Photinia Research Articles

First Report of Brown Leaf Spot Caused by Neofusicoccum parvum on Photinia × fraseri Dress (Christmas berry) in China.

Christmas berry (Photinia × fraseri Dress), known as red tip photinia, is an important landscape color plant in South China (Zhu et al., 2021). In summer 2021, brown leaf spots of Christmas berry were observed with an incidence of 45-70% on the campus of Nanchang Institute of Technology, Jiangxi Province (28°41'32.61"N, 116°1'53.75"E), China. These spots have a negative influence on the photosynthetic activity and severely reduce the ornamental value of these plants. Lesions originally occurred on the margins or tips of the leaves as red patches (Figure 1 A) and then developed into irregular reddish-brown necrotic spots with yellow halos (Figure 1 B) that finally were grey lesions with dark brown ring circles surround with yellow halos (Figure 1 C). Ten leaf samples with typical symptoms from five plants were collected. The tissue between the healthy and necrotic area (ca. 5 mm × 5 mm) was cut with a sterile scalpel and surface sterilized in 70% alcohol for 45 s, followed by 2% NaClO for 2 min and washed in sterile deionized water three times, The sterilized leaf parts were placed on potato dextrose agar (PDA) and incubated at 25℃ for 3 to 5 days. A total of 28 fungal isolates were obtained from ten symptomatic leaves, which were classified into five species by morphological characteristics. Neofusicoccum was the genus with the highest isolation frequency (50%). For pathogenicity tests, healthy leaves of Christmas berry were surface-sterilized, wounded using a sterile needle and inoculated with mycelial plugs (6 mm in diameter) on the left site of the leaves. Five representative isolates were chosen and ten leaves were used for every isolate. The controls on the same leaves on the right side of the leaves were treated with sterile PDA plugs. All samples were placed in an artificial climate box (RH 90±3%, 27±1℃, 12 h light) for 3 days. Only the leaves inoculated with isolate NH7 showed dark brown leaf spots (Figure 1 D). The control leaves and those inoculated with the other four isolates remained symptomless. To confirm pathogenicity, mycelial plugs of isolate NH7 were applied on punctured leaves of Christmas berry in the field as the artificial climate box (Figure 1 E-H). Inoculation with a sterile PDA plug served as control. All the leaves were covered with plastic bags for 48 h to maintain high relative humidity. Seven days later, symptoms similar to those observed in the field developed on all leaves inoculated with isolated NH7, while the controls remained symptomless. To fulfill Koch's postulates, fungal isolates were reisolated from symptomatic leaves and identified by morphological and molecular characteristics. The colony of isolate NH7 developed aerial hyphae, which had a grey center surrounded by grey-white hyphae (Figure 1 I). Conidia were aseptate, primarily fusiform and measured 11.1-19.8 × 3.2-7.1 µm (n = 50) (Figure 1 J). For further confirmation of the identity, five genes, including ITS (White et al., 1990), RPB2 (Pavlic et al., 2009), tub2 (Glass & Donaldson, 1995), and tef1 (Carbone & Kohn, 1999) were sequenced. The sequences were deposited in GenBank (OL584411 for ITS, OL606622 for ACT, OL694623 for tub2, OM141481 for RPB2 and OM141482 for tef1), Based on the phylogenetic tree analysis using IQ-TREE, isolate NH7 clustered with Neofusicoccum parvum (Figure 2). N. parvum has been reported to cause leaf spot disease on different plants including Myristica fragrans (Jayakumar et al., 2011), Ginkgo biloba (Mirhosseini et al., 2014), Vitis heyneana (Wu et al., 2015), rubber tree (Liu et al., 2017) and Geodorum eulophioides (Du et al., 2021). To our knowledge, this is the first report of N. parvum causing leaf spot disease on Christmas berry in China. As one of the most widely planted ornamental shrubs in China, the detailed knowledge of the pathogens targeting Christmas berry is critical.

The rooting capacity of red tip photinia; Photinia × fraseri hardwood cuttings under the effects of cutting time and IBA concentration

The experiment was conducted at the lath house in the nursery of Bakrajo Technical Institute campus, Sulaimani Polytechnic University, Bakrajo, Sulaimani city, Iraq, during 2021-2022, in order to study the effect of the date of taking cuttings (October 15th, November 15th, and December 15th) and IBA (Indole-3-butyric acid) concentration (0, 2000, 4000 and 6000 mg. L-1) on rooting, some vegetative and root growth characteristics of red tip photinia, Photinia x fraseri. A two-factor experiment was carried out according to a complete randomized design (CRD) with three replications. The results showed that the cuttings taken on November 15th were significantly superior in most of the studied parameters; rooting percentage (10.0%), shoot length (7.00 cm), number of shoots per plant (1.0), number of leaves per plant (5.0), average leaf area (21.07 cm2), shoot fresh weight (1.32 g), shoot dry weight (0.39 g), shoot diameter (1.95 mm), longest root (7.33 cm), average root number per plant (1.67), root fresh weight (0.55 g) and root dry weight (0.20 g). While, IBA at 6000 mg. L-1 caused significant differences in most of the previously mentioned parameters, giving the values 43.33%, 25.67, 1.67, 15.33, 77.28, 13.61, 5.39, 4.31, 27.33, 6.33, 2.48, and 0.71 respectively. Additionally, the interaction between the three cutting times; (October, November and December) and four concentrations of IBA; (0, 2000, 4000, 6000 mg. L-1), the interaction of concentration 6000 mg. L-1 of IBA and the date November 15th showed significant superiority in all studied parameters.

Performance of Two Bioswales on Urban Runoff Management

This study evaluated the effectiveness of two bioswales eight years after construction in Davis, California. The treatment bioswale measured 9 m × 1 m × 1 m (L × W × D). Engineered soil mix (75% native lava rock and 25% loam soil) replaced the native loam soil. Four Red Tip Photinia (Photinia × fraseri Dress) trees and two Blueberry Muffin Hawthorn (Rhaphiolepis umbellata (Thunb.) Makino) shrubs were planted in the bioswale. Runoff flowed into the bioswale from an adjacent 171 m2 panel of turf grass. An identically sized control bioswale consisting of non-disturbed native soil was located adjacent to the treatment bioswale. Surface runoff quantity and quality were measured during three experiments with different pollutant loads. When compared to the control, the treatment bioswale reduced surface runoff by 99.4%, and reduced nitrogen, phosphate, and total organic carbon loading by 99.1%, 99.5%, and 99.4%, respectively. After eight years, tree growth characteristics were similar across both sites.

Entomosporium Leaf Spot Control on Red-tip Photinia in the Landscape

Abstract In 2006, 2007, and 2008, efficacy of the soil-applied fungicide drench All-In-One Rose & Flower Care [All-In-One] (tebuconazole) was compared with the foliar-applied fungicides Daconil Weather Stik (chlorothalonil), Immunox Multipurpose Fungicide (myclobutanil), RosePride Disease Control Concentrate (triforine), and Disease Control for Roses, Flowers & Shrub Concentrate (tebuconazole) for the control of Entomosporium leaf spot on field-grown red-tip photinia (Photinia × fraseri ‘Birmingham’). While the label rate of All-In-One drench was poured over the soil surface around the base of each plant at monthly intervals, the foliar applied-fungicides were applied at label rates at 2-week intervals to runoff. Over the study period, drenches of All-In-One failed to protect photinia from Entomosporium leaf spot, while the foliar-applied fungicides significantly reduced disease levels. Defoliation on the non-fungicide treated controls was similar to the All-In-One drench and ranged over the study period from 25 to nearly 75%. In contrast, little if any leaf spotting and no defoliation occurred in any of the study years on the photinia treated with Daconil Weather Stik, Immunox Multi-purpose Fungicide, RosePride Disease Control Concentrate, and Disease Control for Roses, Flowers & Shrub Concentrate. Poor efficacy of the All-In-One was attributed to an inadequate concentration of the fungicide component tebuconazole when applied at the label drench rate.

Corrections in Cotoneaster (Rosaceae) in Taiwan

In Taiwan, Cotoneaster bullatus Bois was treated as a new species, Photinia kudoi Masamune, and was identified as C. konishii Hayata. In this paper, we clarify the identity of C. bullatus Bois in the flora of Taiwan. Line drawings, color photos, and a taxonomic description are also provided in the paper. Photinia kudoi Masamune and Pourthiaea kudoi (Masamune) Masamune are designated as 2 new synonyms of C. bullatus Bois. This species, C. bullatus Bois, is similar to C. konishii Hayata, but they can be distinguished by the floweret number of the inflorescence and the shape of the leaves. Cotoneaster bullatus has biggish leaves (5~13×1.5~5.5 cm), the upper surface is conspicuously bullate, and the inflorescence is 7~21-flowered, which differ from these of C. konishii which has smaller leaves (1.3~5×1~3.5 cm), the upper surface is not bullate, and the inflorescence is 3~5-flowered (rarely ~7).

Olfactory responses of the egg parasitoid, Gonatocerus ashmeadi Girault (Hymenoptera: Mymaridae), to host plants infested by Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae)

Gonatocerus ashmeadi Girault is an egg parasitoid with potential use in glassy-winged sharpshooter (GWSS), Homalodisca vitripennis (Germar), biological control in California. We tested the hypotheses that (1) G. ashmeadi uses chemical volatiles as cues to find hosts, (2) its success in host finding varies among plant species, and (3) the release of semiochemicals is systemically induced by GWSS feeding and oviposition. Using a glass Y-tube olfactometer, we determined G. ashmeadi’s preference for volatiles of infested versus uninfested lemon, grapevine, red-tip photinia, and crape myrtle plants. The parasitoid’s first choice to, its residence time, and the number of visits per Y-tube arm were used to assess its plant choice. G. ashmeadi chose the infested lemon, red-tip photinia, or grapevine plant significantly more often (62%, 67%, and 63%, respectively) than uninfested hosts, whereas they chose infested and uninfested crape myrtle equally often (49%). Females spent more time in and made more visits to the olfactometer arm connected to the infested plant than to the arm connected to the uninfested plant, except when testing crape myrtle. When testing for a systemic plant response to GWSS infestation, only infested lemon was significantly more attractive to the parasitoids than was an uninfested plant. These results suggest that G. ashmeadi females use chemical volatiles as cues to find GWSS egg masses and that host finding success varies among GWSS host plants. Some plants used by GWSS as oviposition hosts may serve as an escape from parasitization by G. ashmeadi and act as reservoirs for new GWSS individuals.

Preemergence Herbicide Effects on Nursery Crop Root and Shoot Growth

Abstract The effects of preemergence herbicides on root and shoot growth of redtip photinia (Photinia × fraseri Lindl.), abelia (Abelia× grandiflora × A. Schumannii Rehd.), azalea (Rhododendron obtusum Planch. ‘Tradition’) and Japanese holly (Ilex crenata Thunb.‘Helleri’) were evaluated in container studies. Experimental design was a randomized complete block with four replications and five containers of each species per plot. Root and shoot weights were recorded five weeks after either one, two or three herbicide applications. Ronstar (oxadiazon) and Ornamental Herbicide II [OH2 (oxyfluorfen plus pendimethalin)] had essentially no adverse effect on shoot or root development of the four species. Rout (oxyfluorfen plus oryzalin), Surflan (oryzalin), Gallery (isoxaben), and Factor (prodiamine) decreased root and/or shoot development of certain species, especially at the first two harvests. Plant size at treatment may be a factor in the extent of stunting caused by preemergence herbicides, with larger plants being more tolerant. Stunting of shoot and root growth appeared to be temporary.

Phytotoxicity and Nutsedge Control in Woody and Herbaceous Landscape Plants with Manage (MON12037)

Abstract Manage applied foliarly at 9 and 18 g/ha(0.13 and 0.26 oz/A) provided 87 to 91% purple nutsedge and 79 to 84% yellow nutsedge control. Regrowth measurements taken 5 WAT showed an 88 to 90% reduction in purple nutsedge resprouting and a 75 to 83% reduction in yellow nutsedge resprouting of Manage applied at 9 g/ha and 18 g/ha (0.13 and 0.26 oz/A), respectively. Azalea, redtip photinia, green liriope, white petunias, red petunias, lavender petunias, celosia, vinca, African marigolds, bronze-leaved begonias, and purple salvia tolerated both rates of Manage. Shore juniper, French marigolds, red salvia, geranium, and green-leaved begonias exhibited >10% injury 4 WAT with Manage.

Evaluation of Three Imidazolinone Herbicides for Control of Yellow and Purple Nutsedge in Woody and Herbaceous Landscape Plants

Abstract Foliar-applications of Pursuit applied at 280 and 560 g/ha (4 and 8 oz/A) provided 97% purple nutsedge and 86% yellow nutsedge control at 560 g/ha (8 oz/A). Foliar-applications of Cadre applied at 70 g/ha(1 oz/A) provided 95% purple nutsedge and 61% yellow nutsedge control. Image provided 70 and 77% yellow nutsedge and 56 and 59% purple nutsedge control applied at 430 g/ha (6 oz/A) and 560 g/ha (8 oz/A), respectively. Azalea ‘Macrantha Orange’ was not tolerant to any of the imidazolinone herbicides tested. Likewise, shore juniper exhibited 17 to 35% growth reduction from the imidazolinone herbicides 4 WAT. Juniper growth reductions increased to between 25 and 37% 8 WAT. Redtip photinia was tolerant to Image at 430 and 560 g/ha (6 and 8 oz/A) and Cadre applied at 35 g/ha (0.5 oz/A). Pursuit-treated photinia exhibited 26 to 33% growth reductions 4 WAT. Green liriope was tolerant of all herbicide treatments 4 WAT. Of the 13 bedding plant taxa tested only French marigolds were found tolerant of Pursuit.

826 PB 301 WATER USE OF LANDSCAPE SHRUBS SURROUNDED BY 4 DIFFERENT MULCHES

A study was conducted to explore how different mulches affect water use of landscape plants. Plots 4.9 m × 7.3 m, were covered with 5cm pine bark, cypress, white rock, or clay aggregate. 3 potted plants of Ligustrum japonicum (wax-leaf ligustrum) and Photinia × fraseri (red tip photinia) were placed in each plot so that the top of each pot was at ground level. 1 plant of each species was planted directly into each plot. Water loss was measured on a daily basis, both gravimetrically and using heat balance stem flow gauges, during both the 1992 and 1993 growing seasons. Stomatal conductance was measured periodically during each growing season. Surface, air, and soil temperatures at two depths were recorded. During 1992, pine bark mulched plants consistently used more water than the other treatments, as opposed to summer 1993 when the most water was used by plants over white rock. Surface temperatures of pine bark, cypress and clay aggregates were higher than those of white rock both years, by as much as 20C, while temperatures under the mulch varied as much as 5C between pine bark and white rock.

Cooling and Warming Effects on Cold Hardiness Estimations of Three Woody Ornamental Taxa

Cooling treatments of 2, 4, and 6C/hour or warming at 25, 4, or 0C influenced the cold hardiness estimates of x Cupressocyparis leylandii (A.B. Jacks. and Dallim.) Dallim. and A.B. Jacks. (Leyland cypress), Lagerstroemia indica L. (crape myrtle), and Photinia ×fraseri Dress `Birmingham' (redtip photinia) at four times during the year. New growth from all taxa, especially spring growth, was injured or killed at higher temperatures by the fastest cooling rate and/or by warming at 25C. Cold hardiness of Leyland cypress was unaffected by the cooling and warming treatments. Crape myrtle had a significantly higher lowest survival temperature (LST) when warmed at 25C than at 4 or 0C. Photinia leaves and stems cooled at 6C/hour or warmed at 25C generally resulted in a higher LST than those cooled more slowly or warmed at lower temperatures. Cooling rates of 14C/hour and warming at 0 to 4C should be used in freeze tests with Leyland cypress and crape myrtle. For leaves and stems of photinia, 2C/hour cooling and warming at 0 to 4C should be used.

Tolerance of Woody Nursery Stock to Classic (chlorimuron) and Harmony (thiameturon)

Abstract Classic and Harmony applied at rates ranging from 0.009 kg ai/ha (0.008 lb ai/A) to 0.067 kg/ha (0.06 lb/A) provided excellent preemergence and postemergence control of common groundsel (Senecio vulgaris L.) 5 weeks after application to container-grown nursery plants. Classic at 0.034 kg/ha (0.03 lb/A) and 0.067 kg/ha (0.06 lb/A) reduced yellow nutsedge (Cyperus esculentus L.) growth by 50 to 77% 5 weeks after preemergence or postemergence treatments. Harmony did not affect yellow nutsedge from either type of application. ‘Seagreen’ juniper (Juniperus chinensis L.), ‘Blue Pacific’ juniper (Juniperus conferta Parl.) and ‘Bennetts Compacta’ holly (Ilex crenata Thunb.) tolerated all rates of Classic and Harmony. ‘Girard's Rose’ (Rhododendron kaempferi Planch.) and ‘Coral Bells’ azale(Rhododendron obtusum (Lindl.) Planch.), and redtip photinia (Photinia × Fraseri Dress) were initially injured by these herbicides, but outgrew the foliar damage.

Tolerance of Leyland Cypress and Red-Tip Photinia to Soil and Foliar Applied Sodium Chloride

Abstract NaCl at 0.15 N was applied 3 times per week as a soil drench or foliar spray to established container-grown plants of Leyland cypress [× Cupressocyparis leylandii (A. B. Jacks. & Dallim.) Dallim. & A. B. Jacks.] and red-tip photinia (Photinia × fraseri Dress ‘Birmingham’). Soil-salt applications were more injurious than spray applications. Leyland cypress did not develop necrosis, but dry weights of plants drenched with salts were reduced. Photinia leaves were necrotic in both salt treatments but dry weight was reduced only with plants receiving soil salts. Tissue Na levels did not reflect the degree of injury while Cl levels correlated with injury. Leyland cypress displayed high salt tolerance and red-tip photinia low tolerance.

Ornamental Response to Two Methods of Oxadiazon Application

Abstract Oxadiazon was applied conventionally as a granular and compared to the emulsifiable concentrate injected into sprinkler irrigation system (chemigation) at 60- day intervals on 20 species of container-grown ornamentals. In general, phytotoxicity increased proportional to the number of applications and was most prevalent during cold weather. Moderate to severe phytotoxicity at 2 × and 4 × rates was observed on aucuba (Aucuba japonica Thunb.), azalea [Rhododendron (AZ) ‘Formosa’ and R. (AZ) ‘Fashionaire’], liriope [Liriope muscari (Decne) L. H. Bailey], pampas grass [Cortaderia selloana (Schult. & Schult. f.) Asch. & Graebn.], Japanese black pine (Pinus thunbergiana Franco), and red tip photinia (Photinia ‘Fraseri’ Dress). Increased injury was observed on aucuba, Japanese black pine, and azalea when oxadiazon was applied via chemigation. On the other species, the degree of phytotoxicity was proportional to the rate applied. Both monocots showed moderate (18%) to severe (45%) injury. The only cultivar with significant growth reductions after 8 months was the ‘Formosa’ azalea when chemigated. The only species with reduced marketability due to the herbicide was liriope. After the second application, the weight and number of weeds decreased proportional to the herbicide rate or number of applications. Chemical name used: 3-[2,4-dichloro-5-(1-methylethoxy)phenyl]-5-(1,1-dimethylethyl)-1,3,4-oxadiazol-2(3H)-one (oxadiazon).