scholarly journals First Report of Resistance to Quinoxyfen in Podosphaera xanthii, Causal Agent of Cucurbit Powdery Mildew, in the United States

2017 ◽  
Vol 18 (2) ◽  
pp. 94-94 ◽  
Author(s):  
M. T. McGrath

This brief reports the first known occurrence of resistance to quinoxyfen, a quinoline (FRAC Group 13) fungicide, in Podosphaera xanthii in the United States. This fungus causes powdery mildew in cucurbit crops, the most common disease of this important crop group. Mobile, targeted fungicides, which have moderate or high resistance risk, are the most effective management tool for this disease. The pathogen is a documented high resistance-risk organism, having already developed resistance to fungicides in FRAC Groups 1, 3, 7, and 11.

2018 ◽  
Vol 19 (3) ◽  
pp. 222-223 ◽  
Author(s):  
Margaret T. McGrath ◽  
Zachary F. Sexton

This report is about the first known occurrence of resistance to cyflufenamid, a Fungicide Resistance Action Committee (FRAC) code U6 fungicide, in Podosphaera xanthii in the United States. This fungus causes powdery mildew in cucurbit crops, the most common disease of this important crop group. Knowledge about resistance is important for guiding fungicide programs. Mobile, targeted fungicides, which have moderate or high resistance risk, are the most effective management tool for this disease. The pathogen is a documented high resistance risk organism having already developed resistance to fungicides in FRAC groups 1, 3, 7, 11, and 13.


2017 ◽  
Vol 18 (2) ◽  
pp. 93-93 ◽  
Author(s):  
M. T. McGrath ◽  
C. A. Wyenandt

The most effective management tool for powdery mildew on cucurbit crops is mobile, targeted fungicides having a moderate or high resistance risk and the causal pathogen has proven to be a high-risk organism. Information about occurrence of resistance to a new chemical group and impact on resistance management is important for guiding fungicide programs and contributing to scientific knowledge about resistance development. This brief reports the first known occurrence of resistance to a succinate dehydrogenase inhibitor fungicide in Podosphaera xanthii in the United States.


2007 ◽  
Vol 132 (6) ◽  
pp. 790-795 ◽  
Author(s):  
Angela R. Davis ◽  
Amnon Levi ◽  
Antonia Tetteh ◽  
Todd Wehner ◽  
Vincent Russo ◽  
...  

Powdery mildew [Podosphaera xanthii (Castagne) Braun & Shishkoff (syn. Sphaerotheca fuliginea auct. p.p.)] is now a common disease on watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai] in the United States. In this study, the entire available U.S. Plant Introduction collection of Citrullus Schrad. ex Eckl. & Zeyh. species was evaluated for resistance to P. xanthii race 1W. The collection consists of four Citrullus species and one Praecitrullus Pangalo species [C. lanatus var. citroides (L.H. Bailey) Mansf., C. colocynthis (L.) Schrad., C. rehmii De Winter, and P. fistulosus (Stocks) Pangalo]. Wild-type accessions tended to be more resistant more often than the cultivated species, C. lanatus var. lanatus. None were immune, eight of the 1573 accessions exhibited high levels of resistance, and another 86 demonstrated intermediate resistance. Stem and leaf disease severity were weakly correlated (r 2 = 0.64, P = 0.001). The majority of accessions having resistance were collected in Zimbabwe. Resistance was found in four species.


Plant Disease ◽  
2018 ◽  
Vol 102 (7) ◽  
pp. 1290-1298 ◽  
Author(s):  
Chandrasekar S. Kousik ◽  
Mihir Mandal ◽  
Richard Hassell

Powdery mildew (PM) is a major foliar disease causing serious economic losses of cucurbit crops grown in the United States. The pathogen Podosphaera xanthii, which causes PM, is known to infect seedlings, stems, foliage, petioles, and fruit of cucurbit crops. In recent years, grafting watermelon on resistant rootstocks for managing soilborne diseases has been gaining popularity in the U.S.A. However, grafting for managing foliar diseases has not yet received adequate attention. Three greenhouse experiments were conducted during the summer months of 2012, 2013, and 2014 to determine if PM-resistant rootstocks could impart resistance to a susceptible watermelon scion. Susceptible watermelon scion ‘Mickey Lee’ seedlings were grafted onto 25 watermelon (Citrullus lanatus, C. amarus, C. mucosospermus) and four bottle gourd (Lagenaria siceraria) rootstocks. Grafted plants were inoculated with a 2 × 104 conidia ml−1 suspension of P. xanthii conidia and disease severity was rated 14 days after inoculation. Mickey Lee grafted on six PM-resistant watermelon rootstocks had significantly (P ≤ 0.05) lower PM severity on cotyledons, 2nd true leaf, and upper leaves (rating for 3rd to 7th or 8th true leaf) compared with Mickey Lee grafted on susceptible watermelon USVL677-PMS or bottle gourd USVL848-PMS rootstocks. However, some of the resistant watermelon rootstocks did not impart significant resistance to the scion. The resistant bottle gourd rootstocks USVL482-PMR and USVL351-PMR provided significantly greater levels of resistance, compared with many of the resistant watermelon rootstocks. Grafting watermelon on resistant rootstocks may help mitigate the effects of PM on susceptible scion seedlings.


Plant Disease ◽  
2003 ◽  
Vol 87 (8) ◽  
pp. 1007-1007 ◽  
Author(s):  
M. T. McGrath ◽  
N. Shishkoff

Resistance to strobilurin fungicides was documented in isolates collected from three fungicide efficacy experiments conducted in research fields in Georgia (GA), North Carolina (NC), and New York (NY). In these fields in 2002, strobilurins (fungicide group 11, quinone outside inhibitors [QoI]) when used alone on a 7-day schedule (use pattern not labeled) did not effectively control cucurbit powdery mildew. Strobilurin efficacy declined dramatically after the second application in New York (3). Efficacy also was reduced in commercial fields in Kentucky and research fields in Arizona, California, Kentucky, Illinois, Michigan, and Virginia in 2002 where strobilurins were used predominantly or exclusively. Isolates were collected on 22 July and 8 and 17 October after the last of four, five, and five applications of strobilurin (trifloxystrobin formulated as Flint or azoxystrobin formulated as Quadris) in experiments conducted by J. D. Moore in Chula, GA, M. McGrath in Riverhead, NY, and G. J. Holmes in Clayton, NC, respectively. A leaf-disk bioassay was used to determine fungicide sensitivity (2). Strobilurin sensitivity was determined using trifloxystrobin at 0, 0.5, 5, 50, and 100 μg/ml. Four of nine NY isolates, 19 of 21 GA isolates, and 13 of 15 NC isolates were resistant to strobilurins (grew well on disks treated with trifloxystrobin at 100 μg/ml). The geometric mean of the azoxystrobin baseline was 0.258 μg/ml for Podosphaera xanthii isolates collected in 1998 and 1999 in North America (4). Poor control with strobilurins under field conditions was associated with reduced sensitivity in vitro. Strobilurin sensitivity appeared to be qualitative as reported elsewhere (1). Two sensitive and three resistant isolates responded similarly when tested in another laboratory using kresoxim-methyl and pyraclostrobin (H. Ypema, personal communication). These findings and experiences elsewhere with QoI-resistant P. xanthii indicate that cross-resistance probably extends among multiple QoI's (1). Strobilurins have been available for commercial use in the United States since 1998, when azoxystrobin received Section 18 registration in some states. Federal registration was granted in March 1999. Strobilurin resistance was detected after 2 years of commercial use elsewhere in the world (1). All isolates tested in the current study were from research fields where selection pressure for resistance could have been higher than in commercial fields where strobilurins are used with demethylation inhibitors (DMIs; fungicide group 3) and contact fungicides in alternation or tank mixtures to prevent or delay resistance development. Resistance in commercial fields will reduce the utility of strobilurins, including those not yet registered, and eliminate an important tool for managing DMI resistance. Strobilurins and DMIs are the only systemic fungicides registered for cucurbit powdery mildew in the United States. Managing DMI resistance may be challenged by multiresistant strains. Strobilurin-resistant isolates also exhibited reduced sensitivity to DMIs, tolerating triadimefon at 50 to 100 μg/ml (2). One suggestion to improve resistance management is to apply a contact fungicide with strobilurins as well as DMIs. References: (1) H. Ishii et al. Phytopathology 91:1166, 2001. (2) M. T. McGrath et al. Plant Dis. 80:697, 1996. (3) M. T. McGrath and N. Shishkoff. Fungic. Nematic. Tests. (In press). (4) G. Olaya et al. Phytopathology (Abstr.) 90 (suppl):S57, 2000.


Plant Disease ◽  
2020 ◽  
Vol 104 (3) ◽  
pp. 951-957 ◽  
Author(s):  
Y. Xiang ◽  
A. N. Miller ◽  
M. McGrath ◽  
M. Babadoost

This research was conducted to identify species causing powdery mildew on cucurbits and to determine genetic variations among isolates of the pathogen. We collected 109 isolates from six cucurbit species hosts (Cucumis melo, Cucumis sativus, Cucurbita maxima, Cucurbita moschata, Cucurbita pepo, and Lagenaria siceraria) in California, Illinois, Indiana, Michigan, New York, Texas, Washington, and Wisconsin in the United States and in Italy. By sequencing the internal transcribed spacer region of the nuclear rDNA of these 109 isolates, Podosphaera xanthii was found as the only species causing powdery mildew on cucurbits in the United States. Genotyping-by-sequencing was applied to these 109 isolates to investigate their genetic diversity, which showed a trend of isolates clustering from New York and Italy. In addition, the virulence of 36 isolates was compared and a significant difference (P < 0.0001) was found among them. Furthermore, results of the virulence tests of 28 isolates from Illinois showed significant effects of collection years, hosts, and locations on the virulence of the isolates.


2020 ◽  
Author(s):  
Haya Jarad ◽  
Junhua Yang ◽  
Abeed Sarker

BACKGROUND Opioid misuse is a major health problem in the United States, and can lead to addiction and fatal overdose. The United States is in the midst of an opioid epidemic; in 2018, an average of approximately 130 Americans died daily from an opioid overdose and 2.1 million have an opioid use disorder (OUD). In addition to electronic health records (EHRs), social media have also been harnessed for studying and predicting physical and behavioral outcomes of OUD. Specifically, it has been shown that on Twitter the use of certain language patterns and their frequencies in subjects’ tweets are indicative of significant healthcare outcomes such as opioid misuse/use and suicide ideation. We sought to understand personal traits and behaviors of Twitter chatters relative to the motive of opioid misuse; pain or recreational. OBJECTIVE . METHODS We collected tweets using the Twitter public developer application programming interface (API) between April 13, 2018 – and May 21, 2018. A list of opioid-related keywords were searched for such as methadone, codeine, fentanyl, hydrocodone, vicodin, heroin and oxycodone. We manually annotated tweets into three classes: no-opioid misuse, pain-misuse and recreational-misuse, the latter two representing misuse for pain or recreation/addiction. We computed the coding agreement between the two annotators using the Cohen’s Kappa statistic. We applied the Linguistic Inquiry and Word Count (LIWC) tool on historical tweets, with at least 500 words, of users in the dataset to analyze their language use and learn about their personality raits and behaviors. LIWC is a text processing software that analyzes text narratives and produces approximately 90 variables scored based on word use that pertain to phsycological, emotional, behavioral, and linguistic processes. A multiclass logistic regression model with backward selection based on the BIC criterion was used to identify variables associated with pain and recreational opioid misuse compared to the base class; no-opioid misuse.. The goal was to understand whether personal traits or behaviors differ across different classes. We reported the odd ratios of different variables in both pain and recreational related opioid misuse classes with respect to the no-opioid misuse class. RESULTS The manual annotation resulted in a total of 1,164 opioid related tweets. 229 tweets were assigned to the pain-related class, 769 were in the recreational class, and 166 tweets were tagged with no opioid misuse class. The overall inter-annotator agreement (IAA) was 0.79. Running LIWC on the tweets resulted in 55 variables. We selected the best model based on BIC. We examined the variables with the highest odd ratios to determine those associated with both pain and recreational opioid misuse as compared to the base class. Certain traits such as depression, stress, and melancholy are established in the literature as commonplace amongst opiod abuse indiviuals. In our analysis, these same characteristics, amongst others, were identified as significantly positively associated with both the Pain and Recreational groups compared to the no-opioid misuse group. Despite the different motivaions for opiod abuse, both groups present the same core personality traits. Interestingly, individuals who misuse opioids as a pain management tool exhibited higher odds ratios for psychological processees and personal traits based on their tweet language. These include a strong focus on discipline, as demonstrated by the variables “disciplined”, “cautious” and “work_oriented”. Their tweet language is also indicative of cheerfulness, a variable absent in the recreational misuse group. Variables associated with the reacreational misuse group revolve around external factors. They are generous and motivated by reward, while maintaining a religious orientation. Based on their tweet language, this group is also characterized as “active”; we understand that these individuals are more social and community focused . CONCLUSIONS To our best knowledge, this is the first study to investigate motivations of opioid abuse as it relates to tweet language. Previous studies utilizing Twitter data were limited to simply detecting opiod abuse likelihood through tweets. By delving deeper into the classes of opioid abuse and its motivation, we offer greater insight into opioid abuse behavior. This insight extends beyond simple identification, and explores patterns in motivation. We conclude that user language on Twitter is indicative of significant differences in personal traits and behaviors depending on abuse motivation: pain management or recreation.


2010 ◽  
Vol 11 (1) ◽  
pp. 32 ◽  
Author(s):  
Christian A. Wyenandt ◽  
Steven L. Rideout ◽  
Beth K. Gugino ◽  
Margaret T. McGrath ◽  
Kathryne L. Everts ◽  
...  

Foliar diseases and fruit rots occur routinely on tomato, an important crop grown throughout the Mid-Atlantic and Northeast regions of the United States where it is produced for both fresh-market and processing. To enable these tomato growers to more effectively manage economically important diseases, a fungicide resistance management table has been developed which promotes the importance of understanding FRAC (Fungicide Resistance Action Committee) codes and provides an integrated pest management tool for tomato growers which will allow them to develop season-long disease control programs with an emphasis on fungicide resistance management. Accepted for publication 19 July 2010. Published 27 August 2010.


2021 ◽  
Author(s):  
◽  
Folabi Ariganjoye ◽  

The prevalence of prediabetes and diabetes in the United States and around the world has increased faster than expected in the last 30 years. The economic burden this costs a nation can be astronomic both in terms of expense and loss in productivity. One-third of U.S. adults, 86 million people, have prediabetes. Effective management is needed that can reach these 86 million, and others at high risk, to reduce their progression to diagnosed Type 2 diabetes. After the literature review, there was not enough literature to support how these led to the progression to diabetes. The abundant literature is centered on how to prevent complications and improve the quality of life of those living with type 2 diabetes. This paper will focus on the longitudinal association between these social determinants and how they may predispose to the progression to Type 2 diabetes.


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