Gouldhensley3772

2 to 33.9°C. Pathogenicity tests were conducted on 9-month-old olive potted plants (Arbequina) inoculated with mycelial plugs. C. luteo-olivacea, Phaeoacremonium minimum, and Phaeomoniella chlamydospora isolates from grapevine were included in the pathogenicity tests for comparative purposes. Prior to inoculation, the effect on the infection by inoculation with conidial suspensions or mycelial plugs was evaluated, with the second method being the most effective. C. luteo-olivacea was the fungus most aggressive to olive, followed by Phaeoacremonium minimum.Fusarium oxysporum f. sp. vasinfectum (FOV) race 4, is a causal agent of Fusarium wilt of cotton (Gossypium spp.). This study aimed to characterize the existing distribution and frequency of current field populations of FOV race 4 genotypes in the San Joaquin Valley (SJV) of California and Lower Valley El Paso, Texas and examine representative isolates for aggressiveness during different stages of seedling development. A survey was conducted from 2017 to 2019 across 13 locations in the SJV and one location in El Paso, Texas during 2018. #link# From the SJV, isolates identified as the FOV race 4 T genotype were dispersed across the SJV, while isolates identified as the FOV race 4 N genotype were most frequently isolated from cotton fields in the northern county of Merced. The FOV race 4 isolates from the Texas location were identified as the MT genotype. A selection of representative isolates was evaluated using three inoculation assays, a rolled towel, FOV infested-oat seed, and a root dip inoculation assay to test the isolates' abilities to produce symptoms during seedling stages of cotton development. All isolates tested were capable of producing symptoms on cotton, however isolate aggressiveness varied within and across inoculation assays. In all assays, higher levels of disease development were observed in the moderately susceptible Pima (G. barbadense L.) cultivars (DP-340 or PYH-830) when compared to the moderately tolerant Upland (G. hirsutum L.) cultivar (FM-2334). However, no correlation was found among the different response variables for the rolled towel assay when compared with the root dip and infested-oat seed assays. learn more suggest that different genes are involved in the resistance response during the early seedling development stage measured in the rolled towel assay compared to the later seedling development stages measured during the root dip inoculation and infested-oat seed assays, revealing the complexity of the Fusarium wilt disease and host-plant resistance mechanisms.Leucophyllum frutescens (Scrophulariaceae family), commonly known as Texas sage or cenizo, is an evergreen shrub native to southwestern United States and northern Mexico. This plant is commercially sold as a native, drought-tolerant ornamental. During the spring of 2019 and 2020, typical symptoms of powdery mildew were found on cenizo plants growing as ornamentals in urban areas in the municipality of Ahome, Sinaloa, Mexico. Disease incidence was 95% from a sampled population of 120 plants. Initial symptoms of powdery mildew developed as irregular white colonies on upper leaf surfaces which expanded as infections progressed. In severe infections, leaves became distorted, exhibiting premature defoliation. link2 Microscopic examination showed nipple-shaped appressoria. Conidiophores (n= 30) were hyaline, cylindrical, erect, 89.4 to 134.2 μm long, and forming catenescent conidia. Foot-cells were cylindrical, 35.7 to 65.3 × 10.2 to 13.5 μm, followed by 1-3 shorter cells. Conidia (n= 100) were hyaline, ellipsoid to ovoidery mildew on a member of Scrophulariaceae, specifically L. frutescens in Mexico and worldwide. Further studies for monitoring and control strategies of powdery mildew on Texas sage are required.Kiwifruit (Actinidia spp.) is an economically important fruit crop globally. China is the largest kiwifruit-growing country in the world, and Shaanxi Province is the major kiwifruit-growing region in China. A systematic survey detected various symptoms in kiwifruit plants grown in a commercial kiwifruit field in Shaanxi Province. Samples were collected from kiwifruit plants showing symptoms and used for virus detection by high-throughput sequencing. In addition to 10 known kiwifruit viruses, three new viruses were detected and tentatively named Actinidia yellowing ringspot virus (AYRSpV), Actinidia yellowing virus 1 (AcYV1), and Actinidia yellowing virus 2 (AcYV2). The genome sequences of the three new viruses and four known viruses were determined. Based on the demarcation criteria of the International Committee on Taxonomy of Viruses, AYRSpV might be a new member of the genus Ilarvirus in the family Bromoviridae, AcYV1 might be a new virus of the genus Waikavirus in the family Secoviridae, and AcYV2 might be a novel virus in the family Tombusviridae. Spherical viral particles were found in the samples infected with AYRSpV, AcYV1, and AcYV2 by transmission electron microscopy. Further analysis showed that all 13 viruses can infect both Actinidia deliciosa and A. chinensis but the incidences of these infections vary among different kiwifruit cultivars in different regions. These results provide valuable information for understanding the virome of kiwifruit in China.Amygdalus triloba (Rosaceae; previously Prunus triloba) is a deciduous, flowering shrub that is widely used in the greening and beautification of lawns, parks and courtyards in China. In late May 2019, a leaf spot disease of A. triloba was observed on approximately 35% of plants in the Xinjiang Alaer city (40˚33'20N, 81˚17'19E). The disease symptoms began as small, suborbicular, brown spots on the leaves. As the disease progressed, the spots enlarged and coalesced into large necrotic areas and resulted in premature defoliation. Leaf sections (5 x 5 mm) from infected leaves were surface - sterilized with 75% ethanol for 30 s and 0.1% HgCl2 for 1 min, rinsed three times in sterile distilled water and then incubated on potato dextrose agar (PDA). Fifteen fungal isolates showing similar morphological characteristics were obtained by single-spore isolation. On the PDA plates, all fungal colonies had a dark olive color with loose, cottony mycelium. On the potato carrot agar, the fungus formed unbranched spore cdson, G. C. 1995. Appl. Environ. Microbiol. 611323. Simmons, E. G. 2007. Alternaria An Identification Manual. CBS Fungal Biodiversity Centre, Utrecht, The Netherlands. White, T. J., et al. 1990. PCR Protocols A Guide to Methods and Applications. Academic Press, San Diego, CA. Xie, Y., et al. 2017. link3 Liaoning Agricultural Sciences. 6 73.Rubbery taproot disease (RTD) of sugar beet was observed in Serbia for the first time in the 1960s. The disease was already described in neighboring Bulgaria and Romania at the time but it was associated with abiotic factors. In this study on RTD of sugar beet in its main growing area of Serbia, we provide evidence of the association between 'Candidatus Phytoplasma solani' (stolbur phytoplasma) infection and the occurrence of typical RTD symptomatology. 'Ca. P. solani' was identified by PCR and the sequence analyses of 16S ribosomal RNA, tuf, secY, and stamp genes. In contrast, the causative agent of the syndrome "basses richesses" of sugar beet-namely, 'Ca. Arsenophonus phytopathogenicus'-was not detected. Sequence analysis of the stolbur strain's tuf gene confirmed a previously reported and a new, distinct tuf stolbur genotype (named 'tuf d') that is prevalent in sugar beet. The sequence signatures of the tuf gene as well as the one of stamp both correlate with the epidemiological cycle and reservoir plant host. This study provides knowledge that, for the first time, enables the differentiation of stolbur strains associated with RTD of sugar beet from closely related strains, thereby providing necessary information for further epidemiological work seeking to identify insect vectors and reservoir plant hosts. The results of this study indicate that there are differences in hybrid susceptibility. Clarifying the etiology of RTD as a long-known and economically important disease is certainly the first step toward disease management in Serbia and neighboring countries.In April 2018, damping-off of rice (Oryza sativa L.) seedlings at the 2-to-3-leaf stage was observed in three fields in the counties of Wharton and Matagorda of Texas and Jefferson-Davis Parish of Louisiana. All affected areas were 1 ha or greater, with 10 to 20% of the seedlings showing the symptoms. Infected seedlings showed dark-brown necrotic lesions on the roots and/or mesocotyls where white superficial mycelium was usually present. Symptomatic tissues excised from 10 diseased seedlings of each field were surface sterilized with 1% NaOCl, double rinsed in sterilized distilled water, and plated on potato dextrose agar (PDA). The plates were incubated at 25°C with a 12-h photoperiod in a growth chamber. After 48 h, hyphal tips of fungal colonies were transferred onto PDA and 12 isolates were obtained. Clamp connections and dolipore septa were observed in young hyphae, indicating that these isolates were a basidiomycete fungus. Young hyphal cells were binucleate based on safranin O stain (Bandoni 1979). No WB strain (ATCC 28344) causing stem rot of snap bean in Florida was further identified as M. graminum based on nuclear large subunit rRNA gene (Vinnere et al. 2005). Comparing the ITS region of this isolate (AY445120) with our isolate revealed a 99% similarity. To our knowledge, this is the first report that the SWB fungus M. graminum causes seedling blight in rice. Identification of this new disease will help to develop management strategies for control of stand loss in rice.Xanthomonas arboricola pv. pruni (Xap) causes bacterial spot of leaves and fruits, defoliation, fruit dropping and twigs, branches or trunk cankers in most cultivated and ornamental Prunus species. The bacterium is listed as an EPPO (European and Mediterranean Plant Protection Organisation) A2 quarantine pathogen. Xap was first detected in 2019 on peach [Prunus persica L., unknown cultivar (cv.)] leaves in a 13-year-old orchard located in Irig (GPS 45°6'10.538 N, 19°54'8.04 E), with a disease incidence of 10-20%. Thereafter, Xap was detected in 2020 on apricot (Prunus armeniaca L., cvs. NS4, NS Rodna and Roxana) leaves and fruits in a 5-year-old orchard located in Bešenovo (GPS 45°04'59.0 N, 19°41'23.0 E), with disease incidence of 30-50%. Symptoms on leaves appeared along leaf midribs or margins in form of brown to black spots, with a pale green to yellow halo, evident on both leaf surfaces. The diseased area on leaves dropped out giving a shot-hole appearance, leaves turn yellow and drop prematurelyhe same as the original using PCR (1), fulfilling Koch's postulates. This is the first report of Xap in Serbia, which has occurred with a limited distribution in the Fruška Gora region (Vojvodina). Only two orchards in Serbia have been deteched with Xap so far. In the diseased peach orchard Xap was eradicated by uprooting trees. The apricot orchard is still under official control to limit disease spread. Appropriate cultivation practices, national inspection and surveillance is in place to prevent further pathogen spread and establishment to new hosts and regions in Serbia.