Postinfection Application of Fenhexamid at Lower Doses in Conjunction with Captan Slowed Fungicide Resistance Selection in Botrytis cinerea on Detached Grape Berries.

Fungicide resistance is a limiting factor in sustainable crop production. General resistance management strategies such as rotation and mixtures of fungicides with different modes of action have been proven to be effective in many studies, but guidance on fungicide dose or application timing for resistance management remains unclear or debatable. In this study, Botrytis cinerea and the high-risk fungicide fenhexamid were used to determine the effects of fungicide dose, mixing partner, and application timing on resistance selection across varied frequencies of resistance via detached fruit assays. The results were largely consistent with the recent modeling studies that favored the use of the lowest effective fungicide dose for improved resistance management. In addition, even 10% resistant B. cinerea in the population led to about a 40% reduction of fenhexamid efficacy. Overall, our findings show that application of doses less than the fungicide label dose, mixture with the low-risk fungicide captan, and application postinfection seem to be the most effective management strategies in our controlled experimental settings. This somewhat contradicts the previous assumption that preventative sprays help resistance management.

Validation of fungicide spray strategies and selection for fenhexamid resistance in Botrytis cinerea on greenhouse-grown grapevines.

In this study, in planta assays were conducted to assess the effects of fungicide spray tactics, such as the reduction of the labeled fungicide dose and mixture with a multi-site fungicide, on fungicide resistance selection and disease control using Vitis vinifera 'Cabernet Sauvignon' grown in a greenhouse for two years. The entire clusters were inoculated with B. cinerea isolates at varying frequencies of fenhexamid resistance, followed by fungicide sprays, disease and fenhexamid resistance investigations at critical phenological stages. Our findings indicate that the lower dose of the at-risk fungicide, fenhexamid, effectively managed fenhexamid resistance and disease as well as the higher, labeled dose. In addition, mixture with the multi-site fungicide captan generally resulted a net-positive effect on both resistance management and disease control.

Diffuse Associations Between Drosophila suzukii and Filamentous Fungal Microbes May Alter Caneberry Disease Dynamics.

Interactions between microorganisms and frugivorous insects can modulate fruit rot disease epidemiology. Insect feeding and/or oviposition wounds may create opportunities for fungal infection. Passive and active dispersal of fungal inoculums by adult insects also increases disease incidence. In fall-bearing raspberries and blackberries, such vectoring interactions could increase crop damage from the invasive pestiferous vinegar fly Drosophila suzukii (spotted-wing drosophila). Periods of peak D. suzukii activity are known to overlap with several species of primary fruit rot pathogen, particularly Botrytis cinerea and Cladosporium cladosporioides, and previous work indicates that larvae co-occur with and feed on various filamentous fungi at low rates. To further our understanding of the epidemiological consequences that may emerge from these associations, we surveyed the filamentous fungal community associated with adult D. suzukii, isolating and molecularly identifying fungi externally and internally (indicating feeding) from field-collected adults over 3 years. We isolated and identified 37 unique genera of fungi in total, including known raspberry pathogens. Most fungi were detected infrequently, and flies acquired and carried fungi externally at higher richness, frequency, and density relative to internally. In a worst-case scenario laboratory vectoring assay, D. suzukii adults were able to transfer B. cinerea and C. cladosporioides to sterile media at 0, 24, 48, and 72 h after exposure to sporulating cultures in Petri dishes. These results collectively suggest an adventitious vectoring association between D. suzukii and fruit rot fungi that has the potential to alter caneberry disease dynamics.

Utilizing Disease Prediction Models to Time Fungicide Applications for Controlling Ripe Rot, Caused by Colletotrichum spp., in Maryland Vineyards.

Two previously published ripe rot prediction models, DF2-NN and GH2-DT, were evaluated for fungicide application timing efficacy in Maryland vineyards. Both models utilize leaf wetness duration (LWD), temperature, and grape cluster phenological stages as model parameters. These three parameters were tracked throughout the 2021 to 2023 seasons in three vineyards. The fungicide efficacy trials started at the veraison phenological stage and included a nontreated control, a 12-day interval treatment, and two model-triggered treatments when risk predicted by the models crossed a threshold. The severity of ripe rot on the clusters in each treatment was assessed when the fruit were mature. Ripe rot severity in the nontreated controls was higher during seasons with more LWD and more precipitation. Days in which the models were triggered by the environmental conditions primarily coincided with precipitation events and lengthy LWDs. The model-triggered treatments never had significantly higher ripe rot severity than the 12-day interval treatment but had significantly lower severities than the nontreated control in most trials which had high ripe rot pressure. Furthermore, the model-triggered treatments resulted in fewer fungicide applications than the 12-day interval treatment on average. The DF2-NN model appeared to be more accurate and useful for ripe rot prediction and treatment than the GH2-DT model because it triggered fewer fungicide applications while reducing ripe rot. This model may be useful for improving or maintaining ripe rot control with fewer fungicide inputs, which may be beneficial for the environment and the reduction of fungicide resistance selection.

Acid Radical Tolerance of Silane Coatings on Calcium Silicate Hydrate Surfaces in Aggressive Environments: The Role of Nitrate/Sulfate Ratio.

Silane is known as an effective coating for enhancing the resistance of concrete to harmful acids and radicals that are usually produced by the metabolism of microorganisms. However, the mechanism of silane protection is still unclear due to its nanoscale attributes. Here, the protective behavior of silane on the calcium silicate hydrate (C-S-H) surface is examined under the attack environment of nitrate/sulfate ions using molecular dynamics simulations. The findings revealed that silane coating improved the resistance of C-S-H to nitrate/sulfate ions. This resistance is considered the origin of silane protection against harmful ion attacks. Further research on the details of molecular structures suggests that the interaction between the oxygen in the silane molecule and the calcium in C-S-H, which can prevent the coordination of sulfate and nitrate to calcium on the C-S-H surface, is the cause of the silane molecules' strong adsorption. These results are also proved in terms of free energy, which found that the adsorption free energy on the C-S-H surface followed the order silane > sulfate > nitrate. This research confirms the excellent protection performance of silane on the nanoscale. The revealed mechanism can be further used to help the development of high-performance composite coatings.

Identification and Pathogenicity of Cladosporium, Fusarium, and Diaporthe spp. Associated with Late-Season Bunch Rots of Grape.

Fungal pathogens continue to pose a significant threat to grape production. Previous studies of pathogens associated with late-season bunch rots in Mid-Atlantic vineyards had elucidated the primary causal agents of these diseases, but the significance and identity of the less commonly isolated genera was unclear. Therefore, to more fully understand the identity and pathogenicity of Cladosporium, Fusarium, and Diaporthe spp. associated with late-season bunch rots of wine grapes in the Mid-Atlantic, phylogenic analyses and pathogenicity assays were conducted. Isolates were characterized to the species level by sequencing the TEF1 and Actin, TEF1 and TUB2, and TEF1 genes for 10, 7, and 9 isolates of Cladosporium, Diaporthe, and Fusarium, respectively. Four Cladosporium, three Fusarium, and three Diaporthe species were identified, and C. allicinum, C. perangustum, C. pseudocladosporioides, F. graminearum, and D. guangxiensis had not yet been isolated from grape in North America. The pathogenicity of each species was evaluated on detached table and wine grapes, and D. eres, D. ampelina, D. guangxiensis, and F. fujikuroi were found to be the most aggressive on both table and wine grapes. Further investigations through more extensive isolate collection and of myotoxicity testing may be warranted due to the prevalence and pathogenicity of D. eres and F. fujikuroi.

Targeted deep sequencing reveals APC mutations as predictors of overall survival in Chinese colorectal patients receiving adjuvant chemotherapy.

Objective: Targeted deep sequencing was used to characterize the mutational spectrum of APC in Chinese colorectal tumors in comparison to that in Caucasians from The Cancer Genome Atlas (TCGA) and to investigate whether APC mutations can predict overall survival in CRC patients receiving adjuvant chemotherapy.Methods: A total of 315 Chinese CRC patients including 241 stage II/III patients receiving fluorouracil-based adjuvant chemotherapy were included in this study. Next generation sequencing was carried out to detect somatic mutations on all APC exons. The associations between APC mutations and overall survival were determined by the Cox proportional hazards model.Results:APC was mutated in 221 of 315 colorectal tumors (70.2%). Chinese CRC had a much higher frequency of missense mutations (16.2% vs. 2.4%), but a lower frequency of nonsense (41.0% vs. 54.2%) and frameshift mutations (10.5% vs. 18.4%) than Caucasian CRC. Among stage II/III patients receiving fluorouracil-based adjuvant chemotherapy, APC mutations showed a significant association with worse survival (HR = 1.69; 95% CI, 1.10-2.62; p = .0179). Of the mutation types, frameshift mutations conferred the highest risk of death (HR = 2.88; 95% CI, 1.54-5.37; p =.0009). Among individual mutation sites, Arg232Ter, the most frequent mutation in Chinese CRC, exhibited the strongest negative impact on survival (HR = 2.65; 95% CI, 1.16-6.03; p =.0202).Conclusion:APC overall mutation was an independent predictor for overall survival of stage II/III CRC patients receiving fluorouracil-based chemotherapy.

Metal-free hydroalkoxylation of ynesulfonamides with alcohols.

Efforts for developing a convenient and expeditious method for synthesizing alkoxy-substituted enamides via nucleophilic addition of alcohols to ynesulfonamides are described. This sequence is completely regioselective and highly stereoselective, and leads to the hydroalkoxylation products in high yields under mild reaction conditions.

Ontogenic Susceptibility of Grapevine Clusters to Ripe Rot, Caused by the Colletotrichum acutatum and C. gloeosporioides Species Complexes.

Natural infection by Colletotrichum spp. and the subsequent development of ripe rot were observed in susceptible grape (Vitis vinifera) clusters either protected or exposed to environmental conditions and naturally occurring inoculum by the application or removal of paper bags at various phenological stages at two Mid-Atlantic vineyards. During each of the three experimental seasons, most treatments with grape clusters that were exposed between veraison and harvest developed significantly more severe ripe rot than clusters that were exposed during only the early season or protected throughout the entire season. Spore traps were placed in one vineyard over two seasons and were analyzed via quantitative PCR. DNA of the Colletotrichum acutatum and C. gloeosporioides species complexes was detected from the bloom to the harvest stage, with a higher quantity of C. acutatum DNA than C. gloeosporioides DNA. From ripe rot symptomatic clusters, 417 isolates were collected, and a multilocus phylogenetic analysis of 51 representative isolates identified six Colletotrichum spp., with C. fioriniae (C. acutatum complex) being the most frequently isolated. Weather data were also monitored, and ripe rot-conducive conditions were observed at multiple times throughout each season. In summary, only clusters that were exposed to inoculum and environmental conditions in the late season developed severe ripe rot. The data collected in this study suggest that grape clusters have ontogenic susceptibility to ripe rot, becoming more susceptible as they mature, in contrast to the susceptible bloom stage for other fruit rotting diseases of grapevine.

Off-target selection of resistance to azoxystrobin in Aspergillus species associated with grape late season rots.

Due to recent evidence of Aspergillus uvarum pathogenicity on wine grapes and variable fungicide sensitivity to quinone outside inhibitor (QoI) fungicides, the identity and QoI sensitivity of Aspergillus isolates from the Mid-Atlantic United States was investigated. Phylogenic analysis of 31 isolates revealed 26 as A. uvarum and 5 as A. japonicus, both of which have been previously isolated from grape. The A. uvarum isolates had variable sensitivities to the QoI azoxystrobin, and the genomic region that codes for the target of QoIs, cytochrome b, was sequenced. Translation of the cytochrome b coding sequence revealed that the most resistant isolates (termed cytb3) contained three mutations, S108A, F129L, and A194V, and the moderately sensitive isolates (termed cytb2) contained two mutations S108A and A194V. This is the first report of an amino acid variation in cytochrome b at position 108. Cytb3 isolates were significantly less inhibited than the cytb2 and wild-type isolates (cytbWT) in vitro, and were significantly less inhibited than the cytbWT isolates on detached fruit. Molecular docking analysis revealed similar differences, with azoxystrobin binding most securely in the cytbWT variant of cytochrome b than cytb2 and cytb3. As Aspergillus rot has not been a target disease of fungicide sprays in the U.S., the selection of resistant phenotypes is likely resultant from sprays for other diseases. Resistance is of concern due to the pathogenicity of A. uvarum and A. japonicus on wine grapes, and the ability of these species to be mycotoxigenic or pathogenic for humans.

Bioremediation of quinclorac injury on tobacco by a rhizosphere bacterium.

The presence of herbicides residues in soil represents a serious problem for agriculture. Quinclorac is a common herbicide applied in rice field, but its residue can cause abnormal growth in successive crop of tobacco in Southern China. Remediation by microorganisms is considered to be an environmentally friendly method to remove such pollutants injury. The aims of this study were to obtain quinclorac remediation isolates and to investigate the possible mechanism(s) of remediation. Six bacterial isolates were obtained from rhizosphere of rice-tobacco rotation fields, and were found to be capable of degrading quinclorac on a mineral salt medium (MSM), with degradation efficiency ranging from 2.1 to 23.7%. Among these isolates, J5 had the highest degradation efficiency, and was identified as Klebsiella variicola based on phylogenetic analyses and a metabolic profile generating by Biolog GEN III system. Bioremediation of quinclorac injury was confirmed using pot assays with tobacco, in which J5 reversed the detrimental effect of quinclorac on leaf area, leaf number, and plant height. The J5 isolate also seemed to promote plant growth, in terms of tobacco seedling growth and seed germination, which were 2.2 times and 1.6 times higher compared to untreated control, respectively. The mechanisms of plant growth promoting (PGP) traits were found to involve nitrogen-fixing, indole-3-acetic acid (IAA) production, and phosphate solubilization ability. In addition, proteomic analysis and relative quantitative PCR revealed an elevated level of 4-hydroxyphenylacetate 3-monooxygenase (HPMO) in quinclorac-treated J5, suggesting that this enzyme may play an important role in quinclorac remediation. This study showed that the J5 isolate could be exploited to not only assist in soil remediation due to quinclorac residue issues but also promote tobacco growth.

A High-Quality Genome Resource of Botrytis fragariae, a New and Rapidly Spreading Fungal Pathogen Causing Strawberry Gray Mold in the United States.

Although Botrytis fragariae was only recently identified as a new Botrytis species that causes strawberry gray mold, its prevalence extends to many states of the eastern United States. Compared with B. cinerea, which is known to be the causal agent of gray mold on many crop plants including strawberry, B. fragariae appears to have specifically adapted to strawberry and exhibits distinct fungicide sensitivity. This is the first presentation of a high-quality genome assembly of B. fragariae with gene annotation based on sequence homology and deep transcriptome data. The genome sequence information from B. fragariae is expected to help reveal genomic features underlying its host specialization and evolution of distinct fungicide resistance and other novel pathogenicity mechanisms.

Diversity, Pathogenicity, and Fungicide Sensitivity of Fungal Species Associated with Late-Season Rots of Wine Grape in the Mid-Atlantic United States.

Late-season bunch rots cause major losses in grape production every year in the Mid-Atlantic United States, but the causal agents are not well characterized. In this study, 265 fungal isolates were collected from rotten grapes from 2014 to 2020 and identified to the genus level according to internal transcribed spacer sequences. The most prevalent of the 15 genera were Botrytis, Colletotrichum, Aspergillus, Alternaria, Pestalotiopsis, and Neopestalotiopsis. Of these, isolates within three prevalent, yet understudied, genera were identified to be Aspergillus uvarum, Alternaria alternata, and Neopestalotiopsis rosae. The pathogenicity of these three fungal species was evaluated in two field trials by artificially inoculating wounded and nonwounded grapes (Vitis vinifera) of four cultivars at the phenological stages of bloom, véraison, and preharvest. Upon ripening, fruit were weighed and assessed for severity of multiple diseases. On nonwounded fruit, A. uvarum caused significantly higher disease severity than the control in both seasons. On wounded fruit, each inocula caused significantly higher disease than the respective controls in the first season, but only A. uvarum and Botrytis cinerea caused this in the second season. Also, wounding was found to have a detrimental effect on cluster weight, which was significantly influenced by inoculation timing and cultivar. Lastly, A. uvarum and N. rosae were tested for sensitivity to azoxystrobin, boscalid, and difenoconazole. The A. uvarum isolates were found to be more sensitive to boscalid and difenoconazole in general, with varying sensitivity to azoxystrobin. N. rosae isolates were resistant to boscalid and azoxystrobin but displayed much higher sensitivity to difenoconazole. Evidence from the isolate collection and field trials demonstrates that A. uvarum could be a significant pathogen of wine grapes in the Mid-Atlantic United States. Results from this study will be useful for the identification and management of the understudied Alternaria, Aspergillus, and Neopestalotiopsis fruit rots of wine grapes.

Identification and Characterization of Fungicide Resistance in Botrytis Populations from Small Fruit Fields in the Mid-Atlantic United States.

From 2014 to 2019, 249 isolates of Botrytis sp. were collected from blackberry, black raspberry, grape, red raspberry, and strawberry showing gray mold symptoms. All isolates were phylogenetically characterized as Botrytis cinerea. A mycelial growth assay determined the following overall frequencies of resistance to fungicides: 92% to pyraclostrobin, 86% to cyprodinil, 71% to thiophanate-methyl, 48% to fenhexamid, 47% to iprodione, 26% to boscalid, 11% to fludioxonil, 8% to penthiopyrad, 7% to benzovindiflupyr, 4% to pydiflumetofen , and 4% to isofetamid. Isolates collected from blackberry, red raspberry, and strawberry had a higher median chemical class resistance value compared to isolates from black raspberry and grape. Resistance conferring mutations were found in a selection of isolates characterized as resistant to thiophanate-methyl, iprodione, pyraclostrobin, fenhexamid, and boscalid including E198A in ß-tubulin; I365N/S, Q369P, and N373S in bos1; G143A in cytb; P238S, N369D, and F412I/S in erg27; and P225F and H272R/Y in sdhB, respectively. Also, multiple drug resistance phenotypes MDR1 and MDR1h were identified by analyzing fludioxonil sensitivity and mrr1 sequences. MDR1 and MDR1h isolates had multiple amino acid variations and two insertions in mrr1 that resembled the group S genotype . A detached grape assay confirmed that the aforementioned mutations in isolates from different small fruit crops resulted in field-relevant resistance. An additional in-vitro assay found that EC50 values of B. cinerea isolates to pydiflumetofen and inpyrfluxam averaged 0.4 and 1.0, 0.8 and 0.7, 149.8 and 23.2, 0.9 and 0.9, and 38.8 and 48.8 µg/ml for the wild-type, H272R, H272Y, N230I, and P225F genotypes, respectively. These results revealed widespread fungicide resistance in B. cinerea from Mid-Atlantic small fruit fields, highlighting the need for resistance management alternatives.

Resistance to Azoxystrobin and Thiophanate-Methyl Is Widespread in Colletotrichum spp. Isolates From the Mid-Atlantic Strawberry Fields.

Multiple Colletotrichum species have been found to be responsible for strawberry anthracnose, and prevalence of each species seems to vary by regions and/or host tissues. In this study, a total of 200 Colletotrichum isolates were obtained from different strawberry cultivars displaying anthracnose symptoms in the mid-Atlantic fields. Analysis of g3pdh, tub2, and/or internal transcribed spacer sequences revealed four Colletotrichum species, including C. nymphaeae, C. fioriniae, C. siamense, and C. lineola. C. nymphaeae was the predominant species, representing 90% of all isolates collected. This species was found from all strawberry organs/tissues examined, whereas C. siamense and C. fioriniae were limited to the crown and fruit, respectively. Further, all Colletotrichum isolates were screened for resistance to azoxystrobin in vitro, and all C. siamense isolates were additionally screened for resistance to thiophanate-methyl. The overall frequency of resistance to azoxystrobin and thiophanate-methyl was 48 and 67%, respectively. G143A in the cytochrome b gene was found in all C. nymphaeae and C. siamense isolates with high level of resistance, with EC50 >100 µg/ml, while F129L was found in two of the five C. nymphaeae isolates with moderate resistance, with EC50 values ranging from 2.6 to 7.8 µg/ml. All C. fioriniae isolates tested were found to be less sensitive to azoxystrobin, with EC50 values ranging from 9.7 to 14.4 µg/ml, despite no mutations detected in the cytochrome b gene. Moreover, E198A in tub2 was linked with C. siamense isolates resistant to thiophanate-methyl (EC50 >100 µg/ml). These results revealed that resistance in Colletotrichum spp. to primary fungicides is widespread in the mid-Atlantic strawberry fields.

Validation of the Strawberry Advisory System in the Mid-Atlantic Region.

Anthracnose fruit rot (AFR) and Botrytis fruit rot (BFR) are primary diseases affecting strawberry (Fragaria × ananassa), which typically drive fungicide applications throughout the growing season. The Strawberry Advisory System (StAS), a disease forecasting tool, was originally developed in Florida to better time the fungicide sprays by monitoring AFR and BFR infection risk based on leaf wetness and temperature input in real-time. Thirteen field trials were conducted in Maryland and Virginia between 2017 and 2019 to evaluate the StAS performance in the Mid-Atlantic region. As a result, 55, 18, and 31% fewer sprays were recorded on average in the model-based StAS treatment compared with the grower standard treatment in 2017, 2018, and 2019, respectively. Marketable yield, as well as AFR and BFR incidence, were largely comparable between the two treatments. However, poor disease control occurred during the StAS treatment in four trials in 2017, presumably because of a missed fungicide spray during a high-risk infection event and attributable to heavy rainfall that led to impassable fields. The implementation of the StAS may be further challenged by the employment of floating row covers that are essential for growing strawberries in plasticulture systems in open fields in the Mid-Atlantic region. Preliminary results indicated that row covers can alter canopy-level microclimatic conditions, possibly increasing the risk for disease occurrence. Overall, the StAS can be a valuable tool for Mid-Atlantic growers to control AFR and BFR, but sprays may need to be promptly applied when consecutive or heavy rainfalls are predicted, especially for highly susceptible cultivars. Complications in disease forecasting and management arising from the use of row covers need to be further addressed in this region because of its highly diverse climate.

Paralogous CYP51 Genes of Colletotrichum spp. Mediate Differential Sensitivity to Sterol Demethylation Inhibitors.

Colletotrichum spp. isolates contain two paralogous CYP51 genes that encode sterol 14-demethylase enzymes; however, their role in sensitivity to demethylation inhibitor (DMI) fungicides is yet to be determined. In this study, each of the two genes from Colletotrichum fioriniae and C. nymphaeae was able to rescue the function of CYP51 in the yeast Saccharomyces cerevisiae, demonstrating their independent function. Deletion of CYP51A led to increased sensitivity to propiconazole, diniconazole, prothioconazole, cyproconazole, epoxiconazole, flutriafol, prochloraz, and difenoconazole in C. fioriniae, and to the same fungicides and tebuconazole in C. nymphaeae, with the exception of prochloraz. Deletion of CYP51B in C. fioriniae and CYP51B in C. nymphaeae made mutants increasingly sensitive to five of nine DMI fungicides tested. The results suggest species-specific, differential binding of DMI fungicides onto the two CYP51 enzymes. Pairing DMIs with different effects on CYP51A and -B deletion mutants resulted in synergistic effects, as determined in mycelial growth inhibition experiments. Deletion mutants showed no fitness penalty in terms of mycelial growth, sporulation, and virulence. Our study elucidates the effect of CYP51A and CYP51B of Colletotrichum spp. on DMI sensitivity, suggesting that using a mixture of DMIs may improve the efficacy for anthracnose management.

Competitive ability of multi-fungicide resistant Botrytis cinerea in a blackberry planting over three years.

Botrytis cinerea isolates with multi-fungicide resistance have frequently been isolated from small fruit fields such as strawberries and blackberries. Individual B. cinerea isolates have been found resistant to up to seven chemical classes of fungicides. Fitness costs and less competitiveness have been observed in multi-fungicide resistant isolates, but this has not been examined under field conditions. In the spring of 2016, flowers of field-grown blackberries were either not inoculated or inoculated with B. cinerea isolates sensitive (0CCR), resistant to five or six chemical classes excluding phenylpyrroles (5CCR), or resistant to six or seven chemical classes including phenylpyrroles (6CCR/MDR1h). The experimental field was left unsprayed for the duration of this study and isolates of B. cinerea were collected from flowers and/or fruit in each of the three experimental years. Isolates collected in summer of 2016 revealed resistance phenotypes in each plot closely matching those of the respective inoculum, with 95% 0CCR, 55% 5CCR, and 91% 6CCR/MDR1h isolates recovered from 0CCR, 5CCR, and 6CCR/MDR1h inoculation plots, respectively. In the 2017 and 2018 isolate collections, 6CCR/MDR1h resistance phenotypes were found in plots inoculated and non-inoculated with this phenotype, indicating their persistence and movement between plots. Resistance phenotypes different from the inoculum were also recovered each year, indicating that the inoculum was successfully competing with a native Botrytis population. Despite the competition, 6CCR/MDR1h isolates were recovered in high frequency from all inoculated plots in 2018. G3pdh and mrr1 sequences of 6CCR/MDR1h isolates collected in 2018 were identical to the sequences of the inoculum, indicating that these isolates likely descended from the inoculum. This study demonstrates that isolates carrying multi-fungicide resistant phenotypes, specifically 6CCR/MDR1h, are competitive in the absence of fungicide selection pressure.

Reduced sensitivity of azoxystrobin and thiophanate-methyl resistance in Lasiodiplodia theobromae from papaya.

Stem-end rot caused by Lasiodiplodia theobromae is one of the most devastating diseases of papaya in northeastern Brazil. It is most effectively controlled by applications of fungicides, including site-specific fungicides at risk for resistance development. This study investigated the molecular mechanisms of reduced sensitivity to the QoI fungicide azoxystrobin and resistance to the MBC fungicide thiophanate-methyl in L. theobromae from Brazilian orchards. The EC50 values for azoxystrobin in sixty-four isolates ranged from 0.36 µg/ml to 364.24 µg/ml and the frequency distribution of EC50 values formed a multimodal curve, indicating reduced sensitivity to azoxystrobin. In detached fruit assays reduced sensitive isolates were not controlled as effectively as sensitive isolates at lowest label rate. Partial fragments were obtained from target genes ß-tubulin (751 bp) and Cytb (687 bp) of isolates resistant to thiophanate-methyl and reduced sensitivity to azoxystrobin. Sequence analysis of the ß-tubulin fragment revealed a mutation corresponding to E198K in all thiophanate-methyl-resistant isolates, while reduced sensitivity to axoxystrobin was not attributable to Cytb gene alterations. The target gene-based mechanism conferring resistance to thiophanate-methyl will likely be stable even if selection pressure subsides. However, the mechanism conferring reduced sensitivity to azoxystrobin is not based on target gene modifications and thus may not be as stable as other genotypes with mutations in Cytb gene.

Experimental realization of sequential weak measurements of non-commuting Pauli observables.

Sequential weak measurements of non-commuting observables are not only fundamentally interesting in terms of quantum measurement but also show potential in various applications. Previously reported methods, however, can only make limited sequential weak measurements experimentally. In this article, we propose the realization of sequential measurements of non-commuting Pauli observables and experimentally demonstrate for the first time the measurement of sequential weak values of three non-commuting Pauli observables using genuine single photons.