplocarpon rosae Wolf, the Causal Agent of Rose Black Spot Disease

HortScience ◽  
2020 ◽  
Vol 55 (11) ◽  
pp. 1756-1758
Author(s):  
David C. Zlesak ◽  
Darcy Ballantyne ◽  
Matthew Holen ◽  
Andrea Clark ◽  
Stan C. Hokanson ◽  
...  
Keyword(s):  
Fungal Pathogen ◽  
Durable Resistance ◽  
Black Spot ◽  
Ongoing Research ◽  
Knock Out ◽  
Spot Disease ◽  
Diplocarpon Rosae ◽  
Leaf Chlorosis ◽  
New Races ◽  
Black Spot Disease

The fungal pathogen, Diplocarpon rosae, infects only roses (Rosa spp.) and leads to rose black spot disease. Rose black spot is the most problematic disease of outdoor-grown roses worldwide due to the potential for rapid leaf chlorosis and defoliation. Eleven races of the pathogen were previously characterized from isolates collected in North America and Europe. Isolates of D. rosae obtained from infected leaves of the roses Brite EyesTM (‘RADbrite’; isolate BEP; collected in West Grove, PA) and Oso Easy® Paprika (‘CHEwmaytime’; isolate PAP; collected in Minneapolis, MN) proved to have unique infection patterns using the established host differential with the addition of Lemon FizzTM (‘KORlem’). The new races are designated race 12 (BEP) and race 13 (PAP), respectively, and Lemon FizzTM should be included in the updated host differential because it distinguishes races 7 and 12. Additionally, inconsistent infections and limited sporulation were found in the host differential Knock Out® (‘RADrazz’) for races 7 and 12. Expanding the collection of D. rosae races supports ongoing research efforts, including host resistance gene discovery and breeding new rose cultivars with increased and potentially durable resistance.

scholarly journals Spatio-Temporal Distribution and Fixed-Precision Sampling Plan of Scirtothrips dorsalis (Thysanoptera: Thripidae) in Florida Blueberry

Insects ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 256
Author(s):  
Babu R. Panthi ◽  
Justin M. Renkema ◽  
Sriyanka Lahiri ◽  
Oscar E. Liburd
Keyword(s):  
Negative Binomial ◽  
Probability Distributions ◽  
Leaf Growth ◽  
Temporal Distribution ◽  
Sampling Plan ◽  
Control Measures ◽  
Sampling Unit ◽  
Central Florida ◽  
Scirtothrips Dorsalis ◽  
Spatio Temporal

Scirtothrips dorsalis Hood is an invasive and foliar pest of Florida blueberry that reduces plant growth by feeding on new leaf growth. A sampling plan is needed to make informed control decisions for S. dorsalis in blueberry. Fourteen blueberry fields in central Florida were surveyed in 2017 and 2018 after summer pruning to determine the spatial and temporal distribution of S. dorsalis and to develop a fixed-precision sampling plan. A sampling unit of ten blueberry shoots (with four to five leaves each) was collected from one blueberry bush at each point along a 40 × 40 m grid. Field counts of S. dorsalis varied largely ranging from zero to 1122 adults and larvae per sampling unit. Scirtothrips dorsalis had aggregated distribution that was consistent within fields and temporally stable between summers, according to Taylor’s power law (TPL) (aggregation parameter, b = 1.57), probability distributions (56 out of 70 sampling occasions fit the negative binomial distribution), Lloyd’s index (b > 1 in 94% occasions), and Spatial Analysis by Distance IndicEs (31% had significant clusters). The newly developed fixed-precision sampling plan required 167, 42, seven, or three sampling units to estimate a nominal mean density of 20 S. dorsalis per sampling unit with a precision of 5%, 10%, 25%, or 40%, respectively. New knowledge on S. dorsalis distribution will aid in evaluating the timing and effectiveness of control measures.

scholarly journals Incidence and Etiology of Postharvest Fungal Diseases of Persimmon (Diospyros kaki Thunb. cv. Rojo Brillante) in Spain

Plant Disease ◽  
2015 ◽  
Vol 99 (10) ◽  
pp. 1416-1425 ◽  
Author(s):  
Lluís Palou ◽  
Clara Montesinos-Herrero ◽  
Ignacio Tarazona ◽  
Cristina Besada ◽  
Verónica Taberner
Keyword(s):  
Colletotrichum Gloeosporioides ◽  
Black Spot ◽  
Dna Amplification ◽  
Severity Index ◽  
Penicillium Expansum ◽  
Diospyros Kaki ◽  
Wound Infections ◽  
Postharvest Diseases ◽  
Local Conditions ◽  
Microscopic Morphology

‘Rojo Brillante’ is currently the most important persimmon cultivar in Spain. The incidence and etiology of postharvest diseases affecting this cultivar were determined under local conditions. Latent and wound pathogens were assessed for two consecutive seasons on commercially grown persimmons from two orchards. Healthy persimmons were either surface-disinfested or artificially wounded on the rind and placed in humid chambers at 20 or 25°C for up to 9 weeks. Additionally, decay was assessed on commercially handled persimmons stored at 1°C for up to 20 weeks. In all cases, the most frequent disease was alternaria black spot (ABS) caused by Alternaria alternata and an ABS severity index specific for ‘Rojo Brillante’ persimmons was established. Other minor pathogens causing latent infections, mostly stem-end rots, included Botrytis cinerea, Lasiodiplodia theobromae, Neofusicoccum spp., Pestalotiopsis clavispora, and Colletotrichum gloeosporioides. Penicillium expansum and, to much a lesser extent, Cladosporium cladosporioides were other pathogens causing wound infections. These two fungi and A. alternata and B. cinerea were also isolated from cold-stored fruit. Common isolates were identified by macroscopic and microscopic morphology and/or DNA amplification and sequencing. Pathogenicity of selected isolates was demonstrated by fulfilling Koch’s postulates. Disease development at 20 and 5°C was characterized on artificially inoculated persimmons.

scholarly journals Performance of `Hamlin' Orange on 16 Rootstocks in East-central Florida

HortScience ◽  
1995 ◽  
Vol 30 (1) ◽  
pp. 41-43 ◽  
Author(s):  
Heinz K. Wutscher ◽  
Laura Lee Hill
Keyword(s):  
Citrus Sinensis ◽  
Poncirus Trifoliata ◽  
Trifoliate Orange ◽  
Poor Growth ◽  
East Central ◽  
Central Florida ◽  
Citrus Rootstock ◽  
Citrus Blight ◽  
Freeze Damage ◽  
Swingle Citrumelo

`Hamlin' orange (Citrus sinensis L. Osbeck) was grown on 15 rootstocks: four citrumelos [C. paradisi Macf. × Poncirus trifoliata (L.) Raf.], five mandarin × trifoliate orange hybrids (C. reticulata Blanco × P. trifoliata), two pummelo × trifoliate orange hybrids [C. grandis (L.) × P. trifoliata], Vangasay lemon (C. limon Burm. f.), Norton citrange (C. sinensis × P. trifoliata), and two Smooth Flat Seville (C. aurantium L. hybrid?) hybrids. These scion–rootstock combinations were compared to trees on Swingle citrumelo, the most widely used citrus rootstock in Florida. One Smooth Flat Seville hybrid was eliminated early because of poor growth and variability in size, and the Vangasay lemon rootstock was eliminated because of severe freeze damage. At age 5, the trees on Norton citrange developed citrus blight and were eliminated. Remaining in the experiment for 7 years, `Hamlin' trees on six of the 13 rootstocks produced more fruit than trees on Swingle citrumelo. Of these six, HRS 852 (Changsha mandarin × English large-flowered trifoliate orange) was the best overall rootstock, with trees on it producing large quantities of high-quality fruit on medium-sized canopies.

scholarly journals Difference between isolates from brown eye spot and black spot lesions in coffee plants

2019 ◽  
Vol 54 ◽  
Author(s):  
Deila Magna dos Santos Botelho ◽  
Mário Lucio Vilela de Resende ◽  
Juliana Costa de Rezende ◽  
Pedro Martins Ribeiro Júnior ◽  
Camila Cristina Lage de Andrade ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Mycelial Growth ◽  
Black Spot ◽  
Infection Process ◽  
The State ◽  
Cercospora Leaf Spot ◽  
Conidial Morphology ◽  
Coffee Plants ◽  
The Difference ◽  
Brown Eye Spot

Abstract: The objective of this work was to evaluate the difference between the isolates from two cercospora leaf spot symptoms (brown eye spot and black spot) in relation to conidial morphology, mycelial growth, cercosporin production, and reproduction of symptoms in coffee leaves collected in three municipalities in the state of Minas Gerais, Brazil. There was a difference between the isolates for the studied variables, but without any relation to the type of symptom. The differences found were not associated with the origin of the isolates. The symptoms characterized as black spot were associated with different host conditions during the infection process.

scholarly journals Growth and Flowering of Petunia and Impatiens: Effects of Competition and Reduced Water Content Within a Container

HortScience ◽  
2009 ◽  
Vol 44 (5) ◽  
pp. 1302-1307 ◽  
Author(s):  
Tijana Blanusa ◽  
Eleni Vysini ◽  
Ross W.F. Cameron
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Primary Objective ◽  
Plant Quality ◽  
Single Plant ◽  
Flower Number ◽  
Flower Production ◽  
Bedding Plant ◽  
Reduced Water

The primary objective of this research was to determine how the presence of more than one plant and more than one species in a container influence plant quality, particularly when the volume of water given to the container is reduced. Petunia ×hybrida ‘Hurrah White’ and Impatiens ‘Cajun Violet’ were chosen as typical bedding plant species. Plants were grown in 2 l containers either under “100% ETp” (i.e., replacing all the water lost by evapotranspiration in the previous 24 h) or under a moisture-restrictive regime of “25% ETp,” in which plants received 25% of the “100% ETp” value. An ancillary experiment investigated whether low watering resulted in floral buds being aborted. Results demonstrated that watering requirements of Petunia under “100% ETp” (i.e., replacing all the water lost by evapotranspiration in the previous 24 h) were on average 30% greater than those of Impatiens. However, when two Petunia plants were growing in the same container, the volume of water required to maintain soil moisture content at container capacity was on average only 10% greater than for a single plant. Under a “25% ETp” regime in which plants received 25% of the “100% ETp” value, flower number, plant height, and flower size were reduced by 50%, 33%, and 13%, respectively, in Petunia compared with “100% ETp.” For example, flower numbers decreased from an average of 71 to 33 flowers per plant in “100% ETp” and “25% ETp,” respectively. Petunia plants in the “25% ETp” regime, however, were more efficient at producing both biomass and flowers in relation to the volume of water applied. Petunia plants that experienced both competition from other plants in the container and lower irrigation rates had enhanced efficiency of flower production (i.e., more flowers per unit biomass). For Impatiens, however, the growing of single plants at “25% ETp” was plausible, but the addition of a Petunia plant at “25% ETp” was detrimental to plant quality (Impatiens flower numbers reduced by 75%).

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