Fusarium Wilt of Korean Blackberry Caused by Fusarium cugenangense

Wilt symptoms were frequently observed in Korean blackberry (Rubus coreanus) plants grown in farmers’ fields located in Gochang and Jeongeup, Jeonbuk Province, Korea during disease surveys in July 2020. The disease occurred in 10 of the 13 fields surveyed in the two locations. The incidence of diseased plants in the fields was 5-80%. Seven isolates of Fusarium sp. were obtained from the diseased plants and examined for their morphological and molecular characteristics. All the isolates belonged to Fusarium oxysporum species complex based on the morphological characteristics but were identified as F. cugenangense based on the molecular characteristics. Two isolates of F. cugenangense were tested for pathogenicity on Korean blackberry plants by artificial inoculation. Pathogenicity of the two isolates on the plants was confirmed with the inoculation tests, which showed wilt symptoms similar to those observed in the diseased plants in the fields investigated. This is the first report of F. cugenangense causing Fusarium wilt in Korean blackberry.

Risk, worry and motivation: How is public knowledge of dementia shaped?

Background and Objectives Due to the concern over global rising rates of dementia, increased emphasis has been placed on understanding and moulding the public’s knowledge and awareness of the condition. There has been limited previous research into predictors of dementia knowledge; overall knowledge amongst the public is low, and it has been widely agreed that more needs to be done to raise awareness of this condition. This study seeks to solidify understanding of public dementia knowledge and introduces dementia worry, motivation to seek information and risk perception as novel concomitants of this knowledge. Research Design and Methods A convenience sample of 311 UK adults completed a survey on dementia knowledge including Alzheimer’s disease-specific questions, worry about developing dementia, motivation to seek information and perceived personal risk of getting the disease. Surveys were completed face-to-face and included both closed and open-ended questions. Results Overall dementia knowledge scores were low, achieving an average of 33% of the total possible score, with 88% of the sample scoring below 50%. Bivariate correlations were performed between dementia knowledge and key variables, revealing significant positive relationships with risk perception ( r = 0.179, p = .002), worry ( r = 0.140, p = .016) and motivation to seek information ( r = 0.139, p = .016). When knowledge was dichotomised into high and low, worry about ( p = .28) and perceived risk ( p = .19) of dementia was significantly lower for people with low knowledge scores than for people with higher dementia knowledge scores. Motivation to seek information was not significantly different between the high and low knowledge groups ( p = .071). Discussion and Implications Despite the relatively low knowledge scores, findings show a positive relationship between modifiable factors and dementia knowledge, suggesting areas to consider for both further research and publication campaigns. Further implications and limitations of this study are discussed.

A comparative baseline of coral disease across the central Red Sea

The Red Sea is a unique environment for corals with a strong environmental gradient characterized by temperature extremes and high salinities, but minimal terrestrial runoff or riverine input and their associated pollution. Disease surveys were conducted along 22 reefs in the central Red Sea along the Saudi Arabian coast in October 2015, which coincided with a bleaching event. Our objectives were to 1) document types, prevalence, and distribution of coral diseases in a region with minimal terrestrial input, 2) compare regional differences in diseases and bleaching along a latitudinal gradient of environmental conditions, and 3) use histopathology to characterize disease lesions at the cellular level. Coral reefs of the central Red Sea had a widespread but a surprisingly low prevalence of disease (<0.5%), based on the examination of >75,750 colonies. Twenty diseases were recorded affecting 16 coral taxa and included black band disease, white syndromes, endolithic hypermycosis, skeletal eroding band, growth anomalies and focal bleached patches. The three most common diseases were Acropora white syndrome (59.1% of the survey sites), Porites growth anomalies (40.9%), and Porites white syndrome (31.8%). Over half of the coral genera within transects had lesions and corals from the genera Acropora, Millepora and Lobophyllia were the most commonly affected. Cell-associated microbial aggregates were found in four coral genera resembling patterns found in the Indo-Pacific. Differences in disease prevalence, coral cover, amount of heat stress as measured by degree heating weeks (DHW) and extent of bleaching was evident among sites. Disease prevalence was not explained by coral cover or DHW, and a negative relationship between coral bleaching and disease prevalence was found. The northern-most sites off the coast of Yanbu had the highest average DHW values but absence of bleaching and the highest average disease prevalence was recorded. Our study provides a foundation and baseline data for coral disease prevalence in the Red Sea, which is projected to increase as a consequence of increased frequency and severity of ocean warming.

Incidence, Severity, and Characterization of Phytophthora Foot Rot of Citrus in Texas and Implications for Disease Management

Phytophthora-induced foot rot, also known as gummosis, is an important disease affecting citrus production worldwide. In Texas, the third-largest citrus-producing state in the United States, limited information is available on the etiology and epidemiology of foot rot in commercial orchards. This study comprises a survey of foot rot incidence and severity in Texas and the characterization of Phytophthora isolates associated with the disease. Surveys in 2015 and 2017 of 30 orchards in the Lower Rio Grande Valley (LRGV) region where commercial citrus production is concentrated in the state revealed that foot rot occurred in 97% of the orchards assessed. Overall, foot rot symptoms were observed on 33.7% of the trees evaluated and the disease severity index in the region was rated at 14.2 and 16.5% in 2015 and 2017, respectively. Lesions were mostly present on the scion, while the rootstock (sour orange) was not affected. Phytophthora nicotianae was the only Phytophthora sp. isolated from the surveyed orchards and from five additional residential sites on the Texas Coastal Bend (TCB). Sporangia and chlamydospores from 34 representative LRGV isolates of P. nicotianae were larger than those of TCB isolates. In both LRGV and TCB, A1 and A2 mating types were present in the same location, albeit the A2 mating type was more prevalent. All isolates were sensitive to mefenoxam (50% inhibition in the presence of mefenoxam [EC50] < 0.5 µg/ml), except for one TCB isolate (EC50 = 143.6 µg/ml). Our research indicates that treatment for Phytophthora foot rot in the region is necessary and, although mefenoxam is still useful, alternating chemistries for resistance management are required.

Survey and Identification of Rice Diseases in South Gondar Zone, Amhara Region, Ethiopia

Disease surveys were conducted in rice grown districts of Libokemkem, Dera and Fogera in south Gondar zone in 2016 and 2017 cropping seasons. The study was designed to identify and record rice disease flora, their distribution in the districts, prioritize according to the importance and document for future use. Forty-six and 48 rice fields were assessed from nine Peasant Association (PA) in 2016 and 2017 cropping seasons, respectively. Rice diseases; Leaf blast, Panicle Blast, Brown spot, Sheath rot, Sheath brown rot, Sheath Blight, Bacterial blight, Rice Yellow Motile Virus, Kernel smut, Downy mildew were identified in 2016 cropping season and nine rice diseases: Leaf blast, Panicle Blast, Neck Blast, Node blast, Brown spot, Sheath rot, Sheath brown rot, Rice Yellow Motile Virus, Kernel smut were identified in 2017. The overall mean prevalence of sheath rot and sheath brown rot diseases were above 60%, while the others had prevalence below 21%. The incidences and severities of these two diseases were higher than the other diseases implying that both diseases were important. In the present studies many rice diseases were recorded in lowland ecosystem as compared to upland ecosystem. From the assessment X-jigna cultivar was more susceptible to rice disease and followed by Gumera. The results indicate that a sheath rot, and sheath brown rot, were important across the districts and years. Loss assessment studies should be initiated in order to know the yield damage caused by the diseases.

Sugarcane Mosaic Distribution, Incidence, Increase, and Spatial Pattern in Louisiana

Sugarcane mosaic is a historically important disease in Louisiana currently caused by sorghum mosaic virus (SrMV). Successful breeding for resistance reduced the disease to low incidence in commercial cultivars. However, mosaic was detected in experimental clone evaluations at multiple locations, leading to uncertainty concerning the current distribution and incidence in the state. Field surveys were conducted from 2016 to 2018 in breeding program yield trials and experimental clone seed cane increase fields. Mosaic symptomatic plants were observed in a newly released cultivar, HoCP 09-804, in three of five production areas, with incidences ranging from 0 to 10%. Mosaic also was observed in nine additional experimental clones. Single leaf samples were tested for SrMV using reverse transcription PCR. All symptomatic samples and a low percentage (0.3%) of asymptomatic samples tested positive for SrMV, confirming that it continues to be the causal species. Runs analysis detected aggregation of infected plants within at least 70% of rows in 94% of surveyed fields. The spatial pattern and geographical distribution of disease incidence suggested that infected seed cane was the source of the disease. Surveys conducted in the same fields of HoCP 09-804 through two subsequent crops detected disease incidence increases in some fields and decreases in the others in first ratoon, but observed incidence was lower compared with plant cane in all fields in second ratoon. The results indicated that disease increase owing to aphid transmission did not occur under the prevailing conditions.

Timing of Grape Downy Mildew Onset in Bordeaux Vineyards

Grapevine downy mildew (GDM) is a severe disease of grapevines. Because of the lack of reliable information about the dates of GDM symptom onset, many vine growers begin fungicide treatments early in the season. We evaluate the extent to which such preventive treatments are justified. Observational data for 266 untreated sites for the years between 2010 and 2017 were used to estimate the timing of GDM onset on vines and bunches of grapes in South West France (Bordeaux region) through survival analyses. The onset of GDM was not apparent on vines and bunches before early to mid-May, and the rate of GDM symptom appearance was highly variable across years. Depending on the year, 50% of the plots displayed symptoms between mid-May and late June for vines. For several years, our statistical analysis revealed that the proportion of plots with no symptoms was high in early August on vines (27.5 and 43.7% in 2013 and 2016) and on bunches (between 23 and 79% in 2011, 2013, and 2016). We found a significant effect of the amount of rainfall in spring on the date of symptom appearance. These results indicate that preventive fungicide application is unjustified in many vineyards, and that regional disease surveys should be used to adjust fungicide treatment dates according to local characteristics, in particular according to rainfall conditions in spring.

Comprehensive Disease Survey of U.S. Sunflower: Disease Trends, Research Priorities and Unanticipated Impacts

Between 2002 and 2015, a comprehensive survey of sunflower fields across seven Midwestern U.S. states was conducted 12 times and continues to be conducted every other year. The surveyors collected data on yield, agronomic management factors, disease, insect, weed, and bird damage. All surveyors were volunteers and came from universities (extension and research staff), USDA-ARS, and seed and chemical companies. In the 12 years the survey was conducted, data from 2,267 fields were collected. The results are presented annually at the National Sunflower Association Research Forum and are used to set sunflower research priorities. While 10 diseases are surveyed annually, we focus this article on the importance, findings, implications, and impacts of the five most important: downy mildew, Phomopsis stem canker, rust, Rhizopus head rot, and Sclerotinia head rot. This survey is unique among field crops in both scope and scale, and this manuscript discusses salient and clandestine benefits of intense and long-term disease surveys.